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TTTHHHEEE GGGEEEOOOTTTHHHEEERRRMMMAAALLL AAASSSSSSOOOCCCIIIAAATTTIIIOOONNN
OOOFFF IIIRRREEELLLAAANNNDDD ... Newsletter
SECRETARIAT: c/o Groundwater, Geological Survey of Ireland, Beggars Bush, Haddington Road, Dublin 4
Tel. +353.1.678 2874; fax +353.1.6782569; www.geothermalassociation.ie
Chairman Brian Connor, Vice-Chair John Burgess, Secretary Monica Lee & Taly Hunter Williams, Treasurer Marie Keane,
Editor Gareth Ll. Jones, International Liaison Róisín Goodman, Developments Paul Sikora, Events Officer Alistair Allen, James Byrne
The Geothermal Association of Ireland was formed in January 1998.
To Promote the Development of Geothermal Resources in Ireland. The GAI is a member of the
European Geothermal Energy Council and of the International Geothermal Association.
Issue No. 17 AUGUST 2010
SPECIAL EDITION
The World Geothermal Congress 2010
Bali, Indonesia
WGC 2010 2
World Geothermal Congress, Nusa dua Bali, 25th – 30
th April, 2010, Róisín Goodman 3
The Seven Irish papers presented at WGC2010 6
Note there is no newsletter pagination for these papers
157. Developments in Geothermal Utilisation in the Irish Republic
Alistair Allen, John Burgess
315. GTR-H - Geothermal Legislation in Europe
Goodman, R., Pasquali, R. Dumas, P., Hámor T., Jaudin F., Kepinska, B., Reay, D.,
Rueter, H., Sanner, B., Van Heekeren, V., Bussmann, W., Jones, G.Ll.
630. Glucksman Art Gallery, University College Cork, Ireland: Innovative Space Heating Development
Kondwani T. Gondwe, Alistair Allen, John Burgess, Donal Browne and Paul Sikora
1156. Investigation of Source and Conduit for Warm Geothermal Waters, North Cork, Republic of Ireland.
Brecan Mooney, Alistair Allen, Paul K!niger
1159. Low Enthalpy Geothermal Resources of Ireland Maps Encourage Geothermal Projects
Gareth Ll. Jones, Róisín M. Goodman, John G. Kelly
1614. Methodology in Assessment and Presentation of Low Enthalpy Geothermal Resources in Ireland
Róisín Goodman, Gareth Ll. Jones, John G. Kelly
1625. The Geothermal Potential of Northern Ireland
R. Pasquali, N. O’Neill, D. Reay, T. Waugh
Other papers
905. Geotrainet – A New European Initiative for Training and Education of Planners,
Drillers and Installers of Geothermal Heat Pumps
Burkhard Sanner, Philippe Dumas, Isabel Fernandez Fuentes, Manuel Regueiro
166. Country Update for the United Kingdom
Tony Batchelor, Robin Curtis, Peter Ledingham
1638 Geothermal Prospects in the United Kingdom. Abstract page
Jon Busby
3145 Revisiting Deep Geothermal Power in the United Kingdom. Abstract page
Ryan Law, Tony Batchelor and Pete Ledingham
TTTHHHEEE GGGEEEOOOTTTHHHEEERRRMMMAAALLL AAASSSSSSOOOCCCIIIAAATTT IIIOOONNN OOOFFF IIIRRREEELLLAAANNNDDD Newsletter No. 17
August 2010
2
WGC2010
Four Irish delegates: Róisín Goodman, Alistair Allen, Riccardo Pasquali and Kondwani Gondwe travelling
from Malawi, as well as several thousand others, attended WGC2010 in Bali, Indonesia to present their
papers and a poster was also displayed.
This special edition of the GAI Newsletter compiles the seven Irish papers that were delivered, plus the
poster of paper 1159.
It also carries the GEOTRAINET paper since Ireland is a partner in that project. Finally we carry the UK
update and the abstract pages of the two other UK papers which carry Northern Ireland map data, but no
write up of any Northern Irish activity.
The whole is introduced by an account of the Congress and of the thrust of the presentations by Róisín,
illustrated with some of Ric’s photographs.
Opening Ceremony of the World Geothermal Congress April 2010, Bali, Indonesia,
TTTHHHEEE GGGEEEOOOTTTHHHEEERRRMMMAAALLL AAASSSSSSOOOCCCIIIAAATTT IIIOOONNN OOOFFF IIIRRREEELLLAAANNNDDD Newsletter No. 17
August 2010
3
THE WORLD GEOTHERMAL CONGRESS, WGC2010
NUSA DUA BALI, 25TH
– 30TH
APRIL, 2010
Róisín Goodman, SLR Consulting
The tropical island of Bali at the southern end of the
Indonesian archipelago was the setting for the 2010
World Geothermal Congress. There was a turnout of
2,168 attendees at the conference - up from around
1,000 in Antalya, Turkey in 2005. By all accounts the
conference was a success in attracting key worldwide
geothermal industry players as well a providing a
broad snapshot of the state of the world geothermal
industry and research developments in 2010. There
were a total of 1,032 papers presented in 312 sessions
in the congress venue at the Westin Conference centre
on the Nusa Dua peninsula at the south of the Island.
Given the location of the congress there was an
understandably strong flavor of high enthalpy
resources and electricity but all aspects of geothermal
were very well represented with 17 sessions (5 papers
per session) on heatpumps, district heating, direct use
and hydrogeology. Many other relevant papers were
presented in sessions on exploration, geology,
geophysics, legal and regulatory, environmental and
societal aspects, case studies and of course the country
updates.
Opening addresses by the Presidents of Iceland and of Indonesia
There were also many interesting presentations on
innovative applications and new almost futuristic
technology ideas, such as undersea power generation
in areas of high enthalpy some of which were seeking
funding for demonstration projects. Due to the
number of papers one had to be very selective in
deciding which to attend. I will not focus on the
papers here, particularly as the papers of direct Irish
interested are reprinted in this newsletter in full.
Other papers can be accessed through a search of the
relevant topic on the IGA website, using the link
http://www.geothermal-
energy.org/304,iga_geothermal_conference_database.
html
Some of the special guest speakers at WGC2010 were
the Indonesian President Susilo Bambang
Yudhoyono, the President of Iceland, Olafur Ragnar
Grimsson; the Indonesian Minister of Energy and
Mineral Resources, Dr. Darwin Zahedy Saleh and the
president of International Geothermal Association
(IGA), Ladislaus Rybach.
Striking the ceremonial gong to open the Congress.
For the international audience the official opening of
the Congress by the Indonesian President Yudhoyono
was a particular honour and gave a strong
endorsement of the future of geothermal development
in Indonesia. According to the President’s address as
reprinted in the ‘WCG2010 Daily News’ Indonesia is
aware of the importance to develop renewable and
environmentally-friendly energy and will facilitate the
development of geothermal projects to generate
electricity. Indonesia is currently only using 1,100
MW, some 4.2% of geothermal reserves in the
country, which constitutes about 40% of the world’s
geothermal potential. “This is going to change. It is
my intention that Indonesia will become the largest
user of geothermal energy,” Yudhoyono added.
Indonesia already have in place a set of long term
policies for the development of geothermal energy, as
embodied in the Geothermal Development Roadmap
of 2004-2025. Indonesia envisions that by 2025, about
five percent of Indonesia’s national energy needs, will
be met through the use of geothermal energy.
As is the custom of the WGC a cultural night was held
to showcase the best of local traditions. For
WGC2010 this was held at the famous Garuda Wisnu
Kencana and featured the ‘Bayu Pertiwi’ (the force of
TTTHHHEEE GGGEEEOOOTTTHHHEEERRRMMMAAALLL AAASSSSSSOOOCCCIIIAAATTT IIIOOONNN OOOFFF IIIRRREEELLLAAANNNDDD Newsletter No. 17
August 2010
4
nature) dance specially created for the World
Geothermal Congress 2010.
According to the concept developer and script writer,
Dr. Herman Darnel Ibrahim, the idea of the dance
emerged from the need to portray geothermal as a
clean energy capable of creating happiness and
prosperity without changing Bali’s strong culture. The
result is a colossal dance involving more than 200
dancers. The dance was choreographed by Dr. Ni
Made Ruastiti, a senior lecturer at the island’s most
famous dance institution in Denpasar. The epic dance
performance lasted about 30 minutes. It was a
spectacular event with typically Balinese costumes
and dance styles – a true feast for the eyes.
The Garuda Wisnu Kencana venue is a stunning
‘natural’ amphitheatre - the remains of a cut stone
quarry with vertical walls of 8-10m.
The warm evening atmosphere was perfect for an
outside performance and was matched in equally large
measures by adornment of the venue and uniquely
Balinese etiquette of the hosts - an unforgettable
evening. The torrential tropical rain that dowsed the
participants and audience from about 15 minutes into
the performance did not shortcut the evening – though
the chairs were a little soggy.
José Martins Carvalho, Portugal copes with the rain!
There was general satisfaction with the congress not
least in its rapidly growing audience despite world
recession. WGC2010 was hailed as happening at a
crucial moment in the move toward the enhancement
of geothermal use throughout the world with the
geothermal industry in a strong upward development
cycle. All in all the congress will be a hard act to
follow for the 2015 hosts Australia and New Zealand.
The Australian Geothermal Energy Group (AGEG), the Australian
Geothermal Energy Association (AGEA) and the New Zealand
Geothermal Association (NZGA) invite you Down Under in 2015
for the next World Geothermal Congress.
TTTHHHEEE GGGEEEOOOTTTHHHEEERRRMMMAAALLL AAASSSSSSOOOCCCIIIAAATTT IIIOOONNN OOOFFF IIIRRREEELLLAAANNNDDD Newsletter No. 17
August 2010
5
The organising committee with IGA President Ladsi Rybach in the centre.
TTTHHHEEE GGGEEEOOOTTTHHHEEERRRMMMAAALLL AAASSSSSSOOOCCCIIIAAATTT IIIOOONNN OOOFFF IIIRRREEELLLAAANNNDDD Newsletter No. 17
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6
The Irish Papers
Alistair & John deliver the Ireland update which
carries a wealth of information on the most recent
developments while showing the present state of
geothermal activity.
Róisín and her partners presents the final report on the
GTR-H project dealing with geothermal regulation for
heat across Europe.
It is good to see the detailed work that Kondwani and
the team have done on the Glucksman Gallery
outlined here.
The presentation of the results of Brecan’s work on
the warm springs conduit in north Cork, completed
just before he died is a poignant reminder of his loss.
We are grateful that we have a record of his work.
Gareth suggests that the work done for SEI has paid
off with the development of projects around Ireland.
This is also seen as a poster.
In an important paper, Róisín’s group describes the
methodology that was used in the SEI study and
which may be applicable in other places.
Finally Riccardo and colleagues look at the
geothermal resources of Northern Ireland and in
particular at the reservoir potentials.
GAI GAI GAI GAI GAI GAI GAI GAI GAI GAI GAI GAI GAI GAI GAI GAI GAI GAI GAI GAI GAI GAI GAI GAI
TTTHHHEEE GGGEEEOOOTTTHHHEEERRRMMMAAALLL AAASSSSSSOOOCCCIIIAAATTTIIIOOONNN
OOOFFF IIIRRREEELLLAAANNNDDD
Proceedings World Geothermal Congress 2010
Bali, Indonesia, 25-29 April 2010
1
Developments in Geothermal Utilization in the Irish Republic
Alistair Allen1, John Burgess
2
1Dept of Geology, University College Cork, Cork, Ireland
2 Arup Consulting Engineers, 16 Oliver Plunkett St., Cork, Ireland
[email protected]; [email protected]
Keywords: heat pumps; low enthalpy
ABSTRACT
Geothermal energy exploitation in Ireland has expanded
rapidly over the last few years, despite low geothermal
gradients (<25oC/km) and limited geothermal resources.
Emphasis is on exploitation of low temperature resources
for space heating, employing heat pump technology, but a
major new development is the first deep drilling project to
source warmer water at depth for district heating projects,
with a trial well drilled to over 1.3 km in the western
suburbs of Dublin.
There has been a huge increase in the number of heat pump
units installed in Ireland, since the last update in 2004,
which now stands at approximately 9500 units. Take up has
been mainly in the domestic market, with most heat pumps
approximately 15 kW in size, but the number of larger scale
installations ranging from about 100-450 kW servicing
public buildings and institutional/commercial premises is
increasing rapidly, and a few even larger developments
have been recently installed or are in progress. Recently
completed, a 3 MW open loop system at the Athlone City
Centre Retail Complex is the largest individual geothermal
space heating project in the country. Most domestic systems
employ horizontal closed loop collectors, with the more
expensive vertical closed loop collector systems mainly
employed in urban areas where space is at a premium. Open
loop collectors are less popular in the domestic market but
preferred for larger systems, particularly in areas underlain
by shallow gravel and karst aquifers, and enhanced in urban
situations by slightly magnified groundwater temperatures
due to the ‘heat island’ effect. A few projects have also
employed open loop systems exploiting surface water
sources such as ponds and reservoirs, where these exist.
Current total geothermal energy usage in the form of heat
pump capacity is estimated at 164 MW.
The rapid take up of heat pumps in the domestic market has
largely resulted from the introduction from 2006 of various
government grant schemes for renewables including GHP’s
to provide incentives to individual householders and
developers to incorporate geothermal and other renewable
energy systems into new or existing buildings. Another
important recent government initiative has been a wide
ranging consultation process with geothermal stakeholders
as the initial step in bringing in regulatory controls to guide
the development of geothermal energy in Ireland, and
Ireland is also involved in the GTR-H project to standardize
geothermal regulations throughout the EU. A further
significant development is the initiation by Irish higher
level institutions of new undergraduate and graduate degree
programs in energy engineering, with geothermal energy
and heat pump technology part of the curricula.
1. INTRODUCTION
Concerns about greenhouse gas emissions and its
relationship to climate change, together with uncertainties
regarding peak oil and security of supply of oil and gas has
led the Irish Government in the last 4-5 years to heavily
promote the development of renewable energy. Even so, in
2007, 96% of all energy used in Ireland (population ~ 4.5
million) was generated by fossil fuels (Howley et al,
2008a), with only a little over 1.5% generated by
renewable, mainly wind and solid biomass. About 33% of
the total primary energy supply in Ireland in 2007 was used
for thermal purposes (space, process and water heating and
also cooking), with a renewable energy contribution of
3.5%. Targets for future renewable energy contributions for
2010 and 2020 are 5% and 12% respectively (Howley et al,
2008a; 2008b). Of thermal energy usage, the residential
sector accounts for the largest share (42%). and use of
renewable energy for home heating represented 13% of the
total renewable energy thermal energy usage in Ireland in
2007, although geothermal energy contributed only 0.3% of
this amount (Howley et al, 2008a; 2008b). Furthermore,
from 1990 to 2007, total CO2 emissions increased by 51%
(Howley et al, 2008a), significantly exceeding Irelands
Kyoto Protocol commitment of maintaining CO2 emissions
to 13% above 1990 levels by 2012 (Fig. 1).
Nevertheless, geothermal energy exploitation in Ireland has
expanded rapidly over the last few years, despite low
geothermal gradients and limited geothermal resources
apart from 42 warm springs concentrated in two groups, in
the SW and E of the country. Emphasis is on exploitation of
low temperature resources for space heating, employing
heat pump technology, but a major new development is the
first deep drilling project to source warmer water at depth
for district heating projects, with a trial well drilled to over
1.3 km in the western suburbs of Dublin.
The main agencies involved in the development of
geothermal energy in Ireland are the Geothermal
Association of Ireland (GAI), Sustainable Energy Ireland
(SEI), the Geological Survey of Ireland (GSI), 15 energy
agencies throughout Ireland, (O’Brien 2001), the Irish
Association of Hydrogeologists (IAH), and some private
companies. The GAI is a voluntary organization consisting
of professionals from both the commercial and academic
sectors with various backgrounds including geologists and
hydrogeologists, service and mechanical engineers, heat
pump suppliers and installers, well-drillers and lawyers. Its
aim is to promote awareness and utilization of geothermal
energy in Ireland. Of the 15 energy agencies, the most
active are in the Cork area. SEI is an Irish government
organization set up in 2002 with a mission to promote and
assist the development of sustainable energy in the Irish
Republic.
Allen and Burgess
2
2. GEOLOGY BACKGROUND
Ireland generally consists of a mountainous rim composed
of Precambrian to Lower Palaeozoic crystalline rocks
surrounding a lowland interior largely underlain by U.
Devonian to L. Carboniferous sandstone, shale and
limestone (Figs. 2 & 3). Late Palaeozoic, Mesozoic and
Tertiary rocks are absent, apart from in the NE corner of the
island, where they are preserved beneath the basalt plateau
of the 50-60 Ma Tertiary North Atlantic Igneous Province
associated with the opening of the North Atlantic. However,
there is evidence that they were also deposited over much
of the rest of the island, but were stripped away by the
intense erosion and peneplanation which accompanied the
opening of the North Atlantic.
Fig. 1: Trend in Annual GHG Emissions for the Period 1990 to 2007 (Howley et al, 2008)
Fig. 2: Landsat Topographic Map of Ireland showing
tectonic boundaries referred to in the text.
KMFZ - Killarney-Mallow Fault Zone
Fig. 3: Geological Map of Ireland. L. Carboniferous
limestone (pale blue) underlies much of the
interior of the country
IAPETUS
SUTURE
KMFZ
Allen and Burgess
3
U. Palaeozoic bedrock, whilst underlying much of the
interior of Ireland, is generally buried beneath a cover of
Pleistocene glacial till and Holocene peat deposits, and is
rarely exposed. Widely developed L Carboniferous
limestone (Fig. 3) is extensively karstified, but overburden
deposits are relatively thick and surface expression of karst
is generally absent. Thus, most of Ireland’s limestone
bedrock consists of buried karst.
Ireland lies within the Caledonian orogenic belt (Fig. 4),
which affected all Precambrian and L. Palaeozoic units. The
Iapetus Suture (Fig. 2), marking the collision zone of
Laurentia and Avalonia, runs diagonally across Ireland
from the Shannon estuary to Clogher Head, 50 km to the
north of Dublin. All of the warm springs in the Irish
Republic lie to the south of this tectonic line.
The late Carboniferous Variscan (Hercynian) Orogeny
affected the very south-west of Ireland, which represents
the westernmost extension of the external Rheno-Hercynian
Zone of the Variscan Orogenic Belt. Its northern boundary,
the Variscan Front, is the Killarney-Mallow Fault Zone
(KMFZ), which runs E-W, midway between the south coast
of Ireland and the Shannon estuary (Fig. 2). The
southwestern group of warm springs are all situated just to
the north of this tectonic boundary.
3. GEOTHERMAL RESOURCES AND POTENTIAL
Due to its within-plate setting distant from plate boundaries,
and an absence of recent volcanism or tectonism,
geothermal gradients in the Irish Republic are low
(<25°C/km) (Goodman et al, 2004). Thus Ireland is
unlikely to possess any high temperature geothermal
resources. Typical groundwater temperatures in Ireland
vary from approximately 10-12°C, whilst soil temperatures
are between 8-12°C Aldwell (1997). These temperatures
reflect the balance between solar and geothermal recharge,
and radiation from the ground surface as quantified by
Aldwell & Burdon (1986), and remain relatively constant
throughout the year due to Ireland’s temperate maritime
climate. Modern heat pump technology allows heat to be
extracted from soil and groundwater at these low but
consistent temperatures, in Ireland mainly for space heating
and cooling uses.
Springs, seepages and spring wells are ubiquitous in
Ireland, particularly in Dinantian limestone bedrock that
underlies much of the Irish midlands. Potentially
exploitable geothermal resources occur where relatively
warm groundwater (>13oC) is able to rise rapidly to the
surface (Aldwell, 1996), discharging as low enthalpy
geothermal springs. 42 of these warm springs, mainly
located in limestone, and ranging in temperature from 13-
24.7°C have been recorded (Aldwell & Burdon, 1980;
Burdon, 1983; Brück et al, 1986; Aldwell 1996; Goodman
et al, 2004), and are concentrated in two groups in the east
and southwest of the country (Fig. 5). One of the earliest
recorded warm springs in Ireland occurs at Mallow in the
southwest, where the spring at Lady’s Well gave rise, in the
18th and 19th Centuries, to a spa resort. Apart from this
spring, which has more recently been harnessed to heat the
municipal swimming pool (O’Brien, 1987), little utilization
of these warm water energy resources has taken place,
mainly because of the rural settings in which most occur,
that in the past has limited potential options for their
exploitation.
Geothermal gradients in the island of Ireland generally
increase from SW to NE, from lows of approximately
10°C/km in the south to highs associated with the Tertiary
igneous activity in the NE, where a maximum of 35°C/km
has been measured (Goodman et al, 2004). Low yields of
relatively hot water at 88°C were encountered in the early
1980’s in a borehole to 2.8 km depth at Larne to the NE of
Belfast, within the Permo-Triassic Sherwood Sandstone, an
aquifer widespread in Britain, but only present in Ireland in
the extreme NE preserved beneath the Tertiary Basalt
plateau. This temperature represents a geothermal gradient
of about 27.5°C/km.
Fig. 4: Irelands Tectonic Setting.
Allen and Burgess
4
Fig. 5: Location of Warm Springs and Large Scale Installations in Ireland.
In the Irish Republic, conditions for generation of hot water
at depth are not favorable, but the presence of 42 warm
springs, indicates that aquifers do occur at depth, and that
moderate geothermal resources, which could be exploitable,
do exist. A borehole drilled to 1.4 km in the western
suburbs of Dublin in 2008 encountered warm water at
46.2°C, representing a geothermal gradient of about
26.5°C/km. At the borehole location, a thick overlying layer
of impermeable shales blankets and insulates the underlying
aquifer.
Also, a well drilled for water supply purposes by Cork
County Council in 2003 at Johnstown in the Glanworth area
of North Cork in the southwest encountered, at a depth of
40m, warm groundwater at temperatures of 23-26°C. This,
the warmest shallow groundwater as yet recorded in the
Republic of Ireland, probably represents groundwater from
a depth in excess of 1.5km, which has migrated rapidly up a
fault conduit (Mooney et al, this volume). Finally, a well
drilled on University College Cork campus within gravels
close to the northern margin of the Lee Buried Valley
(Allen et al, 1999) intersected limestone bedrock at 20m
and encountered water with an anomalous temperature of
19-20°C. A caliper log of the borehole revealed a parallel
temperature and conductivity increase downwards,
indicating that the warm groundwater is not of
anthropogenic origin and comes from the limestone
bedrock, probably also representing groundwater from
depth that has migrated up a fault conduit.
4. GEOTHERMAL UTILIZATION
Since Ireland has no high temperature geothermal
resources, there is no electricity generation in the republic.
Generally direct heat usage involves extraction of low
enthalpy heat, which is employed with heat pumps mainly
for space heating. As indicated above, none of Irelands
warm springs are exploited apart from the Lady’s Wells
spring at Mallow, which with the aid of a heat pump is used
to heat the municipal swimming pool (O’Brien, 1987), the
first exploitation of geothermal energy in Ireland.
There has been a huge increase in the number of domestic
heat pump units installed in Ireland, since the last update in
2004, and this now stands at approximately 9,500 units as
of September 2009, with a further 300 installations in
progress. This is an increase of about 8,000 installations in
the last 5 years, brought about mainly due to the
introduction by SEI of the Reheat and Greener Homes
Grant Schemes in 2006, which aim to increase the use of
sustainable energy technologies within both public and
commercial buildings, and in domestic dwellings. The
grants cover, amongst other space heating technologies,
heat pumps using horizontal or vertical closed loop, well
water open loop or air source collectors. Of the different
GSHP collector systems, horizontal closed loop are the
most popular (67.5%) followed by vertical closed loop
(30%), and open loop (2.5%).
The popularity of horizontal closed loop systems is
governed by the fact that Ireland has a high proportion of
domestic dwellings with gardens, so space is available for
horizontal collectors which are considerably cheaper to
install than vertical collectors. In addition, horizontal heat
collectors are very efficient due to Ireland’s temperate
maritime climate with its limited annual temperature range
and abundant year round rainfall. Therefore there is little
annual variation in soil temperature below depths of about
50 cm and soil moisture contents are typically high, so
conditions are ideal for shallow horizontal collectors.
Vertical closed loop collectors are more common in cities
where space is at a premium, but are considerably more
expensive to install, although they attract larger grants from
SEI. A small number of domestic units operate with open
loop collectors, where a suitable aquifer underlies the site.
A significant proportion of domestic heat pumps (>1500)
employ an air source, which may reflect a lack of
understanding of the principles of heat pumps by the
homeowner or misleading advice by the installer.
Commercial heat pump installations are far less common
than domestic units, but show a significant increase since
the previous update report (O’Connell et al, 2005).
Approximately 30 commercial GSHP projects have
Allen and Burgess
5
benefited from the SEI Reheat grant scheme, and another
10 public projects have been grant aided by the SEI Public
Sector Program.
Most commercial heat pump projects have relatively small
capacities being less than 50 kW, but quite a few are larger
than 100 kW ranging up to a 3 MW system commissioned
recently at Athlone city centre retail complex. In general,
Cork leads the way in GHP development, with Cork City
Council and UCC taking advantage of the combination of a
shallow gravel aquifer underlying Cork (Allen & Milenic,
2003), and the ‘heat island’ effect (Allen et al, 2003). A
significant number of public buildings in Cork are now
heated by GHP systems. The flagship projects are a 200 kW
open loop system heating and cooling an art gallery on
UCC campus (Gondwe et al, this volume), a 1 MW open
loop system heating a new IT complex at UCC, an 88 kW
open loop system at the UCC Environmental Research
Institute (ERI), and a 450 kW open loop system at the new
Cork County Library. In addition, the Electricity Supply
Board, the semi state body which until recently has had a
monopoly on Irish electricity supply has also installed a 250
kW open loop GHP system at its Cork headquarters. Fig. 5
shows the locations of some of the larger commercial
GSHP installations
Few retrofit systems have been undertaken in Ireland, but of
note are three installations. The first is the conversion of the
Swedish Ambassadors residence in Dublin, where a 21 kW
heat pump with vertical closed loop heat collectors installed
in 3 x 130 m boreholes, is delivering 60°C water to existing
radiators and some additional under-floor heating areas. In
Cork, the Lifetime Lab is a 19th century waterworks pump
house complex, which has been converted to an educational
and conference centre with a 70 kW open loop system
operating with under-floor heating. The Fermoy Leisure
Centre in County Cork is a swimming pool complex, which
has been converted to geothermal via a 160 kw open loop
heat pump system.
The current estimate by SEI of heat pump capacity in the
Irish Republic is 164 MW as of the end of 2008. The
majority of systems are in domestic dwellings, with a total
capacity of 148 MW, whilst installations in public buildings
and commercial premises account for 16 MW total
capacity. The average installed load capacity is about 15
kW for domestic dwellings, and of the order of 55 kW for
public and commercial buildings
A major development in Ireland is the first deep geothermal
exploration project since the Larne borehole in 1982. This
borehole mentioned earlier was sunk in 2008 into the
Dublin Basin at Newcastle in the western suburbs of Dublin
in search of geothermal water for a potential commercial
district heating scheme. The borehole reached a depth of
1.337 km encountering groundwater with a temperature of
46.2°C. Although a porosity of 22% has been established
for the host rock, no hydraulic conductivity has been
determined. Owing to a slump in the construction industry,
resulting from the economic downturn in Ireland, this
project has progressed no further. University College
Dublin (UCD) is also investigating the feasibility of drilling
a deep borehole into the Dublin Basin on its Belfield
campus in the SE of Dublin to generate a campus district
heating scheme.
5. DISCUSSION
The capacity factor for Irish heat pump installations (Table
1) is low due to the mild climate and the design of the heat
pump systems. Heating is only required for 8 months of the
year and air conditioning is not required for the domestic
sector. The average annual air temperature is 9°C. The
average mean daily minimum temperature in winter is
2.5°C. Average annual ground temperatures are of the order
of 10ºC. Heat pump installations are designed to operate on
the cheaper night rate electricity during the winter and so
the compressor would be switched on for 7 hours out of 24.
Heat is delivered to the building by under floor heating and
so discharged slowly throughout the day.
Air conditioning is generally achieved by direct cooling,
which circulates fluid from the collector in coils or circuits
installed in the building ceilings or floors. Reversible heat
pumps are typically used, but in many commercial building
applications conventional water cooled chillers connected
to heated and cooled buffer vessels are common. As the
ground or water temperature is sufficiently low during the
summer direct cooling can be used to provide some cooling.
The installed capacity estimate is based on the projected
cooling load for the building. Requirements for air
conditioning or summer cooling are generally less than half
the winter heating load.
A number of swimming pool projects (Table 2) use heat
pumps not direct heating. The Fermoy pool, commissioned
in 2008, is the largest. The capacity factor, estimated at
0.311, is larger than the other space heating installations
because the heating demands of the swimming pool and
showers are much greater.
The number of professional people involved in geothermal
in Ireland is shown in Table 3. The majority work in GSHP
and the rapid growth in the GSHP industry can be seen
through the dramatic increase in installers and consultants
working in the industry. Almost 350 installers, mainly
plumbers, are registered with SEI, but the majorities are not
solely employed in the GSHP sector, and most probably
have limited specialized training in heat pump systems.
Similarly, a significantly increased number of HVAC
consulting companies have become involved in the design
of geothermal systems, but their portfolios would not be
restricted to geothermal, so in Table 7 an estimate of full-
time equivalent persons has been entered. There are
however a limited number of small dedicated geothermal
consultants.
There are no dedicated persons working on geothermal or
GSHP in state funded organizations such as SEI and the
local Energy Agencies, but over 50% of enquiries received
regarding renewable energy are about GSHP, and 23% of
applications under the Greener Homes Scheme have been
for heat pump grants. Again a nominal number of full-time
equivalents are entered in Table 2.
In Universities and Institutes of Technology, postgraduate
research has been conducted on GSHP collector efficiency
(e.g. Lohan et al, 2006), on optimal configurations of GSHP
collectors (Liddy, 2008) on general assessment of the
technology (O’Connell, 2004), and on performance analysis
of installed heat pump systems (Gondwe et al, this volume).
Geological aspects of geothermal such as delineation of
fault conduits controlling ascent of geothermal waters
(Mooney et al, this volume), and the impacts of GSHP
groundwater withdrawals on saline/freshwater relations in
estuarine environments and on subsidence in clays in
interlayered clay/gravel sequences are also being
investigated. Estimates of investment in geothermal is
indicated in Table 4.
Allen and Burgess
6
Table 1: GSHP Heat Pump Installations
Locality Ground or Typical Heat Pump Number of Type2)
COP3)
Htg & Clg Thermal Cooling Electrical
water temp. Thermal Rating Systems Equivalent Energy Energy Energy
Htg / Clg Capacity Full Load Used Used Input
(oC)
1) (kW) Hr/Year
4)(TJ/yr) (TJ/yr) (TJ/yr)
Domestic Installations Nationwide 10 15 9500 H 3.5 1363 699.0480 0.0000 199.7280
Dolmen Centre, co. Donegal 10 45 1 H 3.5 1363 0.2208 0.0000 0.0631
Tralee Motor Tax Office, Co Kerry 10 120 1 H 3.5 1922 0.8304 0.2418 0.2373
SHARE Hostel, Cork 15 120 1 W 3.5 1363 0.5887 0.0000 0.1682
UCC Glucksman Gallery, Cork 15 200 1 W 3.65 1922 1.3841 0.4030 0.3797
Fexco HQ, Killorglin, Co Kerry 11 310 1 W 3.65 1922 2.1453 0.6246 0.5885
Glenstal Abbey, Co Limerick 10 150 1 W 3.5 1363 0.7358 0.0000 0.2102
Musgrave HQ, Cork 10 160 1 V 3.65 1922 1.1073 0.3224 0.3037
Killarney International Hotel, Co Kerry 11 60 1 W 3.5 1363 0.2943 0.0000 0.0841
Cork Co Council Environmental Labs 11 90 1 W 3.5 1363 0.4415 0.0000 0.1261
Cliffs of Moher Visitor Centre, Co. Clare 10 120 1 H 3.5 1363 0.5887 0.0000 0.1682
Killorglin Town Centre, Co Kerry 11 160 1 W 3.65 1922 1.1073 0.3224 0.3037
Fermoy Leisure Centre, Co Cork 11 160 1 W 3.5 2725 1.5698 0.0000 0.4485
Tory Top Road Library, Cork 13 80 1 W 3.5 1363 0.3924 0.0000 0.1121
Coraville, Blackrock, Cork 13 36 1 W 3.5 1363 0.1766 0.0000 0.0505
Castleisland, Co Kerry 11 135 1 W 3.5 1363 0.6623 0.0000 0.1892
ESB Administration Offices, Cork 13 250 1 W 3.65 1922 1.7301 0.5037 0.4746
Cork County Library, Cork 13 450 1 W 4.00 560 0.9067 0.9067 0.2267
Swedish Ambassador’s Residence, Dublin 12 21 1 V 3.5 1363 0.1030 0.0000 0.0294
Cowper Care, Kilternan, Dublin 8 100 1 V 3.5 1363 0.4906 0.0000 0.1402
Cowper Care, Rathmines, Dublin 8 66 1 V 3.5 1363 0.3238 0.0000 0.0925
Cowper Care, Dublin 11 86 1 V 3.5 1363 0.4219 0.0000 0.1205
Vista Health Care, Naas, Co Kildare 10 400 1 W 3.65 1922 2.7682 0.8059 0.7593
UCC Western Gateway IT Building, Cork 15 1000 1 W 3.65 1922 6.9204 2.0148 1.8983
Athlone City Centre Retail Complex, Westmeath 10 2786 1 W 3.65 1922 19.2802 5.6132 5.2887
Lifetime Lab, Cork 12 70 1 W 3.5 1363 0.3434 0.0000 0.0981
Bagenalstown Swimming Pool, Co. Carlow 11 18 1 W 3.5 1363 0.0883 0.0000 0.0252
Croi Anu Creative Centre, Co. Kildare 10 8 1 H 3.5 1363 0.0392 0.0000 0.0112
Rathmore Community Childcare, Co. Kerry 11 12 1 V 3.5 1363 0.0589 0.0000 0.0168
Treacys Hotel Co. Wexford 11 450 1 V 3.65 1922 3.1142 0.9067 0.8542
Fairy Bush Childcare Centre, Co Roscommon 11 23.5 1 V 3.5 1363 0.1153 0.0000 0.0329
Tinnypark Nursing Home, Co. Kilkenny 10 32 1 H 3.5 1363 0.1570 0.0000 0.0449
Goretti Quinn Creche, Co. Kildare 11 12 1 V 3.5 1363 0.0589 0.0000 0.0168
CloCeardlann na gCnoc, Co. Donegal 10 18.3 1 H 3.5 1363 0.0898 0.0000 0.0256
St John's National School, Co. Mayo 10 14.2 1 H 3.5 1363 0.0697 0.0000 0.0199
Dubin Dockland Development Authority 12 17.5 1 H 3.5 1363 0.0858 0.0000 0.0245
Dunmore House Hotel, Co. Cork 11 18 1 W 3.5 1363 0.0883 0.0000 0.0252
Comhaltas Cosanta Gaeltachts Chuil Aodha, Cork 11 16 1 V 3.5 1363 0.0785 0.0000 0.0224
David Cuddy, Rathbranagh, Co. Limerick 11 11.5 1 V 3.5 1363 0.0564 0.0000 0.0161
Skeaghanore Farm Fresh Duck, Co. Cork 11 12 1 V 3.5 1363 0.0589 0.0000 0.0168
Kanturk Sheltered Housing, Co. Cork 11 8.3 1 V 3.5 1363 0.0407 0.0000 0.0116
Comhlacht Forbartha an Tearmainn, Co. Donegal 11 33.6 1 V 3.5 1363 0.1648 0.0000 0.0471
Feohanagh Special Needs Housing, Co Limerick 11 17 1 V 3.5 1363 0.0834 0.0000 0.0238
CLS Rosmuc, Co. Galway 10 19.8 1 H 3.5 1363 0.0971 0.0000 0.0278
Vicarious Golf, Co. Wicklow 10 13 1 H 3.5 1363 0.0638 0.0000 0.0182
Inis Oirr Health Centre, Co. Galway 10 12 1 H 3.5 1363 0.0589 0.0000 0.0168
Children's and Adults Respite Centres, Co. Galway 11 21 1 V 3.5 1363 0.1030 0.0000 0.0294
Kilcurry Community Development, Co. Louth 11 17 1 V 3.5 1363 0.0834 0.0000 0.0238
Ardara Community Childcare, Co. Donegal 11 22.1 1 W 3.5 1363 0.1084 0.0000 0.0310
Seawright Swimming School Co. Cork 11 31 1 W 3.5 1363 0.1521 0.0000 0.0434
Cope Foundation, Bandon, Co. Cork 11 30 1 V 3.5 1363 0.1472 0.0000 0.0420
Parklands Apartment Development, Co. Wicklow 11 40 1 V 3.5 1363 0.1962 0.0000 0.0561
Ballyconnell Central National School, Co. Cavan 11 12 1 V 3.5 1363 0.0589 0.0000 0.0168
James B Joyce & Co, Co. Galway 11 18.3 1 V 3.5 1363 0.0898 0.0000 0.0256
Poor Clare Monastery, Co. Louth 11 18 1 W 3.5 1363 0.0883 0.0000 0.0252
Tralee Community Nursing Unit, Co. Kerry 11 100 1 V 3.5 1363 0.4906 0.0000 0.1402
Brook Lodge Hotel, Co Wicklow 10 134 1 H 3.5 1363 0.6574 0.0000 0.1878
Hudson Bay Hotel, Athlone, Co. Westmeath 11 132 1 W 3.5 1363 0.6475 0.0000 0.1850
Hotel Europe, Killarney, Co. Kerry 10 110 1 W 3.5 1363 0.5396 0.0000 0.1542
Rathass Housing Estate, Tralee, Co. Kerry 8 70 1 H 3.5 1363 0.3434 0.0000 0.0981
Whites Hotel, Wexford 10 21 1 H 3.5 1363 0.1030 0.0000 0.0294
Belinter Hotel, Navan, Co. Meath 10 306 1 H 3.65 1922 2.1176 0.6165 0.5809
Bellview Woods Childcare, Killarney, Kerry 8 30 1 H 3.65 1922 0.2076 0.0604 0.0569
D&G Electrinics Ltd, Castleisland, Co Kerry 8 21 1 H 3.5 1363 0.1030 0.0000 0.0294
Oilgate Nursing Home 8 100 1 V 3.5 1363 0.4906 0.0000 0.1402
Youghal Town Hall, Co Cork 8 21 1 V 3.5 1363 0.1030 0.0000 0.0294
151696.1 756.0798 13.3420 215.5126
Allen and Burgess
7
Table 2: Summary Table of Direct Heat Use
Use Installed Capacity1)
Annual Energy Use2)
Capacity Factor3)
(MWt) (TJ/yr = 1012
J/yr)
Individual Space Heating4)
None
District Heating 4)
None Air Conditioning (Cooling) 6.622 13.342 0.064 Greenhouse Heating NoneFish Farming None Animal Farming None
Agricultural Drying5)
None
Industrial Process Heat6)
None Snow Melting None
Bathing and Swimming7)1.452 7.9078 0.173
Other Uses (specify) None Subtotal 8.074 21.2498 0.083
Geothermal Heat Pumps (Heating) 151.696 744.1605 0.156
TOTAL 159.770 765.4103 0.152
Table 3: Allocation of Professional Personnel
Year Professional Person-Years of Effort
(1) (2) (3) (4) (5) (6)
2005 10 (equiv.) None None None None 10 (equiv)2006 15 (equiv.) None None None None 20 (equiv)2007 15 (equiv.) None None None None 30 (equiv)
2008 15 (equiv.) None None None None 40 (equiv)2009 15 (eqiuiv) None None None None 50 (equiv)
Total 70(equiv) None None None None 150 (equiv)
Table 4: Total Investments in Geothermal
Research & Field Development Utilization Funding Type Period Development Including Production
Incl. Surface Explor. Drilling && Exploration Drilling Surface Equipment Direct Electrical Private Public
Million US$ Million US$ Million US$ Million US$ % %
1995-1999 0.2 0.5 70 30
2000-2004 1 16 80 20
2005-2009 7.5 225 90 10
The huge increase in the number of GSHP systems installed
in Ireland over the last 4 years, which has raised the total
heat pump capacity from about 40 to 164 MW has stemmed
from public concern for climate change and reduction in
CO2 emissions, and also the desire by businesses and
individual householders to reduce heating costs. In addition,
the grant aid introduced by SEI on behalf of the Irish
Government for both domestic, commercial and public
sector projects, through the Greener Homes, Reheat and
Public Sector programs has also had a major effect in
stimulating this growth. However, failure of heat pump
systems, or systems that fail to perform up to expectations
are problems which threaten the development of the whole
sector. A number of reasons for these failures are:
• installation by insufficiently qualified installers
• poor and misleading advice on the most suitable
heat collection system
• failure to size the collector system properly
• unsatisfactory commissioning of the heat pump
system
• failure to install a Building Management System
(BMS) or installation of a BMS without a data
archival feature
• failure to instruct the client in operation and
adjustment of the BMS and heat pump system
• absence of post installation monitoring and back-
up by installer
These and a lack of confidence in heat pumps by many
HVAC engineers, have hindered the growth of heat pumps
in the commercial sector of the Irish market.
On the brighter side, over the last few years in Ireland there
has developed a heightened interest in renewable energy
technologies and energy issues in general, associated with
concerns about CO2 emissions, climate change, energy
security and peak oil. This has led to the development of a
number of third and fourth level degree programmes in
Energy Engineering in Irish higher education institutes.
UCC for example has been running an MSc programme in
Sustainable Energy for 5 years, and has also introduced an
undergraduate Energy Engineering degree program. In all
these programs, geothermal energy and heat pump
technology form part of the curricula.
Allen and Burgess
8
Commercial and government interest in geothermal energy
has also developed in Ireland over the last few years to the
extent that the GAI saw the opportunity to organize its 10th
anniversary conference in November 2008 entitled
‘Geothermal Resources in Ireland - Commercial
Opportunities’. In addition, the Irish Government has
moved to establish regulatory controls to guide the
development of geothermal energy in Ireland, and as the
initial step has engaged in a wide ranging consultation
process with geothermal stakeholders. This has developed
in parallel with Ireland’s participation in the EU
Altener/IEEA funded Geothermal Regulation for Heat
(GTR-H) project to standardize geothermal regulations
throughout the EU, which culminated in the GTR-H
conference in Dublin in Autumn 2009. Government and
commercial recognition of the potential of geothermal
energy to aid reduction in CO2 emissions and dependence
on fossil fuel imports can only benefit development of the
geothermal industry, and to this end a carbon tax which
may be introduced by the Irish Government in its December
2009 budget will further enhance this growth.
6. FUTURE DEVELOPMENT AND INSTALLATIONS
Future projects on the island of Ireland include a 1MW
proposed open loop system for heating and cooling the
Critical Care Unit of Victoria Hospital in Belfast, and the
prospect of including GHP as part of the overall mix for a
20MW energy centre also at Victoria Hospital, Belfast. In
addition, investigations are taking place at Cookstown also
in Northern Ireland into the feasibility of drilling a deep
borehole in limestones to generate an open loop GHP
system to heat and cool new buildings to house the Police
Service of Northern Ireland (PSNI) and the Fire Training
Centre for Northern Ireland. Furthermore, the company
which drilled the deep borehole at Newcastle, Co Dublin
has recently developed a partnership with Ballymena
Borough Council in Northern Ireland with the intention of
also exploring the possibility of developing a deep
geothermal borehole for a district heating system for the
town.
Another large GHP project underway is a 1 MW vertical
closed loop system in Dublin to heat and cool the new
headquarters of one of Ireland’s major banks. Collector
systems have been installed in a total of 72 x 200m deep
boreholes, but the project is presently suspended due to the
current financial position of the bank.
Finally, the Cork Docklands Development Agency, tasked
with regenerating the Cork Docklands area, is currently
undertaking an investigation into the potential of using open
loop heat pump systems to generate district heating for
apartment complexes, hotels, shopping malls and
commercial premises. The site is a low lying estuarine area
subject to tidal influence, where salt water intrusion is a
potential problem. Owing to the economic downturn in
Ireland, this project is also likely to be delayed.
7. ACKNOWLEDGEMENTS
We wish to thank various people, who helped compile the
statistics presented in this paper, in particular Amanda
Barriscale of SEI Statistics Office, Ann Crotty of SEI
Reheat Program and Ruth Buggy of SEI Greener Homes
Scheme, and consultants Paul Sikora, David Roome, Roisin
Goodman and Gareth Jones. Also thanks to Brecan Mooney
for help with the diagrams.
REFERENCES
Aldwell, C.R.: Low-Temperature Geothermal Energy in
Ireland, Seminar on ‘Geothermal Energy from Public
Water Supply Sources’, Tramore, Ireland (1997).
Aldwell, CR.: Mallow Springs, Co. Cork, Ireland.
Environmental Geology, 27, pp 82-84 (1996)
Aldwell, CR., Burdon, DJ.: Hydrogeothermal Conditions in
Ireland. 26th Int. Geol. Cong. Paris; Sec.14.2 Fossil
Fuels; Abstracts 1043 (1980)
Aldwell, C.R., Burdon, D.J.: Temperature of Infiltration
And Groundwater Conjunctive Water Use (Proc.
Budapest Symposium, July 1986). IAHS Publ. No.
156. (1986)
Allen, A.R., McGovern, C., O’Brien, M., Leahy, K.L.,
Connor, B.P. Low Enthalpy Geothermal Energy for
Space Heating/Cooling from Shallow Groundwater in
Glaciofluvial Gravels, Cork, Ireland. In: Fendekova,
M., Fendek, M. (Eds) Hydrogeology and Land Use
Management. XXIX IAH Congress, Bratislava, Slovak
Republic, IAH, Bratislava, pp 655-664, (1999)
Allen, A.R., Milenic, D.: Low Enthalpy Geothermal Heat
Resources from Groundwater in Glaciofluvial Gravels
of Buried Valleys. Applied Energy, 74, 9-19 (2003)
Allen, A.R, Milenic D., Sikora, P.: Shallow Gravel
Aquifers and the Urban 'Heat Island' Effect: a Source
of Low Enthalpy Geothermal Energy. Geothermics,
32, 569-578 (2003)
Brück, PM., Cooper, CE., Cooper, MA., Duggan, K.,
Gould, L., Wright DJ., The Geology and Geochemistry
of the Warm Springs of Munster. Ir. J. Earth Sci., 7,
169-194 (1986)
Burdon, DJ.: Irish Geothermal Project, Phase 1.
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Ireland. Minerex Ltd., Dublin, 150/75/15 (1983)
Gondwe, KT., Allen, AR., Burgess, J., Browne, D, Sikora,
P.: The Glucksman Art Gallery, University College
Cork, Ireland: an Innovative Space Heating
Development (this volume)
Goodman R. Jones, G., Kelly, J., Slowey, E., O’Neill, N.: A
Geothermal Resource Map of Ireland, Final Report for
Sustainable Energy Ireland (SEI). CSA Dublin (2004)
Howley, M., O’Gallachoir, B., Dennehy, E.: Energy in
Ireland: Key Statistics 2008. Sustainable Energy
Ireland, 31pp, http://www.sei.ie/Publications/Statistics
(2008a)
Howley, M., O’Gallachoir, B., Dennehy, E., O’Leary, F.:
Renewable Energy in Ireland: 2008 Report – Focus on
Wind Energy and Biofuels. Sustainable Energy
Ireland, 30pp, http://www.sei.ie/Publications/Statistics
(2008b)
Liddy, S., Evaluation of Optimal Conditions for Horizontal
Closed-Loop Collector Systems for Ground Source
Heat Pumps. Unpublished MSEng. Minor Thesis,
Department of Civil and Environmental Engineering,
University College Cork (2008)
Lohan, J., Burke, N., Greene, M.: Climate Variables that
Influence the Thermal Performance of Horizontal
Collector Ground Source Heat Pumps. Proceedings
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Engineering Systems Design and Analysis, Torino,
Italy. (2006)
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Mooney, B., Allen, AR., Koeniger, P. Investigation of
Source and Conduit for Warm Geothermal Waters,
North Cork, Republic of Ireland (this volume)
O’Brien, M.: The development of Geothermal Resources in
the Mallow Area for Heating Purposes, Unpublished
MSEng Thesis, Department of Civil Engineering,
UCC, Cork, Ireland. (1987)
O’Connell, S.: Renewable Energy in Buildings – Ground
Source Heat Pumps. Unpublished MSEng. Thesis,
Department of Mechanical and Manufacturing
Enginering, Cork Institute of Technology, Ireland.
(2004)
O’Connell, S., Allen, AR., Cassidy, S.: Utilization of
Geothermal Resources in the Irish Republic. In:
Horne, R., et al. (eds.) Geothermal Energy: The
Domestic Renewable Green Option. Proceedings
World Geothermal Conference, Antalya, Turkey, 5pp
(2005).
Proceedings World Geothermal Congress 2010 Bali, Indonesia, 25-29 April 2010
1
GTR-H - Geothermal Legislation in Europe
1Goodman, R.,
2Pasquali, R.
3Dumas, P.,
4Hámor T.,
5Jaudin F.,
6Kepinska, B.,
7Reay, D.,
8Rueter, H.,
3Sanner, B.,
9Van Heekeren, V.,
8Bussmann, W.,
10Ll Jones, G.
1SLR Consulting (Ireland) Ltd. (SLR),
2GT Energy Ltd., (GTE),
3European Geothermal Energy Council (EGEC),
4Hungarian
Office for Mining and Geology (MBFH), 5Bureau de recherches geologiques et minieres (BRGM),
6Polish Academy of Sciences
(PAS-MEERI), 7Geological Survey of Northern Ireland (GSNI),
8Geothermischen Vereinigung e.V (GtV),
9Stichting Platform
Geothermie (SPG), 10
Conodate Geology Ltd.
Keywords: GTR-H, geothermal regulation, heat, framework, EU, Altener, IEEA
ABSTRACT
The IEEA, Altener funded GeoThermal Regulation – Heat
(GTR-H (www.gtrh.eu)) project ran from October 2006 to
October 2009 with the aim of identifying and reviewing the
regulatory barriers and deficiencies for geothermal heat in
unregulated EU countries. The GTR-H project aims to
develop a template framework for geothermal regulation in
the EU which would provide the basis for the development of national framework documents.
Barriers both in the ‘target’ and the BP countries included
resource ownership/usage, multi resource licensing, limits
of geothermal reservoirs, financial barriers and support for
geothermal. Geothermal regulation in the project’s partner
countries, as well as in the EU-27 and broadly in the
international context, is influenced predominantly by the
preceding natural resources legislation. Guidelines for the
establishment of a framework document for geothermal
regulation in the EU 27 have been developed and
disseminated to a broader international audience. The
GTR-H project builds on previous EU projects such as K4RES-H in the renewable energy sector.
1. INTRODUCTION
This project is currently in its final stages and will conclude
its major deliverables with a closing conference to be held
in Dublin, Ireland on 30th
September and 1st October 2009.
The Irish based geoservices consultancy, the CSA Group
who initiated and coordinates the project recently merged
with the UK based International environmental consultancy
SLR Consulting Ltd. and currently coordinates the project under the title of SLR Consulting (Ireland) Ltd.
Four ‘target’ countries were chosen which had a poorly
functioning regulation or no geothermal regulation:
Hungary, Ireland, Northern Ireland/UK and Poland.
Expertise in four regulated or ‘Best Practice’ (BP) countries
France, Germany and Netherlands provided a review of
best practice geothermal legislation.
The project consortium for GTR-H comprises a range of
government bodies, intuitions and associations, each
representing a country with the exception of the European
Geothermal Energy Council (EGEC) representing the
geothermal sector in Europe (partner names and logos are included in Table 1).
The project was designed with a process of discussion and
consultation with key target actors and stakeholders at a
national level at each stage of review and included a series
of study tours to assess the effectiveness of the regulation in
each case. The ultimate aim of the project is to increase
overall sectoral investment in the exploration and
exploitation of geothermal heat across the EU.
2. BACKGROUND
The GTR-H project follows on from the Kistelek
Declaration which was announced in Hungary in April
2005 (see reference list) and did the initial work in
identifying the key strategies needed for development of geothermal resources and regulation in the EU as follows;
- Secure the environmentally friendly use of geothermal
energy, in particular concerning protection of underground
drinking water resources, emissions, etc.
- Regulate competing uses and securing sustainable use of geothermal energy
- Grant investors certain right to use geothermal energy in a
given area and to a given extent, as the basis for business plans.
Both from the K4RES-H project conclusions (EGEC 2006)
and initial results from the GTR-H project it is apparent that
the present lack of regulation for geothermal energy
exploitation over most of the EU is inhibiting the effective
exploitation of this underutilized resource. The project was
planned to outline and encourage investment in geothermal
energy by private and public sector partnerships.
3. EXPECTED RESULTS AND BROADER IMPACTS
The project’s major measure of performance is government
level acceptance of the need to accommodate geothermal
energy exploitation in national environmental, water and
resource legislation in the Target countries. This is to be
accompanied by consultation between the relevant ministry
and the geothermal stakeholders and initiation of drafting
new geothermal legislation or adaptation of existing legislation.
On a broader basis it is envisaged that there will be
transferability of the framework to suitable legislative and
regulatory schemes in the remaining EU-27 countries to facilitate geothermal energy exploitation
The framework will also assist in the creation of new
market opportunities resulting from transparency in the
international geothermal sector and therefore the
opportunity for increased private sector cross border investment.
Goodman and Pasquali, et al.
2
IEEA Altener
programme
CSA Group
(Coordinator –
Ireland)
Geological Survey of
Northern Ireland
(GSNI)
European Geothermal
Energy Council
(EGEC)
Hungarian Office for
Mining and Geology
(previously Hungarian
Geological Survey)
Polish Academy of
Sciences
Bureau de recherches
geologiques et
minieres
Geothermischen
Vereinigung e.V
Stichting Platform
Geothermie
Table 1: GTR-H Partners
4. METHODOLOGY OVERVIEW
The review of best practice and deficient regulations and
consultation with the stakeholders and key target groups has
been the key element providing the data necessary to allow
the definition of a framework which can accommodate the
legislative, environmental, energy, planning and financial
considerations. This has been completed for each of the target and best practice countries.
The project consulted broadly with the national geothermal
sector through each partner. The key target groups
identified and consulted with as stakeholders in the
geothermal sector are as follows: Decision Makers at
national government level, Government agencies (water,
energy, environment and planning), Trade and industry
associations, Bank and financing institutions, Legal
representatives, Geothermal educational facilities and
associations, Geothermal exploration/resource assessment
consultants, Geothermal end users.
Figure 1: GTR-H project structure
The project has provided for dissemination of information
and discussion and interaction between all partners at every
stage of the project as this is seen as key to the success of a
regulatory framework. Regular committee meetings with
workshops allowed discussion of the issues raised and
solutions to be found. Provision was made for the
observation of team partners in local workshops therefore
giving opportunities for alternative country views to be
included in the local discussion and a broader view of the potential solutions to be considered throughout the process.
The results have been summarized to produce a ‘matrix’
which relates the identified barriers to geothermal
development to the solutions been applied in the best
practice countries and further afield. This has been adapted
to provide a basic framework of the issues that are likely to
arise and a proposed approach for dealing with them in any
national regulation being considered. Details are provided
below.
5. RESULTS SO FAR – A PRELIMINARY
FRAMEWORK
The following summary sets out a draft text indicating
some of the issues for inclusion and consideration in a
geothermal framework for national regulation/legislation as
concluded from work so far completed in the GTR-H
Project. The issues to be dealt with generally separate into
three main areas as follows; legal guidelines, financial
incentives guidelines and general guidelines for flanking
measures.
5.1. Legal Guidelines
5.1.1 Definition of Geothermal energy
Of primary importance in the development of any
geothermal regulation is a clear definition of geothermal
energy. The consortium has discussed this and liaised
widely and has agreed that the following definition as
defined by the RES Directive (EU, 2009) is most appropriate:
‘Geothermal Energy is the energy stored in the form of
heat beneath the surface of the solid earth’.
Additional parameters could be used for specifications to
account for resource type extraction. Depth, temperature,
Goodman and Pasquali, et al.
3
flow rates, end use, systems capacity/size could be used to
steer the permitting process and exact parameters should comply with existing resource regulations:
5.5.2. Clarification of geothermal resource ownership
Primary national legislation (through existing or modified
natural resource legislation or separate geothermal
legislation) needs to clearly define the ownership of the
resource at a national level as well as nominating an
authority with power to issue licences for exploration and
development of the resource. There are a number of issues that may be relevant in different countries as follows;
The ownership of the geothermal resource may be treated
like a mineral or petroleum resource. Initially countries
could choose between the existing mineral or the petroleum exploration and development legislation.
The state may own the geothermal resource or govern the
right to use of the resource and grants licences to a company to explore for and produce geothermal energy.
A new single Geothermal Act could follow at a later date to
take account of lessons learned after several years of geothermal exploration.
5.1.3. Adoption of a licensing system
A system of licensing for exploration and exploitation for
geothermal resources should be in place as a primary
requirement to develop and regulate the national geothermal sector.
For shallow geothermal exploration and development where
licensing is required, the local authorities could be the
licensing body. Initially for deep geothermal resources
exploration and development the licensing authority could
be the department responsible for mineral or other resources
exploration.
The provision of one e-government portal for deep geothermal exploration applications is recommended.
The application procedure for deep geothermal exploration
and exploitation licences should be clearly stated in specific
guidelines to potential applicants. The application process
should be managed by the relevant licensing authority.
These guidelines should help streamline application submissions.
The system should grant the licensee the exclusive right to
exploration and exploitation of geothermal resources over a defined area for a defined period.
The administrative process for the granting of a deep
geothermal exploration licence should not exceed an overall period of six months.
Geothermal exploration licence duration should be no
longer than six years and should include facility for annual
(or bi-annual) reviews by the licensing authority based on a
submitted and agreed work programme by the potential licence holder.
Deep Geothermal Energy exploitation permits should have
a duration of no less than 20 years, thus lasting the normal
minimal lifetime of an average well doublet. A renewal
option for a period of not less than 5 years should be made
available to the licence holder, subject to review of the
production rates and their associated impacts on other natural resources.
Programme plan and results data relating to any geothermal
energy projects (shallow or deep) should be submitted to
the appropriate national licensing authority. These data
should fulfil all requirements of the legislation covering the
natural resource, planning, EIS, groundwater and environmental areas.
Confidentiality of submitted data associated with licensed
geothermal operations should be set out in the primary
regulatory structure as for other strategic natural resources.
Where the resource is included in other legislation (ie:
mineral, petroleum legislation) a confidentiality period
during the granted licence period and for a period
subsequent to the surrender of the licence should be
outlined specifically for geothermal energy. This should
clarify the periods where data are confidential, while also
providing guidelines for making monitoring data available
to the licensing/monitoring authority during the licensing
period and subsequent to surrender. This period should be between 4 to 6 years after surrender of the license.
Groundwater abstraction permits for geothermal energy
production should be based on the national groundwater
abstraction/pollution control regulatory regime with due regard to specific issues of geothermal systems.
The cost of geothermal exploration licences should be set
lower than the petroleum and mineral exploration licensing
costs to reflect the comparatively lower economic return
potential and to promote a national renewable energy action plan.
5.1.4. Simplification of regulations and administrative
procedures
Shallow geothermal energy usage should be regulated
where necessary through local planning laws where large
sized commercial systems are installed. A flow rate cut-off
for pumping groundwater as a heat source could be applied
to define which projects require a licence in order to comply with national groundwater abstraction legislation.
Small size domestic systems and closed loop collectors
should be the subject of a simple information submission
form to a nominated government agency to ensure suitable
monitoring at national level of resource usage and
protection especially in vulnerable areas. These should
require no exploration licence; however, the reporting of
new heat pump installations to the competent authority is required for registration reasons.
Existing national planning, natural resource, environmental,
water abstraction and building legislation should be used,
with modifications if necessary, to regulate the shallow, commercial geothermal sector.
Deep geothermal energy abstraction should fall in line with
the EU groundwater policy Groundwater Framework
Directive (EU, 2000) where implemented and national
groundwater legislation by requiring the use of re-injection or closed circuit systems.
5.1.5. Nomination of an administrative body
A national geothermal authority or independent expert body
(competent professional body or cooperative network of
competent authorities) is recommended to have the
responsibility to promote the geothermal energy sector,
issue licences for exploration and development of the
resource, review licence case specific applications and
facilitate the geothermal licensing application system. The
key issue here is that professional competence, specifically
Goodman and Pasquali, et al.
4
in the geothermal area, should be a prerequisite for the
authority responsible for reviewing, issuing and monitoring licences.
Initially the licensing authority could be the department
responsible for mineral exploration if appropriate. For
shallow geothermal, the local authority could be the
licensing authority. For deep geothermal exploration and
production the department responsible for mineral
exploration and development could be the licensing authority with input from the regional authority
The authority responsible for granting the license can be a different authority from the one that monitors the project.
The authorities need to recruit geothermal energy experts
with professional accreditation and use established geothermal standards.
5.1.6. Reporting for geothermal resources inventory &
statistics
There is a need for each country to adopt a national strategy
that establishes the geothermal potential, identifies targets
and increases the public awareness of geothermal energy. The issues that need to be covered are as follows;
Insufficient data base; Presently, statistics on the heating
sector and inventories of the geothermal resources in
general are weak. A speedy establishment of robust market
data and reliable statistics that allow the establishment of a baseline as well as progress monitoring is essential.
Shallow and deep geothermal resource borehole drilling
should be reported, as part of the permit requirements, to
the relevant national government agencies, to ensure that
there is a record of installed shallow and deep geothermal
systems. This will help the implementation of a successful
national geothermal energy development strategy. There
should be a requirement to furnish basic borehole
information to a centrally maintained borehole inventory
that will be used for planning decisions at the local level.
Yearly monitoring data from large commercial producing
systems should be submitted to the relevant licensing
authority together with all other data of significance to the
resource parameters and its exploitation.
Monitoring data should include heat production,
temperature of the carrier fluid at surface, flow rates,
pressure, temperature of the injected fluid; chemistry of the
produced water.
Monitoring data should be made publicly available subject
to the set confidentiality period of the exploitation licence. Domestic systems should be exempt from this.
5.2. Financial incentives guidelines
A key conclusion of the GTRH project is that Financial
Incentives (FIS) can play an important role in promoting
geothermal heating and cooling, if they are well designed,
carefully managed and accompanied by appropriate
flanking measures. Without proper design their positive
effect is limited and can be even counter-productive to the
development of the geothermal sector in the medium and long term.
It can be shown that national government financial
incentives for the installation of shallow ground source heat
pump systems have significantly increased uptake in
shallow geothermal sectors throughout Europe. The key
positive effects of well designed and managed financial incentive schemes are:
• Reduction of the upfront investment costs,
• Psychological effect: signal of the public authority to the
potential users
5.2.1. Reducing Financial burden
There should be no licence fee or royalty payment for
geothermal systems (shallow or deep) because the heat is
not permanently removed from the rock. The heat resource
is renewable and therefore not “mined” in the conventional sense.
Exploration permit fees for the licence area should be a
once off set fee included in the initial licence application.
There should be no additional fees (programme related) to carry out exploration during the licence period.
The application of Royalty fees to producing deep
geothermal energy plants should be especially discouraged
if national legislation stimulates the usage of re-injected
geothermal systems on the basis that no resource is being removed (or ‘mined’).
Groundwater abstraction fees and permitting should be
waived in accordance with national groundwater legislation
if the producing net water abstraction budget from shallow and deep systems is 0m
3/d or below the national guidelines.
5.2.2. Recommendations for financial incentive schemes
National taxation law is encouraged to promote increased
capital investment in geothermal energy (eg: renewables tax
incentives, preferential VAT rates). Other renewable
energy resources are actively incentivised by national
governments in Europe with prices for electricity
generation from other renewable technologies helping
national markets to diversify electricity production. This is
currently not the case for national and European heat
markets. Incentives for delivering heat from renewable
energy sources such as geothermal energy should be encouraged through national taxation systems.
Grants or other financial support schemes for both
commercial and residential sector systems should be available.
For large commercial systems these could be made
available, subject to a review of the projected production of the system by the applicant.
Residential sector support could be granted, subsequent to
the submission of drilling or system installation notification to the relevant national government agency.
Financial incentives have to be based on the long term, and
measures should only be announced when they are
available, in order to minimize confusion and maximize the impact of the measure.
Administrative procedures should be as simple as possible
Deep geothermal energy projects should be promoted by
national, regional and local government authorities by
financial incentives.
Appropriate exemptions or allowances from the national
planning regulation and environmental impact assessment
regulations should be considered for the development of
Goodman and Pasquali, et al.
5
geothermal energy projects, in order to assist in the development of the sector.
National research and development funding schemes should
clearly have geothermal energy research, pilot projects and spin-off activities amongst the priority fields.
5.3. General Guidelines for Flanking Measures
Any technical parameter linked to the eligibility for a FIS
should be strictly oriented to European standards and certification.
Incentives could include financial assistance for initial
feasibility studies, grants or low interest rate loans for capital investment.
Geothermal energy should receive incentives equal to the
support received by other renewable energy sources in the
form of grants, low interest rate loans, risk insurance, preferential VAT rate, feed in tariffs etc.
Preferential VAT rates for heat sales from operating
geothermal power plants should be below the higher rates
of 16-21.5%. These should be designed to encourage fossil
fuels substitution and provide a competitive price for
geothermal energy based on national domestic and commercial energy rates.
A geothermal insurance and risk fund (particularly for deep
exploratory and/or development drilling, is encouraged to
be made available based on the substitution for fossil fuel
use and on the potential for national CO2 emission savings
that can be achieved through the development of
geothermal energy projects. This type of risk fund typically
covers the risk associated with the drilling for the
exploration and assessment of the resource.
A ground source heat pump guarantee fund for large
commercial systems >30kW and exploiting aquifers shallower than 100m should be considered.
Specific agreements on electricity service fees for heat pumps are encouraged.
Incentives could be based on the CO2 emission avoidance
from operating geothermal plants and/or a set of agreed feed in tariffs based on a national feed in tariff strategy.
The development of a CO2 emission credits system for the
operation of geothermal energy projects should be
encouraged at national level to incentivise sector investment.
Innovative applications of geothermal energy should benefit from specific discount.
In countries where national drilling permits are required for
the completion of geothermal energy boreholes, a cost
waiver should be applied or the cost reduced for the
geothermal sector. This should be considered for a period of 15 – 20 years until the sector is established.
Where applicable there should be a waiver/reduction on
natural resource data acquisition costs to a licence applicant
for review of geothermal energy data prior to application submission.
REFERENCES
EGEC 2006, Key Issues for Renewable Heat in Europe
K4resH, EU contract EIE/04/204/S07.38607
EU 2000, EU Directive 2000/60/EC, Water Framework
Directive.
EU 2009, EU Directive 2009/28/EC on the promotion of
the use of energy from renewable sources.
Kistelek Declaration 2005. Regulatory and Economic
Tools Governing the Enhanced Exploitation of
Geothermal Energy in the European Union.
Proceedings World Geothermal Congress 2010
Bali, Indonesia, 25-29 April 2010
1
The Glucksman Art Gallery, University College Cork, Ireland: An Innovative Space Heating
Development
Kondwani T. Gondwe, Alistair Allen, John Burgess, Donal Browne and Paul Sikora
Department of Geology, University College Cork, Ireland
Keywords: Heat pumps; Open loop system; Performance
analysis; Payback time
ABSTRACT
The Lewis Glucksman Art Gallery is a cultural and
educational institution promoting the visual arts at
University College Cork (UCC), Ireland. Opened in
October, 2004, the 2350m2 building is serviced by a
geothermal heating and cooling system, which allows
heating and cooling to be provided at the same time using
two water-cooled heat pumps. This enables a liquid chiller
installation to serve as a full service heat source
simultaneously with its refrigeration function.
Situated adjacent to the River Lee on UCC campus, and
overlying a shallow gravel aquifer, groundwater at 12m
depth and ~ 15°C, is fed via an open loop collector to
geothermal heat pumps through plate heat exchangers. In
order to ensure the preservation and safe keeping of its art
collections, critical exhibition and storage space in the
Glucksman requires a highly controlled environment,
including humidity control by dehumidification, which
demands that heating and cooling be supplied
simultaneously to closed control areas. A range of climate-
control technologies connected to the heat pumps optimise
energy efficiency, whilst meeting the requirements of each
viewing space. Two water cooled chillers at the same time
generate both chilled water at 6°C and heating water at
45°C (30°C when providing cooling only). The rejected
heat from the cooling process is fed directly into the heating
circuits. Excess heat or cooling is transferred to the
groundwater through a plate heat exchanger, and is
discharged to a holding tank for use in toilet flushing and
landscape irrigation. Excess water is discharged to the
River Lee. The system capacity is 170kW and 200kW for
cooling and heating respectively against corresponding
loads of 130kW and 190kW.
In 2005 and again in mid 2008, assessments of the
performance of the geothermal heating/cooling system for
the Glucksman Gallery were undertaken to evaluate the
operational efficiency of the geothermal system and to
compare its performance to that of a conventional system.
The studies also evaluated the economics and operational
savings of the system relative to a conventional system and,
based on fossil fuel and electricity prices over the period
from commissioning of the building, estimated its payback
time and future savings over the lifetime of the heat pumps.
The investigations have indicated potential for considerable
savings of 75% in energy consumption over that of
conventionally equipped buildings. Post occupancy
evaluation using recorded data from the building
management system shows a remarkable correlation in
energy consumed to the pre-construction design estimates.
Due to significant increases in energy costs since the
building was commissioned, payback time has been
significantly reduced relative to pre-construction design
estimates.
1. INTRODUCTION
The Lewis Glucksman Art Gallery is a cultural and
educational institution in University College Cork (UCC),
Ireland that promotes research, creation and exploration of
the visual arts in an international context. The building,
which was completed and commissioned in October 2004,
has a total floor area of 2350m2, spread over 7 floors. It
provides a public gallery with international curatorial
standard environmental controls for University College
Cork's modern art collection as well as for travelling and
special exhibitions (Burgess, 2003).
The building contains four exhibition spaces, multifunction
rooms, lecture facilities, a basement gallery store, a
riverside restaurant and gallery shop (O’Regan, 2007). The
four interlocking exhibition spaces vary in size and are
staggered over three of the upper floors. The artworks are
displayed in the exhibition spaces and stored in the
basement store.
The Glucksman Gallery is situated on the southern bank of
the South Channel of the River Lee, 10m from the river and
about 1.7 km from Cork city centre. The architectural brief
for the building was for an environmentally sympathetic
design to complement the riverside location and its
surroundings of mature trees and grassy lawns, with an
emphasis on external wood and glass (Fig. 1). That it
achieved these objectives is indicated by the fact that the
building was short listed for the 2005 Stirling Prize for
outstanding architectural achievement.
The 0.5 km wide floodplain of the River Lee, is underlain
by a Pleistocene buried valley infilled by gravel deposits of
variable thickness ranging up to at least 60m and possibly
as much as 140m in places (Allen & Milenic, 2003),
overlain by only a metre of alluvium. The south side of the
building is located about 10m from the southern margin of
the buried valley, which is marked by a small limestone
scarp. The hydraulic conductivity of the gravels is of the
order of 5 x10-3 ms-1, making them an excellent source of
groundwater for a geothermal space heating/cooling system
employing a heat pump with an open loop collector..
2. DESIGN SPECIFICATIONS
The Glucksman Gallery requires a highly controlled
environment for the preservation and safe keeping of its art
collections. This demanded exceptionally close control of
temperature, humidity and natural light. Thus, in order to
prevent deterioration of the artistic works, it was essential
that the heating/cooling system design be capable of
maintaining constant year round relative humidity (RH) of
the order of 50%±5% and temperatures of 19 ± !oC in the
critical close control areas. These are represented by the
Gondwe et al.
2
exhibition spaces and the basement storage. The other areas
require only temperature control.
Dehumidification is required to achieve the humidity
control requirement. The dehumidification process demands
that air be cooled and reheated simultaneously which is an
energy intensive operation.
To maintain the design within the environmental aspiration
of a low energy solution, the building-services consultant,
Arup selected a range of climate-control technologies to
meet the requirements of each viewing space. In view of the
existence of a ready heat source in the form of the
groundwater supply beneath the site, it was decided that
much of the heating and cooling loads be supplied by a
geothermal system. The building utilises two geothermal
heat pumps (GHP’s) in conjunction with air handling units
(AHUs) to maintain the exhibitions and stores of art works
at controlled temperature and humidity.
2.1 System Components
2.1.1 Geothermal System
Figure 1: The Glucksman Art Gallery, Ireland
The geothermal system is located below ground level in the
basement of the Glucksman Gallery, and is supplied by
groundwater at 15°C sourced from two 12m wells adjacent
to the building. The heat pumps, which were designed,
supplied and installed by Dunstar Ltd, have a lifetime of at
least 20 years. System capacity for cooling and heating is
170kW and 200kW respectively against corresponding
loads of 130kW and 190kW.
The system’s major components are:
2 Heat Pumps; Cold and Hot Buffer Tanks; Plate Heat
Exchangers and Three Way Valve
Heat Pumps: Two York International water-cooled liquid chillers act as
heat pumps. These are two stage chillers. one (YCWM75)
comprising two 37.5kW compressors and the other
(YCWM 120) two 60kW compressors. Actual single stage
cooling capacities are 29kW and 47kW, whilst their
corresponding heating capacities are 38.8kW and 64.3kW
respectively (York Polaris 1999). These simultaneously
generate chilled water at a temperature of 6°C and heating
water at 45°C, (30°C when providing cooling only). On
starting a unit, both compressors start and then one stops so
that the unit runs at half capacity for part load application.
The system operates by any combination of the four
compressors depending on the load requirement at that
particular time. If all four compressors are running, the
capacities are 152kW for cooling and 206kW for heating,
whilst the power input is 55.2kW.
The refrigerant is R407C, a zeotropic mixture of three
HFC’s, R32, R125 and R134a in the proportions 23:25:52
by weight, which is non ozone depleting and also has high
thermal characteristics since it is a mixture of three
different substances.
Cold and Hot Buffer Tanks: Two buffer tanks act as
energy storage. Chilled water is stored in the cold buffer
tank to be circulated through the AHU cooling coils when
cooling is required, whilst the hot buffer tank stores heated
water for circulation through the AHU heating and reheat
coils when heating and/or dehumidification is required.
Plate Heat Exchangers: There are two stainless steel
brazed plate heat exchangers, one to allow excess heat to be
rejected to the groundwater aquifer and the other for heat
extraction from the groundwater. Plate heat exchangers
were used because they are more efficient than other types
of heat exchangers.
Three Way Valve: A motorized three-port valve is,
depending on operational mode, used to direct the
geothermal water flow to either the heating side plate
exchanger or to the cooling side plate exchanger.
2.1.2 Air Handling Units
Three air handling units serve different functions and floors
of the Glucksman Gallery. AHU1 provides temperature and
humidity control to the basement gallery store, serving the
need for close control of both temperature and humidity for
the proper storage of the art works there. The unit, which
consists of a carbon filter, bag and panel filter, heating coil,
cooling coil, humidifier and supply fan, has fresh and return
air intakes. The treated air is ducted to the room directly
below (Browne, 2005).
AHU2 provides temperature control second and fourth floor
galleries and to these areas. The unit consists of a bag and
panel filter, heating coil, cooling coil and dual speed supply
and return fans. The plant room acts as a fresh air plenum
and return air is taken by duct from both rooms through a
shadow gap at high level with a bell mouth in the ceiling
void. The supply is provided through vertical duct drops to
floor grilles (Browne, 2005). Unlike AHU1 and AHU3, this
unit does not offer humidification. However it does provide
dehumidification through the efficient use of the cooling
and (re)heating coils both of which are fed from the
evaporator and condenser sides (respectively) of the water
cooled chillers.
AHU3 serves the close control gallery and multi media
room, and is comprised of a return fan, mixing box, cooling
coil, steam humidifier, supply fan and terminal reheat
boxes. The return section is on the fifth floor consisting of
fresh air mixing, a carbon filter, return fan, bag filter and
panel filter whilst the supply section on the third floor
consists of heating, cooling, humidification and two-speed
supply fan.
2.1.3 Ancillary Plant
In addition the system includes water circulation units
consisting of the borehole pumps, cold and hot loop
circulating pumps, withholding tank and pipe networks.
The borehole pumps are two equally rated submersible
pumps, each driven by its own variable speed drive unit, set
at the bottom of the two wells at depths of 12m. The pumps,
configured as a duty/standby pair, have maximum pumping
rates of 10 l sec-1 and are used to pump groundwater to the
Gondwe et al.
3
heat pump circuit so that heat is either extracted from it or
fed into it.
Geothermal hot and cold loop pump sets, each consist of
two duty/standby circulating pump pairs. One is for
circulating heated water between the hot buffer vessel and
the geothermal hot plate exchanger, and the other for
circulating chilled liquid between the chilled buffer vessel
and the geothermal cold plate exchanger (Browne, 2005).
The withholding tank keeps processed geothermal water for
use in flushing toilets or irrigation. The pipe network acts as
a connection media between various components to transfer
geothermal water from the production wells through the
heat exchangers, withholding tank and discharge of excess
water to the River Lee. It is also used to circulate chilled
water or hot water from cold/hot buffer tanks to AHU’s for
cooling or heating or both in the case of dehumidification.
2.1.4 Ventilation and Air Circulation Units
Apart from the air handling units described above, there are
a number of supply fans and extraction fans, which operate
independently of the air handling units. Each fan operates
so as to maintain the required air changes for particular
floors and spaces. Of note due to its reasonable heating
capacity is the kitchen ventilation (supply and exhaust)
system which heats the colder winter air (0°C up to a
minimum operating temperature of 15 °C) using the
condenser water from the chiller sets.
2.1.5 Gas Boilers
Two 102 kW Remeha 350 model gas boilers, with a total
capacity of 204 kW are located in the upper floor. One acts
as a lead boiler, the other as a lag boiler to heat the LPHW
water for circulation through a limited number of radiators
in select areas of the building such as the trench radiators
for the glazed entrance lobby and radiant panels for the tall
glazing element in the entrance lobby. Their main function
is to be used as a backup system for the GHP’s in case of
failure.
2.1.6 Underfloor Heating
Heat from the condenser side of the water cooled chillers is
used to warm the flooring of the entrance lobby, toilets and
cafeteria. This again maximizes the use of the low grade
heating circuit that is in essence the heat rejection
(condenser) side of the water cooled chiller plant.
3. SYSTEM OPERATION AND MONITORING
3.1 System Operation
The submersible pumps drive groundwater from the
boreholes to the basement plant room where it is piped to
the two water-cooled chillers, which act as heat pumps,
generating chilled water at 6ºC and Low Gradient Hot
Water (LGHW) at 45ºC (30ºC for cooling only in summer).
Rejection of heat from the chillers cooling process is
utilized by the heating circuit. Excess heat or cooling is
transferred back to the groundwater, via a plate heat
exchanger. The processed groundwater is held in a storage
tank and is used for toilet flushing and irrigation, with
excess water being discharged into the river.(Kennett,
2005)
There are basically four operational configurations based on
modes of operation (O’Regan, 2007), which are:
Active Geothermal Cooling, Geothermal Heating Mode
Passive Geothermal Cooling and Combined Geothermal
Heating and Cooling
Based on the different operating modes, the system has
different coefficients of performance (COP), ranging from 3
to as high as 20 (Table 1)
Table 1. The Glucksman GSHP, COPs for Different
Operating Modes (O’Regan, 2007).
Operating Mode COP
Active Geothermal Cooling (Heat Pump
Enabled)
3
Active Geothermal Heating (Heat Pump
Enabled)
4
Active Geothermal Cooling and Heating (Heat
Pump Enabled)
7
Passive Geothermal Cooling (Heat Pump
Disabled)
20
3.2 Building Management System
A Building Management System (BMS) monitors all data
for temperatures, pressures, running hours, electricity and
gas consumption. The version employed for the Glucksman
Gallery is BMS 963 of Trend 963 – Lite BMS supervisor
software. The Trend 963 – Lite is a graphical, real-time user
interface for the BMS. It enables the user to monitor the
plant or building services, change the operational settings
and refine control strategies with experience (Huston,
2003).
The BMS is also programmed to report all alarms in case of
a problem, and to record and archive all data for future
reference and plot trends using its graphical, real–time
interface. However, it was found on investigating the BMS
for the Glucksman that the archiving facility had not been
switched on.
4. SYSTEM APPRAISAL AND PERFORMANCE
Geothermal heat pump systems are evaluated on the basis
of three major performance parameters. These are:
Technical performance; financial performance and the
environmental performance
For all of these performance pillars, it is necessary to
determine the annual cooling and heating loads and their
respective annual running hours, annual cooling and heating
energy consumptions and the total annual energy
consumption. There is also a need to ascertain the
efficiency of the conventional system and emission factors
for the driving electricity for the GHP and fossil fuels for
the conventional system.
The overall performance of the GHP installation is
dependent on the performance of the different components
that are interlinked to it within the total HVAC system.
4.1 System Appraisal
4.1.1 Technical Performance
Initial technical analysis during the design stage suggested a
COP of 4 for the heating mode and a COP of 3 in the
cooling mode. In the combined heating and cooling mode,
as the COP for heating and cooling is the summation of the
two, a COP of 7 can be achieved.
Gondwe et al.
4
This was verified by a post occupancy assessment
completed in April 2005 (Browne, 2005), which indicated
that initial performance was in line with design expectations
after six months of operation. Different COPs for both
cooling and heating modes were determined for standard
lift from an average cold inlet of 10°C and hot water outlet
of 45°C. This analysis found the COPs to be 2.98 and 3.93
for YCWM 120 and 3.05 and 4.02 for YCWM 75. These
also give averages of 3 for cooling, 4 for heating and a total
COP of 7 for combined heating and cooling (Browne,
2005).
4.1.2 Financial Performance
During the design phase, a comparison of the estimated
energy usage and running costs for the conversional system
and geothermal heating and cooling system was undertaken.
The comparison in capital cost showed the conventional
system to be cheaper by !175,000 (Burgess, 2007). The
comparison in running costs and cost savings are shown in
Table 2.
Table 2. Energy Use and Running Cost Comparison –
Design Phase (Burgess, 2007).
System Type Energy Usage
in kWh
Unit Price Annual Cost
Conventional
System
Chiller
61,512
! 0.07410
! 4,558.04
Boiler
1,690,758 !
0.01775
! 30,010.95
Total Annual Running Cost ! 34,568.99
GSHP System
GSHP
268,644
!
0.07410 ! 19,906.52
Boiler
176,779
!
0.01775 ! 3,137.83
Total Annual Running Cost ! 23,044.35
Annual Cost Saving = Difference in
Running Costs
!11,524.64
Using a simple pay back period calculation:
Payback Period = Difference in Capital Cost ÷ Annual Cost
Saving
Payback Period = ! 175,000.00 ÷ !11,524.64 = 15.2 years.
In the 9 month period after commissioning, Browne (2005)
found that energy usage by the GHP system was
considerably less than initially calculated, indicating that it
was operating more efficiently than anticipated (Table 3).
This allowed him to revise down the payback period to 11
years, although changes in fuel and electricity prices over
this period were not factored into his calculations.
Table 3. Energy Use and Running Cost Comparison –
One Year of Operation (Browne, 2007).
System Type Energy
Usage
in kWh
Unit Price Annual Cost
Conventional
System
Chiller
61,512
! 0.07410
! 4,558.04
Boiler
1,690,758
! 0.01775
! 30,010.95
Total Annual Running Cost
! 34,568.99
GSHP
System
GSHP 230,000
! 0.07410 ! 17,043.00
Boiler 100,000
! 0.01775 ! 1,775.00
Total Annual Running Cost ! 18,818.00
Annual Cost Saving = Difference in Running
Costs
!15,750.99
Simple Pay Back = Difference in Capital Cost ÷ Difference
in Operational Cost
Simple Pay Back = !175,000 ÷ !15,750.9 = 11.1 years
4.1.3 Environmental Performance
The design consultants, ARUP also undertook an evaluation
of CO2 emissions generated by the Glucksman Gallery
resulting from utilisation of different sources of electrical
power. It was estimated that the GHG system would bring
about a reduction of 256,249 Kg CO2 compared to the
conventional system, if the electricity was supplied by the
UCC Combined Heat and Power (CHP) plant. This gave an
environmental pay back of 10 years (Burgess, 2007).
4.2 Current Performance Analysis
Since commissioning of the geothermal system in the
Glucksman Gallery in October 2004, fuel and electricity
prices have risen sharply in response to various market
factors, together with uncertainty of supply due both to
political events and peak oil concerns. Consequently there
was a need to re-examine the performance of the system
and to recalculate its economics. This was undertaken in
August-September 2008 (Gondwe, 2008), enabling
financial savings for the four years of operation to be
established in order to assess their effect on the payback
period and also to assess the system in terms of its
continuing performance relative to design specifications
and expectations.
Gondwe et al.
5
A number of system performance assessment models were
investigated (Gondwe, 2008). Those most applicable to the
Glucksman Gallery heating and cooling system were the
RETScreen – Open Loop System Model, the Exergy
System Analysis Model and a model entitled ‘The
Glucksman Heating and Cooling Assessment Model’
developed by Browne (2005), which has subsequently been
upgraded to incorporate special financial and technical
analysis tools (Gondwe, 2008). It has the capability of
carrying out Exergy System Analysis and also Life Cycle
cost analysis and payback period with uneven cash flows.
In addition the RETScreen and the Exergy Analysis Models
were compared.
4.2.1 Annual Load Profile
Based on modelling with RETScreen 4, it is found that the
system is basically running in two modes per year at 0%
non weather dependent load and in a single mode per year
with 15% non weather dependent loads as shown in Figs. 2
and 31
Figure 2: Annual Load Profile with 0% Non Weather
Dependent Load
Figure 3: Annual Load Profile with 15% Non Weather
Dependent Load
Fig. 2 indicates that the system runs in heating mode from
November to April and then in heating and cooling mode
from April to November, whilst Fig. 3 shows that the
system runs in heating and cooling mode throughout the
year. The latter case applies when dehumidification is
required for humidity control throughout the year. In both
cases heating loads are at peak in December and January
and minimum in July and August. The reverse applies for
the cooling loads. The two figures represent the base case
only.
4.2.1 Annual Heating and Cooling Hours
Since no historical data on compressor run times and
operation mode was archived on the BMS, RETScreen 4
was used to determine the load profiles and the
corresponding heating and cooling hours.
From Fig. 2, it is established that Annual Heating Hours
(AHH) are 8760 hrs whilst Annual Cooling Hours (ACH)
are 5856 hrs, whereas Fig. 3 indicates that both are 8670 hr
The final performance analysis including projections
through the project life time was done using the
performance model developed. This has been outlined in
section 5 below.
5. THE PERFORMANCE MODEL
5.1 Model Description
The Glucksman Heating and Cooling System –
Performance Model is an MS Excel model used to calculate
and predict the system performance factors, financial
savings and emission savings (Gondwe, 2008). The model
has three major sections:
5.1.1 Input Section
The model operates with two sets of inputs. The inputs are
grouped into System Inputs and User Inputs.
System Inputs: These are default inputs specifying the
system data including the initial design cost of the system.
This set of inputs acts as a data storage. In addition the
system data input provides a list on natural gas and
electricity price projections.
User Inputs: This section consists of two sheets, “Input
Data” and “Valid Data Values”. The user enters the data in
the Input Data Sheet and the model tests its validity in the
Valid Data Values Sheet. The model uses the “Accepted
Values” in the Valid Data Values as its input.
There are four entry tables for entering past energy
consumption, efficiencies and emission factors for the grid,
prices for electricity and natural gas, power connection
times for the CHP and the grid. The entry tables are
numbered 1 to 4 with corresponding tables in the Valid
Data Values.
5.1.2 Computation Section
This section consists of three sheets in which performance
calculations are undertaken. System technical performance
is determined in the “Technical Performance Sheet”, whilst
financial performance is established in the “Financial
Calculation Sheet” and the environmental performance is
determined in the “Emission Calculation Sheet”.
5.1.3 Output Section
Although most of the performance information can be
obtained from the computation section, a special output
section has been set in the “Summary Graphs Sheet”. This
is a simplified graphical presentation of all the findings and
results.
Gondwe et al.
6
5.2 Electricity and Natural Gas Prices
5.2.1 Available Price Data
Based on data from UCC Buildings and Estates Office,
Bord Gais Energy Supply and Sustainable Energy Ireland,
Natural Gas prices rose from !0.033/kWh in 2004 to
!0.057/kWh in 2008. This gives an overall growth of
72.26% with an average annual growth of 19.9%.
Over the same period electricity from the campus CHP rose
from !0.101/kWh to !0.117 giving an overall growth of
15.29% and an average annual growth of 4.86% whereas
grid electricity rose from !0.131/kWh to !0.159/kWh
giving an overall growth of 21.37% with an average annual
growth of 6.67%
5.2.2 Price Projection – 2005 to 2029
The model was used to compute price projections and their
relative variation from 2005 to 2029. These are
demonstrated in Figs. 4 and 5.
Figure 4: Natural Gas and Electricity Price Projection
in Ireland (2005 – 2029)
Figure 5: Relative Price Growth for Natural Gas and
Electricity in Ireland (2005 -2029)
Fig. 4 shows the projected variation in prices, whereas Fig.
5 shows the relative price growth for each of the three
energy sources. Applying projected growth rates supplied
by Sustainable Energy Ireland, price deflators in the system
and the fuel data sheet of the model, it was found that there
will be a huge price rise in Natural Gas from !0.033/kWh in
2005 to !0.063/kWh in 2029 giving an overall rise of 91%
compared to 33% for grid electricity and 27% for CHP
electricity as shown in Fig. 5. Prices for electricity per kWh
will rise from 10.1 cents and 13.1 cents in 2005 to 12.8
cents and 17.5 cents in 2029 for CHP and grid supply
respectively as shown in Fig. 4.
5.3 Performance Results and Discussions
Based on the available BMS data, Chillers’ Design
Specifications and the price projections, the model
produced the following results:
5.3.1 Technical Analysis
Since no flow rates were available, COPs were calculated
using interpolation on the design specification and the
calculated COPs from the model. Results are:
From August to September 2008
Chiller Leaving Temperature (Mean) - 7.94oC
Evaporator Leaving Temperature (Mean) – 48.53oC
By interpolation, COPc = 2.63
COPh = 3.59
COP (h+c) = 6.21
From November 2007 to September 2008
Chiller Leaving Temperature (Mean) – 6.67oC
Evaporator Leaving Temperature (Mean) – 42.98oC
By interpolation, COPc = 2.88
COPh = 3.93
COP (h+c) = 6.89
COPs for the period October 2007 – September 2008 are
shown in Fig. 6. These have been calculated based on CHW
and LGHW flow temperatures shown in Fig. 7.
Figure 6: CHW and LGHW Flow Temperatures (Oct
2007 – Sept. 2008)
Gondwe et al.
7
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
8.00
Oct-07 Nov-07 Dec-07 Jan-08 Feb-08 Mar-08 Apr-08 May-08 Jun-08 Jul-08 Aug-08 Sep-08
Month of the Year
Co
eff
icie
nt
of
Pe
rfo
rm
an
ce
COPc
COPh
COP(h+c)
Figure 7: COPs Based on CHW and LGHW
Temperatures (Oct 2007 – Sept. 2008)
From Figs. 6 and 7, the mean COPh is 3.9 whilst that of
COPc is 2.93. Mean CHW flow temperature is 7.36oC
whilst that for LGHW flow temperature is 44.07oC.
5.3.2 Financial Analysis
5.3.2.1 Financial Cost Savings
Based on energy consumption data obtained from UCC
Buildings and Estates and both past and projected prices,
model results obtained were:
Actual Cost Savings: The model showed that there have
been cost savings of !28,808.22 in 2005, !48,258.47 in
2006, !56,911.21 in 2007 and !71,402.96 for 2008. This
gives a total saving of !205,380.85 for the four years of
operation. These are shown in Fig. 8. The figure shows
actual savings and its resulting cumulative value for that
year. The graph can be updated in the model for future
years.
Figure 8: Life Cycle Cost Analysis (LCCA)
Using the projected natural gas and electricity prices, a
modelled Life Cycle Cost Analysis was carried out to
determine the cost savings and the break even point. The
results from the model were:
Break - even Point: Break even point is the point at which
the balance on capital cost becomes zero. LCCA modeling
resulted in a break even point of 3.57 years after
installation. This is presented in Fig. 9:
Figure 9: Break – even Point with LCCA
5.3.2.2 Project Payback Period
The model also evaluates the systems payback period based
on the designer’s method – simple payback method. It
further computes the payback period with actual savings
(uneven cost savings). The results of the modelling are:
Simple Payback Method: Model results were, 14.6 year for
Arup design case, 11.1 years for the Browne assessment
and 6.1 years based on actual energy consumption and
prices for the first year of operation (2005).
Fig. 10 shows all three lines of constant savings. Where
they intersect the line of capital cost is the payback for each
of them.
Figure 10: Simple Payback with Even Cost Savings
Payback Period with Uneven Cost Savings
Payback period with uneven cost savings was found to be
3.57 years. This is shown graphically in Fig.11.
Comparison between Simple Payback Method and Payback
with Uneven Cost Savings
Comparing the two approaches in determining the payback
period it was found that the payback period dropped from
14.6 years to 3.57 years (11 years) when comparing the
uneven approach with the simple payback approach –
Arup’s design case. On the other hand, there was a drop
from 6.1years to 3.57 years (2.5 years) when compared with
the 2005 expected case. This comparison is shown in Fig.
12.
Gondwe et al.
8
Figure 11: Payback Period with Uneven Cost Savings
Figure 12: Comparison between Simple Payback
Method and Payback with Uneven Cost Saving
5.3.3 Environmental Analysis
Modelling of environmental impacts was undertaken to
determine the actual CO2 savings and the environmental
payback.
5.3.3.1 Emission Savings
The emission savings were calculated using both the TEWI
and the yearly emission savings projections.
Yearly Calculations: Yearly calculations were used to
determine the actual emission savings and the
environmental life cycle analysis.
The model results on computing the emission savings were,
92.59 tCO2 in 2005, 149.26 tCO2 for 2006, 141.01 tCO2 for
2007 and 139.66 tCO2 for 2008. This gives a cumulative
saving of 522.51 tCO2 for the four operational years. These
are illustrated in Fig. 13, whilst environmental life cycle
analysis results are shown in Table 5.
Applying the TEWI approach, emission savings for the four
years of operation were found to be 824.7 tCO2 and for 25
years mechanical life were 4,947.8 tCO2.
Environmental Payback Time
Results for environmental payback time also referred to as
CO2 payback time (CPT) are shown in Fig. 14.)
Figure 13: Actual emission savings for the four
operational years
Table 5. Environmental Life Cycle Analysis.
Value at: Cumulative Savings
(tCO2)
Balance on the
Emissions during
construction
(tCO2)
4 years operational
period
523
- 2,037
End of Design Life
(20yrs)
2,642
+ 82
End of Mechanical Life
(25yrs)
3,304
+ 744
Total Equivalent Warming Impact (TEWI) Approach
Figure 14: CO2 Payback Time
Gondwe et al.
9
The CO2 payback times were found to be 10.4 years for the
Arup design case, 15 years for the expected case (based on
2005 data) and 11.9 years for the actual line with uneven
CO2 savings.
6. DISCUSSION
6.1 Technical Performance
Due to unavailability of data for the flow rates and the VSD
frequencies, an interpolation method was employed.
According to York International, interpolation is done in
two stages. The first is to determine the COP’s for the
actual evaporator leaving temperature for the standard
CHW flow temperature, whilst the second is used to
determine the COP’s for the actual CHW flow temperature
at the actual evaporator leaving temperature.
The results obtained are not much different from the design
assumptions for COPs of 3 for cooling, 4 for heating and 7
for heating and cooling.
The small internal close control gallery AUH (3) and
basement archival store AHU (1) successfully achieve low
room temperatures of 19°C at 50% RH. The main wrap
around galleries on 2nd and 4th floors can and do provide
dehuimidifcation in the summer without the need for fossil
fuel fired reheating. The large gallery exhibition spaces are
able to achieve straight-line control during the shoulder and
summer seasons when active humidification is not required.
6.2 Financial Performance
It is noted from the results the simple payback period
dropped by 8 years from 14.6 years for the design case to
6.1 years for the actual case (based on 2005 data). A 5 year
drop is also noted when compared to the Browne (2005)
case, which gave a payback period of 11.1 years. This has
been principally due to the rise in natural gas prices from
2002 to 2005. For simplicity of comparison Browne (2005)
used 2002 prices instead of 2005 prices.
In Fig.12, a comparison between payback with uneven cost
savings and that from simple payback is made. Payback
with uneven cost savings is found to be 3.57 years. This has
been mainly due to the rise in natural gas prices from 2005
to 2008.
In Fig. 8 and Table 4, it is noted that savings to date are
!205,380.85 and will reach as high as !2,886,724.07 by the
end of the heat pumps mechanical life. The huge projection
in cost savings is due to the fact that natural gas is projected
to rise by up to 52.4% from !0.033/kWh in 2005 to
!0.063/kWh in 2029.
6.3 Environmental Performance
In Fig.13, the actual CO2 savings are shown to be
considerably lower than the design prediction of 256t
CO2/year. This is also depicted in Fig. 14 where the CO2
payback time has increased from 10 years for the design
case to 19.38 years for the actual case with uneven emission
savings.
This has been contributed by two main factors; firstly the
designer assumed that electricity would be sourced from the
on-campus CHP only, at an efficiency of 89%, against the
actual situation where supply comes from both the grid and
the CHP, with the CHP’s actual electrical efficiency
reaching only 39.9%. Secondly the improved fuel mix in
the Irish electricity generation increased the ratio of
emissions of the CHP compared to those for the grid.
Table 5 shows that the emission savings as at present are at
522.5 tCO2 and are expected to rise to 3,304.5 tCO2 by the
end of the heat pumps mechanical life. This will lead to a
net emission saving of 744 tCO2.
Emission savings using TEWI are higher than those
obtained by the yearly approach because it assumes average
consumption applies to all years and uses average grid
efficiency and emission factors.
CONCLUSION
The highly sophisticated GHP heating and cooling system
installed in the Lewis Glucksman Art Gallery provides
precise and constant year round temperature and relative
humidity to critical close control areas for the preservation
and safe keeping of its art collections.
A performance analysis has shown that a well designed,
correctly installed geothermal system can generate
significant savings in heating and cooling costs for
buildings. The ongoing monitoring and use of the BMS for
data collection is critical to fine-tuning and optimization of
the GHP systems.The energy consumption over the 4 years
of operation of the GHP system of the Glucksman Gallery
to September 2008, is remarkably close to the design
estimates used for the original life cycle cost and sensitivity
analysis undertaken in 2001.
Although the Glucksman is only a medium sized building
with modest heating and cooling loads (190 kW and 130
kW respectively), the !200,000 savings generated in only 4
years of operation are quite spectacular. Much of these
savings have resulted from steep rises in natural gas and
electricity prices in Ireland over the period 2004-2008, due
to global political instability and market volatility, and
future projections of oil and gas prices envisage much more
subdued markets. However, the projected rise in gas and
electricity prices over the next 20 years is quite
conservative, and should political events lead to future
instability in world energy markets over this period, the
projected savings of nearly !3 million by the Glucksman
geothermal system over the lifetime of the installation may
be significantly enhanced.
REFERENCES
Allen, A.R., Milenic, D., (2003) Low enthalpy geothermal
heat resources from groundwater in glaciofluvial
gravels of buried valleys. Applied Energy, 74, 9-19
Browne, D. (2005) Lewis Glucksman Art Gallery. Final
year project thesis, Cork Institute of Technology, April
2005. (Unpublished)
Burgess, J. (2005) Advanced Heating and Cooling Solution
for Large Buildings, Ground Energy Thermal Transfer
System at UCC Lewis Glucksman Art Gallery. Arup,
CIBSE
Burgess J (2007) State of the Art – Inside the ECO Gallery.
Construct Ireland, 2007.
http://www.constructireland.ie/articles/0207gallery.ph
p.
Gondwe, K.T. (2008) Performance Assessment of the
Glucksman Art Gallery Geothermal Heating and
Cooling System. MSc Thesis, University College
Cork, Ireland, 77pp (Unpublished)
Gondwe et al.
10
Huston, A. (2003) “03032 UCC Art Gallery & Restaurant
MCC01 - Control Strategy Narrative .Doc”, Standard
Control Systems, Dublin, November 2003.
Kennett, S. (2005) “Tall Story”. Building Services Journal,
08/05, August 2005
O` Regan K (2007) UCC Heat Pump Case Study - The
Lewis Glucksman Gallery., SEI Awards 2005 -
Overall Winner - Category C – Thermal Energy
Project. SEI Alternative Heat Roadshow
York Polaris (1999) York Polaris Water Cooled and
Remote Air Cooled Chillers. Doc. No.
PC0001/04.99/9B
Proceedings World Geothermal Congress 2010
Bali, Indonesia, 25-29 April 2010
1
Investigation of Source and Conduit for Warm Geothermal Waters,
North Cork, Republic of Ireland.
Brecan Mooney1,2
, Alistair Allen1, Paul K!niger
3
1Dept of Geology, University College Cork, Cork, Ireland
2WYG Environmental and Planning (Ireland) Limited, Unit 2, University Technology Centre, Curraheen Rd., Cork, Ireland
3Geochronology and Isotope Hydrology, Leibniz Institute for Applied Geophysics, Geozentrum Hannover, Stilleweg 2, 30655
Hannover, Germany
E-mail: [email protected]; [email protected]; [email protected]
Keywords: Source aquifer, fault conduit, Caledonian
lineament, Variscan orogeny, well temperature survey,
hydrochemical analysis, geophysical survey
Brecan Mooney was tragically drowned on Thursday 19
November, 2009, soon after this paper was finalized. He
was only 31 years old, a professional hydrogeologist with
an enormous zest for life. He was conducting this
investigation in his spare time for an MSc degree in the
Department of Geology, UCC.
ABSTRACT
Far from plate boundaries, with no recent volcanism or
tectonism, and with geothermal gradients of <25°C/km,
Ireland has few geothermal resources apart from 42 warm
springs ranging in temperature from 13-24.7°C. These are
concentrated in two groups, in the south-west and east
central parts of the country. Recently groundwater at 26°C
was encountered at a depth of 40m during routine well
drilling operations near the town of Mitchelstown in the
south-west, the warmest groundwater encountered to date in
the shallow Irish subsurface. It is interpreted to have
migrated upwards from greater depth via a steep fault
structure. A research project is in progress with the aim of
identifying the source aquifer and fault conduit, controlling
upwards movement of the warm water, and also to assess the
potential of the warm water for district heating purposes.
A major NE–SW lineament, identified on landsat images, of
probable Caledonian (425-395 Ma) age, possibly
subsequently reactivated during the Variscan Orogeny (295-
315 Ma), passes close to the Mitchelstown well. It extends
30 km SW to the town of Mallow, where a 22°C warm
spring, which formed the basis for a spa resort in the 19th
century, is today being utilised with a heat pump to heat the
municipal swimming pool. Geophysical surveys are being
conducted to accurately delineate this structure on the
ground.
A temperature survey of all water wells and springs in the
Mallow-Mitchelstown area and further to the NE has been
conducted. Although average groundwater temperatures in
Ireland are of the order of 9-11.5°C, a number of the wells
surveyed record anomalous temperatures in excess of 12°C,
interpreted to represent mixing of warm deep groundwater
with cooler near surface groundwater. To test this
hypothesis, a programme of hydrochemical analyses has
been undertaken for normal and trace components and the
stable isotopes 18O/16O and 2D/1H. Lower nitrate and
chloride/bromide ratios and possibly higher lithium in the
anomalous wells appears to differentiate the warmer water
from depth from cooler near surface water with which it has
mixed. This it is hoped will also fingerprint the source of the
warm waters. The ultimate objective is to locate the fault
conduit sufficiently accurately to make it possible to drill to
intersect the fault at moderate depth in order to tap the
migrating warm water where it can be utilized, and to this
end it is hoped to develop a methodology which can be
applied in other similar situations.
1. INTRODUCTION
Ireland is located far from any plate boundaries, and has not
been subject to volcanism or tectonism in the recent past, so
geothermal gradients are low (<25°C/km) (SEI, 2004), and
in the south of the country, geothermal gradients are as little
as 10°C/km (Goodman et al., 2004). Thus Ireland is unlikely
to have any high temperature geothermal resources. Typical
groundwater temperatures in Ireland vary from
approximately 9 -11.5°C (Aldwell & Burdon, 1986), whilst
soil temperatures are usually around 10°C. These
temperatures represent the balance between solar and
geothermal recharge, and radiation from the ground surface,
quantified by Aldwell & Burdon (1986), and remain
relatively constant throughout the year due to Ireland’s
temperate maritime climate. Heat can be extracted from soil
and groundwater at these, seemingly low but consistent,
temperatures for a plethora of uses, utilizing modern heat
pump technology.
Springs, seepages and spring wells are ubiquitous in Ireland,
particularly in the Dinantian limestone bedrock underlying
much of the Midlands of Ireland. Exploitable geothermal
resources occur in unusual geological settings where
groundwater that is warmer than normal (>12oC) rises up
through limestone catchments (Aldwell, 1986), discharging
at the surface as low enthalpy geothermal springs. 42 of
these warm springs, mainly located in Dinantian Limestone,
and ranging in temperature from 13-24.7°C have been
recorded (Aldwell et al. 1980; Burdon, 1983; Aldwell and
Burdon 1986; Goodman et al, 2004), and are concentrated in
two groups in the E and SW of the country. The earliest
recorded warm spring in Ireland occurs at Mallow in the SW
where the spring at Lady’s Well gave rise, in the 18th and
19th Centuries, to a spa resort. Apart from this spring, which
has subsequently been harnessed to heat the municipal
swimming pool (O’Brien, 1987), little utilisation of these
warm water energy resources has taken place, mainly
because of the rural settings where most occur that in the
past has limited potential options for their exploitation.
The Mallow spring has an average temperature of 19.5°C ±
2.5°C, with higher temperatures recorded in summer and
lower temperatures recorded in winter, thought to reflect
greater dilution of the warm water with colder water runoff
during periods of higher rainfall.
The origin of these warm water resources is uncertain, but it
is generally assumed that they represent deep groundwater
Mooney et al.
2
sources brought rapidly to the surface from considerable
depth by faults (e.g. Aldwell and Burdon, 1986; Murphy &
Brück, 1989). Such deep circulation would be facilitated by
bedrock permeability related to deep faulting. The specific
factors causing deep circulation are summarised by Aldwell
& Burdon, (1986) as:
• structural aspects favoring vertical over horizontal
flow;
• topography leading to higher head pressures;
• increased precipitation and thus enhanced recharge;
• high infiltration; and
• karstification, particularly palaeokarst, essential for
facilitation of deep circulation in Irish carbonate
rocks.
Geothermal waters heated at depth in confined aquifers may
reach the surface if the source aquifer is penetrated by a
permeable fault zone, and if the water is under sufficiently
high piezometric pressures to generate artesian conditions.
The 42 warm springs in Ireland represent situations where
both these conditions are met, but situations where
piezometric pressures are subartesian, or where an
impermeable obstacle prevents the geothermal water from
reaching the surface, may be more widespread.
Two methods of investigating the existence of such
resources, is by deep drilling programmes to the postulated
source aquifer in favourable sites, which is generally
extremely costly, or by identifying a fault structure, up
which warm water has migrated, and drilling to intersect the
fault at moderate depth in order to extract the warm water
within it. Once a fault is identified and its location,
orientation and extent delineated accurately, it may be
tapped at a number of points. This represents a much less
expensive option, and is the objective of the present
investigation.
Sometimes geothermal waters are encountered unexpectedly
at shallow levels during routine drilling operations, and
represent situations where either insufficient piezometric
pressures prevail, or some obstacle prevents the geothermal
waters from flowing to the surface. However, the heated
water has almost certainly reached shallow levels by
migration up a fault intersecting the source aquifer.
Regardless of whether the geothermal water penetrates to the
surface, or what prevents it from reaching the surface, such
heated water is an exploitable geothermal resource and
should be further investigated to determine if additional
heated groundwater resources exist at shallow levels where
they can be readily tapped and utilised.
Recently, a well drilled for water supply purposes by Cork
County Council at Johnstown in the Glanworth area of
North Cork in SW Ireland, encountered moderate quantities
of warm groundwater at temperatures of 23-26°C at a depth
of 40m, the warmest shallow groundwater as yet recorded in
the Republic of Ireland. In this investigation, we attempt to
establish the source aquifer and the conduit controlling
migration of this warm water towards the surface, with the
intention of assessing the extent of the resource, and the
potential for exploiting it. In addition, we wish to develop a
methodology of investigation, which can be universally
applied in other similar situations.
2. RATIONALE AND METHODOLOGY
This project is being undertaken in light of concerns over the
use of fossil fuels as a means of energy supply, and the need
to develop alternative clean safe inexpensive secure and
renewable sources of energy. The Kyoto protocol commits
Ireland to reduce CO2 emissions to 115% of the levels in
1990 by 2012. At the present time Ireland is falling short of
this target and fines will be imposed unless a concerted
effort is made to reduce CO2 emissions. The study has
identified significant hydro-geothermal resources in the
North Cork area that may be exploited, resulting in
considerable benefits for the region.
A temperature survey of groundwater wells was carried out
in and around the Mallow and Mitchelstown area. This
served a twofold purpose:
• firstly as an initial screening process it would
identify any more geothermal anomalies existing in
the area enabling any patterns that may exist to be
studied with the purpose of providing explanations
for these anomalies;
• secondly, the well survey data quantifies ambient
groundwater temperatures in the region which
together with known aquifer productivity maps from
the Geological Survey of Ireland (GSI) give an
approximation of the geothermal resource in the
North Cork area.
Following the well survey a 2-D resistivity study was
undertaken to further characterize the bedrock aquifers in
which anomalies were observed. The hypothesis is that
geological structures present in the subsurface provide a
conduit bringing warm water to the surface from depth in
these areas exhibiting higher than average groundwater
temperatures. As permeability in the Palaeozoic sediments
of the Munster Basin is almost always fracture related, 2-D
resistivity was a relatively inexpensive way to augment the
literature search and provide some structural context in two
anomalous areas that were lacking in outcrop.
A hydrochemical analytical program was subsequently
undertaken in order to further pinpoint a possible source for
the thermal waters and these results are also discussed.
3. REGIONAL GEOLOGY AND HYDROGEOLOGY
Ireland generally consists of a mountainous rim composed of
Precambrian to Lower Palaeozoic crystalline rocks
surrounding a lowland interior largely underlain by U.
Devonian to L. Carboniferous sandstone, shale and
limestone (Fig. 1).
Late Palaeozoic, Mesozoic and Tertiary rocks are absent,
apart from in the NE corner of the island, where they are
preserved beneath the basalt plateau of the 50-60Ma Tertiary
North Atlantic Igneous Province associated with the opening
of the North Atlantic. However, there is evidence that they
were also deposited over much of the rest of the island, but
were stripped away by the intense erosion and peneplanation
that accompanied the opening of the North Atlantic.
U. Palaeozoic bedrock, whilst underlying much of the
interior of Ireland, is generally buried beneath a cover of
Pleistocene glacial till and Holocene peat deposits, and is
rarely exposed. L Carboniferous limestone, which dominates
the U. Palaeozoic, is extensively karstified, but overburden
deposits are relatively thick and surface expression of karst
is generally absent. Thus, most of Ireland’s limestone
bedrock consists of buried karst.
Mooney et al.
3
Ireland lies within the Caledonian orogenic belt, which
affected all Precambrian and L. Palaeozoic units.
The Iapetus Suture, marking the collision zone of
Laurentia and Avalonia, runs diagonally across
Ireland from the Shannon estuary to Clogher Head,
50 km to the north of Dublin. All of the warm
springs in the Irish Republic lie to the south of this
tectonic line.
Figure 1: Relief Map of Ireland showing NE-SW
trending morphology in south-central Ireland.
(NASA)
The late Carboniferous Variscan (Hercynian) Orogeny
affected the very south-west of Ireland, which represents the
westernmost extension of the external Rheno-Hercynian
Zone of the Variscan Orogenic Belt. Its northern boundary,
the Variscan Front, is the Killarney-Mallow Fault Zone
(KMFZ), which runs E-W, midway between the south coast
of Ireland and the Shannon estuary. The southwestern group
of warm springs are all situated just to the north of this
tectonic boundary.
Tectonism with accompanying fault activity in the SW of
Ireland can be summarized as:
• Caledonian orogenesis (c. 425–395Ma) associated
with oblique sinistral closure of the Iapetus Ocean
manifested by NE-SW strike–slip faulting in a
transpressional regime (Phillips, 2001), and low
grade metamorphism leading to complete
recrystallisation of L. Palaeozoic and older rocks and
complete loss of primary porosity.
• Extensional development of the Munster Basin of
SW Ireland (c. 395-350Ma), related to evolution of a
stretched passive continental margin, and resulting in
repeated reactivation of the pre-existing NE-SW
Caledonian strike-slip faults as basin bounding
normal faults. This was accompanied by progressive
subsidence, with deposition of thick accumulations
of high porosity U. Devonian Old Red Sandstone
terrestrial clastics, and subsequent marine
transgression and deposition of low porosity L
Carboniferous marine clastic and biogenic sediments.
• Variscan orogenesis (c. 350-320Ma) associated with
N-S collision of Laurussia and Gondwana, and the
formation of a very low grade fold-thrust belt in SW
Ireland. The E-W Killarney–Mallow Fault has been
postulated to represent the sole thrust (e.g. Landes et
al. 2002), and is marked by a sharp discontinuity in
deformation intensity (Gill, 1962), with almost
complete loss of primary porosity of the U.
Palaeozoic rocks to the south of this structure, but
very weak deformation and possibly very little
reduction in primary porosity to the north. NE-SW
Caledonian faults are thought to have been further
reactivated, some as thrusts and others possibly as
strike-slip faults.
Geothermal gradients in the island of Ireland although
overall relatively low, generally increase towards the NE,
where a maximum of 35°C/km has been found in County
Antrim (Goodman et al, 2004), due to enhancement of
geothermal gradients by the Tertiary igneous activity. Low
yields of relatively hot water at 88°C were encountered in
the early 1980’s in a borehole to 2.8 km depth at Larne to
the NE of Belfast, within the Permo-Triassic Sherwood
Sandstone, an aquifer widespread in Britain, but only present
in Ireland in the extreme NE preserved beneath the Tertiary
Basalt plateau. In the Irish Republic, conditions for
generation of hot water at depth are not favourable, but the
presence of 42 warm springs, indicates that aquifers do
occur at depth, and that moderate geothermal resources,
which could be exploitable, do exist.
4. IDENTIFICATION OF THE FAULT CONDUIT
The first task was to identify the fault conduit which has
controlled the upwards migration of the geothermal waters.
The borehole with the warm water at Johnstown near
Mitchelstown in North Cork is located approximately 20 km
to the northeast of the Lady’s Well spring at Mallow and
other historically mentioned, but lesser known warm springs
in the Mallow area. There is a strong possibility that a
relationship may exist between the two geothermal
occurrences, which may have a similar source aquifer and a
similar migratory path from depth. This would suggest that
their upwards migration may have been controlled by a steep
NE-SW Caledonian trending structure. However, the
Mallow-Mitchelstown area is relatively flat with virtually no
outcrop, and the geological map of this area (Fig.2) shows
no evidence of a major NE-SW structure.
Figure 2: Geological map of area of investigation. (After
Geol. Survey of Ireland (GSI) Regional Map)
Mooney et al.
4
A landsat map of the Mallow-Mitchelstown area (Fig. 3)
emphasises the local relief, and clearly illustrates the NE to
SW Caledonian trending physiography of the region. The
region is transected by the E-W flowing Blackwater River,
which exploits the KMFZ, and to the north of this is
dominated by the Galtee Mountains in the north and the
Knockmealdown Mountains in the east. A faint but
conspicuous NE-SW trending lineament can be discerned
emanating from Mallow in the SW and projecting
northeastwards towards Mitchelstown and onwards along
the southern margin of the Galtee Mountains. It appears to
be one of a series of sub-parallel lineaments, which splay
southwestwards from the southern margin of the Galtee
Mountains. These lineaments have been referred to as the
Dingle-Galtee Mountains Fault Zone (DGMFZ) (e.g.
Vermeulen et al., 2000), regarded as the basin-controlling
and bounding structures for the Munster Basin. It is likely
that these structures have been offset by minor N-S strike-
slip faults, which appear to represent late Variscan
compartmental faults associated with thrust tectonics, and it
is possibly truncated by the KMFZ at Mallow. Close
examination of the landsat image indicates that the structure
passes close to the Spa Glen in Mallow and the vicinity of
the Johnstown well near Mitchelstown.
Figure 3: 1:40,000m Relief Map of investigation area
with possible fault conduit lineages
To the northeast of Mitchelstown, a major steep southwards-
dipping NE-SW reverse fault defines the southern margin of
the Galtee Mountains inlier, and brings a sequence of steep
southerly dipping U. Devonian sandstones and
conglomerates in the footwall into juxtaposition with
synclinally folded L Carboniferous limestones and shales.
Any of these U. Devonian formations could be a candidate
for the source aquifer.
In the southwest of the study area at Mallow, a number of
parallel southerly-dipping E-W faults mark the KMFZ again
with southerly-dipping units on their footwalls. However,
most of these are siltstone/shale or limestone units, none of
which would appear to be likely candidates for a source
aquifer. L. Carboniferous limestones, although widely
karstified in the Irish midlands are unlikely to represent the
source aquifers, as karstification appears to have mainly
taken place during the Tertiary, subsequent to any tectonism
in Ireland, and since karstification is a relatively superficial
process, it is doubtful whether deeply buried limestones
would have sustained karstification.
The minor N-S strike-slip faults offset northeasterly striking
geological units in the Mallow-Mitchelstown area and
beyond along the southern margin of the Galtee Mountains.
The Lady’s Well spring at Mallow is situated in an
entrenched narrow N-S valley, the Spa Glen, which exploits
one of these latter faults, and many of the anomalous wells
may also be located on such minor cross faults. These faults
are however not interpreted to represent the fundamental
fault which has controlled migration of the warm
groundwater from depth, but may have provided final
pathways for circulation of the warm groundwaters at
shallow crustal levels.
5. GROUNDWATER TEMPERATURE SURVEY
In order to test the validity of the interpretation of the NE-
SW fault conduit for the geothermal waters at Mallow and
Mitchelstown, a temperature survey of groundwater wells in
the Mallow-Mitchelstown area was conducted.
Shallow groundwater (<100m depth) in the southern part of
Ireland typically records an annual average temperature
range of 10.48-11.08oC (Aldwell & Burdon, 1986) due to a
balance of surface recharge, incident solar radiation and
outgoing radiation from the Earths surface as mentioned
earlier. Care is required in measuring groundwater
temperatures in boreholes that do not have natural flow:
temperatures representative of the groundwater aquifer
“tapped” by the borehole must first be attained by slow
purging of at least three well volumes of water from the
borehole before measurement of the temperature of the
boreholes should be attempted. Heat generated due to
pumping also affects temperature, so it is preferable to hand
purge wells with bailers and to turn off pumps in pumping
wells for a minimum of 24 hours prior to measuring the
temperature. Purging was not considered necessary in wells
that were known to be in constant use and these wells were
monitored following periods when the pump was not in use.
Purging was also not required in flowing springs and one
artesian well that had a constant flow.
In this study, groundwater temperatures were measured
directly in the borehole using a down borehole probe. The
survey was carried out in accordance with the sampling
protocol of British Standard Code of Practice for Site
Investigations (BS 5930: 1999).
The temperature survey has quantified the spatial
distribution of groundwater temperatures in the area between
Mallow, Co. Cork and Cahir, Co. Tipperary, 20 km to the
NE of Mitchelstown and has compared these temperatures to
normal observed groundwater temperatures within Ireland.
For the purposes of this study a conservative “normal”
temperature range of 10-12°C is assumed. The survey
indicates that a correlation may exist between the presence
of crustal faults and elevated groundwater temperatures.
Monitoring points were identified from the Geological
Survey of Ireland (GSI) groundwater well database, Cork
County Council records, ordnance survey maps which were
particularly useful for identifying springs, and interviews
with local hydrogeological consultants, drilling contractors,
and with local inhabitants. A total of seventy wells were
monitored between July 2006 and July 2008. Stagnant water
was purged from the wells prior to measurements being
taken and a sonde was employed that allowed temperature
and conductivity readings to be measured simultaneously.
Well locations and recorded temperatures are listed in Table
1 and on topographic and geological maps of the Mallow-
Cahir area (Figs. 4 & 5). Of the 70 well temperatures
recorded in the survey, 67 readings are considered accurate
representations of the groundwater aquifer. Suspected
surface water intrusion could not be ruled out in 3 of the
wells (Nos. 30, 62 and 63) and therefore these elevated
temperatures have not been included in the geothermal
maps.
Mooney et al.
5
Table 1. Well Temperature Survey Data.
!"##$%& '()*#+*, &+-" .+/-0*1 2(3-40*1 'ºC 5(66"*-/
1 Leaselands 01/08/2006 555 993 12.9 Well depth 100m (Hydrogeological report available)
2 Leaselands 01/08/2006 555 993 13.1 Well depth 100m (Hydrogeological report available)
3 Kilknockan, Mallow 20/05/2006 547 996 10.9 Farm supply well
4 Annabella, Mallow 20/05/2006 544 987 10.71 Well depth 100m (Hydrogeological report available)
5 Annabella, Mallow 20/05/2006 544 987 10.62 Well depth 100m (Hydrogeological report available)
6 Annabella, Mallow 20/05/2006 544 987 10.24 Well depth 100m (Hydrogeological report available)
7 Johnstown, Mitchelstown 23/05/2006 774 111 25.9 County Council Supply Well
8 Gooldshill, Mallow 27/05/2006 552 965 11.5 Disused farm production well
9 Ballydeloughy, Kildorrery 04/07/2006 745 097 10.55
10 Ballydeloughy, Kildorrery 04/07/2006 745 097 10.79
11 Ballydeloughy, Kildorrery 04/07/2006 745 097 10.95
12 Killdorrery 15/01/2006 685 100 10.9 Hydrogeological report available
13 Ballyvoddy, Kildorrery 04/07/2006 706 076 12.54 Yield Approx. 300 Ga/Hr
14 Ballyvoddy, Kildorrery 04/07/2006 706 076 10.42 (35m West of CF1)
15 Ballendangan 04/07/2006 754 091 11.22 EPA IPC monitoring well 1,000-1,200 Ga/Hr
16 Ballendangan 04/07/2006 754 091 10.92 EPA IPC monitoring well 1,000-1,200 Ga/Hr
17 Ballendangan 04/07/2006 754 091 10.85 EPA IPC monitoring well 1,000-1,200 Ga/Hr
18 Ballykenly 05/07/2006 762 075 10.46
19 Broomhill 05/07/2006 783 118 11.21
20 Carriganleigh 06/07/2006 792 121 10.57 500-600 Ga/Hr
21 Ballyenahan 06/07/2006 723 090 10.71 Total Depth of well 55 ft.
22 Derryvillane 06/07/2006 736 074 11.03 Total Depth of well 225 ft.
23 Derryvillane 06/07/2006 739 071 11.07 Total Depth of well 50m approx.
24 Gortnagreiga 07/07/2006 562 951 11.22
25 Carrigaduff 07/07/2006 570 949 10.41
26 Clogheen, 07/07/2006 573 932 11.1 Well Depth 120ft.
27 Ballinvussig Waet 07/07/2006 581 946 10.73
28 Ballynamona Br. 07/07/2006 564 930 10.63 110 Ft. Well ORS
29 Monavooria 08/07/2006 603 985 11.49
30 Ballymacmoy, Killavullen 08/07/2006 986 636 13.02 Dug Well, probable surface water source.
31 Ahaunboy, Killavullen 08/07/2006 633 998 11.05 400ft. Well.
32 Mallow 08/07/2006 564 986 20.01
33 Ballygarrane Cross Roads 09/07/2006 644 025 11.79
34 Ballyveelick 09/07/2006 643 025 10.8 Static water level 23m
35 Ballygrilihane 09/07/2006 684 031 12.53 Probable surface water source.
36 Carrigpark 23/09/2006 60957 01497 11.08 Well depth 160ft. Drilled 5 - 6 weeks previously.
37 Carrig Demesne 23/09/2006 61377 00499 12.29 Old well, not in use. Donal Turner
38 Kilcanway 23/09/2006 62546 00239 11.57 Spring.
39 Keatley's Close 24/09/2006 57891 99210 10.68 Domestic supply well.
40 Spring 24/09/2006 65003 00077 11.9 Spring.
41 Powerstown 24/09/2006 62880 04203 11.02 Domestic suply well.
42 Newberry 14/01/2007 51661 97086 12.9 7.37 pH Artesian well drilled into Limestone
43 Newberry 14/01/2007 51634 97064 12.11 Well drilled into sandstone.
44 Newberry 14/01/2006 51591 47031 12.12 7.35 pH, Natural spring in sandstone.
45 Mallow 14/06/2008 54962 01879 11.49 Domestic supply well. SWl 4.78m
46 Mallow 14/06/2008 55981 02029 11.17 Domestic supply well. SWL 2.15m Well depth 19.3m.
47 14/06/2008 56172 02367 10.84 Domestic supply well. SWL 5.9m. Well depth 35m.
48 14/06/2008 56088 04092 10.69 Domestic supply well. SWL 5.9m. Well depth 35m.
49 Ballybrack 14/06/2008 58548 03829 10.67 Domestic/farm supply well. SWL 2.3m.Well depth 40m.
50 14/06/2008 58250 02852 11.84 SWL 1.95m. Total depth 43.68m.
51 14/06/2008 58837 02209 11.68
52 14/06/2008 57179 01312 11.26 SWL 6.50m BGL Total depth 30.48m.
53 Dromdeer, Doneraile 14/06/2008 63006 05431 10.74 SWL 6.2m BGL. Coal seams reported historically
54 14/06/2008 62512 05440 10.87 SWL 3.8m Total depth 27m.
55 14/06/2008 62270 06798 11.04 SWL 7.85m BGL
56 Doneraile 14/06/2008 63657 07384 11.54 Domestic supply well
57 Cregg 02/06/2008 R 000 770 10.82 SWL 11.00m. Domestic well
58 Cornhill, Fermoy 02/06/2008 R 022 778 11.45 Farm supply well
59 Ballyhooley South 02/06/2008 W 997 736 11.6 Domestic well
60 Kilbehenny PWS 28/07/2008 R 865 157 11.72 Spring (Farm Supply)
61 Coolagarranroe 28/07/2008 R 902 174 11.16 Domestic
62 Ballyhuroo 28/07/2008 R 961 198 18 Pond - Mainly surface water influence
63 Kilcaran GWSS 29/07/2008 R 986 217 13.56 Domestic group water scheme, surface water ingress
64 Scartnaglorane 29/07/2008 R 998 219 10.44 Farm and domestic supply well
65 Benguragh 29/07/2008 S 044 257 11.15 Farm well
66 Holy Well 29/07/2008 S 042 258 11.16 Domestic well (Dug stone lined well)
67 Benguragh 29/07/2008 S 042 256 11.39 Holy Well - Spring
68 Tarrent Concrete 30/07/2008 S 054 264 11.01 Tarrant concrete production well
69 Rossadrehid 30/07/2008 S 054 274 11.92 Domestic well
70 Rockwell College 30/07/2008 S 071 343 10.94 Rockwell College Supply well
Mooney et al.
6
Figure 4: Well Temperature Survey Data Plotted on Ordnance Survey of Ireland Regional Map
Figure 5: Location and Temperature of Wells Plotted on the GSI Regional Bedrock Geology Map
Mooney et al.
7
Of the remaining 67 wells, 57 (85%) had temperatures that
fell within the conservative “normal” range. Temperatures of
10-10.5ºC were recorded by 4 wells (Nos. 14, 18, 25 and
64); 21 wells (No.’s 3, 4, 5, 6, 9, 10, 11, 12, 16, 17, 20, 21,
27, 28, 34, 39, 47, 48, 49, 53 and 70) recorded temperatures
of 10.5-11ºC; 24 wells (No.’s 15, 19, 22, 23, 24, 26, 29, 31,
36, 41, 45, 46, 50, 52, 54, 55, 57, 58, 59, 61, 65, 66, 67 and
68) gave temperatures of 11-11.5ºC and 8 wells (No.’s 8, 33,
38, 40, 51, 56, 60 and 69) gave temperatures of 11.5-12ºC.
None of the wells surveyed recorded temperatures below the
normal range for groundwater in Ireland.
The remaining 10 wells (15%) recorded temperatures that
exceed the normal range for Irish groundwater of 10-12ºC.
Temperatures of 12-12.5ºC were recorded by 3 of the wells
(No.’s 37, 43 and 44). Four of the wells (No.’s 1, 13, 35 and
42) recorded temperatures of 12.5-13ºC; One well (No. 2)
gave a temperature of 13.1 ºC. Two wells (No. 7 and No.
32, Spa House Mallow and the Johnstown County Council
Well) recorded temperatures in excess of 20ºC.
The topographic map (Fig. 4) shows that the wells with the
anomalous temperatures are strung out in a NE-SW linear
trend and are spatially related to a line projecting from
Mallow to Mitchelstown. This represents the location of the
lineament identified on the landsat map, the postulated
conduit controlling upwards migration of the geothermal
waters.
Given a geothermal gradient of around 10oC/km for this part
of Ireland (Goodman et al, 2004), the observed maximum
temperatures of 22°C at Mallow and 26oC at Johnstown,
would reflect groundwater from depths of ca. 1,100m and
ca. 1,500m respectively, assuming normal surface
temperatures of 11°C for this region. Should dilution be a
significant factor, the warm groundwater may have
circulated from greater depth.
Of the 70 wells surveyed and listed in Table 1, a significant
proportion (15%) recorded temperatures in excess of 12°C.
The GSI has classified warm springs as springs recording
temperature in excess of 13°C, but this does not necessarily
mean that all springs with temperatures below this level
represent shallow circulating meteoric waters of surface
origin. If the range of shallow groundwater temperatures in
Ireland is less than 11.5°C, then the wells in excess of 12°C
must contain a component of warmer water.
The volume and temperature of warm spring waters reaching
the surface, depends on the porosity and permeability of the
source aquifer and fault conduit, and on the geothermal
gradient. The higher the geothermal gradient, the greater is
the likelihood of encountering high temperature groundwater
resources at shallow depth. However, if the fault conduit
intersects other aquifers at shallower depths, groundwater
from the shallower aquifers will cool the warmer
groundwater as it migrates up the fault, to the extent that it
may be reduced to normal shallow groundwater
temperatures. In much of SW Ireland, karstified deposits of
the Waulsortian Limestone Formation at shallow depth, may
be the source of cooler groundwaters which reduce the
temperature of deep warm groundwaters during their
upwards migration. It is possible that all of the warm water
springs in SW Ireland may be sourced from a single deep
aquifer, but that the circulating warm groundwaters have
been differentially affected by cooler waters during their
upwards migration, accounting for the range in temperatures
of these springs. Indeed many well waters with temperatures
in the ‘normal’ range of groundwater may have a component
of warm groundwater that has been so diluted by cooler
waters at shallow levels that the temperatures have been
lowered to below 12°C.
Figs. 6 and 7 illustrate the location and temperature of wells
on the GSI regional aquifer classification and aquifer
vulnerability maps. The purple areas on Fig. 7 indicate
limited knowledge of the depth to bedrock due to a subsoil
cover usually in excess of three metres. Thick deposits of
Pleistocene glacial overburden, which blankets much of
Ireland, may have buried a NE-SW trending structure in the
underlying bedrock.
Thus the temperature survey of water wells carried out
between Mallow and Mitchelstown indicates anomalous
temperatures along a NE-SW trend suggesting the possible
presence of a buried Caledonian-aged fault. The thick clay–
rich overburden in the Mallow-Mitchelstown area may have
blanketed this structure and acted as a confining layer,
preventing geothermal waters from penetrating to the
surface. Intersection of minor N-S compartmental faults of
Variscan age with this fundamental fault may have aided
some of the geothermal waters to reach the surface as at
Mallow and at Johnstown, and elsewhere may also have
provided pathways for groundwater migration.
6. GEOPHYSICAL INVESTIGATIONS
In areas of poor to non-existent outcrop such as the Mallow-
Mitchelstown area, geophysical techniques are powerful and
essential tools in gaining a reasonable understanding of the
bedrock geology. Geophysical investigations also play an
important role in identifying aquifer systems and outlining
aquifer configurations under varying hydrogeological
conditions. In addition, geophysical surveys can be very
useful in delineating accurately the location of buried faults.
Surface electrical resistivity surveys utilising the vertical
electrical sounding (VES) technique has proved particularly
useful for groundwater studies due to its simplicity and cost-
effectiveness. A well-planned, non-invasive, geoelectrical
investigation is capable of mapping aquifer systems,
confining layers (i.e., clay formations), depth and thickness
of aquifers, and groundwater quality (Jha et al., 2008).
A limited preliminary electrical resistivity survey was
undertaken involving the acquisition of vertical geoelectrical
soundings across two profiles in the study area. The
locations of the profiles took into consideration data
acquired during a literature search and also data from the
well temperature survey. The profiles were thus conducted
in areas where elevated groundwater temperatures had been
identified during the well survey and therefore where there
was the possibility of a buried Variscan-reactivated
Caledonian structure affecting groundwater circulation and
migration.
The two traverses were undertaken adjacent to the
Johnstown borehole and in the Carrig Demesne area on the
outskirts of Mallow adjacent to one of the anomalous wells
and relatively close to the Spa Glen and Lady’s Well. The
geolectrical soundings and the interpreted geophysical
profiles are presented in Fig. 8.
Mooney et al.
8
Figure 6: Location and Temperature of Wells Plotted on GSI Regional Aquifer Classification Map
Figure 7: Location and Temperature of Wells Plotted on GSI Regional Aquifer Vulnerability Map
Mooney et al.
9
Figure 8: Diagrams of the Geoelectrical soundings and the geoelectrical geophysical profile in the area of the well at
Johnstown, Mitchelstown (Well Survey Reference No. 7) (top) and Sean and Liz Turner’s well, Carrig Demesne
(Well Survey Reference No. 37)
The interpretation of electrical resistivity data from the
Johnstown borehole indicates karst permeability in a
fracture/conduit zone dipping approximately 30° south of
the borehole location and for the Carrig Demesne locality,
two sub-horizontal conduit zones running beneath the well.
This interpretation of the geo-electrical data supports the
hypothesis that thermal waters are travelling laterally along
karst structures having circulated to some great depth via
fault related conduit permeability.
A further geophysical project to delineate the precise
location and orientation of the fault conduit is planned for
Autumn 2009. The intention is to conduct a series of NW-
SE traverses at 1-2 km intervals across the postulated line of
the fault utilising a combination of the electrical resistivity
lateral mapping technique and the electromagnetic VLF
method. This it is hoped will confirm the presence of the
fault, and enable any future drilling programme seeking to
tap into and exploit a warm water supply along the line of
the fault to make a more informed selection of borehole
sites.
7. GEOCHEMICAL INVESTIGATIONS
Geochemical investigations were undertaken in order to
fingerprint the warm geothermal waters, with the hope that
distinctive hydrochemical characteristics may be established,
allowing the source aquifer and the circulatory pathway of
the warm waters to the surface to be distinguished. Similar
exercises have been successful in identifying source and
pathways of geothermal waters elsewhere (e.g. Andrews et
al. 1982).
Major Ions
A survey conducted by Burdon (1983), ascertained that in
general the ionic content of Irish warm spring waters is
typical of Irish groundwater as a whole. This could be
interpreted as an indication that most Irish warm springs
Mooney et al.
10
water have mixed with cooler near-surface groundwater
during their ascent to the surface
The chemistry of the Lady’s Well spring at the Mallow Spa
was investigated by University College Cork over the period
September 1981-January 1983 (Brück et al, 1986). The
results of this study indicates that the water is of calcium
bicarbonate type and similar to the local groundwater in the
limestone aquifers. The main differences are slightly lower
calcium, bicarbonate, and nitrate concentrations in water
from Lady's Well. Further geochemical analyses of 10
representative samples of both thermally anomalous and
normal wells and springs were undertaken to augment the
existing knowledge base as part of this study (Table 2).
Temperatures listed in Table 2 were those taken during
sampling, and are lower than those in Table 1, as sampling
took place in winter when rainfall was greater and water
table levels higher.
Earlier observations were confirmed during this study, with
all ten of the samples analysed for major ions recording
calcium bicarbonate type water characteristic of the local
limestone aquifers. Generally the trend was for thermally
anomalous wells to have slightly lower levels of all three of
the ionic parameters of calcium, bicarbonate and nitrate.
Nitrate
In this intensely farmed area, the presence of nitrate in
groundwater reflects an anthropogenic origin and indicates
recent recharge of the shallow groundwater within all of the
wells in the study area. However, concentrations of nitrate
are significantly lower in the thermal wells indicating less
mingling of the thermal waters with more recent shallow
groundwater (Table 3).
The lowest concentration of nitrate was observed in the well
which recorded the highest temperature, the Johnstown well
(Table 1, No. 7), followed by three other thermal wells and
springs: the Sugar Factory spring, the Sugar Factory artesian
well and the Lady’s Well, Mallow (Table 1; Nos. 44, 42 and
32), whilst the next two lowest values also were recorded by
wells which exhibited anomalous thermal values in the
original survey. The remaining four wells, which exhibited
normal groundwater temperatures during the original survey
exhibited significantly higher concentrations of nitrate.
These results suggest that due to its anthropogenic origin
nitrate is a useful indicator of mixing of geothermal water
with shallow cooler recently recharged groundwater, and
that the higher the value of nitrate in the geothermal water
the greater the degree of dilution of the geothermal water by
shallow groundwater.
Table 2. Ionic Composition of Wells.
Well Survey Ref. No. 7 32 42 44 37 21 13 59 33 19 Units
Sampling Date (d.m.2009) 31.01 24.01 24.01 07.02 08.02 07.02 07.02 07.02 31.01 31.01 mg/l
Temperature 23 17.5 12.1 11.2 11.2 11.1 10.9 10.8 10.4 10.35 °C
Sulphate 12.08 18.13 14.11 11.24 14.22 11.19 6.15 10.64 13.31 11.19 mg/l
Chloride 16.5 24.2 19.2 17.7 18.7 42.7 21.3 16.4 25 42.7 mg/l
Flouride <0.3 <0.3 <0.3 <0.3 <0.3 <0.3 <0.3 <0.3 0.7 <0.3 <0.3
Nitrate as No3 4 10.8 12.5 5.5 18 60 19.9 32.9 48.8 60 mg/l
Ortho phosphate as PO4 <0.06 <0.06 <0.06 <0.06 <0.06 <0.06 <0.06 <0.06 <0.06 <0.06 mg/l
Total Alkalinity as CaCo3 164 192 200 180 176 132 236 236 300 132 mg/l
Calcium -dissolved 60 85 80 72 85 59 110 120 129 59 mg/l
Magnesium - Dissolved 14 10 12 10 6 16 8 6 7 16 mg/l
Potassium - dissolved 1 1 1 2 5 1 1 4 2 1 mg/l
Sodium - dissolved 12 15 12 12 11 17 9 10 11 17 mg/l
Iron - dissolved <0.02 <0.02 <0.02 <0.02 <0.02 0.022 <0.02 <0.02 <0.02 <0.02 mg/l
Manganese - dissolved <0.002 <0.002 <0.002 <0.002 <0.002 0.019 <0.002 <0.002 <0.002 <0.002 mg/l
Nickel - dissolved <0.002 <0.002 <0.002 <0.002 <0.002 0.009 <0.002 <0.002 <0.002 <0.002 mg/l
Copper - dissolved <0.007 <0.007 <0.007 <0.007 <0.007 0.016 <0.007 <0.007 <0.007 <0.007 mg/l
Lithium - dissolved 0.006 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 mg/l
Strontium - dissolved 0.086 0.110 0.219 0.198 0.071 0.078 0.054 0.069 0.086 0.097 mg/l
Bromide 18 10 8.8 3.3 2.5 6.9 2.5 2.9 5.9 6.9 mg/l
Silica <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 mg/l
HCO3 200 234 244 219 215 161 289 288 366 161 mg/l
CO3 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 mg/l
Mooney et al.
11
Table 3. Concentrations of Nitrate in the Study Area.
Table 4. Chloride/Bromide Ratios.
Chloride/ Bromide Ratios
The thermally anomalous groundwater samples have much
lower Cl-/Br- ratios than groundwater from the other shallow
wells sampled during this survey (Table 4). This relationship
is possibly due to:
• chemical characteristics of the source aquifer host
rock
• longer residence time for the thermal waters in the
source aquifer, resulting in a greater degree of
substitution of Br- ions for Cl- ions through
groundwater interaction with the host rock
• temperature conditions in the source aquifer
• chemical characteristics of the host rocks encountered
during accent from depth
• degree of mixing with shallow groundwaters during
accent
The similar ratios for Lady’s Well, Mallow and the Sugar
Factory artesian well in Mallow suggests a similar history
for the groundwater at these locations. The lower Cl-/Br-
ratio for the well at Johnstown correlates with its higher
temperature and possibly indicates a longer residence time
or less dilution of thermal waters with more recent shallow
groundwaters. The Cl-/Br- ratio thus shows a correlation
with groundwater temperature and may provide a fingerprint
for the source aquifer. However, the numerous possible
explanations for the lower Cl-/Br- ratios make it difficult to
categorically assign it as an indicator of the hydrochemical
characteristics of the source aquifer.
0
10
20
30
40
50
60
70
1 2 3 4 5 6 7 8 9 10
T
Cl-/Br-
Nitrate
Fig 9: Negative correlation of T°C with [Cl-/ Br-] & NO3-
Lithium
The trace element Lithium was detected above the
laboratory detection limit of 0.005mg/l in just one of the
samples, the thermal well at Johnstown, with a concentration
Mooney et al.
12
of 0.006mg/l. This is regarded as significant as the
Johnstown well gave the highest temperature value in the
groundwater temperature survey and probably reflects the
least diluted geothermal water in the North Cork area. The
lithium value in this sample may thus reflect a compositional
characteristic of the source aquifer, which has not been
obscured by dilution.
Isotopic and Gas Analyses
Isotopic and gas analyses from Lady's Well showed 4HE x
107 at about 170 and Tritium (TU) of 11. Aldwell
interpreted these results as reflecting deeper circulation and
longer residence time than usual for Irish groundwater.
(Aldwell, 1996).
Fifteen samples of thermally anomalous and normal
groundwaters from the North Cork wells and springs have
been analysed for hydrogen (2D/1H) and oxygen (18O/16O)
isotopes together with a sample of surface water from the
River Blackwater at Mallow and a rainwater sample taken in
Cork city (Table 5). The hydrogen and oxygen isotopic
compositions of the thermal waters demonstrate that it is of
meteoric origin. The isotopic compositions lie close to the
worldwide meteoric water line (Fig. 10) and the ratios are
very similar to those for other shallow groundwater in the
region, analysed at the same time.
All of the wells cluster together along the right side of the
global meteoric water line. The local precipitation sample,
taken in Cork City, consisted of a mixture of rainwater and
snow and plots to the left of the meteoric water line relative
to the shallow well and River Blackwater samples.
Table 5. Isotopic Composition of Groundwater in N.
Cork.
Well ID
(Shallow Well Survey Reference)
Sampling
Date !!H(‰VSMOW) !18O(‰VSMOW)
Johnstown Well (7) 31/01/2009 -40.5 -6.48
Spa House (32) 24/01/2009 -39.7 -6.19
Sugar Factory Artesian Well (42) 24/01/2009 -39.6 -6.28
Greencore Spring (44) 07/02/2009 -40.0 -6.22
Sean and Liz Turner (37) 31/01/2009 -38.9 -6.16
Holy Well (39) 25/01/2009 -39.2 -6.25
Richard Coughlan (19) 07/02/2009 -41.6 -6.62
James Kennedy (21) 07/02/2009 -37.5 -6.18
Carey Ballyhooley (59) 31/01/2009 -39.3 -6.28
Jerry McSweeney (25) 24/01/2009 -39.7 -6.73
Leaselands 1 (1) 07/02/2009 -38.2 -6.12
Leaselands 2 (2) 07/02/2009 -40.0 -6.30
Ballyvoddy (13) 07/02/2009 -38.2 -6.23
Ballyvoddy (13) 07/02/2009 -38.2 -6.23
River Blackwater (n/a) 24/01/2009 -38.7 -6.57
Local Precipitation Sample (n/a) 04/03/2009 -50.7 -9.20
Figure 10: Plot of !!H (‰ VSMOW) (y axis) against !18O
(‰ VSMOW) (x-axis)
Geothermometry
Geothermometers allow us to calculate the temperature at
which ground water equilibrated chemically with the rocks
within its aquifer (Henley et al. 1984, Domenico &
Schwartz, 1998). They are used widely in geothermal
exploration, as they can indicate the presence at depth of hot
water. Unfortunately they cannot be applied in this study for
various reasons. Firstly, the temperatures of the North Cork
wells are too low for use of the alkaline geothermometer and
unrealistic results were obtained. Secondly, the various Si4+
geothermometers could not be applied, as Si4+ was not
detected above the laboratory detection limit in any of the
samples from the study area.
CONCLUSIONS
North Cork contains an abundant groundwater resource in its
bedrock aquifers. The consistent 10-12°C temperature of
this resource throughout the year, make it an ideal source for
water based heating, cooling, or heating and cooling systems
using heat exchanger and heat pump technology. Anomalous
areas of elevated groundwater temperatures have hitherto
been explained as representing groundwater that has
circulated to deep levels and traveled to the surface again via
fault related conduit permeability. A shallow borehole
temperature survey has verified this relationship.
Landsat imagery indicates the presence of Caledonian aged
NE–SW trending structures in the region, likely to be
responsible for the deeper circulation and longer residence
times of the thermal groundwater. The minimum depth of
circulation is 1100m in Mallow and 1,500m in Johnstown,
with greater depths likely considering heat loss during the
ascent of the groundwater and potential mingling of deeper
sourced thermal water with the cooler shallow groundwater.
2-D Resistivity surveys in areas with anomalous
temperatures indicate extensive karstification of shallow
limestone bedrock aquifer enhancing the permeability for
horizontal flow of groundwater. These horizontal structures
intersect deeper vertical structures.
Geochemical analyses indicate that all of the groundwater is
of meteoric origin and is of a calcium bicarbonate type,
typical of groundwater in carbonate aquifers, indicating that
the thermal and non-thermal waters have chemically
equilibrated with the host carbonate bedrock aquifer. Trends
of chloride, bromide and nitrate ionic concentrations
suggests that the thermal waters have a longer residence
time than the groundwater exhibiting temperatures more
typical of Irish groundwater.
Mooney et al.
13
It is anticipated that this study, will encourage the use of
these ubiquitous low enthalpy hydro-geothermal energy
resources in the North Cork area, as an economically viable
and environmentally sound alternative to fossil fuels. It is
recommended that further research be undertaken which will
identify specific projects where the low enthalpy hydro-
geothermal resources that have been identified can be
harnessed for the benefit of all stakeholders in the study
area. There is a case for local government to lead the way, as
private developers can sometimes be slow to adapt to
innovative new technologies; investment in successful
flagship projects will reap economic and environmental
benefits and provide the example for private entrepreneurs to
follow suit.
ACKNOWLEDGEMENTS
Sergei Kostic and Dejan Milosovic of Geofizika-Ing,
Belgrade, Serbia are thanked for conducting the geophysical
investigations.
REFERENCES
Aldwell, C.R., 1996. Mallow Springs, Co. Cork, Ireland.
Environmental Geology, 27, 82-84.
Aldwell, C.R., Burdon, D.J., 1980. Hydrogeothermal
Conditions in Ireland. XXVI Int. Geol. Cong, Paris.;
Sec. 14.2 Fossil Fuels, Abstracts, 1043.
Aldwell, C.R., Burdon, D.J. 1986 Temperature of infiltration
and groundwater Conjunctive Water Use (Proceedings
of the Budapest Symposium, July 1986). IAHS Publ.
No. 156,
Andrews, J.N., Burgess, W.G., Edmunds, W.M., Kay,
R.L.F., Lee, D. J. 1982 The thermal springs of Bath.
Nature 298, 339 – 343
Burdon, D.J. 1983. The Irish Geothermal Project. Phase 1
(June 1981-March 1983). Report to the Geological
Survey of Ireland, Minerex Ltd., Vol 1 &2.
Brück, PM., Cooper, CE., Cooper, MA., Duggan, K., Gould,
L., Wright DJ., The Geology and Geochemistry of the
Warm Springs of Munster. Ir. J. Earth Sci., 7, 169-194
(1986)
Craig, H. 1963. The isotopic geochemistry of water and
carbon in geothermal areas. In Nuclear Geology on
Geothermal areas. Spoleto, Sept.9-13, 1963. Consiglio
Nazionale delle Ricerche, Laboratorio di Geologia
Nucleare, Pisa, 53pp.
Domenico, P.A., Schwartz, F.W. 1998 Physical and
Chemical Hydrogeology (Second Edition) 506pp
Gill, W.D., 1962. The Variscan fold belt in Ireland. In: Coe,
K. (Ed.), Some Aspects of the Variscan Fold Belt.
University Press, Manchester, pp. 41–64.
Goodman R. Jones, G., Kelly, J., Slowey, E., O’Neill, N.
2004. A Geothermal Resource Map of Ireland, Final
Report for Sustainable Energy Ireland (SEI). CSA
Dublin
Henley, R. W., Truesdell, A. H., Barton, P. B. (1984) Fluid-
mineral equilibria in hydrothermal systems. Reviews
in Economic Geology, 1, Society of Economic
Geologists).
Jha, K., Kumar, S., Chowdhury, A. 2008. Vertical electrical
sounding survey and resistivity inversion using genetic
algorithm optimisation technique Madan J. Hydrology,
359, pp 71 – 87.
Landes, M. Prodehl, C., Hauser, F., Jacob, A.W.B.,
Vermeulen, N.J. 2000. VARNET-96: influence of the
Variscan and Caledonian orogenies on crustal structure
in SW Ireland Geophysical Journal International 140
(3), 660–676.
Burdon, D.J. 1983. The Irish Geothermal Project. Phase 1
(June 1981-March 1983). Report to the Geological
Survey of Ireland, Minerex Ltd., Vol 1 &2.
Murphy, F.X. Bruck, P.M. 1989. An investigation of Irish
low enthalpy geothermal resources with the aid of
exploratory boreholes, Final Report. September 1989.
Contract number EN3G00660-IRL(GDF) Report 98/13.
O’Brien, M. 1987. The development of Geothermal
Resources in the Mallow area for Heating Purposes.
M.Eng. Thesis, University College Cork (unpublished).
Phillips, A. 2001. “Caledonian Deformation” in The
Geology of Ireland (Ed.) Holland, Dunedin Academic
Press.
Vermeulen, N.J., Shannon, P.M., Masson, F., Landes, M.
2000. Wide-angle seismic control on the development
of the Munster Basin, SW Ireland (in New perspectives
on the Old Red Sandstone) Geological Society Special
Publications, 180, 223-237.
Proceedings World Geothermal Congress 2010 Bali, Indonesia, 25-29 April 2010
1
Low Enthalpy Geothermal Resources of Ireland Maps Encourage Geothermal Projects
Gareth Ll. Jones*, Róisín M. Goodman†, John G. Kelly
†
*Conodate, Dublin; †
SLR, Dublin
Keywords: Ireland, geothermal resources, deep, potential, district heating
ABSTRACT
The Geothermal Resources of Ireland maps of 2005
(Goodman et al. 2004, Kelly et al. 2005) were published as
a public resource to establish a modern baseline in
geothermal energy resources and demonstrated the probable
extent of geothermal resources across the island of Ireland
to a depth of 5km. These maps for groundwater
temperatures at 10m, 100m, 500m, 1,000m, 2,500m,
5,000m were reported at EGC 2007 in Unterhaching (Jones
et al 2007). They have allowed the development of a
number of exploitation scenarios across the island and have
initiated a number of investigative projects in identified target zones where further exploration is warranted.
1. INTRODUCTION
In the period since the publication of the maps the
following developments have taken place.
2. SHALLOW RESOURCES
Figure 1: Surface / 10m depth temperatures.
Encouraged by government grants, recommended by
Goodman et al. (2004) and a parallel 2004 Arsenal study
(Boesworth, R. 2004), rapid development has taken place
across the island (Allen in press). Warm moist ground
conditions (Fig.1) have allowed the development of shallow
resources. Horizontal loops are common for buildings with
sufficient available ground area, whilst vertical closed loop
borehole collectors are now common and multiple borehole
fields recently starting to appear. Installed capacity has
risen very rapidly from an estimated 0.5MW in 2000 to some 250MW in 2008 (Fig.2).
Figure 2: Recent steep rise in installed capacity..
In the region east of the warm spring at Mallow, Co. Cork
an investigative study has been initiated (Allen & Mooney
in press) to define the newly identified continuation of the warm spring zone to the Glanworth area (Fig. 3).
Figure 3: The geothermal anomaly in the Glanworth
area.
Shallow aquifers with high yields have been successfully
developed as seen in the very efficient open loop borehole
systems of the Offaly County Council offices, Tullamore
(Fig.4), the Cork City Council, the University College Cork
schemes (Figs.5,6) and the 400kW system at Vista Medical Centre, Naas, Co. Kildare (Fig.7).
There are a number of moderate sized systems (up to
15kW) Open and Closed loop collectors from water bodies, used for both heating and cooling.
Medium sized projects with fields of multiple closed-loop boreholes are now being developed.
3. MEDIUM DEPTH RESOURCES
Ireland has no recognised deep aquifer systems, except in
Mesozoic sediments in Northern Ireland (Figs.8, 9), where
Jones et al
2
there is good potential for district heating from doublet systems (Kelly et al. 2005).
Figure 4: Offaly County Council offices, Tullamore
Figures 5, 6: UCC Cork IT building and plant room
Figure 7: Vista Medical Centre, Naas, Co. Kildare
Figures 8, 9: 8. Deep geology of Ireland. 9. Modelled
temperatures at 2.5km depth.
The Geological Survey of Northern Ireland (GSNI) have
drilled a 900m borehole at Kilroot in Co. Antrim (Fig.10),
targeting the Sherwood Sandstone and Permian aquifers.
This stratigraphic hole, together with magnetotelurics and
infill gravity, will detail the geothermal potential of the area.
Figure 10: Drilling the GSNI Kilroot borehole. Picture T.
Rosowski
Fracture ‘aquifers’ are common in the Carboniferous
sequence which underlies over 50% of the country and are
likely to provide numerous high flow low temperature
geothermal resource sites as the market develops and their geometry and hydrodynamics are traced at depth.
More detailed investigations (O’Neill & Pasquali 2005,
Jones et al. 2007) recommended specific sites for further
study. Deeper resources are now being investigated and
already two projects are proceeding to target geothermal
resources associated with a major Palæozoic fault at 2.5km
in the Dublin area for potential district heating development.
Other resources, that include deep crystalline rock settings,
have been identified for potential exploration activities but
they will need further development of the market for deep drilling to begin.
Jones et al
3
Figure 11: Geology of the Blackrock-Rathcoole Fault
separating the Carboniferous Dublin Basin to the
north from the older Leinster Massif to the south
The combination of deep faults and crystalline rocks have
been identified in Germany and other countries as having
the biggest geothermal resource. This combination exists
south of Dublin where the Blackrock/Rathcoole Fault
occurs adjacent to the Leinster granite and Lower
Palæozoic Massif (Fig.11). GT Energy Ltd. have already
carried out deep exploratory drilling in the south-west
(Fig.12), whilst University College Dublin are evaluating their location.
Figure 12: GT Energy’s Marriott rig exploring a
fracture aquifer south-west of Dublin.
4. DEEP RESOURCES AND ELECTRICITY
POTENTIAL
The 5km depth resource map (Fig.13) indicates that there is
significant potential for electricity generation in some areas,
especially in the north-east. Development of this resource
depends largely on additional drilling and on new data
being collected. At 5,000m depth across Northern Ireland
and a number of other locations, modelled temperatures
show a number of potential ‘hot-spots’ with values of
115ºC - 165ºC in the Lough Allen Basin, 115ºC - to 150ºC
in the Larne - Lough Neagh Basins and a potential 180ºC in the Rathlin Basin.
Figure 13: Modelled temperatures at 5km depth
The Geological Survey of Northern Ireland (GSNI) is
investigating the geothermal potential in the Tertiary
Mourne Granite with a 600m deep exploration borehole
(Fig.14). They will geothermally log the borehole and carry
out conductivity tests on the samples, which, with infill gravity to create a 3D model, will characterise the batholith.
Figure 14: Setting up the GSNI drill rig for the Mourne
granite assessment borehole. Pic T. Rosowski
At present only binary or Organic Rankin Cycle (ORC)
power plants can be considered for electricity generation
production at temperatures down to 100 °C in Ireland from geothermal heat.
A perceived barrier to the investigation and development
of medium-deep resources, is the lack of protective
legislation. GTR-H, an EU funded research project, has
looked at regulation across Europe and is developing a
template (Pasquali & Goodman 2008). An Irish government
geothermal working group is consequently drafting
Jones et al
4
legislation to cover this area and to provide security of tenure to geothermal companies (King & Dhonau 2008).
The successful development of Hot Dry Rock (HDR)
technology and hydraulic stimulation techniques elsewhere
in Europe will increase the perceived geothermal
production capacity of Irish sites significantly and thereby
accelerate the development in this area to look at electricity production from higher temperature resources.
5. CONCLUSION
A combination of resource assessment and government
support has promoted the development of shallow resources
and stimulated the investigation of specific geothermal
locations for deeper projects.
REFERENCES
Allen, A. In press. Developments in Geothermal Utilisation
in the Irish Republic. Proceedings World Geothermal
Congress 2010.
Boesworth, R. 2004. Campaign for take-off for renewable
heat pumps in Ireland. Unpublished Arsenal Research
report to Sustainable Energy Ireland, April 2004.
139pp.
King, J. & Dhonau, B. 2008. Development of Policy for
Geothermal Energy in Ireland. Geothermal Resources
in Ireland Commercial Opportunities. Geothermal
Associaition of Ireland Conference, Kilkenny 5
November 2008.
Goodman, R., Jones, G.Ll., Kelly, J., Slowey, E., O’Neill,
N., 2004. Geothermal Energy Exploitation In Ireland
– Review of the Current Status and Proposals for
Optimising Future Utilisation. Final report to
Sustainable Energy Ireland. CSA rept no. 3085/02.04
September 2005. 93pp + XII App.
Jones, G.Ll., Goodman, R., Pasquali, R., Kelly, J.G.,
O’Neill, N., Slowey, E. 2007. The Status of
Geothermal Resource Development in Ireland. Proc.
European Geothermal Congress 2007, Unterhaching,
Germany, 30 May-1 June 2007. 3pp.
Jones, G.Ll., Pasquali, R., Antin, G., Grummel, T.,
Goodman, R., Glanville, P., O’Neill, N. 2007.
Feasibility Study & Market Research for the
Development of a Deep Geothermal Borehole on the
University College Dublin Campus. Final Report to
Sustainable Energy Ireland. Conodate Geology rpt
3533-DG February 2007, 73pp + VI App.
Kelly, J., Goodman, R., Jones, G.Ll., O’Neill, N., Pasquali,
R. 2005. Geothermal Energy Review of Northern
Ireland – Final Report to INTERREG. CSA rept no.
3194/01.05 September 2005. 79pp + XI App.
O’Neill, N. & Pasquali, R. 2005. Deep Geothermal Site
Characterisation, Final Report to Sustainable Energy
Ireland. CSA rept no. 3366. October 2005, 34pp. (+
Apps in Interim rpt.).
Mooney, B. & Allen, A. In press. Characterising low
enthalpy hydrogeothermal resources at Glanworth, Co.
Cork. Proceedings World Geothermal Congress 2010.
Pasquali, R. & Goodman, R. 2008. Progress & Draft
Template Regulatory Framework. Geothermal
Resources in Ireland Commercial Opportunities.
Geothermal Associaition of Ireland Conference,
Kilkenny 5 November 2008.
11
59
.
L
ow
En
tha
lpy
Ge
oth
erm
al
Re
so
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es
of
Ire
lan
d M
ap
s E
nc
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eo
the
rma
l P
roje
cts
Ga
reth
Ll. J
on
es*,
Ró
isín
M.
Go
od
ma
n†,
Jo
hn
G.
Ke
lly†
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on
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ap
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t 1
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were
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rap
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Pro
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11
56)
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Ge
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Gla
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ms (
up
to
15kW
) O
pe
n a
nd
Clo
se
d l
oo
p c
olle
cto
rs f
rom
w
ate
r b
od
ies,
use
d fo
r bo
th h
ea
tin
g a
nd
co
olin
g.
!
Me
diu
m s
ized
pro
jects
with
fie
lds o
f m
ultip
le c
lose
d-l
oo
p b
ore
ho
les a
re n
ow
be
ing
de
ve
lop
ed
.
Me
diu
m D
ep
th R
es
ou
rces
"
Ire
lan
d h
as n
o r
ecog
nis
ed
de
ep
aq
uifer
syste
ms,
exce
pt
in M
eso
zo
ic s
ed
ime
nts
in N
ort
he
rn I
rela
nd
, w
here
th
ere
is g
oo
d p
ote
ntia
l fo
r d
istr
ict
he
ating
fro
m d
ou
ble
t syste
ms.
"
Th
e G
eo
log
ica
l S
urv
ey o
f N
ort
he
rn Ir
ela
nd
(G
SN
I) 9
00
m str
atig
raph
ic b
ore
ho
le a
t K
ilro
ot,
C
o.
An
trim
, ta
rge
ted
S
he
rwoo
d S
an
dsto
ne
an
d P
erm
ian
a
qu
ifers
. M
ag
ne
tote
luri
cs w
ith in
fill
gra
vity,
will
d
eta
il th
e
ge
oth
erm
al p
ote
ntia
l.
P
ic T
. R
oso
wski
De
ep
ge
olo
gy
of
Ire
lan
d.
Mo
de
lle
d t
em
pe
ratu
res
at
1k
m,
2.5
km
de
pth
. T
he
GS
NI K
ilro
ot
bo
reh
ole
"
Fra
ctu
re a
qu
ife
rs in
th
e C
arb
on
ifero
us,
un
derlyin
g 6
0%
of
the
co
un
try,
are
lik
ely
to
pro
vid
e n
um
ero
us h
igh-
flo
w lo
w t
em
pera
ture
ge
oth
erm
al re
so
urc
e s
ite
s.
"
A c
om
bin
ation
of
de
ep
fau
lts a
nd
cry
sta
llin
e r
ocks,
iden
tifie
d a
s h
avin
g t
he
big
ge
st
ge
oth
erm
al
reso
urc
e,
exis
ts w
he
re t
he
Bla
ckro
ck/R
ath
coo
le F
au
lt s
ep
ara
tes t
he D
ub
lin B
asin
fro
m t
he
Le
inste
r M
assif. F
ollo
win
g
the
O’N
eill
& P
asq
ua
li (2
00
5)
an
d J
one
s e
t a
l. (
20
07
) spe
cific
site
re
co
mm
en
datio
ns,
GT
En
erg
y L
td.
ha
ve
ca
rrie
d o
ut
dee
p e
xp
lora
tory
dri
llin
g to
th
e w
est,
wh
ilst
Un
ive
rsity C
olle
ge
Du
blin
are
eva
lua
tin
g in
th
e e
ast.
G
T E
ne
rgy
’s M
arr
iott
rig
ex
plo
rin
g a
fra
ctu
re a
qu
ife
r s
ou
th-w
es
t o
f D
ub
lin
.
G
eo
log
y o
f th
e B
lac
kro
ck
/ R
ath
co
ole
Fa
ult
"
Oth
er
dee
p c
rysta
llin
e r
ock s
ett
ing
s r
eso
urc
es,
will
ne
ed
fu
rth
er
ma
rke
t g
row
th f
or
de
ep
dri
llin
g t
o b
eg
in.
D
ee
p R
eso
urc
es a
nd
Ele
ctr
icit
y P
ote
nti
al
M
od
ell
ed
te
mp
era
ture
s a
t 5
km
de
pth
.
P
ic T
. R
oso
wski
Th
e G
SN
I d
rill
rig
fo
r th
e M
ou
rne
gra
nit
e a
ss
es
sm
en
t
T
he
5km
de
pth
re
so
urc
e m
ap
in
dic
ate
s s
ign
ific
an
t p
ote
ntia
l fo
r e
lectr
icity g
en
era
tion
, e
sp
ecia
lly i
n t
he
no
rth-e
ast.
D
eve
lopm
en
t re
qu
ires a
dd
itio
na
l dri
llin
g
an
d n
ew
da
ta c
olle
ctio
n.
At
5,0
00m
de
pth
, m
od
elin
g s
ho
ws a
nu
mbe
r o
f p
ote
ntia
l ‘h
ot-
sp
ots
’: 1
15
ºC -
16
5ºC
in
th
e L
ou
gh
Alle
n B
asin
, 1
15
ºC -
to
15
0ºC
in
th
e L
arn
e -
Lo
ug
h N
ea
gh
Ba
sin
s a
nd
180
ºC in
th
e R
ath
lin B
asin
.
G
SN
I in
ve
stig
ate
d t
he
ge
oth
erm
al
po
ten
tia
l in
th
e T
ert
iary
Mo
urn
e G
ran
ite
with
a 6
00
m d
ee
p b
ore
ho
le.
Ge
oth
erm
al
log
gin
g,
co
nd
uctivity t
ests
on
th
e
sa
mp
les,
plu
s in
fill
gra
vity to
cre
ate
a 3
D m
ode
l, w
ill c
ha
racte
rise
th
e b
ath
olit
h.
A
t p
rese
nt
on
ly B
inary
or
Org
an
ic R
an
kin
Cycle
(O
RC
) p
ow
er
pla
nts
ca
n b
e c
on
sid
ere
d f
or
ele
ctr
icity g
en
era
tio
n p
rod
uction
in I
rela
nd
for
tem
pe
ratu
res d
ow
n
to 1
00
°C
fro
m g
eo
therm
al he
at.
A
ba
rrie
r to
in
ve
stig
ation
an
d d
eve
lop
me
nt
of
me
diu
m-d
ee
p r
eso
urc
es,
is t
he
la
ck o
f p
rote
ctive
le
gis
latio
n.
GT
R-H
, a
n E
U f
un
de
d r
ese
arc
h p
roje
ct,
loo
ke
d a
t re
gu
latio
n a
cro
ss E
uro
pe
an
d d
eve
lop
ed
a t
em
pla
te (
Go
odm
an e
t a
l th
ese
Pro
ce
ed
ing
s p
ap
er
03
15
).
An
Iri
sh
go
ve
rnm
en
t w
ork
ing g
rou
p h
as d
raft
ed
le
gis
latio
n p
rovid
ing
se
curi
ty o
f te
nu
re t
o g
eo
the
rma
l com
pa
nie
s (K
ing
& D
ho
nau
20
08
).
S
ucce
ssfu
l d
eve
lop
me
nt
of
Ho
t D
ry R
ock te
ch
no
log
y a
nd
h
yd
rau
lic stim
ula
tio
n te
ch
niq
ue
s e
lse
wh
ere
, in
cre
ase
s th
e p
erc
eiv
ed
g
eo
the
rma
l p
rod
uctio
n
ca
pa
city o
f Ir
ish
site
s s
ign
ific
an
tly a
nd
th
ere
by a
cce
lera
tes t
he
in
tere
st
in t
his
are
a to
loo
k a
t e
lectr
icity p
rod
uctio
n fro
m h
igh
er
tem
pe
ratu
re r
eso
urc
es.
.
Proceedings World Geothermal Congress 2010
Bali, Indonesia, 25-29 April 2010
1
Methodology in Assessment and Presentation of Low Enthalpy Geothermal Resources in
Ireland
1Róisín Goodman,
2Gareth Ll. Jones and
1John G. Kelly
1SLR Consulting (Ireland) Ltd, 7 Dundrum Business Park, Windy Arbour, Dublin 14, Ireland. 2Conodate Geology, 7 Dundrum
Business Park, Windy Arbour, Dublin 14, Ireland.
[email protected], [email protected], [email protected]
Keywords: Ireland, Low enthalpy, geothermal data
modelling,
ABSTRACT
Studies were carried out in 2004 and 2005 across the island
of Ireland, to develop a database and a series of index maps
for the geothermal resources of Ireland. The objective of
the projects was to produce a GIS-linked geothermal
database, an up-to-date map series, and a report with
recommendations for the next steps necessary in expanding
the use of Ireland’s geothermal energy from both shallow
resources and the somewhat unknown deeper resources.
Some of the difficulties involved in finding a best approach
to such an exercise are discussed and some of the strength
and weaknesses of the results of such a study are presented.
However the value of carrying out such an exercise is
highlighted as a first tool in geothermal resource
assessment. A number of geothermal depth plans have
been produced for surface, 100m, 500m, 1,000m, 2,500m
and 5,000m depths. The maps may be viewed using free
MapInfo-Proviewer software.
INTRODUCTION
The Geothermal Resource Map Series of Ireland study
(Goodman et al. 2004) was performed by the CSA Group
(now SLR Consulting (Ireland) Ltd.) in co-operation with
Conodate Geology, Cork Institute of Technology and the
Geological Survey of Ireland. It was a Public Good
contract carried out on behalf of Sustainable Energy
Ireland.
The goals of the study were to identify potential resources
of geothermal energy in Ireland and use these to create
geothermal plans of Ireland by gathering the necessary
hydrothermal, geological and structural data to facilitate the
production of a GIS-linked database and create a series of
geothermal maps of Ireland. The work also reviewed the
current status and utilisation of geothermal energy
resources in Ireland and recommendations were made on
best approach to future potential exploitation of the
geothermal resource in Ireland in the context of
International Best Practice. A later all-island study included
more detailed data on Northern Ireland and was also
completed by the CSA Group, under EU, INTERREG
funding (Kelly et al. 2005).
It was expected that new data and reinterpreting Ireland’s
geothermal database would significantly enhance the value
of the available information on Ireland’s geothermal
potential and provide a concise review of earlier work
allowing easier integration of the available information with
the European geothermal databank. The public availability
of the data was emphasized as a key aspect of the work in
order to increase awareness of the potential of geothermal
energy in Ireland. As the first review of its kind since the
1980s it was hoped to identify strategies for geothermal
energy development.
The base data presented for this study are in effect a partial
data set and the methods employed to extrapolate were
simple and include broad assumptions. The results are
presented as a first approach to handling sparse geothermal
data and as a first pass for assessing geothermal resource
potential as a tool perhaps to encourage further exploration
and dedicated drilling programmes to quantify the actual
resources.
DATA USED FOR THE STUDY
The study started with a review of the available data
sources in the relevant government departments including
the Geological Survey of Ireland within the geothermal
archives, the Exploration and Mining Division and the
Petroleum Affairs Division. Previous studies were
reviewed and data incorporated into the study – in
particular the Irish Geothermal project 1981-1983 (Aldwell
1984, Burdon 1983a,b) and Murphy & Brück (1989).
Figure 1: Borehole distribution used for the study.
Mineral exploration companies were contacted to gather
any available information from recent exploration
programmes which were not yet publically available. A
borehole and spring temperature monitoring programme
was carried out at accessible sites. The study included
Goodman, Jones and Kelly
2
geological, structural and hydrothermal analysis of the areas
with potential and attempted to use these data to provide a
more reliable estimate of the resources and potential. It was
first reported at the Unterhaching EGC (Jones et al. 2007).
Data compilation
Initially as part of the study, data were compiled on heat-
pump usage and groundwater temperature trends in warm
springs and shallow boreholes <100m depth, a total of 80
sites. A programme of temperature monitoring was also
completed for 32 open boreholes to obtain new temperature
profiles. The new boreholes ranged in depth from 40m to
810m. The deepest borehole monitored was No. 01-541-
03, Co. Galway in the west midlands (Figure 1).
Temperature data from 68 historical mineral and oil
exploration holes ranging in depth from 300m to 2,300m
(deepest borehole Drumkeeran (No. 1), Co Leitrim) were
then compiled from boreholes monitored since the previous
geothermal studies. Data sources included Mineral
Exploration reports EMD / GSI 1970–2003a,b and Oil
company reports 1970-2001a,b PAD / GSNI.
Temperature records from active oil and mineral
exploration companies provided data on nine new
boreholes ranging in depth from 391m to 1,550m with
five holes deeper than 1000m.
New data were then combined with data from earlier
studies, Aldwell 1984, 1990; Aldwell & Burdon 1980,
1984, 1986; Brock 1989; Burdon 1983a,b).
Mineral Exploration Data
Ireland has had a very active mineral exploration and
mining sector for over 50 years and as such there has been a
significant amount of shallow (50-300m) drilling in parts of
the country though predominantly located in areas
underlain by Carboniferous aged limestones covering much
of the midlands of the country (Figure 2). Despite this
exploration activity there are still many areas with sparse
drilling and therefore poor geological detail at depth.
Though there has been limited onshore oil and gas
exploration there are few areas with boreholes deeper than
500m. As a result the data available are sporadically
distributed and somewhat biased to particular lithologies.
QUALITY OF DATA
As mentioned the compiled data are heavily biased towards
areas of economic interest, primarily the Carboniferous
Limestone areas for metals, Carboniferous coals and the
Permo-Trias Basins for hydrocarbons, halites. The
maximum depth from which temperature measurements
were available was 2300m with much of the data coming
from shallower than 500m. Only temperature
measurements from boreholes greater than 500m deep have
been used to provide geothermal gradients for extrapolation
to depths below 1,000m. Large areas of the country have
little or no exploratory drilling; this includes granite
batholiths, metamorphic areas, Namurian outliers and
Lower Palæozoic and Devonian inliers. Some of the
specific issues encountered in modelling geothermal
gradients and extrapolating temperatures in the related to
local geology are documented in the following sections.
Carboniferous Midland Basins
Though the majority of the boreholes are located in the
Carboniferous Limestone, many are <300m depth and as
the influence of fracturing and karst in the Carboniferous is
more intense than in other units care is needed in
extrapolation to depth.
Figure 2: Ireland summary geology Basalt and Mesozoic
Basins (pale purple (Northern Ireland only)),
Carbonates (blue), Devonian sandstones (yellow),
Lower Palaezoic sediments (orange), Caledonian
metamrphics (green), Granite (red)
Munster basin
Most of the Munster Basin with Devonian and
Carboniferous clastic sediments has no deep drilling or
temperature data available. One deep drillhole in the
northwestern edge of this basin records very low
temperatures of 33.8ºC at a depth of 1,690m (Meelin no. 1
borehole). The low gradient of 14.3°C/km recorded has
influenced all modelling for this region. It is essential that
more extensive information is obtained in the future to
reduce the reliance on this single data point.
Granites
The batholiths of Leinster, Galway and Donegal are
completely untested except for a number of shallow
(<150m) boreholes for which heat flow data have been
measured (Figure 3). However there are few data to
indicate whether these areas would be of interest for
Enhanced Geothermal Systems and more data are required.
One point of interest is that the Mourne Mountain Complex
and Slieve Gullion Complex (Young et. al, 2009) on the
northeast coast is known to have the highest radioactivity of
any batholith in the UK and Ireland and has become the
focus of deep geothermal investigation by the Geological
Survey of Northern Ireland in the past year.
Metamorphic / Crystalline basement and Lower
Palaeozoic basement sediments
Little data were available for the metamorphic basement
which underlies most of the Ireland and is exposed in the
vicinity of the Leinster Massif, within midland inliers and
Goodman, Jones and Kelly
3
especially in the south-east and in the Longford-Down belt
from the north midlands to the Co. Down coast.
Exposures in the north-west and west have no temperature
data. However it is likely that these rocks control much of
the deep geothermal potential An attempt was made
during the study to produce level plans mapping the
occurrence of crystalline basement at the depth studied.
This was abandoned due to insufficient geological data.
Figure 3: Modelled Heat Flow
EXTRAPOLATION OF THE DATA TO DEPTH
Once data had been compiled in excel format, a major issue
with the project was how to best utilise these temperature
and geothermal gradients to provide best estimates of
temperatures in areas and at depths for which there were no
data. It was clear that the dataset required extensive
extrapolation as there were insufficient data for simple
contouring of measured data at the depths for which maps
were required. Extrapolation of temperature using
geothermal gradient was carried out on data from all
boreholes greater than 300m depth in order to provide
sufficient coverage for map production.
Calculation of gradients in earlier studies often assumed a
single gradient for the whole borehole and thereby resulted
in conservative overall gradients in many cases due to the
influence of locally depressed surface gradients due in part
to surface water influx through karst and fractures. In fact
looking at these same data it is apparent that in 40% of
cases the gradient is seen to increase with depth (the
opposite is observed in 30% of cases). The controls on
these changes in geothermal gradient are complex and
critically dependent on local conditions i.e. lithology,
porosity and permeability and fracturing/structure.
For this study all new and historic data were reviewed and
the gradient chosen in each case for extrapolation was as far
as possible more representative of deeper parts of the
borehole and the deeper geology.
The relationship between the measured gradients and the
geology was also examined in each case and helped in
choosing a preferred gradient for extrapolation. An attempt
was made to categorise the likely gradients in common
lithologies encountered in the drilled sequences. However
this was found to be impossible with the available data
though some qualitative statements can be made about the
general influence of more mud rich versus more karstic or
sand rich sequences. Comments on these are included in
the sections below.
It is noted that in similar modelling exercise of geothermal
gradients in Belgium by Vanderberghe and Fock (1989), a
strict limit was placed on the depth to which data from a
borehole would be extrapolated. This has not been applied
in this study as the distribution of data is insufficient to give
any meaningful estimate of geothermal gradient at depth
without extrapolation from most boreholes available.
GIS, DATA MODELLING & MAP CONTOURING
The final database contains measured records from 75
boreholes between 300m and 2,300m depth. Of these
boreholes 49 extend to a minimum of 500m depth and have
been used for deeper temperature modelling. Data on many
other boreholes <300m deep are available and have been
used for modelling to 1000m but have not been included in
deeper.
The data were uploaded to a GIS software package and data
contouring was conducted using gridding software
embedded within the GIS package. The GIS software used
was Mapinfo and the grid modelling was conducted using a
Mapinfo add-in, Vertical Mapper. Some interpolation
techniques produce more reasonable surfaces when the
distribution of points is truly random. Other techniques
work better with point data that are regularly distributed.
Highly clustered data, such as the geothermal data for the
springs and boreholes, presents problems for many
interpolation techniques.
Geothermal data form a particularly difficult dataset for
contouring due to the highly variable distribution of the
data points. The data points fall primarily within a number
of data clusters (Northeast Permo-Trias, Northwest
Carboniferous, North Leinster and the Mallow area) with
scattered data points outside these four regions. In addition,
parts of the country had no data available.
To model such a clustered dataset, it was decided to
conduct the initial contouring using a variety of modelling
techniques and parameters to determine which modelling
technique would give the best solution. Following initial
results, it was determined that natural neighbour
interpolation was best suited to model the datasets and all
detailed modelling was conducted using this method.
Interpolated data points
As mentioned the data distribution is highly skewed to
geological regions of economic interest, and a number of
geological regions contained no data. Where such regions
were considered to significantly differ in properties to
adjacent data-rich regions, a small number of calculated
data points were inserted into the database before
contouring.
STRUCTURE AND OTHER PHYSICAL CONTRILS
ON GEOTHERMAL GRADIENT
Some comments are included below on the influences of
local lithological changes, weathering and rock structure on
geothermal gradients.
Goodman, Jones and Kelly
4
Karst development and shallow groundwater mixing
Much of the upper 200-300m of the Carboniferous
Limestone in Ireland is known to have had significant karst
development during periods of lower sea levels. There are
indications that karstification may have reached even lower
levels in some places. Many karst conduits are still
operative at these depths.
In the compiled database examination of the relationship
between the geothermal gradient and borehole depth
indicated that the top 200-300m of most of the boreholes
demonstrated mixing of surface run-off waters and shallow
groundwater. This rapid percolation of surface water
through deep fractures and karst had thereby disrupted the
geothermal gradients at these depths. Therefore for this
study only geothermal gradients from boreholes >300m
were utilised for extrapolation to depths of 1,000m and only
geothermal gradients from boreholes >500m were used for
extrapolation to depths of >1,000m.
Insulation effect of Shale rich Units
The presence of shale layers is considered in many studies
of deep geothermal potential to be important in
“blanketing” deep heat and preventing it from flowing
easily to the surface. Because of the abundance of shaley
limestone and shales in parts of Ireland the recognition of
this setting will be important in identifying deep geothermal
targets.
Warmer temperatures have been recorded in some areas of
the Irish midlands where there is thick limestone cover,
especially in Westmeath and Offaly into east Galway.
These temperatures may reflect enhancement by the
insulating effect of limestones (which also have lower heat
conductivity than quartz rich sediments) and the associated
shale cover.
Fracture flow ‘aquifers’
Most Irish rocks are strongly lithified and primary porosity
is low. Permeability thus relies heavily on the secondary
porosity of fracture fields. There are few true bedrock
aquifers in Ireland and fracture flow predominates in
porosity and permeability and hydrological connectivity.
On the other hand fracturing and deep penetrating faults are
common throughout Ireland due to its position straddling
the remnants of the Lower Palaeozoic Iapetus Suture, a
palaeo-continental collision zone running in a northeasterly
trend from Limerick to Drogheda. Variscan tectonism
produced generaly east-west fractures south of the Iapetus
suture. Also Tertiary joint and fracture sets were emplaced
during Atlantic opening tectonism. Areas with significant
fracture flow are considered important for hydro-thermal
development. There are likely to be a number of very
important secondary aquifers which can be considered for
the development of deep geothermal projects.
It was noted in temperatures and gradients recorded in the
borehole database that depressed temperatures at depth in
boreholes could in some cases be attributed to possible
influx of shallow ground-waters to depth along adjacent
fracture zones. Similarly, warm springs or warm shallow
groundwater were investigated in detail at the Mallow
warm spring (O’Brien 1987) can be attributed to rapid
access of deeper waters to surface along fracture zones.
These observations have influenced the choice of gradients
to calculate deeper temperatures used in this study.
However further investigation is required to fully quantify
these effects.
In the vicinity of the Iapetus Suture in the midlands there
are numerous zones of anomalous warmer or colder
temperatures and associated variations in geothermal
gradient. Again the distribution of boreholes available for
testing has produced some bias in the data. A zone of
enhanced geothermal gradients was previously interpreted
by Phillips (2001) to lie along the trend of the suture zone
where it is linked with Paleogene age fault activity in the
area. In this study cooler zones along the suture trend are
interpreted to result from zones of fractures /joints and/or
karst development, allowing localised rapid infiltration of
cold water from the surface deep into the groundwater,
where it reduces the groundwater temperatures.
Regional and palaeo-tectonic setting
In general, Ireland is considered to be tectonically stable.
The main evidence of tectonism in recent times has been
rare, small earthquakes in the Irish Sea basin and onshore in
northwest Donegal and southeast Wexford. Except for
small warm spring areas there are no strongly geothermally
active regions. However recent work in the Irish Sea
confirms the presence of some previous geothermal activity
in the Irish Sea basin. Ongoing work indicates the presence
of a palaeo hot-spot which may have been active during
pre-Quaternary times. This palaeo hot-spot has been
postulated as possibly influencing the distribution of river
systems draining westward across Ireland and resulting in
the formation of so called ‘palaeo-channels’ in the Irish
midlands (Hardy 2003).
COMBINING HISTORICAL DATA WITH NEWLY
MONITORED DATA
The temperature monitoring equipment used for the
acquisition of new data for this study was a specially
commissioned 1,000m long dual dipmetre and temperature
probe which allowed easy access to borehole sites. For
shallow monitoring a hand held 2m digital recorder was
used.
Figure 4: Modelled Temperatures at Surface indicating
areas of warm springs
Goodman, Jones and Kelly
5
It is noted that temperature readings from more than five
different thermometers have been used in this study. As
much of the data is historical it was not possible to carry out
a calibration exercise between them.
RESULTS
In a regional context, geothermal gradients in Ireland show
an increase from south to north at all levels. An exception
to this is the west of County Clare in western Ireland where
the highest geothermal gradients in the south of Ireland are
located. This trend is also evident in measured temperature
data from the deeper boreholes. This regional trend is
interpreted to be associated with the main structural
divisions in the Irish subsurface in particular the Iapetus
Suture. This is a deep crustal structural feature and marks
the line of the late Silurian collision between two crustal
plates which were previously separated by an ocean.
Although the Iapetus Suture is over 460million years old it
had a long-lived influence on sedimentation patterns and
can still be seen in deep geophysical profiles of the sub-
surface of Ireland (Jacob et al. 1985). The position and
different characteristics of these plates is also seen to mark
a change in the geothermal properties of these areas.
Another significant trend in the data is an east-west trend to
the south of the Iapetus Suture which is observed in both
the North Leinster and North Munster warm spring data
sets. This is Variscan in origin and its associated structures
are interpreted to be generally east-west deep penetrating
faults. The Variscan deformation resulted in the formation
of a number of deep inclined faults in the south of the
country which control the presence of warm springs in the
Cork area. It is interpreted that the thickening of the
sediments in the south, as a result of compressional faulting
during the Variscan, may have resulted in the presence of
lower geothermal gradients due to the thickened crust. It is
postulated here that some component of this low
geothermal gradient in the south is also the higher
conductivity of the quartz rich sediments here allowing
rapid transfer of the near surface heat to the atmosphere.
This is in contrast to the Northern Ireland where the
interpreted presence of thinned crust underlying the Antrim
flood basalts seem to control the higher geothermal values
present. To the north of the Iapetus Suture a subtle north-
south trend also emerges which is interpreted to be
associated with a much later tectonic event of circa. Triassic
age. This is seen in the Kingscourt area, Co. Cavan where
there are enhanced temperatures (15ºC) near surface. The
same structure at Kingscourt may also continue north and
influence the Lough Neagh area in Northern Ireland where
there are high temperatures at depth.
Temperature of shallow (<100m) groundwater & warm
springs
Ireland is fortunate in having a temperate-wet climate
continuously recharging large volumes of relatively warm
water in the subsurface. From this study groundwater is
defined as having temperatures over 12ºC in the south of
the country and over 9ºC in the north of the country (Figure
4). Allen & Milenic (2003) and Davis (2003) delineated
buried shallow, high-flow aquifers in Cork, which have
been, and are being, exploited by several major projects
such as the Glucksman Art Gallery (Gondwe et al.
WGC2010).
Warm spring and enhanced shallow groundwater
temperatures vary from just above normal to a maximum of
23.5ºC, as observed in a borehole at Glanworth Co. Cork
(Mooney et al. WGC2010). This study has confirmed that
the areas with the most abundant warm springs are the
Mallow area in north Co. Cork and the
Dublin/Meath/Kildare area.
Of most importance in the distribution of warm springs is
the presence of deep tapping structures such as the
Carboniferous Basin bounding, Blackrock-Rathcoole fault
at the north side of the Leinster Granite in south Co. Dublin
and the thrust fault at the north side of the Devonian in
Mallow (Mooney et al. WGC2010).
Temperatures and geothermal gradients at 500m
At 500m depth a number of hot-spots are present in west
Clare, north-west Cavan, north Antrim and east Tyrone
where values range from 25ºC-27ºC. Generally more
elevated values are present throughout the midlands as
compared with the west and south where values are mostly
in the range of 17ºC-19ºC. There is some degree of bias
due to the relative abundance of data in the more central
areas. However despite this bias, it is interpreted that there
is some division in deep geothermal activity, from the
colder temperatures and lower geothermal gradients in the
south to the warmer temperatures and higher geothermal
gradients in the north. This feature becomes better defined
at deeper levels.
Temperatures and geothermal gradients at 1,000m
The results of temperature contouring at 1,000m are
included on Figure 5. The borehole temperature map at
1,000m depth has been modelled from measured and
calculated temperatures in 72 boreholes. The modelled data
have been produced from boreholes that reached 1,000m
together with temperatures calculated from geothermal
gradients in boreholes that reached 300m. Some similar
patterns of warmer temperatures and geothermal gradients
as seen at 500m are also seen at this level, as some of the
data have been directly extrapolated from the gradients
present at 500m depth.
Figure 5: Modelled Temperatures at 1,000m
Goodman, Jones and Kelly
6
Generally at 1,000m, gradients in the south of the country
are 10ºC – 15ºC/km and range from 20ºC–30ºC north of the
Iapetus Suture line. Highs in geothermal gradients of
around 35ºC/km are recorded in the more anomalous zones
and represent the areas of most potential in any further
investigation and testing of deep geothermal gradients
The areas showing the higher geothermal gradients are in
the Antrim, northwest Cavan/Fermanagh and Clare areas.
The presence of the Iapetus Suture becomes more strongly
defined at this depth and generally creates a separation
between the north and south midlands. Temperature ranges
between 22ºC–28ºC to the south to 37ºC–46ºC to the north
of this line. There are still some zones of anomalously low
temperatures in areas underlain by potentially karstified
limestones which may be the result of deep circulation of
cold groundwater from surface along fractures.
Figure 6: Modelled Temperatures at 2,500m
Temperatures and geothermal gradients at 2,500m
The results of temperature contouring at 2,500m are
included on Figure 6. The borehole temperature map at
2,500m depth has been modelled from two measured and
47 calculated temperatures from geothermal gradients in 49
boreholes that reached a minimum depth of 500m. As most
of the temperatures here are calculated, more caution must
be used in the interpretation. Additional caution is
necessary also as most measured data are from the
Carboniferous, while at a depth of 2,500m in the midlands
the predominant rock-type is interpreted as Lower
Palaeozoic in age and is a quartz rich sequence compared to
the limestones of the Carboniferous. The map shows a
similar division in temperature values across the Iapetus
Suture from Drogheda to Limerick with ‘hot-spots’ in the
Kildare, Navan and north Cavan areas in the Republic of
Ireland and in the east Tyrone and north Antrim areas of
Northern Ireland. Temperatures vary from a range of 28ºC
to 45ºC in the south to a range of 64ºC to 97ºC in the north
(with a max of 101ºC).
This partly also applies to the Lough Allen Basin, in the
north midlands (where the basin is either Lower
Palaeozoics or Dalradian metamorphics with variable
thicknesses of Old Red Sandstone facies between the
basement and the Carboniferous sequence), in the Larne,
Lough Neagh and Rathlin basins, total sedimentary
sequence thicknesses exceed 3,000m for the Permo-Triassic
alone, with unknown thicknesses of Carboniferous or older
sediments overlying the basement rocks in these areas.
Temperatures and geothermal gradients at 5,000m
Borehole temperature modelled contours at 5,000m depth
are presented on Figure 7.
The temperatures presented on this map have been
modelled using temperatures calculated only from
geothermal gradients in boreholes that reached 500m. The
unavailability of data at depths below 5,000m means the
temperatures presented are of necessity only an indication
of the possible temperatures that may be encountered at this
depth. The patterns of ‘hot spots’ are the same as for the
map for 2,500m, since the data on the 5,000m map are
extrapolated from the data at 2,500m. The models show a
similar division in temperature values across the Iapetus
Suture from Drogheda to Limerick with ‘hot-spots’ in the
Kildare and Navan areas of the Irish Midlands and in the
Lough Allen, Larne, Lough Neagh and Rathlin basins.
Figure 7: Modelled Temperatures at 5,000m
At 5,000m the background temperatures in the southern
parts of Ireland are in the range of 60ºC - 75ºC while they
are significantly higher in Northern Ireland, with values of
115ºC - 165ºC in the Lough Allen Basin, 115ºC - to 150ºC
in the Larne and Lough Neagh Basins and a potential 180ºC
in the Rathlin Basin.
TEMPERATURE VARIATION AND HEAT FLOW
Heat flow density measurements from four sites have been
added to a previous database and modelled (Figure 6). Heat
flow can change with depth and can also result in lower
geothermal gradients where it results in high transmissivity
of heat to the surface resulting in more rapid cooling of the
surface of the crust. Therefore data on measurements of
heat flow need to be applied with caution.
University College Galway looked at heat flow figures
across Ireland (Brock 1989, Brock & Barton 1984, 1988a,b
1989). This suggests that there is very low heat flow in the
south with very high values in the north-east, plus a hot spot
Goodman, Jones and Kelly
7
south of Dublin. The caveat concerning restricted data
points applies to this map also and in particular the
restriction of the data points to intrusive bodies only as
there have been no studies of heat flow in the sedimentary
or metamorphic lithologies in Ireland.
Potential for Enhanced Geothermal Systems or Hot Dry
Rock
Clearly definable geological controls are difficult to
evaluate in relation to geothermal gradients within deeper
levels of the sub-surface in Ireland.
From the data reviewed in this study it is apparent that
considerable uncertainty remains in estimating temperatures
at depths of 2,000m or greater. However, results of this
review indicate a number of areas with the potential for
high temperatures up to >150ºC at a depth of 5,000m.
These areas are the north-western part of Cavan / southwest
Fermanagh, and northern Antrim / Londonderry. Measured
data in both these areas show temperatures of 57ºC in
Cavan at 2,000m and 63ºC in Antrim at 1,500m depth,
indicating overall geothermal gradients between 24ºC/km
and 35ºC/km. In parts of north County Meath there are
geothermal gradients of 25-30ºC/km at 1,500m depth,
which is also encouraging.
CONCLUSIONS
It is concluded that there is justification for extrapolation of
data as carried out in this study as the study provides a
necessary database as an initial baseline of geothermal data.
The modelling approach was successful at the production of
a set of maps and a data base for future update with the
caveat of the importance of stating the assumptions used to
improve future evaluation.
In the case of shallow resources, warm spring data and
surface/shallow groundwater temperatures across Ireland
show two main anomalous zones with temperatures
between 15ºC and 21ºC and a significant Variscan east-
west structural trend. Outside of these areas, average
shallow groundwater temperatures vary regionally from
12ºC in the south to 9ºC in the north of the country.
The major deep geothermal trends observed in this study
are a regional increase in temperatures from about 18°C
in the south to 26°C in the north at a depth of 500m and
from 28°C – 45°C in the south to 64°C – 97°C to the
north at 2,500m depth. The maximum temperature
measured on the island of Ireland is 87.7ºC in Larne No. 1
at 2,882m depth. Indications of the potential for
temperatures in the region of 150°C at 5,000m depth are
present in Northern Ireland.
The highest recorded geothermal gradient at 1,000m in the
republic is 28.4ºC/km and is located in the vicinity of north
Co. Meath in the Navan area. Data from Northern Ireland
indicates that the highest geothermal gradients in both the
Republic of Ireland and Northern Ireland are located in the
Lough Neagh to Ballycastle/Antrim area, e.g. 35.9°C/km
seen in Portmore no. 1. This is interpreted as the result of
thinned crustal rocks underlying the Antrim Flood Basalts.
Modelled temperatures at depths of 500m to 5000m show a
consistent NE-SW break across the centre of Ireland with
higher temperatures in the north-central and north of the
country.
Though only indicative, these results show the potential for
significant geothermal sources with possible applications in
commercial developments. Further definition of the exact
profile and extent of the geothermal sources and
quantification of the resources requires additional data. In
particular deep areas around the periphery of the island
remain untested.
The study was followed by government initiatives to look at
geothermal resources (O’Neill & Pasquali 2007a,b; Jones
et al. 2007a), followed by private investment in exploratory
drilling projects and later by investigative drilling by the
Geological Survey of Northern Ireland of exploratory
geothermal boreholes.
When fractured or karstified the Waulsortian limestone
records cold temperatures unless adjacent to large deep
faults, as karst/fracturing allow relatively cold surface water
to penetrate deep into the groundwater.
Carboniferous and shale rich rocks act as good insulators
and geothermal gradients are relatively low where
fracturing is absent. This results in the presence of
relatively low temperatures even in the more northerly parts
of the Carboniferous basin where the regional geothermal
gradient is high.
Intrusive complexes in Carlingford in Co. Louth and south
Co. Down have been identified as having the highest
radioactivity levels of granites in Ireland and therefore have
the potential for high geothermal gradients at depth.
However no data were available to test this hypothesis in
this study.
REPORT AND DATA ACCESS
The CSA Geothermal report and appendices, may be
downloaded as pdf files from the SEI's website at:
www.sei.ie or on the following link:
www.sei.ie/Grants/Renewable_Energy_RD_D/Projects_fun
ded_to_date/Geothermal_Energy/ .
Alternatively go to “Funded Programme” then “RE RDD”
and select “Projects Funded to Date”. The Geothermal
Resource Map is found in “Geothermal”. If you wish to
work with the temperature maps, they are very large files
and it is better to request SEI to send a free CD.
REFERENCES/BIBLIOGRAPHY
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Potential Development in Ireland. Geological Survey
of Ireland Internal Report. 33pp.
Aldwell, C.R. 1990. The Second Phase of Geothermal
Investigations in Ireland 1986-89 Geological Survey
of Ireland Internal Report, 34pp.
Aldwell, C.R. & Burdon, D.J. 1980. Hydrogeothermal
Conditions in Eire. September-80 International
Geological Congress, Conference Paper.
Aldwell, C.R. & Burdon, D.J. 1984. Energy potential of
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Aldwell, C.R. & Burdon, D.J. 1986. Energy potential of
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Allen, A. & Milenic, D. 2003. Low enthalpy geothermal
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Brock, A. 1989. Heat flow measurements in Ireland.
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Brock, A. & Barton, K. J. 1984. Equilibrium Temperature
and Heat Flow Density Measurements in Ireland. Final
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and Heat Production Studies in Ireland. Periodic
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1987, EEC contract EN3G-0065-IRL (GDF) 6pp.
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Minerex Limited. April 1983. Vol. I. 285pp, Vol. II 5
Appendices
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for Sustainable Energy Ireland, July 2004. 93pp + XII
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Irish Offshore (and other fun). Unpub. presentation to
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resources in the Mallow Area for Heating Purposes.
Unpub. ME thesis, National University of Ireland,
Cork. 219pp.
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Site Characterisation. Interim report to Sustainable
Energy Ireland, July 2005. 85pp.
O’Neill, N., Pasquali, P. 2005b. Deep Geothermal Energy
Site Characterisation. Final report to Sustainable
Energy Ireland, October 2005. 29pp.
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Irish Landscape. Occasional Papers in Irish Science
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Vandenberghe, N. & Fock, W. 1989. Temperature data in
the subsurface of Belgium. Tectonophysics, 164,
Amsterdam, p237-250.
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interpretation of new airborne geophysical imagery of
Northern Ireland. Poster publ. of the Geological
Survey of Northern Ireland. (With contributions from:
David Beamish, Baz Chacksfield, Chris van Dam,
David Jones, Cathy Scheib and Adrian Walker)
Proceedings World Geothermal Congress 2010
Bali, Indonesia, 25-29 April 2010
1
The Geothermal Potential of Northern Ireland
R. Pasquali, N. O’Neill, D. Reay*, T. Waugh**
GT Energy Ltd, Unit H, Greenogue Business Park, Rathcoole, South Co. Dublin, IRELAND
*Geological Survey of Northern Ireland, Colby House, Stranmillis Court, Malone Lower, Belfast BT9 5BF
**Action Renewables, The Innovation Centre, NI Science Park, Queens Road, Belfast BT39DT
Keywords: geothermal resource, Northern Ireland, hydro-
geothermal, district heating
ABSTRACT
The Geothermal Energy Review of Northern Ireland study
completed in 2005 modelled data from previously drilled oil
and gas, mineral exploration and deep geothermal
exploratory boreholes to develop temperature maps at
selected depths in Northern Ireland. This study predicted
suitable lithologies and reservoir characteristics in potential
geothermal aquifers in areas where temperatures above the
normal geothermal gradient were recognised in the
subsurface.
Acquisition of airborne aeromagnetic data by the TELLUS
project in 2007, in conjunction with existing geological data,
has improved the understanding of deep geological
structures throughout Northern Ireland. The new data
allows identification of targets for deep geothermal energy
development as a result of the Sherwood Sandstone and
Lower Permian Sandstone targets being better defined.
Reservoir modelling and preliminary resource assessment
based on newly acquired petrophysical and reservoir
parameters of both targets shows that the Lower Permian
Sandstone target has the highest geothermal potential in the
Larne, Lough Neagh and Rathlin sedimentary basins.
A profile of Northern Ireland’s energy usage shows that
most electricity and heat requirements are met through the
use of conventional fossil fuel technologies. Current
government policy is focussed on the development of
renewable energy solutions to reduce current CO2 emissions.
Deep geothermal energy in Northern Ireland could
significantly contribute to the reduction of these emissions
by providing a renewable heat source to both domestic and
industrial sectors. Geothermal energy utilisation from
Permo-Triassic basins should be considered as a suitable
renewable energy alternative in these locations to supply
heat to current and proposed future developments in order to
meet the targets for the year 2020 set by Renewable Energy
Directive through the national Renewable Energy Action
Plans.
1. INTRODUCTION
Previous desktop studies on the geothermal potential of
Northern Ireland focused on the assessments of temperature,
porosity and related water flow in the Larne No.2
geothermal borehole completed in the 1980s. The findings
of the study identified the reservoir petrophysical parameters
were probably not representative due to damage to the
formation caused during the drilling of the borehole.
The presence of the Sherwood Sandstone in relatively young
sedimentary basins in Northern Ireland combined with an
elevated geothermal gradient identified in a number of
boreholes is comparable to other regions of Europe.
Temperatures of between 70oC and 90oC have been recorded
at depths of between 2km and 3km in a number of other
boreholes.
Further analysis of logs from these boreholes in Northern
Ireland has indicated an additional target in Lower Permian
Sandstones below the Sherwood Sandstone which may
constitute an additional reservoir target for deep geothermal
energy development in the northern and eastern part of
Northern Ireland. The basal Carboniferous sandstones of the
North West Basin in southwest Fermanagh were also
considered. Although the porosity and permeability recorded
from oil exploration wells is low the data is limited and the
hydro-geothermal potential cannot be ruled out.
The recently acquired airborne magnetic and gravity data in
conjunction with existing seismic line data has been used to
refine the parameters and semi-quantitatively estimate the
total energy stored in a given reservoir volume by using a
volumetric analysis method.
This paper focuses on the geothermal energy potential
calculated using physical parameters from bedrock
formations intersected in the oil and gas boreholes to a depth
no greater than 2900m in Northern Ireland.
2. GEOLOGICAL REGIONS OF NORTHERN
IRELAND
Northern Ireland has a number of sedimentary basins that
have been explored in the past because of their potential to
contain oil and gas reserves. The Rathlin, Larne and Lough
Neagh basins in the east and northeast contain in excess of
3000m of Permo-Triassic sediments (Mitchell, 2004) whilst
the North West Basin in the southwest of Northern Ireland
contains a similar thickness of Carboniferous sandstones,
shales and limestones (figure 1).
Figure 1: Sedimentary Basins and Oil and Gas
Exploration Boreholes in Northern Ireland.
Pasquali et al
2
Exploration boreholes for oil and gas (figure 1) in these
basins have improved the understanding of the depth to and
thickness of permeable lithologies that could act as hydro-
geothermal reservoirs. Core samples from these exploratory
wells were used to determine the permeability and porosity
values in the potential reservoir targets. Based on these data
a series of representative sections showing the tops and
bases of the target formations were generated (McCann,
1988 & 1990). No data currently exists for the northeastern
and southwestern areas of Lough Neagh, which have been
identified (Mitchell, 2004) as the main depocentres in the
Lough Neagh Basin and are likely to contain thicker
sedimentary sequences than the areas which have been
tested to date. A summary stratigraphy of the Permo-
Triassic basins is given in Table 1 below.
Table 1. Summary Stratigraphy of the Permo-Triassic
Sequences in the Larne, Lough Neagh and
Rathlin Basins.
Period Group/Formation Lithologies
Lough Neagh Group Clays, lignites, minor sands and
conglomerates
Upper Antrim Basalts Volcanics, pyroclastics and terrestrial
sediments
Interbasaltic Bed Laterised basalts
Lower Antrim Basalts Volcanics, pyroclastics and terrestrial
sediments
Tertiary
Clay with Flints Weathered Cretaceous and
pyroclastics
Ulster White Limestone
Formation Highly indurated chalks with flints
Cretaceous
Hibernian Greensand Glauconitic sandstones
Jurassic Waterloo Mudstone Calcareous mudstone and thin
limestones
Penarth Group Mudstone, siltstone and thin
limestone
Mercia Mudstone Group Mudstones and thick evaporites
(CaSO4 and NaCl in Larne Basin) Triassic
Sherwood Sandstone
Group Fluvial and aeolian sandstones
Belfast Group (“Permian
Marl”)
Mudstone, evaporites, Magnesian
Limestone at base. Ur Perm. Sst.
locally present
Upper Permian Sandstone
Sandstone – only present in Lough
Neagh Basin, replaces (in part) the
Permian Marl
Magnesian Limestone Dolomitic limestones and dolomites
Ballytober Sandstone
Formation (“Lower
Permian Sandstone”)
Conglomerate and breccias passing
up into sandstones
Permian
Inver Volcanic Formation
Basaltic to trachytic volcanics and
tuffaceous siltstones.
Sandstone/conglomerate unit at base
Coal Measures Deltaic clastics and coals
Carboniferous Carbonates, mixed clastics
Marine carbonates, passing up into
sub-tidal to supra-tidal sequence,
overlain by deltaics
Devonian “Old Red Sandstone” Terrestrial redbeds
Ordovician and
Silurian Lower Palaeozoics Metamorphosed basement to basin
2.1 Sherwood Sandstone Group
The Sherwood Sandstone Group occurs in the Rathlin, Larne
and Lough Neagh basins. The Sherwood Sandstone is
typically overlain by thick Triassic mudstones and
evaporites of the Mercia Mudstone group. This
mudstone/evaporite succession acts as an insulating unit to
the porous lithologies of the Sherwood Sandstone Group
below. Typically, both of these are overlain by mudstones
and thin limestones of the Triassic Penarth Group and
Jurassic Waterloo Mudstone, the Cretaceous Ulster White
Limestone, extrusive volcanics of the Antrim Basalt Group
and Oligocene sediments in the Lough Neagh and Rathlin
basins. Figure 3a shows the presence of the Sherwood
Sandstone reservoir in the Rathlin basin based on the
information recorded in the Portmore borehole.
The Sherwood Sandstone group is characterised by
moderate to low porosity sandstones of fluvial and marine
origin that have previously been explored for geothermal
energy in the Larne basin (Larne No.2 Borehole) where it is
recorded at a depth of 1800m with an approximate thickness
of 800m. The Sherwood Sandstone group found in the
Larne boreholes is shown in figure 2a.
Figure 2a: Sherwood Sandstone Group and Permian
Sandstone Group occurrences in the Larne &
Lough Neagh Basins (McCann, 1990).
In the Rathlin Basin to the north, this group shows a
maximum thickness of 600m and is present at a maximum
depth of approximately 1900m.
2.2 Lower Permian Sandstones
This succession has been described from the drilling results
in the Larne No.2 borehole as a sandstone ranging from very
fine grained to very coarse grained units with a total
thickness of approximately 440m. It was intersected at
depths between 1800m and 2220m below ground level. It
has also been encountered in the Portmore borehole at an
approximate depth of 1890m where the base of the unit was
not reached. However, seismic refraction studies on the
edges of the Rathlin basin have shown that this formation
may be thinner than in the Larne basin with thicknesses of
the order of approximately 200m (figures 2b).
Figure 2b: Sherwood Sandstone Group and Permian
Sandstone Group occurrences in the Rathlin
Basin (McCann, 1988).
2.3 Carboniferous Sandstones
Carboniferous sandstones of Chadian age have been
described in the Northwest Basin in the south
Tyrone/Fermanagh region. These sandstones have moderate
to low porosity and are terrestrially derived. The thickness
of this succession is not as well known as the Boyle and
Kilcoo Sandstones that have been frequently intersected by
oil exploration boreholes. However they have been
described as being up to possibly 150m thick at depths of
Pasquali et al
3
between 1600 and 1800m in the Kilcoo Cross and
Slisgarrow boreholes (figure 3).
Figure 3: Carboniferous Sandstones (yellow) in the
North West Basin (George et al, 1976).
The temperatures modelled in the 2005 CSA review have
been used in this study to characterise the geothermal
potential of target reservoir rocks in Northern Ireland in the
vicinity of heat end-user markets.
3 ELEVATED TEMPERATURES:
Borehole temperature information from the hydrocarbon
exploration and mineral exploration boreholes in Northern
Ireland was modelled and assessed during a recent study.
This showed high geothermal gradients and temperatures in
some of the basins in Northern Ireland. Figure 4 shows the
temperature modelled at a depth of 2500m based on
measured borehole temperatures and calculated data.
Figure 4: Modelled Temperature at 2,500m depth and
seismic line locations in Northern Ireland
(Goodman, 2004).
Based on the lithologies encountered in the hydrocarbon
exploration boreholes and the temperature profiles recorded
subsequent to the completion of the drilling a series of
temperatures were modelled for a number of basins at depths
of 1000m, 1500m, 2000m and 2500m. Table 2 below shows
the modelled temperatures in a number of the boreholes
where temperature gradients were measured.
The potential geothermal reservoir targets were intersected
at depths of between 1500m and 2200m. The boreholes
showing highest modelled temperatures at 2000m were
Portmore with 82oC, Ballymacilroy with 74oC and Langford
Lodge with 68oC. These temperatures coincide with the
presence of Permian Sandstones and Sherwood Sandstone
lithologies in the Rathlin and Lough Neagh basins.
These lithologies also occur in the Larne basin, which was
drilled in the 1980s to evaluate geothermal potential, with
similarly high temperatures. However, the recorded porosity
and permeability of the Lower Permian sandstones in the
Larne No. 2 borehole has been observed as anomalously low
compared with other proximal boreholes like the Newmill
No.1 borehole where much higher porosity and permeability
and temperatures values in the Lower Permian Sandstones
were observed. The temperature recorded in the Permian
Sandstones in the Larne No. 2 borehole was 77.5oC at a
depth of 2800m. For the purpose of this study a temperature
of 83oC was used to characterise the reservoir.
Table 2. Modelled Temperatures in Hydrocarbon
Boreholes (Goodman, 2004).
BOR EH OLE N A M E T ( o C) a t 1000m T ( o C) a t 1500m T ( o C) a t 2000m T ( o C) a t 2500m
A nnaghm ore N o. 1 42.33 53.33 64.33 75.33
Ballym acilroy N o. 1 49.28 62.00 74.00 85.00
Bally tober N o. 1 37.50 51.50 66.00 80.00
Big D og N o. 1 33.89 45.60 57.40 69.20
Glenoo N o. 1 33.50 43.00 52.50 61.50
K ilcoo C ross N o. 1 35.00 46.50 57.00 68.00
K illa ry Glebe N o. 1 39.60 51.00 61.00 71.50
Langford Lodge 43.00 56.00 68.00 80.00
Larne N o. 2 43.00 51.00 60.50 70.00
N ew m ill N o. 1 31.00 34.10 50.50 59.90
Ow engarr N o. 1 38.00 43.50 52.50 63.00
Port M ore N o. 1 45.50 62.80 82.00 99.50
Slisgarrow N o. 1 39.00 50.00 57.80 69.50
W ind Farm N o. 1 27.00 40.50 54.50 68.50
Temperature values recorded in the Northwest basin in the
Slisgarrow, Owengarr, Glenoo and Big Dog boreholes were
noted in the 2005 CSA report as being partially inaccurate as
very few temperature profiles were taken following the
completion of the boreholes (one reading 9 hours after
drilling at the end of the Slisgarrow No. 2 borehole was
completed) and in some cases the time of the temperature
log was not recorded. For this reason the temperatures
observed in these boreholes in not believed to be the true
stabilised formation temperature in the Lower Carboniferous
targets. In this characterisation study a higher true stabilised
formation temperature has been used.
4 TELLUS DATA:
The British Geological Survey (BGS) and the Geological
Survey of Northern Ireland (GSNI), in partnership with the
Geological Survey of Finland (GTK), flew a low-level
airborne geophysical survey over Northern Ireland in 2005–
6. The survey completed a total of 86,000 line km at a height
of 56m and collected magnetic field, electrical conductivity
and terrestrial gamma-radiation measurements.
The survey has permitted improved mapping of faults, dykes
and the major volcanic complexes that are overprinted by
late glacial and Quaternary sediments at the surface. The
survey has aided the delineation and definition of the basins
where geothermal reservoir targets are contained.
For the purpose of this study a combination of aeromagnetic
data and previously acquired ground gravity data were
reviewed by BGS and GSNI to refine the existing reservoir
models previously established from older hydrocarbon
seismic data.
Based on the geometry of the reservoir outlined in the
seismic models, the magnetic intensity data collected during
the TELLUS project in conjunction with the GSNI gravity
data was superimposed to identify the correct density
parameters of the reservoir formations and the geometry of
the basin structures controlling the depths of the reservoir by
using the individual modelled data for the seismic lines in
figure 4.
The information gathered from this modelling exercise has
refined the depth of the reservoir lithologies away from the
exploration boreholes. Table 3 below shows the depth of the
top and base of the Permo-Triassic reservoir rocks in three
Pasquali et al
4
key areas where elevated temperatures have been modelled
but where reservoir conditions have not yet been
investigated.
Table 3. Estimated Geothermal Reservoir Thickness
based on airborne geophysical data (TELLUS)..
Top of Reservoir Target (m)
Base of Reservoir Target (m)
Estimated Thickness (m)
Top of reservoir
Target (m)
Base of Reservoir Target (m)
Estimated Thickness (m)
Antrim 1700 2100 400 2400 2600 200Ballymoney 1400 1900 500 2000 2500 500Magheramorne 900 1550 650 1650 1900 250
Sherwood Sandstone Group Lower Permian Sandstones
Data models have shown that the Sherwood Sandstone
Group reservoir is sufficiently thick and occurs at depths up
to 2km. The Lower Permian Sandstones are present at
greater depths in the basin but are not as thick as the
Sherwood Sandstone. Depth considerations indicate that the
Lower Permian Sandstones should be considered as the
primary geothermal reservoir target but it is worth noting
that within the Permian Sandstone succession some non-
porous tuffaceous sediments are also common and that the
estimated thickness of the sandstone succession may be less
than that observed in the models. However, as these units
are generally quite thin (no more than about 10m to 30m
thick) they were not included in the overall reservoir
thickness models for this study.
The modelled data suggests that the estimated depths of both
reservoirs at Antrim may be slightly underestimated, this is
dependant on variations in the thickness of the strata
overlying the Sherwood Sandstone Succession across the
Lough Neagh basin.
Sherwood Sandstone and Permian Sandstone thickness at
Ballymoney is in the region of 500m, where the latter of the
two is estimated to be present at a depth of approximately
2500m. It is worth noting the presence of probable
Carboniferous sandstone targets below the Permian
Sandstones in these models. This would constitute a deeper
additional reservoir target in this area. However, there is no
deep borehole information to verify these models. During
the course of 2008 a hydrocarbon exploration borehole
located 15km north of Ballymoney will be drilled.
Information gathered from this borehole may provide
additional data on potential Carboniferous reservoir targets.
The granites of the Mourne area in Co. Down as well as
probable buried granites in Northern Ireland, may have the
potential for development of enhanced geothermal systems
(EGS) such as Hot Dry Rock technology for the production
of electricity. However, there is no information on the
reservoir properties of these formations, and they were not
assessed in this study. The Mourne granites have the
potential for high radiogenic heat production. These may
also constitute an important target for Hot Dry Rock type
systems. At present there is insufficient information on the
reservoir properties to be able to quantify their potential.
5 VOLUMETRIC ANALYSIS:
Reservoir calculations have been undertaken based on the
volumetric method (Muffler, L. J. P. & Cataldi, R., 1978).
This estimates the total thermal energy contained in a
volume of rock based on basic rock property parameters
such as mean temperature, porosity and specific heat
capacity. These are converted into recoverable heat energy
by estimating a load factor and a life time for a producing
geothermal well doublet. For the purpose of this calculation,
the volume of rock was assumed as being the thickness of
the formation over a 22.5km2 area which is considered the
normal radius of influence of a geothermal well doublet over
a period of 25 years of production.
The modelling exercise was carried out separately for the
Sherwood Sandstone Group, the Lower Permian Sandstones
and the Carboniferous Sandstones of the Northwest Basin.
The potential of the Carboniferous lithologies previously
described in this report in the Ballymoney area were not
included as to date insufficient reservoir parameters are
available. No modelling was possible for the Sherwood
Sandstone Group or Lower Permian Sandstones in the main
depocentres of the Lough Neagh Basin as no data is
available for these areas.
Geological modelling of available data provided reservoir
depths, petrological parameters and thicknesses of the
reservoir targets used in the calculations. Additional
information on the reservoir rock characteristics were
obtained from hydrocarbon exploration boreholes in the
vicinity of the modelled localities. In the absence of actual
lithological properties of the formations below the selected
localities, the adjacent borehole data provides a reasonable
estimate of these parameters.
Only guideline geothermal resource estimates can be given
for the specific sites selected, because specific heat
capacities of the rock formations at the sites chosen are
based on measurements acquired in generic laboratory tests.
For this reason an analogous geothermal well doublet in
Unterhaching (Germany) producing approximately 40MWth
of heat using standard titanium heat exchanger technology,
was included in the calculation for comparative purposes.
The results of the calculations are summarised in Table 4
below.
Table 4: Preliminary Reservoir Calculation for Total
Heat Power stored in Geothermal Reservoirs
formations in Northern Ireland.
Site Location Lithology
Reservoir
Thickness
(m)
Base of
Geothermal
Target
Formation (m)
Volume of
Source
Rock (V )
(m3)
Mean
Calculateda
or Measured
(T ) (oC)
Estimated Re-
injection
Temperature at
the Surface
(T ref ) (oC)
Load Factor1
(% operational
time)
Life
Time2
(years)
Energy
Stored in
the
Reservoir
(kJth)
Total Power
Stored in the
Reservoir
(MW h)
LarneSherwood
Sandstone650 1615 14625000 80 40 0.75 25 1.58E+09 439.53
BallymacilroySherwood
Sandstone420 1870 26250000 84 40 0.75 25 3.54E+09 983.50
LangfordSherwood
Sandstone270 1515 16875000 54 25 0.75 25 1.61E+09 446.12
Port MoreSherwood
Sandstone680 1830 42500000 78 40 0.75 25 5.24E+09 1456.08
AntrimSherwood
Sandstone400 1600 25000000 78 40 0.75 25 2.74E+09 761.35
BallymoneySherwood
Sandstone500 1400 31250000 78 40 0.75 25 3.43E+09 951.69
MagheramorneSherwood
Sandstone650 1600 40625000 82 40 0.75 25 4.62E+09 1281.96
LarneLwr. Permian
Sandstone900 2800 56250000 83 40 0.75 25 8.19E+09 2274.70
AntrimLwr. Permian
Sandstone200 2200 12500000 77 40 0.75 25 1.36E+09 378.22
BallymoneyLwr. Permian
Sandstone500 2200 31250000 82 40 0.75 25 3.86E+09 1073.33
MagheramorneLwr Permian
Sandstone250 2200 15625000 83 40 0.75 25 1.90E+09 528.84
North West
Basin
Carboniferous
Basal
Sandstone
150 2000 9375000 65 30 0.75 25 1.15E+09 318.65
The figures show initial estimates of total heat power
contained in a rock reservoir. The original formulae for
estimating the total energy contained in a given reservoir
normally take into account the characteristics of both rocks
and fluids present at depth. At present the only identified
potential hot brine source of geothermal energy is in the
Permo-Triassic basins in Northern Ireland. For this reason
and the present incomplete geological dataset, a conservative
case for the selected sites was adopted in this study and an
assumption that geothermal energy that can be sourced from
rock at depths of 1500m and 2500m depths only was made.
Hence fluid specific heat capacities and fluid temperatures
were omitted from the calculations.
The calculations of the total energy stored in reservoirs
(Table 4), identifies the Lower Permian Sandstones in the
Larne Basin as the reservoir with the highest geothermal
potential. This is because these formations are thicker and
occur at greater depth in the basin resulting in overall higher
Pasquali et al
5
formation temperatures. A review of the hydrocarbon
exploration data from these basins also indicates better
porosity values in this formation where water flow potential
is higher.
The Sherwood Sandstone Group in the same basins is
located at shallower depths with lower temperatures and
overall is slightly thinner than the Permian Sandstones
below. Permeability and porosity may, however, be more
favourable in the Sherwood Sandstone.
The potential of the Lower Permian Sandstone and the
Sherwood Sandstone in the Lough Neagh Basin depocentres
as outlined in Mitchell (2004) have not been assessed as
only limited geophysical data and no exploration wells have
been completed in these areas.
The availability of petrophysical properties for the
Carboniferous limestones in Northern Ireland is limited to
data from a single well in County Fermanagh. The TELLUS
data has so far not been used to refine the depths of this
target formation and it petrophysical properties. For this
reason the reliability of the modelled energy stored in these
formations is not as good.
Table 5 below shows an overall ranking of the potential for
deep geothermal energy stored in the reservoirs in Northern
Ireland with the Lower Permian Sandstones having the
highest potential.
Table 5: Geothermal Reservoirs formations and Site
Location Ranking in Northern Ireland.
Formation
Ranking
Site
Location
Rank Site Location Lithology
Reservoir
Thickness
(m)
Base of
Geothermal
Target
Formation
(m)
Total
Energy
Stored in
the
Reservoir
(MW h)
1 LarneLwr. Permian
Sandstone900 2800 2274.70
2 BallymoneyLwr. Permian
Sandstone500 2200 1073.33
3 MagheramorneLwr Permian
Sandstone250 2200 528.84
4 AntrimLwr. Permian
Sandstone200 2200 378.22
1 Port MoreSherwood
Sandstone680 1830 1456.08
2 MagheramorneSherwood
Sandstone650 1600 1281.96
3 BallymacilroySherwood
Sandstone420 1870 983.50
4 BallymoneySherwood
Sandstone500 1400 951.69
5 AntrimSherwood
Sandstone400 1600 761.35
6 Langford LodgeSherwood
Sandstone270 1515 446.12
7 LarneSherwood
Sandstone650 1615 439.53
3 1 North West BasinCarboniferous
Basal Sandstone150 2000 318.65
1
2
The results show how depth and formation thickness control
the potential for heat storage across all the basins. In
localities where both the Lower Permian and Sherwood
Sandstone targets are present, the thickness of the modelled
formation is shown as the controlling factor. This is true of
the Antrim and Magheramorne areas where the Lower
Permian Sandstone formations are thinner compared to the
overlying Sherwood Sandstone. Hydrocarbon well data
shows that the porosity recorded in the Lower Permian
formations is also slightly lower than that those of the
Sherwood Sandstone. For this reason higher flow rates at
lower temperatures in the shallower Sherwood Sandstone
may yield more energy than in the Lower Permian
Sandstones.
The Carboniferous Basal Sandstones encountered in the
Northwest basin in Fermanagh have shown from the
modelling to have the lowest stored energy values compared
to the younger formation in other parts of Northern Ireland.
However these are also very thin compared to some of the
other modelled targets.
Figure 5 shows the distribution of geothermal potential of
the given reservoir target formations in Northern Ireland.
Figure 5: Claculated Geothermal Reservoir Potential in
Northern Ireland.
REFERENCES
George, T. N., Johnson, G.A.L., Mitchell, M., Prentice, J. E.,
Ramsbottom, W. H. C., Sevastopulo, G. D., Wilson, R.
B. 1976. A Correlation of Dinantian rocks in the British
Isles. Geol Soc. London., Spec Rep. 7, p87.
Goodman, R., Jones, G. Ll., Kelly, J., Slowey, E., O’Neill,
N., 2004. Geothermal Energy Exploitation In Ireland –
Review of the Current Status and Proposals for
Optimising Future Utilisation. CSA Group Ltd.
McCann, N. 1988. An Assessment Of The Subsurface
Geology Between Magilligan Point And Fair Head,
Northern Ireland. Irish Journal of Earth Sciences, 9,
1988, 71-78.
McCann, N. 1990. The Subsurface Geology between Belfast
and Larne, Northern Ireland. Irish Journal of Earth
Sciences, 10, 1990, 157-173.
McCann, N. 1991. Subsurface Geology of the Lough Neagh
- Larne Basin, Northern Ireland. Irish Journal of Earth
Sciences, 11, 1991, 53-64.The section break that
follows the last words of the paper will cause the
columns to be even.
Mitchell, W. I. 2004. The Geology of Northern Ireland-Our
Natural Foundation (2nd Edition). Geological Survey
of Northern Ireland (Belfast)
Muffler, L. J. Cattaldi., R, (1978). “Methods for Regional
Assessment of Geothermal Resources.” Geothermics
7(2-4): 53-89.
O’Neill, N., Pasquali, R. 2005. Deep Geothermal Site
Characterisation, Interim Report to Sustainable Energy
Ireland. CSA Group Ltd.
Proceedings World Geothermal Congress 2010
Bali, Indonesia, 25-29 April 2010
1
Geotrainet
– A New European Initiative for Training and Education of Planners, Drillers and Installers
of Geothermal Heat Pumps
Burkhard Sanner a, Philippe Dumas a, Isabel Fernandez Fuentes b, and Manuel Regueiro b
a European Geothermal Energy Council, Renewable Energy House, 63-67 Rue d´Arlon, B-1040 Brussels, Belgium
b European Federation of Geologists, c/o Service Geologique de Belgique, 13 Rue Jenner, B-1000 Brussels, Belgium
[email protected], [email protected], [email protected]
Keywords: geothermal heat pumps, Europe, education,
training, certification, designers, drillers, installers.
ABSTRACT
The aim of the project “Geo-Education for a sustainable
geothermal heating and cooling market”, GEOTRAINET, is
to develop the training of professionals involved in Ground
Source Heat Pump installations (GSHP). From the different
groups of professionals involved in a GSHP, the
GEOTRAINET project is focused on two target groups:
designers (who undertake feasibility studies including
geology) and drillers (who make the boreholes and insert
the tubes). The project includes the creation of an EU-wide
certification scheme for both planners and installers of
GSHP. Another project activity will be the definition
and development assistance for the necessary EU-wide
technical standards.
Visible results of the project will be the curricula, learning
tools, manuals, an e-learning platform for the designers and
the trainers, and several courses to be launched during the
project duration. The goal, however, is to co-operate with
the relevant professional associations, teaching institutions,
etc. in order to establish a training and education framework
going farther and lasting longer than the project – and
providing the human resources necessary to sustain a sound
and healthy growth of the GSHP market in Europe.
1. INTRODUCTION
The European Federation of Geologists is the Co-ordinator
of a large group of partners which has made a successful
application to the European Commission, “Intelligent
Energy – Europe” Programme, for a grant to run a project
for the training of professionals to install ground source
heat pumps across Europe.
Ground Source Heat Pumps, GSHP, contribute greatly to
energy saving and emission reduction. In Europe, a
sustainable market has only been established in some
countries like Sweden, Switzerland, Germany and Austria.
Research in Europe shows that one of the barriers to a
sustainable and growing geothermal market is the lack of
appropriate skilled personnel; quality of design and work
are not always satisfactory. Furthermore, to keep quality up,
a certification programme for the GSHP workforce is
required. The objective of this project is to develop a
European Education programme to go towards the
certification of the workforce involved in geothermal
installations. It will prepare an education programme,
didactic materials, training courses, and develop an e-
learning platform. Training structures in 8 EU countries
will be established for professionals of the geothermal
sector. A European certification framework will be
proposed. Standards and codes will be suggested to permit a
certain harmonization.
The need for good work is evident when looking back at the
heat pump industry. With the second oil price crisis in
1980, heat pump sales skyrocketed, as people were asking
for energy efficient heating systems. However, with the oil
price still high, heat pump sales collapsed shortly after the
peak year, 1980 (Fig. 1a and 1b). So clearly not the
economic circumstances, but a frequent lack of quality and
experience in both the heat pump manufacturing and the
system installation created certain resentment against that
technology. With the oil prices rising again in the last years,
another GSHP boom can be seen, and it is up to us to make
sure that the same does not happen as in the early 1980s.
The main goal of the project is to promote geothermal
energy in training geothermal installers, this removing one
of the main barriers for Geothermal Energy on H-&-C in
many European Countries. The results of the project will be
a European Certification to support and improve the quality
of geothermal installations, with an Education programme
to support a Continual Professional Development (CPD) for
Earth Science Experts and Drilling Professionals.
An international platform of experts on Geothermal Energy
H-&-C will be established to provide the knowledge
required for education in this area by Training Courses and
a European E-learning platform for shallow geothermal
applications.
The project will also improve the access to geological data
needed for the design of GSHP installations, and propose
high standards on the professional needs for Geothermal
Energy Heating and Cooling in Europe.
GEOTRAINET is divided into phases permitting the
creation of an education programme to provide a
certification framework and to train geothermal installers.
The work will be as follows: 1) Research into data currently
useful for GSHP installers; 2) Evaluate skills required to
design, drill and install GSHP; 3) Create curricula for
installers: designers and drillers; 4) Create training tools.
Test and optimization of the products; 5) Suggest standards
and codes to create a European market; 6) Propose a
European certification framework; 7) Launch training
courses.
Sanner et al.
2
Figure 1a: 30 years of Heat Pump Sales in France after data from EHPA, BWP, EIA and others
Figure 2b: 30 years of Heat Pump Sales in Germany after data from EHPA, BWP, EIA and others.
The group of partners of GEOTRAINET represents: the
European industry in the sector, the European Geothermal
Energy Council; the European professionals, European
Federation of Geologists; research centres, Arsenal
Research Austria and BRGM France; private companies,
GT Skills, Ireland and Geoexchange Society Romanian;
and Universities, Universidad Politécnica de Valencia,
Spain, University of Lund, Sweden, and Newcastle
University, UK.
The duration of the project will be 30 months from the 1st of
September 2008.
2. CURRICULA FOR GSHP GEOSCIENCES AND
DESIGN
The training of geologists or geoscientists is necessary to
give them a complete GSHP competence:
Sanner et al.
3
. Environmental respect: take into consideration potential
contamination of soil and groundwater, ground stability,
hydrogeological knowledge, ensuring protection of the
environment (in particular groundwater) while drilling;
. Ground thermal conditions: the shallow geothermal
installer training will cover geothermal resources and
ground source temperatures of different regions, soil and
rock identification for thermal conductivity, regulations on
using geothermal resources, determining the most suitable
geothermal heat pump system;
. Technical conditions: familiarity with different drilling
and digging technologies, choice of the optimum drilling
method, ensuring protection of the environment (in
particular groundwater) while drilling, well construction,
pressure testing, logistics, building laws, and safety.
To achieve these objectives the establishment of a European
expert platform will be necessary. This platform will work
on creating Curricula for geosciences and design, and
assigning contents and programmes to the work items
identified in the Curricula.
The professional experience of the expert platform will help
to define in a precise manner the most relevant areas and
knowledge blocks inside the geothermal profession, the
most relevant aspects for a quality technical assessment of
the GSHP installations. The main goal of this Platform of
experts is to work on the programme of education,
including necessary content and skills requirement, the
didactic materials and an identification of profile and
required professional experience of the teachers.
The platform will define the general methodology and the
strategy, agreed and shared by the partners, for the common
activities (data collecting, e-learning modules,…) that are
going to give a common product (database, e-learning
platform, guidelines,…).
The qualification of geologists covers an extensive
spectrum of disciplines. Depending on the employment
demands geologists have continuously adapted their level
of specialisation. There are certain specialisations, such as
Geotechnics, Hydrogeology, Geophysics, that are of
particular relevance for the analysis of the ground in view
of geothermal objectives.
The first task of the Expert platform will be to assess the
data required for geothermal h&c installations, in order to
define the curricula necessary for the Geoscientists active
in GSHP. A second task for the geoscientist's expert
platform is to define the knowledge needed and required to
advise on GSHP ground installations. A third task is to
present the programme of the design training courses in
order to prepare the didactic materials.
3. ASSESSMENT OF GEOTHERMAL DATA
REQUIRED FOR GSHP DESIGN AND
INSTALLATION
Assessment of geothermal data required for design and
installation, involves the following activities:
. Inventory of data available in the Geological Surveys or
other equivalent authorities. A first approach is to realise a
catalogue on ground meta-data dedicated to the GSHP.
. Collect and evaluate data to determine knowledge and
skills required for design and installation of geothermal
heating and cooling.
Site conditions are factors impacting on GSHP (heating and
cooling efficiency, drilling methods, heat exchange
performance, protected areas….). It is essential to have
these data for the feasibility study of the GSHP system. It is
necessary to know for designers in each EU-27 country
how to access the necessary data. In different countries
(Germany, France, UK,…), local documents are available
(local GIS -Geographical information system- or specific
reports) to support decision-makers . In those documents
initial consideration (geological) before installing a GSHP
are presented (more or less detailed). A catalogue of the
types of available information and their mode of
presentation is essential for EU countries to compare and
develop new supports and collect new data mainly for
GSHP.
A best practice case exists in Germany where the
Geological Survey of Nordrhein-Westfalen provides freely
the geological data on a CD-rom. Other Lander are
developing the same products. In some countries, this vital
information for the designers has to be paid for.
The goal is to present what are the geological data available
in 7 EU countries, how they are available for the designers,
and what is the methodology needed to have them available
for designers, in order to replicate these actions in the other
EU countries. The data assessment will also include a
Guideline to facilitate the acquisition of the geological data
for the geothermal professional. This Guideline will be
included in the didactic material. BRGM will coordinate
this task, and EFG, the Panel of Experts on Geothermal
Energy, prepares a report on Geological Studies, the
influence of the ground on the Geothermal installations.
Other partners will collect data for their countries.
The Geological Survey of France, BRGM, will coordinate
the contribution on the project from 6 national geological
surveys (CGS, Czech Republic Geological Survey; IGME,
Spain Geological Survey; PGI, Poland Geological Survey;
INETI, Portugal Geological Survey; BGS, British
Geological Survey; TNO, Dutch Geological Survey)
An internal group of experts will work on the technical
assessment of the project. The result of this group of
experts will be a report on the project by BRGM as project
partner. It will involve listing and categorising all the
geological data produced by these national authorities for
geothermal applications in the countries involved in the
project and will be a template for EU-27, looking in
particular at the following tasks:
. Metadata on the ground;
. Geological maps, hydrogeological conditions, ground
physical characteristics and ground thermal conductivity;
and,
. Local environment to install shallow geothermal systems:
geological conditions and climate.
4. CURRICULA FOR GSHP DRILLING AND
INSTALLATION
A European expert platform dedicated to the drilling and
installation part of a GSHP will be established. It involves
the creation of Curricula for drillers and installers, and the
creation of contents for the work items identified in the
Sanner et al.
4
Curricula. The objective is to provide the content of the
curricula and didactic material for the drillers who would
opt for a professional activity in the GSHP area.
The platform of experts will define the:
. Programme of education, including necessary content and
skills requirements to train drillers;
. Didactic materials to prepare the learning materials for
drillers; and,
. Identification of profile and required professional
experience of the teachers for the training of the trainers.
The objective here is to create European materials, updating
the existing ones, and targeting them more to professionals.
Specific materials have to be created for vocational training
for the drillers. From our point of view, existing training
material for drillers is more or less specific for each country
(legal aspects, but also focuses on a few techniques locally
used).
The objective is to collect existing materials in the EU
countries, and to propose a homogeneous material. This
material could be translated and completed with national
data and legal information.
5. CREATION OF NECESSARY
TEACHING/LEARNING MATERIALS AND OF THE
E-LEARNING PLATFORM
The panel of experts will work to develop the necessary
teaching system to support Geothermal Heating and
Cooling and train professionals (geologists, drillers,
installers, salespersons, planners and others) with an e-
learning platform and other learning tools.
The goal is to develop best practice documentation and to
create all the necessary documents to help in the training
courses. The documents will be used during the courses, to
be disseminated and for the courses organised after the
project. The documents will be in English, German, French
and Spanish. They will be adapted for the 8 project targeted
countries to take into account the national specifications.
An e-learning platform will be created to train mainly
designers all over Europe but the information will be
available publicly. The information will be free and online.
6. ESTABLISHMENT OF CERTIFICATION
FRAMEWORK AT EUROPEAN LEVEL AND
PROPOSAL FOR STANDARDISATION
Certification means that an installer has demonstrated
necessary skills, knowledge and ability typically required of
a practitioner to competently install and maintain a GSHP
installation. Certification is provided via training
programmes for designers, drillers and installers. These
training programs need to be accredited by a credible
authority to make sure they apply sufficiently stringent and
uniform training standards and are suitably designed to
reach their goals. One part of the project aims at presenting
uniform training programmes with a certification
framework to be replicated in the EU.
The goal is to propose a framework permitting the
certification of professionals having followed and
succeeded in the learning and e-learning courses dispensed
by Geotrainet. This framework will result in the adoption of
comprehensive schemes for accreditation and certification
based on jointly elaborated and agreed success criteria.
The certification will concern the different categories;
geologists, designers, installers and drillers. The
certification will be issued on a voluntary basis by the
national competent authorities in close consultation with the
relevant stakeholders, allowing it to be recognized on an
EU-level.
The project will underline the advantages of a Certification:
it can be a help in access to incentive and support
programmes, and may become a requirement with respect
to environmentally friendly drilling and installation.
To complete the European certification framework,
standards and codes will be suggested for the ground part of
a GSHP (from the existing ones or new ones) to contribute
to the creation of an uniform market.
The goal is to avoid unskilled work and develop a
harmonized European market. For the heat pumps, EN
standards are well adapted and allow for a free circulation
of machines and components within the common market.
For the ground side of shallow geothermal installations,
relevant standards and codes exist only in a few countries
with developed GSHP market (AT, DE, SE and CH). In FR,
IE and NL the matter is somewhat covered, and work is
ongoing on developing standards and codes. A common
EU-wide harmonisation is not in sight. An approach for
common standards can be seen between AT, DE and CH,
where geology and work practice is similar.
The eight target countries will organize direct training
courses. The logistic base for each training course will be
ensured by the local partner involved in the project. There
will be 8 direct training courses: 2 for trainers, 3 for drillers
and 3 for designers. In addition, the WP covers two e-
learning courses, one for trainers and one for designers. The
total period for this WP corresponds to month 6 until month
26. The levels of existing skills and knowledge expected of
the people who are to be trained are:
For Designers/Planners:
. Students: post graduate, more than 3 years in geology,
hydrogeology, etc;
. Professionals: engineers, geologists, technicians with 5
years of experience
For Drillers:
. Professionals with 3 years of experience;
. Students with background in mechanics.
In the case of shallow geothermal installers, accredited
training programmes will be offered to installers with
working experience, who have undergone, or are
undergoing, the following types of training: as a driller or
pipe layer and having basic geological skills as a
prerequisite. The evaluation system consists of two parts:
a) an assessment of the skills and knowledge of the
professionals having taken the course
b) an evaluation questionnaire filled in by the course
participants on the quality and relevance of the course
Sanner et al.
5
c) an overall evaluation report on the training courses,
summarising the results of the course and the evaluation
questionnaire filled in by the students
The theoretical part of the shallow geothermal installer
training will cover geothermal resources and ground source
temperatures of different regions, soil and rock
identification for thermal conductivity, regulations on using
geothermal resources, determining the most suitable
geothermal heat pump system, system layout, drilling
technologies, installation of borehole heat exchangers, well
construction, pressure testing, logistics, building laws and
safety.
The training will also provide good knowledge of any
European standards for shallow geothermal, and of relevant
national and European legislation.
At the end, the level of skills achieved and certified as a
result of the proposed training courses will be that the
installers demonstrate the following key competences:
. understanding geological and geothermal parameters of
the ground and knowing their determination, nomenclature
and identification of soil and rock types, preparing borehole
reports including lithology, groundwater, etc.; basic
geological and hydrogeological knowledge;
. familiarity with different drilling and digging
technologies, choice of the optimum drilling method,
ensuring protection of the environment (in particular
groundwater) while drilling;
. ability to install borehole heat exchangers, to grout,
backfill or otherwise complete the ground source system,
and to perform pressure tests; skills for welding of plastic
pipes and other connection methods;
. ability to construct groundwater wells, to install the
relevant pipes, pumps and control systems; and,
. ability to perform the relevant documentation including
identification and drawing of drilling locations.
7. CONCLUSIONS
The European Union adopted in December 2008 the
Climate and Energy Package.
Agreement has been reached on the Directive on the
promotion of the use of energy from renewable sources:
have 20% RES by 2020 in the European Union.
For the first time, each EU Member State has a legally
binding renewables target for 2020 along with a clear
trajectory to follow. By June 2010 the Member States will
draw up Renewable Action Plans detailing the ways in
which they are to meet their 2020 targets, which will then
be submitted to the Commission for assessment. They will
report on how they are doing every two years. These
measures will lead to real progress in the 27 countries.
One important measure is that “Member States shall ensure
that certification schemes are available by 2012 for
installers of shallow geothermal systems and heat pumps”.
Indeed, heat pump, shallow geothermal and other small-
scale installers shall be certified by an accredited training
programme or training provider.
Research in Europe shows that one of the barriers to a
sustainable and growing GSHP market is the lack of
appropriate skilled personal, and quality of design and
works are not always satisfactory. To keep quality up, a
certification program for GSHP workforce is required.
The objective of “Geo-Education for a sustainable
geothermal heating and cooling market” project, is to
develop a European Education program to get towards the
certification of geothermal installations:
Develop the training of professionals involved in Ground
Source Heat Pump installations (GSHP)
Create a EU-wide certification scheme for both planners
and installers of GSHP.
ACKNOWLEDGEMENT
Project GEOTRAINET is funded by the European Union
under the Intelligent Energy Europe Program. Nevertheless,
The responsibility for the content of this publication is with
the authors only.
REFERENCES
Directive 2009/28/EC of the European Parliament and of
the Council of 23 April 2009 on the promotion of the
use of energy from renewable sources and amending
and subsequently repealing Directives 2001/77/EC
and 2003/30/EC
Proceedings World Geothermal Congress 2010
Bali, Indonesia, 25-29 April 2010
1
Country Update for the United Kingdom
Tony Batchelor, Robin Curtis, Peter Ledingham
GeoScience Limited, Falmouth Business Park, Bickland Water Road, Falmouth, Cornwall TR11 4SZ, UK
Keywords: Country update, United Kingdom, low
enthalpy, direct use, GSHP, mine workings, EGS, HDR
ABSTRACT
The exploitation of geothermal resources in the UK
continues to be minimal. There are no proven high
temperature resources and limited development of low and
medium enthalpy resources. Work has continued on
assessment of a completed deep borehole at Eastgate. The
main area of UK activity in the last five years has been in
the rapid growth of ground source heat pump installations.
Following worldwide resurgence of interest in Engineered
Geothermal Systems, new activity in this field has been
rekindled in Cornwall. Two new projects have been
announced; a 10MWe scheme in west Cornwall and a
3MWe scheme to supply electricity and heat to the Eden
Project in mid Cornwall. The use of flooded mine workings
as a source of fluid for major projects continues to be
evaluated.
1. INTRODUCTION
In a worldwide context, the exploitation of geothermal
energy in the UK remains minimal. The geological and
tectonic setting precludes the evolution of high enthalpy
resources close to the surface and only low to moderate
temperature fluids have been accessed by drilling in
sedimentary basins in the south and northeast of England.
are accessible. Elevated temperature gradients and high heat
flows have been measured in and above some granitic
intrusions, particularly in southwest England. These
granites were previously the site of the UK’s earlier Hot
Dry Rock programme in Cornwall. Recent work at the
Eastgate borehole in northeast England also suggests higher
than anticipated temperature gradients and hence increased
focus on the possible application of geothermal heat in that
region.
Two major legislative drivers are now contributing towards
increased interest in geothermal activity in the UK. The first
is the European Union’s 20/20/20 campaign – viz 20%
Renewable Energy (electricity, heat and transport), and
20% CO2 reductions (below 1990 levels) by 2020. The
second is the 2008 UK Climate Change Bill – the first in
the world, that commits current and future UK governments
to publicly declared CO2 reduction targets. These
overarching drivers translate into lower level legislative
drivers such as the energy/carbon components of the
Building Regulations, and planning requirements for new
buildings. To assist with the achievement of these targets a
number of grant aided schemes are in place or are evolving.
As well as ongoing support for mainstream renewable
electricity generation, enabling legislation was passed in
2008 to allow for feed-in-tariffs for both small scale
electricity generation and for renewable heat. The effect of
this is leading to increased activity in the rapidly growing
ground source heat pump industry, and to a renewed
interest in the possibility of EGS systems to deliver
electricity and/or heat.
The new level of interest in all things geothermal in the UK
is possibly reflected in three recent symposia/meetings held
on the subject:
• The Royal Academy of Engineering held a one day
seminar “The heat beneath your feet: Geothermal
energy in the UK” in April 2009 – see
http://www.raeng.org.uk/events/pastevents.htm for
details and presentations)
• The Geological Society held a packed evening meeting
on Enhanced Geothermal Systems in May 2009. (see
http://tinyurl.com/ludrrb)
• The Institute of Civil Engineers devoted its specialist
2009 Geotechnique Symposium in Print to the topic of
“Thermal Behaviour of the Ground” which covered a
number of topics of relevance to geothermalists. A one
day symposium in May 2009 in London reviewed and
discussed all of the papers that were accepted for
publication. (see http://tinyurl.com/n9v9k5).
2. GEOTHERMAL UTILISATION
There is no electric power generation from geothermal
resources in the UK (See Table 1).
The City of Southampton Energy Scheme remains the only
exploitation of low enthalpy geothermal energy in the UK.
The scheme was started in the early 1980s when an aquifer
containing 76oC fluid was identified at approximately 1800
metres in the Wessex Basin. Construction of a district-
heating scheme commenced in 1987 and this has since
evolved and expanded to become a combined heat and
power scheme for 3,000 homes, 10 schools and numerous
commercial buildings. (see: http://www.energie-
cites.org/db/southampton_140_en.pdf )
The famous hot springs at Bath have long been a tourist
attraction among the Roman architecture of the ancient city.
Now the baths, together with four adjacent listed buildings,
have undergone a major refurbishment, which began in
2000 under a Millennium Commission grant. Despite
technical difficulties during the refurbishment, the baths
were reopened in 2008 and are now fully operational. (see
http://www.thermaebathspa.com/ )
Greater use is being made of groundwater for a number of
heating and cooling projects in London. Traditionally used
for hospitals, swimming pools and factories, more novel
applications are now being considered. The new Greater
London Authority building in central London is one of the
greenest buildings in the city, with both passive and active
energy design elements. Among them is the use of water
from the aquifer beneath London, which provides air
conditioning and is then recycled for use in toilets and
irrigation. Open loop geothermal systems have been used to
heat and cool several other prestigious projects in the UK
recently; the Queen’s Gallery, Portcullis House and the
Batchelor, Curtis, Ledingham.
2
Mayor of London’s offices all use this type of system.
These systems in London use water from the naturally
porous chalks and sandstones under the city. Several of
these projects are described in a recent GRC Bulletin on
geothermal energy in the UK (Hodgson 2009).
3. EXPLOITATION OF FLOODED MINES
A number of mine workings have been abandoned in recent
years in the UK and most of them have now flooded, or are
flooding. In many areas these represent a renewable energy
resource that can be exploited now with current technology.
Any project with a heating, hot water or cooling load in the
vicinity of mine workings is a potential candidate to use the
resource.
The mines reached depths in excess of 1000m with rock
temperatures of over 50oC. It is estimated that more than
25% of the mined volume still forms permeable and open
pathways in the rock despite the collapse of the old
workings. This mine water energy resource is one form of
an open loop, low temperature geothermal resource that is
in common use throughout the world. However, the
underground voids created by mining allow the ground
water to accumulate in otherwise low permeability
formations where it can be pumped out for use.
Several projects using mine water as the energy source are
already in operation; two are in Glasgow, heating blocks of
apartments. Major minewater projects described in the 2005
Country Update report (Batchelor, Curtis, Ledingham 2005)
at Midlothian in Scotland and at Camborne in Cornwall
have been in discussion in the last five years – but it
currently seems unlikely that either will proceed in the
near future.
There are no technical barriers to putting the old mine
workings back to work in sustainable developments to
provide heating, hot water and cooling. However, the issues
of surface and subsurface ownership, licences for
abstraction and discharge, the control of pollution and the
potential claims of mineral owners are issues that need
resolution for any particular project. In addition, the UK
still has difficulty in establishing planning and financing
schemes to develop and control district heating schemes.
These legal and commercial issues present major barriers to
the development of these minewater based systems –
despite the urgency for developing low carbon alternatives
to traditional methods of heating and cooling.
4. GSHPS
As with the last update report, the major area of UK
geothermal activity in this period has been the upsurge in
interest in ground source heat pumps (GSHPs). Starting
from a very low base, the level of activity is probably in the
region of about 3000 – 5000 installations per year. Whilst a
handful of these are larger scale open loop systems
(~500kW – 2MW), the majority are closed loop systems.
These range in size from 3.5kW heating only systems in
social housing, through to multi MW installations
delivering heating and cooling. The main driver for this
activity has been the realization that GSHPs connected to
the UK grid can offer significant reductions in overall
carbon emissions compared to traditional methods of heat
delivery. With projected improvements in the carbon
intensity of the UK electricity generation grid, GSHPs will
be able to deliver even larger carbon reductions with time.
The main funding schemes have been the government’s
Low Carbon Building Programme and the new Carbon
Emission Reduction Target (CERT) scheme - both of
which are focused on carbon reductions in the building
sector. The latter has been particularly effective in allowing
the delivery of over 1000 GSHP installations in the social
housing sector where it is particularly challenging to deliver
affordable, whole house, low carbon heating – often as
retrofits to existing housing stock.
The industry is still embryonic in the UK compared to other
northern European and North American countries, but a
wide range of projects are now being tackled. New build
and retrofit social housing schemes through to large
commercial and institutional projects and a wide range of
domestic installations are now operating at locations
throughout the UK. The government grant programmes
have led to the development of the Microgeneration
Certification Standards for GSHPs. The recently developed
EU HP-Cert training course has been trialed at two
locations in the UK, and the first of the GSHP designer and
driller courses developed under the EU GeoTrainet project
has been attended (http://www.geotrainet.eu/moodle/) to
see how it will fit with UK practice. The UK Ground
Source Heat Pump Association (http://www.gshp.org.uk)
evolved from a club to a formalized trade association in
2006 and has held annual conferences since then. A
domestic Heat Pump Association has also been formed by
BEMA (British Electrical Manufacturers Association) for
heat pump manufacturers to actively promote heat pump
activity, including GSHPs, in the UK. All of the major
domestic heating manufacturers now offer GSHPs in their
portfolios of heating (and cooling) equipment. The two
yearly GeoDrilling exhibition and symposium was re-
launched in 2005 with a focus on GSHP activity which has
continued to be reflected in the subsequent bi-annual shows
in 2007 and 2009. Some of the growing interest in this
activity is reflected in two recent publications – an English
translation of a popular German language GSHP
installation manual (Ochsner 2008), and a completely new
book on “Thermogeology” (Banks 2008).
5. THE EASTGATE BOREHOLE
The Eastgate Geothermal Exploration Project commenced
in 2003 to investigate the potential exploitation of the
Weardale Granite in Northeast England. Local minewater
chemistry indicated the presence of shallow mineralized
fluids that had been in contact with rocks at much higher
temperatures and pressures. This water was feeding into the
shallow mine workings from a steeply dipping fracture
structure known as the Slitt Vein, which became the target
for deep exploration drilling.
A 995m deep vertical borehole was completed in 2004,
penetrating more than 700m into the buried granite.
Logging, testing and sampling programmes followed and
interpretation of the results continues to the present. The
maximum bottom hole temperature measured was 46oC. A
highly productive zone at 411m produced significant yields
during testing at temperatures of 27 to 30oC
The data collected has led to a re-evaluation of the local
geological structure and the in-situ geochemical signatures,
and to a revival in interest in applying geothermal potential
to urban areas in the northeast of England. (Manning et al
2007)
The comprehensive work by the British Geological Survey,
(reported by Downing and Gray, 1986) is still the definitive
reference to the geothermal prospects of the UK.
Batchelor, Curtis, Ledingham.
3
6. EGS / HDR
In the 1980s and 1990s Cornwall, in the southwest of
England was the focus of the UK’s research into Hot Dry
Rock geothermal energy.
During 2005 Tester at MIT and a panel of international
experts carried out a review of the potential for EGS
systems. Three UK players (Batchelor, Baria, Garnish)
participated in this consultation which resulted in a
significant publication covering the technology and its
potential for energy generation (Tester et al 2008). The
high profile release of this document in the USA, together
with the current EGS activity in Australia has caused a
worldwide revival of interest in EGS technology.
This is also the case in the UK, where reviews of the
original work at Rosemanowes in the 1970s-80s in the light
of more recent experience, are leading to potential projects.
Most of Cornwall is underlain by high heat production
granites with measured heat flows well in excess of
100mW/m2 and temperature gradients in the range 30 to
40oC/km. The granites outcrop at several locations but are
elsewhere buried beneath Devonian marine sediments up to
several km thick.
The deepest temperature measurements made are at the
HDR research site, where 100oC was recorded at a vertical
depth of 2.7km. Higher temperature gradients are predicted
in other locations, based on near surface heat flow work,
and it is expected that temperatures in the range 160 to
180oC may be encountered at depths of 4 to 4.5km.
At the time of writing, two proposed power generation
schemes are being considered; a 10MWe project in west
Cornwall and a 3.5MWe project to supply power and heat
to the Eden Project in mid Cornwall. Both projects plan to
be drilling deep wells in 2010 or 2011.
7. CONCLUSION
In conclusion, ground source heat pump systems offer the
most immediate opportunity for geothermal utilization in
the United Kingdom. The minewater and deep aquifer
sources offer a strategic resource with local applications
and benefits when appropriate heat loads are located
nearby. Deep and hot formations with temperatures in the
175 – 200oC range at approximately 5000m depth appear to
be limited to south west England and will require
considerable developments in technology to be exploited
effectively.
ACKNOWLEDGEMENTS
The views and opinions stated in this paper are those of the
authors and not of any official or UK Government
organization.
REFERENCES
Hodgson, S: 2009 – Geothermal Resources Council
Bulletin Vol 38, No 1, January/February 2009.
Batchelor, A.S, Curtis, R.H, Ledingham, P: Country Update
for the United Kingdom, WGC Proceedings, Antalya,
Turkey 2005.
Ochsner, K: Geothermal Heat Pumps – A guide for
Planning & Installing, Earthscan, ISBN-13: 978-1-
84407-406-8, 2008
Banks, D: An Introduction to Thermogeology: Ground
Source Heating and Cooling. Blackwell. ISBN: 978-1-
4051-7061-1. 2008.
Manning, D. A. C, Younger, P. L, Smith, F. W, Jones, J. M,
Dufton, D. J. and Diskin, S: A deep geothermal well at
Eastgate, Weardale, UK: a novel exploration concept
for low-enthalpy resources. Journal of the Geological
Society of London, 164, 371-382. 2007.
Tester J et al: The Future of Geothermal Energy – Impact
of Enhanced Geothermal Systems (EGS) on the United
States in the 21st Century, published by MIT, ISBN: 0-
615-13438-6, 2006. Available from
http://geothermal.inel.gov/
Downing, R.A and Gray, D.A: Geothermal Energy. The
potential in the United Kingdom, HMSO, ISBN 0 11
884366 4, 1986
TABLE 1. PRESENT AND PLANNED PRODUCTION OF ELECTRICITY (Installed capacity)
Geothermal Fossil Fuels Hydro Nuclear Other Renewables
(Specify) Total
Capacity
MWe
Gross
Prod.
GWh/yr
Capacity
MWe
Gross
Prod.
GWh/yr
Capacity
MWe
Gross
Prod.
GWh/yr
Capacity
MWe
Gross
Prod.
GWh/yr
Capacity
MWe
Gross
Prod.
Gwh/yr
Capacity
MWe
Gross
Prod.
GWh/yr
In Operation in
May 2009 60,796 291,757 4,256 5,962 12,098 88,686 1,394 6,708 78,544 393,113
Under
Construction in
May 2009
Funds
committed, but
not yet under
construction in
May 2009
Total project
use by 2010
Batchelor, Curtis, Ledingham.
4
TABLE 2. UTILISATION OF GEOTHERMAL ENERGY FOR DIRECT HEAT AS OF MAY 2009
(other than heat pumps)
Maximum Utilisation
Annual Utilisation
Temperature C Enthalpy kJ/kg
Locality
Type
Flow Rate
(kg/s) Inlet Outlet Inlet Outlet
Capacity
(MWt)
Ave Flow
(kg/s)
Energy
(Tj/yr)
Capacity
Factor
Southampton
(Western
Esplanade)
Penryn
(Gabbons
Nursery)
Bath Spa
(Avon)
D
G
B
15
5
13
72
22
46.5
28
10
2.761
0.251
12.5
5
72.545
7.914
0.83
1.0
TABLE 3. GEOTHERMAL (GROUND SOURCE) HEAT PUMPS AS OF MAY 2009
Locality
Ground or
Water
Temp C
Typical
Heat Pump
rating
(kW)
Number of
Units Type COP
Heating
equivalent
Full Load
Hr/Year
Thermal
Energy
Used
(TJ/yr)
Cooling
Energy
(TJ/yr)
~4500
domestic sites
throughout
UK
9 -13 Avg 7 (3.5 to
16 kW) ~ 4500 V And H 3 to 4 1800 204
~ 500
commercial &
institutional
sites
throughout
UK
9 – 13 Avg 200 (30
– 2500 kW) ~ 750 Mainly V 3 to 5 1500 405 250
Total 609 250
Proceedings World Geothermal Congress 2010
Bali, Indonesia, 25-29 April 2010
1
Geothermal Prospects in the United Kingdom
Jon Busby
British Geological Survey, Keyworth, Nottingham, NG12 5GG, UK
Keywords: Geothermal resources, GSHP, EGS, United
Kingdom
ABSTRACT
Geothermal energy development in the UK has been
limited, partly due to the lack of high enthalpy resources,
but also due to the availability of cheap fossil fuels during
the 1980s and 1990s. However, with the advent of
renewable energy sources to combat climate change and the
need to replace diminishing fossil fuels, geothermal is now
in a good position to contribute to the energy mix. In this
paper, some of the geothermal prospects are reviewed and
some recent work from the British Geological Survey in the
following areas is presented:
• The potential of combined heat and groundwater flow
modeling and the latest three-dimensional geological
models are being assessed for use in ground source
heat pump prospecting.
• Temperatures in the shallow sub-surface have been
collated and compared to modeled results in order to
identify thermal anomalies that would be advantageous
for direct use applications or ground source heat
pumps.
• There is renewed interest in EGS within the granite
batholith of southwestern England, and a reappraisal of
the Hot Dry Rock potential of the Scottish granites
suggests that this resource may have been
underestimated.
1. INTRODUCTION
The United Kingdom is situated on the stable foreland of
Europe and is devoid of active volcanism and high heat
flows that result from tectonic activity. This at least
partially explains why geothermal energy plays a very small
role in the UK. It was estimated in 2006 that all renewables
only contributed 1.5% of the UK’s energy mix (DBERR,
2008), and geothermal only contributed a fraction of this.
However, when comparisons are made to countries in a
similar tectonic setting, it is clear that the UK is
underutilizing this potential resource. In 2005, Sweden was
reported to have 3840 MWt of installed direct use
geothermal capacity (Lund et al., 2005). The lack of
geothermal development has largely been a result of the
availability of North Sea natural gas that provided a cheap
and secure energy supply throughout the 1980s and 1990s.
However, with the passing of peak hydrocarbon production
in the North Sea and new renewable energy targets (15% by
2020; DBERR, 2008), geothermal resources are being
reappraised. In this paper, previous assessments of the UK’s
geothermal resources are reviewed, and future prospects are
discussed.
2. THE GEOTHERMAL ENERGY PROGRAM
The geothermal potential of the UK was investigated by a
program funded by the UK government and the European
Commission that ran from 1977-1994. It comprised three
elements: an appraisal of heat flow, an investigation of the
potential of hot brines in deep sedimentary aquifers that
might be suitable for electricity generation or direct use
applications, and an investigation of radiothermal granites
that might be exploited as Hot Dry Rock (HDR) reservoirs.
The results have been summarized in Downing and Gray
(1986a, b), BGS (1988), Parker (1989, 1999) and Barker et
al. (2000).
The heat flow map of the UK is shown in Figure 1 (Lee et
al., 1987; Downing and Gray, 1986a, b; Rollin, 1995;
Rollin et al., 1995; Barker et al., 2000). It comprises 212
heat flow measurements augmented by 504 heat flow
estimates. There is a fairly uniform background field of
around 52 mW m-2. Areas of increased heat flow are
associated with the radiogenic granites in southwestern
England (mean value of 117 mW m-2) and the buried
granites of northern England. Values are also above the
regional background over the batholith in the Eastern
Highlands of Scotland. The average UK geothermal
gradient is 26 °C km-1, but locally it can exceed 35 °C km-1.
Figure 1. Heat flow map of the UK.
Proceedings World Geothermal Congress 2010
Bali, Indonesia, 25-29 April 2010
1
Revisiting Deep Geothermal Power in the United Kingdom
Ryan Law, Tony Batchelor and Pete Ledingham
Geothermal Engineering Ltd, 82 Lupus St, London, SW1V 3EL
Keywords: United Kingdom, Geothermal
ABSTRACT
It is predicted that geothermal power will play an increasing
role in renewable electricity generation (MIT, 2006). In
addition, a growing proportion of geothermal power is
expected to be derived from deep, low permeability rocks.
Trials of deep geothermal systems in low permeability
rocks first started in the mid 1970s, in the United States, the
United Kingdom and Japan. The United Kingdom research
project ran for the best part of 15 years and contributed
substantially to the technical knowledge of rock mechanics
and reservoir development.
This paper summarises the geothermal resource in the
United Kingdom, the previous research project and the
proposed deployment of a 10MW pilot power plant. The
data from the original research project and other studies has
been re-examined and a potential site selected. In addition,
the lessons learnt from the original program will be applied
to both the drilling and reservoir development program.
Drilling of the exploration borehole is expected to start in
2010.
1. INTRODUCTION
As in many countries, the rapid increase in the oil price
during the 1970s led the United Kingdom to investigate
alternative energy resources, including deep geothermal. In
the mid 1970s the British Geological Survey (BGS) was
commissioned to assess the geothermal potential of the
United Kingdom. Despite its location on the stable fore-
land of Europe, remote from active volcanism and strong
tectonism, surface heat flows and geothermal gradients
indicated that economically useful temperatures of 60–
100°C would be reached at depths of 2 to 3.5 km (Dunham
1974).
The research that followed included the production of a
geothermal map of the UK published at a scale of 1:1 500
000 (Downing & Gray 1986) and ten-year deep aquifer
research programme, published by ETSU (1986). A
calculation was also made of the expected temperatures at
significant depth (7kms) and this is shown in Figure 1.
Although the calculated temperatures could be regarded as
relatively low compared to some of the hottest geothermal
resources in the World, it can be seen that, particularly in
far South West of the United Kingdom, the potential does
exist for deep geothermal power generation. These
prospects warranted further research and the Camborne
School of Mines started an extensive research into the rock
mechanics of deep geothermal reservoir creation. This
programme was undertaken at a site in the Rosemanowes
Quarry in Cornwall (Figure 2) and explored the possibilities
of developing the Carnmenellis Granite as a geothermal
reservoir.
2. SUMMARY OF PREVIOUS RESEARCH
The research project on the Carnmenellis granite started in
1977. From 1980, the project was funded mainly by the UK
Department of Energy. The objectives of the project were to
investigate the engineering requirements for developing
deep geothermal reservoirs, and to establish the size and
nature of the deep geothermal resource in southwest
England (Parker 1989). It was one of the largest
hydrogeological experiments carried out in the United
Kingdom, involving staff from a number of institutions.
Figure 1. Predicted temperature in °C at 7kms in the
UK (after Downing and Gray, 1986).
In Phase 1 (1977-80) of the project, boreholes were drilled
to 300 m depth. These were used to demonstrate that is was
possible to establish hydraulic connections between
boreholes by injecting water at high pressures, thus
increasing the permeability of the system by hydraulically
developing the natural joints in the granite. Water was then
circulated through these joints (Batchelor 1982).
Phase 2 (1980–1988) was considered to be more closely
related to the conditions required for commercial
exploitation of the technology and involved drilling two
wells to a depth of 2.1 km. A reservoir was created by