Renewable Energy and low carbon technologies assessment

for the Pembrokeshire Coast National

Park

Jane HawkesEnergy Consultant, National Energy Foundation

Technologies/resources agreed for assessment:

Biomass

Anaerobic digestion/biogas/hydrogen

Small scale hydro

Wind (medium/small)

Micro wind

Photovoltaics

Solar thermal

Heat pumps

District heating

Biomass - output up to 2MW

• Alternative solid fuel to conventional fossil fuels.

• Types of biomass fuel includes logs, wood chips, pellets derived from clean waste wood, forest residue / coppice products, and energy crops such as short rotation coppice (SRC).

• Primary product is heat and can also be used at larger scales for electrical power generation.

Local examples:

•Bluestone Holiday Village 2.5MW•Producers – Pembrokeshire Bio Energy

Anaerobic digestion/biogas/hydrogen

• Example of waste treatment – medium scale up to 2 MW, Small scale from 10kW

• Produces gas with a high methane/hydrogencontent from organic materials

• Feedstocks = agricultural,

household, industrial residues and sewage sludge

• Gas used to generate heat, electricity, or a combination

• Uses waste substances otherwise difficult to dispose of in an environmentally acceptable way.

Local examples:

•Caerfai Farm near St David’s•Proposal at Lawrenny Eco Village•Pemb Waste Strategy •Hydrogen farm - Carmarthenshire

Small scale hydro • Water flowing from a

higher to a lower level

• Passes through turbine to produce mechanical energy then turned into electrical energy by a generator.

• High head hydro sites are more likely to take place in hilly/ mountainous areas.

• majority of schemes are ‘run of river’

• 100kW to 500kW (poss up to 1MW)or 10 kW to 50kW

Local examples:

•Near Dinas off A487•Y Felin – St Dogmaels•Working mills – Solva, Tregwynt, Carew.

Wind • Uses the wind's lift forces to

rotate blades that turn a rotor to create electricity.

• Can be deployed singly, or in small clusters (2-5 turbines), or as windfarms (not considered here).

• Small scale < 25m to blade tip

• Medium scale 25m – 60m to blade tip

• Small/medium output >10kW to 500kW

• Connection to the grid required.

• Life span approx 25 years

Local examples:Carfai Farm – 20kW (above)

(Outside Park)•Lodge Farm N. Hubberston – 500kW•Castle Pill, E. Milford Haven – 490kW

Micro wind turbines

• Range 650W and 6kW• Building or mast

mounted• Connection to batteries

or grid• Typical working life of

20-25 years. • High position on a mast

or tower free from excessive turbulence and obstructions such as large trees, houses etc

Local examples:

Marloes Sands (above)

17 currently within the Park

Photovoltaics (PV)• Exploits the direct conversion

of daylight into electricity in a semi-conductor device.

• roof-mounted or free-standing in modular form

• Integrated into the roof or facades of buildings (solar singles, slates, glass laminates etc).

• Shadows from buildings, trees or other structures can significantly reduce the performance of a PV system.

• PV is one of the most expensive technologies in terms of cost per kW of electricity generated.

Local examples:

Druidston (above) Six currently within the Park

Solar hot water• Two main types of collector

are common in the UK: flat plate collectors and evacuated tube collectors.

• In both types, radiation from the sun is collected by an absorber plate in the collector, and is transferred as heat to a fluid

• Used to convey the energy to the domestic system using a heat exchanger.

Local examples:

Whitesands Café (above) Almost 100 in ParkPen y cwm – Pembrokeshire Housing Association

Heat Pumps (Typical domestic system 8 - 12kW)

• Captures the energy stored in the ground surrounding (or underneath) buildings or from rivers, canals, lakes or underground aquifers.

• Uses low grade thermal energy from ground, water or air and a refrigeration cycle to deliver heat energy at higher temps, (typically 40-45oC) or low temps, using a reverse cycle, for cooling (typically 6-12oC).

Local examples:

Carfai Farm (2 trench systems) (Outside Park domestic systems)Haverford West, Narberth, Carew

District heating

• Uses a centralised boiler to provide heat for a building complex or series of buildings.

• Can be heat from a single boiler, or heat from a combined heat and power (CHP) plant.

• Comprises a highly insulated “heat main” of flow and return pipes distributing hot water

• Connection to buildings via heat exchanger transferring heat via internal heating circuit

• Temperature and flow meters adjust the heat required and monitor heat used.

Local examples:

Proposal for DH scheme using biomass at Old School Business Centre Narberth (PLANED)

Wave & Tidal • Motion of waves & tidal

movement of water generate electricity in turbines offshore

• WAG responsible for planning offshore schemes. PCNPA responsible for onshore connections

• Marine schemes generally conditioned and feed into low-voltage distribution network(Western Power)

• WaveDragon Scheme is 7MW; Ramsey Sound project involves 8 x 1MW units

Local examples:

•WaveDragon (St Ann’s Head)•EoN/Lunar Energy (Ramsey Sound)