Hydro Power in water supply - seea.government.bg

Hydro Power in water supply

BGENERGY WEBINAR 13th April 2021

Jonas Jessen Ruud, Norconsult AS, Norway

• Introduction

• Advantages

• Examples from Norway

• General considerations, possible

challenges and conclusion

Agenda

3

Introduction

• Exchange pressure

reduction valves

• With electricity

producing turbines

• The presented examples from Norway

are roughly big enough to be built in

their own only as a hydro power plant.

• We are not presenting micry hydro,

exchange of reducer valve with specific

turbines. We are presenting proper

hydro power plants.

Introduction

2021-04-10 4

• I will present three hydro/water plants in

operation, with three different

characteristics.

• Hans Olav Nyland will present a plant

under construction, and not realized

projects

Introduction

Advantages

• Where large pressure reduction valves are used, electric

power can be produced by turbines instead

• Existing dams, buildings and penstock pipes can possibly be

utilized

• Water supply dams can have a large reservoir capacity

• It can be economic to utilize the produced power internally,

before selling excess power externally to the electric grid

Examples from Norway

• Examples of power plants in water treatment facilities in

Norway:

• Hydro power inside water treatment – Osavatn

• Hydro power outside water treatment – Espeland

• Hydro power separate from water treatment – Simavik

• Plant under constuction and not realized plants are presented by

Hans Olav Nyland

Osavatn; Hydro power inside water supply

• Initiated due to:

– Enough water pressure and water production

– Usable and existing dams, reservoirs and pressure pipes

– Space for a turbine inside the existing facilities

9

Osavatn and Espeland water supply system

Svartavatn

dam

408 maslOsavatnet

pond

308 masl

Espeland water

treatment plant

158 masl

Water treatment plant supply approx 87 000 inhabitants in Bergen,

Norway, and produce on average 0,4 m³/s drinking water


• Special features: – Hydro power plant with a vertical pelton turbine placed inside the

existing water supply facility.

– Dam and pressure pipe Ø700 utilized.

– The outlet of the turbine is directly into the raw water pond, in parallell with conventional pressure reduction valves.

• Nominal head H 90-100 m

• Nominal flow Q 0,78 m3/s

• Nominal output P 0,6 MW

• Annual production approx. 3,5 GWh

• Time schedule

– Planning starts in 2008.

– Concession 2009

– Tender and procurement 2010

– Construction 2011

– Power plant commissioned 2011-12


Water released directly to

the raw water pond below



– Enough water pressure and water production


– Space for a turbine outside the existing facilities

Espeland; Hydro power outside water supply



• Special features: – Hydro power plant with a vertical pelton turbine placed in a separate

builing outside the existing water supply facility.

– Dam and pressure pipe Ø700 utilized.

– The outlet of the turbine is into the raw water pond

• Nominal head H 145 m

• Nominal flow Q 0.78 m3/s

• Nominal output P 965 kW

• Annual production approx. 5 GWh

• Time schedule


– Concession 2009

– Tender and procurement 2010

– Construction 2011

– Power plant commissioned 2011-12


Inside the valve room


Technical challenges

• Many special challenges solved through the project;

– At Espeland, the intended turbine room is too small; new power

plant

– at Espeland, uncertain foundations for new power plant

– at Espeland; utilizing excess heat

– For both power plants; support, expansion and foundation of

new pipe systems into existing system

– implementation and control for new and existing valves in the

system, and reduce pressure rise.

– hydraulic optimalization for waterways, to minimize head loss

– Transformer inside the plant, with associated explosion and fire

danger

• The water treatment facility in full operation during

construction

Revenue Osavatn and Espeland

• Annual production approx 5+3,5 = 8,5 GWh

• Project costs approx 2,1 MUSD/8,5 GWh = 0,25 USD/kWh

(2011-prices. New penstock cost not included)

• Inhouse electricity is covered first, and excess power sold

comercially to the grid

• Excess heat from turbine generator used for heating the

building (30-70 kW depending on turbine load)

• High revenue and low cost!


– Enough water pressure

– Excess water


– Space for a power plant outside the existing facilities

Simavik; Hydro power separate from water supply


• Special features:

– Hydro power plant with a pelton turbine placed separately from the

water supply facility.

– The outlet of the turbine is into the ocean

• Nominal head H 210 m

• Nominal flow Q 0.7 m3/s

• Nominal output P 1,2 MW

• Annual production 7 GWh

• Time schedule


– Concession 2010

– Tender and procurement 2010-11

– Construction 2013-15

– Power plant commissioned 2015

Damvatn

Penstock pipe.

Existing

Simavika water

treatment plant

Power plant

New New valve

Penstock pipe

New

Dam Damvatn

Existing

Ocean

Water treatment plant supply approx 50 000 inhabitants in Tromsø,

Norway, and produce on average 0,3 m³/s drinking water

Main water supply

from other source



Simavika hydro power plant

Water

treatment plant

New turbine

New power station

Revenue Simavik

• Annual production approx 7 GWh

• Project costs approx 3,1 MUSD/7 GWh = 0,44 USD/kWh

(2015-prices)

• Inhouse electricity is covered first, and excess power sold

comercially to the grid

• High revenue and low cost!

Summary for the examples

• Typical features for interesting projects:

– Excess water resources and/or;

– High pressure and water production

– Innovative organization

– Usable and existing dams, reservoirs, pressure pipes and buldings with

enough space

– Grid connection

Special features for hydro power in water

supply

• Paint approved for drinking water supply

• Reduce risk of oil spill, by using electric actuators and/or

water hydraulic systems

• General use of stainless steel instead of painted steel

• Pelton turbines are chosen for small scale hydro power

because;

– Suitable for operation between 5-100 % load

– Generally low pressure rise in penstock pipe

– Less usage of space

– Can be placed directly on existing floor

Possible challenges

• Governmental rules and regulations; Existing dams and penstockscan suffer from other rules and regulations apliccable for hydropower production

• Retrofit of hydro power plant into existing water treatment plants is complex, reliable consultants, contractors and suppliers are needed

• Owner and operator not used to hydro power production. The ownerhas to be motivated. The organization must consider restructuring to handle the power plant

• Possible downtime for water supply during construction and commissioning of power plant

• Complex control systems and interface issues between power and water production, and the grid

• Grid connection and transformer capacity

Summary

• Where pressure reduction is necessary, power can be

produced

• Existing dam, buildings and penstock pipes can be used, this

means low investment costs.

– The examples from Norway are very economically viable

Questions?

• Thank you for your time!

• Jonas Jessen Ruud

Dam Svartavatn

Upstream Osavatn and

Espeland

Thank you

Documents

Hydro Power in water supply - seea.government.bg