Where will DESIRE get us?

Dr David Toke, Senior Lecturer, University of Birmingham. Note: some slides taken from

presentations made by Anders Andersen and Paul Woods to DESIRE seminar on

November 9th 2005

Aalborg University   PlanEnergi   Universität Kassel   Birmingham University   Tallinn Technical University

Energi- og Miljødata   Institut für Solare Energieversorgungstechnik   EMD DeutschlandLABEiN Technological Centre in Bilbao   Warzaw Technical University

Wind power: what do we do when there is no wind?

• Switch on a power station that would otherwise have been retired!

Having no wind is not a great problem

What can we do when there’s too much wind?

The necessity for CHP plants offering balancing of fluctuating Renewable Electricity Productions

3 last days in October in Western part of Denmark

-2000,0

-1000,0

0,0

1000,0

2000,0

3000,0

4000,020

01-1

0-29

00:0

0-01

:00

2001

-10-

3000

:00-

01:0

0

2001

-10-

3100

:00-

01:0

0

-50%

-30%

-10%

10%

30%

50%

70%

90%

Central Plants

Decentral. Plants

Wind Prod.

Norw ay Imp(+)/Exp(-)

Sw eden Imp(+)/Exp(-)

Germany Imp(+)/Exp(-)

El. consumption Jutland

Wind Share

Options for balancing

• Turn off some windmills

• Turn off a lot of conventional power stations

• Build bigger electricity inter-connectors

• Use CHP to balance wind power

CHP uses less gas than CCGT systems!

How balancing works

• When there’s too much wind……shut down engines and use heat in accumulators

• When there’s not enough wind turn on engines and……pump heat into accumulators

Picture of CHP unit with two heat accumulators (thermal stores) on left

Thermal storage - schematic

Boiler CHP

Thermal Store

Thermal Storage Principles

• Allows CHP to operate in day-time and store surplus heat to meet night-time heat demand

• Allows increase in CHP capacity by smoothing demand and maximising heat from CHP

• Enables a single large CHP to meet a lower summer demand without needing to dump heat

• CHP can operate at full output (for shorter periods) rather than modulating which maximises efficiency

• Hot water storage – temperature difference 30ºC to 40ºC• Chilled water storage – temperature difference 8ºC to 10ºC• Ice storage – latent heat• Eutectic materials

Thermal Store - Delivery

Thermal Storage - after

Charles Dickens Estate Portsmouth• 530 dwellings

• School and Arts and Leisure Centre

• 526kWe gas-engine CHP

• 70m3 thermal store

• Some blocks had electric heating

• New controls - no heat meters

How does balancing help in the short term?

1) CHP plant can co-operate to bid for the short term

operating reserves market, utilising thermal stores

2) CHP operators can use thermal stores to get peak

power prices

How can balancing help in the short term?

3) It can reduce BETTA penalties if CHP and

windfarms co-produce

Danish Gas CHP reduces CO2 emissions a lot better than CCGTs

0

20

40

60

80

100

relative units

(CCGT=100)

CCGT DanCHP dUKesCHP

CO2 emissions: CCGTs compared to Danish and UK statistics on gas engines

How to get a lot more good CHP

• Give CHP incentives according to efficiency of CHP system

• Give market confidence about prices for electricity

• Make good quality CHP mandatory for next 5 or ten years

• Make good quality CHP mandatory for all new buildings (where gas is available)

Country Tariff in p/KWh

Average capacity factor (%)

Annual Return per installed MW (£)

Germany 5.5(declining)

18 87,000

United Kingdom

5.0 (15 yr contract)

6.0 (10 yr contract)

8.0(annual contract)

28 123,000

147,000

172,000

Spain 4.5 28 110,000

http://www.plan.aau.dk/~ana/

United Kingdom2005

5.0 (15 yr contract)

6.0 (10 yr contract)

8.0(annual contract)

28 123,000

147,000

172,000

Country Tariff in p/KWh

Average capacity factor (%)

Annual Return per installed MW (£)

United Kingdom2005

5.0 (15 yr contract)

6.0 (10 yr contract)

8.0(annual contract)

28 123,000

147,000

172,000United Kingdom2011

4.0 (15 yr contract)

4.5 (10 yr contract)

5.3(annual contract)

28 98,000

110,000

130,000

In 2011 the Conservatives might be in office, and they may reduce prices for onshore wind……..