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The Case for Distributed
Storage in Ireland
As its wind capacity becomes
significant
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Executive Summary
• Ireland has an outstanding wind resource...
• ...and can develop windpower commercially
at €50-60 per MWh
• Once capital costs are paid, the long term
marginal costs of wind power are very low
• The fuel-only price of power from gas is
already €70 – 80 per MWh...
• …and is more likely to rise than fall
Distributed storage can make wind penetration
viable up to 3,000 MW and even more
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Distributed Storage...
• ...closes the gap between day before forecasted
wind output and actual wind output
• ...and so reduces the need for spinning and hot
fossil stand-by plant to provide balancing power
• ...delivers primary, secondary and tertiary
operating reserve in the event of a trip in the
generation system
• ...delivers reactive power from many nodes
• ...can deliver a black start capability
The conditions for the commercial roll-out of
distributed storage are the best in Europe
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VRB Demonstration Plants World-wide
Place
Application
Specification
Start date
Kashima Kita PS, Japan
Load levelling
200 kW x 4 h
1996
Office building, Osaka
Load levelling demo
100 kW x 8 h
2000
Sanyo factory
Voltage sag,
load levelling
3000 kW x 1.5 sec
1500 kW x 1 hour
2001
Wind power, Hokkaido
Stabilization wind turbine
output
170 kW x 6 h
2001
Dunlop Golf Course
PV hybrid, load levelling
30 kW x 8 h
2001
University, Japan
Load levelling
500 kW x 10 h
2001
Stellenbosch U, SA
Load levelling
250 kW x 2 h
2001
EPRI, Italy
Peak shaving
42 kW x 2 h
2002
Pacific Corp, Utah
End of line peak shaving
250 kW x 8 h
2004
King Island, Australia
Stabilization wind turbine
250 kW x 8 h
2004
Tomamae Wind farm,
Hokkaido
Stabilization wind turbine
4000 kW x 2 h
2005
Nine Years - no re-invention of wheel needed
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Ireland’s dependence on gas - 1
Irish Generation Capacity by Fuel
Hydro
9%
HFO
13%
SSG & LFG
1%
CHP
2%
Gas
55%
Peat
6%
Coal
14%
55% ...and increasing
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Ireland’s dependence on gas - 2
Gas Capacity by Type
Condensing
steam
22%
OCGT
11%
30% Efficient
51% efficiency
impaired by
cycling
40%
efficient
CCGT
67%
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"Fuel Only" cost of power
Euro per MWh
Winter Price, 2006
August 2005
180
160
140
Price, October 2005
120
100
80
60
40
20
0
0.25
0.3
0.35
0.4
0.45
0.5
0.55
0.6
0.65
0.7
UK Gas, £/therm
CCGT
Condensing steam
Open Cycle GT
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When UK sneezes...
Expect
continued high
prices for gas
into the
indefinite future
Source: FT 6 Oct 2005 & OFGEM, UK
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THE GOOD NEWS!
Low Cost of Irish Wind Power
• High load factors achieved by wind
generators in Ireland...
• ...and low bank interest rates for good
wind projects
• ...mean Irish wind turbine owners can
obtain a good return from a feed-in
price of € 57 – 59 per MWh
John Ward – Murray Associates
October 2005
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But the value of Irish wind Power...
...is reduced by:
1. Stochastic nature of wind
2. Difference between actual wind output
compared with forecast on gate closure
previous day…
3. …therefore a need for balancing power
provided by “firm” fossil units…
4. …so losing CO2 advantages
5. Concentrations in “windy” west means wind
can provide almost no reliable capacity
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What can we learn from
Denmark?
• West Denmark has peak load of about
3700 MW and domestic consumption of
21 TWh (2004)
• Eirgrid’s peak is about 3800 MW and
domestic consumption of 26 TWh
(2004)
Comparably sized electricity systems
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Ireland & West Denmark
Demand 6 January 2004
4,200
3,700
3,200
Dem and 26 June 2004
2,700
2,400
2,200
2,200
2,000
1,700
1,800
1,600
1,200
1,400
1,200
1
2
3
1
4
2
3
5
4
6
5
7 6 8 7 98 10
11
12 13 14 15 16 17 18 19 20 21 22 23 24
9
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
ESB Generation Adequacy Report, 2002
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West Denmark
Wind Power & Net Power Flow
January 2005
Wind Load Factor 46.1%
2500
Wind power over
500 MW is
usually exported
2000
1500
1000
500
-500
-1000
-1500
-2000
Net Power Flow
Wind Power
13
721
701
681
661
641
621
601
581
561
541
521
501
481
461
441
421
401
381
361
341
321
301
281
261
241
221
201
181
161
141
121
101
81
61
41
21
0
1
MWh/h
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West Denmark
How Wind Output Affects Net Power Flow
Jan thro July 2005
2500
Trendline
Clear trend
2000
Wind
Output
kWh/h
Over 500 MW, Wind
net exports
predominate
1500
1000
500
0
-3000
-2500
-2000
-1500
-1000
-500
0
500
1000
1500
-500
Net Power Flows, MWh/h
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Intuition suggests...
• That without storage, wind power feed-in over
500 MW will be progressively more difficult to
manage...
• ...as growing capacity and high load factor
result in frequent output spikes
• Wind does not respect time of day and
seasonal power demand
• Large scale wind capacity needs storage
Curtailment is wasteful!
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Growth in Wind Capacity & Market Share
1000
900
800
West DK wind output
over 500 MW is most
often exported
10%
9%
8%
Expect
Increasing
curtailment
700
600
MW 500
7%
6%
5%
400
4%
300
3%
200
2%
100
1%
0
0%
2003
2004
2005
Wind Capacity
2006
2007
2008
2009
Wind's share of all MWh
EIRGRID: Generation Adequacy Report
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Batteries can restore this value
VRB battery at
Tomamae wind park,
Hokkaido
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Tomamae - Output smoothing
[kW] (2).battery is charging
(1). Sum of generators output
(3).Target output (T=short)
(3).Target output (T=Variable)
(3).Target output (T=large)
(2).Battery is discharging
Time[s]
Acknowledgement to J-Power
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Smoothing at Tomamae supplies
• ...grid quality power to Hokkaido
• reducing the number of fossil plants
required to balance minimum, summer,
night time loads...
• ...from two to just one fossil unit...
• ...saving fuel, operational personnel and
mechanical wear
Scale of Operations on Hokkaido is similar to Ireland
and West Denmark
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Forecasting still not perfect so
storage allows some balancing
Forecasts
Actual output
Source: EON Netz
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Irish Wind Capacity
•Wind’s concentration in West
•Will reduce firm capacity
•Which storage can restore...
•...to total sum of storage
capacity delivered
Acknowledgement: IWEA
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Storage
in milliseconds
50.5
Statutory limit (+/-0.5Hz)
Operational limit (+/-0.2Hz)
Frequency (Hz)
50.2
50.0
49.8
Continuous modulation service
10 s 30 s
60 s
Primary Secondary (to 30 mins)
10 mins
Reserves
49.5
Frequency fall arrested by
primary response
49.2
49.0
Lowest planned frequency
Start of auto demand disconnection
Aknowledgement: Lewis Dale, National Grid
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Also black start
Distributed storage gives system
• Regional clusters of instantly available
power for re-starting fossil units
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Favourable economics depend on...
• ...growing cost difference between raw wind
power and fossil plants, especially gas
• ...ability of storage to eliminate use of spinning
and hot fossil capacity for system balancing
– ...thus saving mechanical wear, fuel and CO2
• ...capacity income attributable from ability to
deliver instant primary and secondary reserve
• ...raising firm capacity offered from wind
– thus saving requirement to purchase new fossil
capacity
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Danish costs of balancing
Jan 2004 thro’ July 2005, West Denmark
1. Generated 7.9 TWh of wind power
2. ELTRA’s balancing costs were € 29.6 million
3. ELTRA purchased 1.97 TWh of balancing
power
•
….mostly for wind power
4. Balancing costs were € 3.74 per MWh of
wind generated
5. Balancing power purchased was 0.25 MWh
per MWh wind generated
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1.1 GW Wind – 200 MW Storage
• Capital cost of storage (say) € 400 M
• Unconstrained wind output 3.4 TWh / y
–
–
–
–
Balanced by 0.85 TWh balancing power
At (say) € 80/MWh costing € 68 million per year
…provided by battery instead of fossil units
Saving (say) > 312,000 t CO2 per year from balance power
• + 300 – 400 MW of instantaneous primary and
secondary reserve capacity at no fuel cost
• + instantaneously available black start capability
• + 200 MW x (say) 4 hours standby capacity
• + 300 – 400 MW, 20 minutes pulse capacity
Eirgrid to provide estimated values from records
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A significant Irish market justifies
study of local manufacture...
...of key components
• Cell stacks that can
be industrially
assembled
• Power Conversion
Units (PCS)
• Thus reducing costs
Cell stacks
PCS Units
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There is an important export
market
• Although the conditions for mass roll-out
of distributed storage are best in Ireland
• ...the underlying conditions making it
attractive in Ireland are common to the
whole of Europe
• Especially Denmark, Sweden, Scotland,
Germany and Spain
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European Market Size - Wind
Country
•
•
•
•
•
Germany
UK
Spain
Portugal
Sweden
Planned Wind Power
GW
25 – 35
10 – 20
20 – 30
5 –10
10 - 20
Ireland is (say) 3 GW
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1.
2.
3.
4.
Agree technical feasibility
Agree economic feasibility
Agree presentation documents
Presentations to, dialogue with
•
•
•
•
•
5.
6.
7.
Next Steps
ESB Grid
Commission for Electricity Regulation
SEI
IWEA
Others
Go – No go!
If go - accelerate significant demonstration at
Meenanilita
Parallel studies & large scale roll-out
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