EPRI/MISO Pumped Storage
Workshop
Insights on Key Modeling Challenges and Studies of Energy
Storage for Ancillary Services
October 4, 2011
Sidart Deb
Storage Modeling Challenges
Fundamental Modeling
 A fundamental approach to analysis captures the financial and physical operations of
each element of the network over time.
Detailed
Representation
of Network
Components
Generation
Transmission
Markets
&
Physics
Detailed
Financial and
Physical
Operations
Temporal
Constraints
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Storage Modeling Challenges
Optimization Time Frames
Market clearing is geared towards
hourly operations
Big storage might need to be optimized
at the daily, weekly, monthly or even
annual level
Limited energy storage might need to
be optimized at the sub-hourly level
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Storage Modeling Challenges
Developing Bids and Offers
Market clearing operation requires that
generator offers and demand bids be
optimized
 For thermal units, offers can be connected to the
marginal cost of operating the unit
 For storage units, the marginal cost may be close
to zero
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Storage Modeling Challenges
Prices: Chicken and Egg Problems
 The best input to the pump/generate decision would
be the prices
 In a comprehensive modeling system, the output
would be the prices
 When prices are low, plants want to pump, but the
fact that they are pumping raises the prices
 When prices are high, plants want to generate, but
the fact that they are generating reduces the prices
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Storage Modeling Challenges
Effectively Considering Ancillary Services
Storage Unit
Generating Size
Pumping Size
Rountrip Efficiency
Spinning Reserve Capability
Market Prices
Energy Price $ 30.00
Time = 1
Spin Price
$ 10.00
Time = 2
Energy Price $ 37.50
Spin Price
$ 10.00
100MW
100MW
0.75%
25MW
Energy-Based Decision
Energy and Ancillary Service Decision
Pump
100 $ (3,000.00) Pump
100 $ (3,000.00)
Generate
Profit
75 $ 2,812.50 Generate
Capacity
$ (187.50)
75 $ 2,812.50
25 $ 250.00
$
62.50
Becomes much more complicated when incorporating other factors
• Multiple Time Steps
• Inventories
• The fact that these prices are not known in advance
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Recent Studies
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Recent Studies
Impacts of Storage in Addressing Regional Wind Penetration
Client’s objective Evaluate the ISO system benefits of energy storage system deployment wind penetration
scenarios
Client
EPRI Energy Storage Program
Regions
ERCOT, NYISO and PJM
Approach



The ERCOT, NYISO and PJM systems were chosen for the energy storage system
assessments. A single study year was selected for the market simulations of energy storage
portfolios which included compressed air energy storage, bulk batteries and distributed battery
systems.
Market simulations were conducted using the UPLAN market simulation model and its
underlying suite of databases as the analytical platform. EPRI provided estimates of cost and
performance of the energy storage options.
Study assumptions included inputs of wind penetration and location and the transmission grid
configuration for the study year.
Benefits



The research findings will help define more clearly the technical, performance, operational and
functional characteristics of storage systems to support renewable integration
EPRI members such as electric utility strategic planners, resource planers, R&D managers and
Independent System Operators can use the results of this work to best estimate how much
storage and what type of storage systems are optimal and what locations are most promising.
Further the understanding of critical variables that influence the role of storage - market rules,
generation mix, T&D robustness, types and sizes of loads, location of wind relative to load, etc.
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Recent Studies
Compressed Air Energy Storage Cost Benefit Analysis
Client’s objective Acquire an independent view of the economic viability of CAES within the generation portfolio
Client type
Utility
Region
ERCOT
Approach




Provide the final specification of the physical and cost characteristics of the storage (cavern or
reservoir) including one or more locations, as well as the engineering, performance and cost
characteristics of the CAES facility itself (compression, turbine/generator, and balance of plant) in
collaboration with the Engineering Group
Perform an independent analysis to forecast the economic value of developing and operating a
CAES facility in conjunction with the procurement of wind power that would help meet renewable
energy goals
Use UPLAN to simultaneously simulate both (i) the ERCOT market – including the transmission
system - and (ii) the CAES and wind facilities to forecast energy and ancillary service prices and
the CAES facility operations, costs and revenues
Conduct sensitivity/volatility analysis to determine the changes in revenues and value of entire
portfolio due to uncertainties in the market fundamentals such as fuel prices and demand
Benefits



Acquisition of detailed analysis of the costs, benefits, risks, and transmission congestion impacts
associated with the incorporation of CAES into the generation portfolio
Ability to evaluate investment performance of specific facilities such as transmission, storage
systems or wind
Societal benefits in terms of avoided transmission upgrades and lower energy prices to load
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Recent Studies
Quantifying the Value of Hydropower in the Transmission Grid
Client’s objective Develop and demonstrate an innovative approach for quantifying and maximizing the benefits
provided by conventional and pumped-storage hydroelectric projects to transmission grids
Client
Department of Energy
Region
WECC
Approach



Develop references cases for 2010 and 2020 including existing and planned transmission, power
plants. Apply detailed modeling.
Evaluate modeling assumptions, plant operations with project stakeholders incorporate feedback
as well as input from other tasks within the project
Develop and compute scenario sensitivities including variations on energy futures, system
conditions and technological advancement
Benefits





A series of scenario analyses to quantify the benefits of conventional and pumped hydro power
A comprehensive set of plant operations under varying conditions
Quantification of expected plant participation in energy and ancillary markets as well as revenues
for each of the services provided
Insight into the flexibility of plants and their contribution to renewable integration
Value of advanced technologies (e.g. variable speed pumps)
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DOE Valuing Hydropower
Footprint and Transmission
 For this analysis, the entire Western Interconnect is being modeled, covering 1.8
million square miles of territory.
 Transmission
•
•
•
•
16,120 Buses
20,945 Lines and Transformers
Latest WECC path ratings
Hurdle Rates
 Functions and Services
•
•
•
•
•
Energy
Regulation Up
Regulation Down
Spin
Non-spin
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Preliminary Results
Annual Energy Generation Differences
 Renewable energy in California displaces fossil fuel based generation
 Pumped storage and renewables are up
50,000
TEPPC Future 1 Vs Baseline 2010
40,000
Biomass
30,000
Coal
Combined Cycle
20,000
CT+CT Oil+Steam+IC
10,000
Geothermal
Hydro
AZ-NM-SNV
CA-MX US
NWPP
RMPA
WECC
(10,000)
Nuclear
Pumped Storage
Solar
(20,000)
Wind
(30,000)
(40,000)
Generation by sub-region and technology (2020 less 2010)
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DOE Valuing Hydropower
Installed Capacity
 CC and CT technology additions to compensate for increasing demand and
renewables
120,000
100,000
Hydro
Solar
Wind
80,000
Pumped Storage
Geothermal
MW
60,000
Biomass
Nuclear
40,000
Steam
IC
20,000
CT Oil
CT
2010
2020
AZ-NM-SNV
2010
2020
CA-MX US
2010
2020
NWPP
2010
2020
Combined Cycle
Coal
WECC Total
Category
Diff (MW) Diff %
Biomass
579
50%
Coal
460
1%
Combined Cycle
4,430
9%
CT
5,131
25%
CT Oil
2
0%
Geothermal
2,253
76%
Hydro
741
1%
IC
0%
Nuclear
0%
Pumped Storage
0%
Solar
11,799
2469%
Steam
(1,812)
-9%
Wind
11,860
105%
RMPA
WECC sub-region
Figure: Installed Capacity in 2010 and 2020 by WECC sub-region (MW)
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DOE Valuing Hydropower
Pumped Storage Ancillary Service Participation
 Pumped Storage participation in markets other than non-spin exhibit a fairly consistent
pattern and favor peak hours when the unit is spinning.
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Simulation & Results
Pumped Storage Regulation Capability
 Variable speed pumps would greatly increase hydro’s ability to participate in ancillary
services.
Synchronous Services Provided
300
Capacity (MW)
250
200
150
With Variable
Speed Pumping
100
Without Variable
Speed Pumping
50
0
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Hour
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DOE Valuing Hydropower
Preliminary Results
 Preliminary results show pumped storage value increasing over time thanks to increased
variable generation and higher gas prices.
BaseLine
2010
AZ-NM-SNV
CA-MX US
NWPP
RMPA
Future 1
2020
AZ-NM-SNV
CA-MX US
NWPP
RMPA
Future 2
2020
Region
AZ-NM-SNV
CA-MX US
NWPP
RMPA
Unit
Size(MW)
198
3,375
314
560
4,447
198
3,375
314
560
4,447
198
3,375
314
560
4,447
Generation
(GWh)
278
4,125
541
1,137
6,081
336
6,750
622
1,173
8,880
335
6,736
620
1,171
8,863
Energy
Revenue
($1000)
16,305
225,097
30,096
62,265
333,763
26,322
467,976
47,764
88,973
631,036
19,299
358,404
35,175
73,900
486,778
Reserve
Revenue
($1000)
2,908
6,714
2,511
2,615
14,748
2,342
7,321
5,348
1,337
16,348
179
4,588
2,926
387
8,079
Net Income
($1000)
4,960
11,974
4,174
11,147
32,255
6,152
19,023
12,327
11,503
49,005
1,344
4,997
5,632
8,331
20,304
© 2011 LCG Consulting. All rights reserved. Do not copy or distribute without express written consent.
Average
Revenue
($/kW)
97
69
104
116
78
145
141
169
161
146
98
108
121
133
111
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Questions?
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