1. ETAAC Energy Sector Energy Storage ------------------------ Smart Grid July 12, 2007 San Francisco, CA

2. 1 Energy Storage Electric energy storage goal of the industry Cost-effective energy storage would benefit all areas of the energy value chain: generation, transmission, distribution, and end-use Key applications: firming large penetration of intermittent renewables, grid support, end-use load shifting, etc. Current energy storage systems are only marginally cost competitive. Costs need to come down by factor of 2-5 times. Need innovation and standardization as well as policy recognition. California is best market for accelerating storage use due to technology base, clean energy emphasis (especially intermittent renewables), and leading-edge policies.

3. 2 Energy Storage Technologies Many different energy storage technologies are available for use in storage for renewable integration applications  Pumped Hydro  Compressed Air Energy Storage  Lead-acid batteries  Nickel-cadmium batteries Each technology has advantages and disadvantages Not all of these technologies are appropriate for all applications  Lithium ion batteries  Sodium-Sulfur Batteries  Flow Batteries  Flywheels  Ultracapacitors

4. 3 Uses of Energy Storage

5. 4 Balancing Function - Area Control Hour Ahead Schedule Incremental Energy Decremental Energy Day Ahead Schedule Real Time Load MW Time Real-Time Economic Dispatch Every 5 minutes Upward Regulation Ancillary Services Regulation Spinning Reserve Non-Spinning Reserve Replacement Reserve Voltage Support Black Start capability Downward Regulation

6. 5 Loads & Resources Source: CEC PIER-funded study by GE Energy, July 2006 Temporal Pattern: July 2003 Average Day

7. 6 July 2006 Heat Wave – Peak Hours Wind Generation Energy Production July 17: (2:41 pm) 46,561 MW July 21: (4:28 pm) 49,036 MW July 24: (2:44 pm) 50,270 MW New Records Record Time of Record Peaks x x x Source: CAISO Planned Capacity Level

8. 7 Need to Shift Some Wind Energy Production from Off-Peak to On-Peak

9. 8 Potential use of Flywheel Energy Storage for Area Control Error and Frequency Control

10. 9 20 25 30 35 40 45 123456789101112123456789101112 System Load (GW) Typical Load Load w/ 4 mil. PHEVs Off-peak load Vehicle-to- grid energy (V2G) Ancillary Services available when vehicles are parked AM PM Plug Hybrid Electric Vehicles Complement Renewables off-peak load

11. 10 Dispatchability Option via Thermal Storage Actual June day Actual September day Actual September day w/ supplemental gas Parabolic Trough Solar Technology for Utility Power Markets in the Southwestern United States, Henry Price, National Renewable Energy Laboratory, August 2004 Solar thermal can add storage or to become more dispatchable.

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14. 13 Next Gen Li-ion? Next Gen Flow Battery?

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18. 17 Compressed Air Energy Storage (CAES)

19. 18 CAES Geology by State

20. 19 Lithium Ion Battery