Energy Storage at PG&E Hal LaFlash Director Emerging Clean Technologies April 5, 2011 Pacific Gas and Electric Company 2009 2010 Energy services to 15 MM people: 5.1 MM Electric customer accounts 4.3 MM Natural Gas accounts 70,000 square miles with diverse topography 20,000 employees Nearly 50,000 customers with PV installed (~430 MW) ~ 35% of the grid connected PV in the U.S. The most aggressive Renewable Portfolio Standard in the U.S. Ranked the greenest utility in the United States in 2009 and 2010 Serve 5% of U.S. population, but produce only 1% of utility sector C0 2 emissions 1
Renewable Resource Mix Projections 13% of load 10% of load Source: California Public Utilities Commission, July 2009 2 Active Interconnection Requests CAISO Technology PV NG Wind Geothermal Biomass Landfill Gas Solar Thermal Hydro MW in PG&E 6,650 4,830 850 80 60 20 20 10 12,520 MW in SCE 8,760 2,940 8,240 530 6,680 27,150 MW in SDG&E 3,480 2,660 2,960 30 Total MW 18,890 10,430 12,050 610 90 20 7,700 50 1,000 40 10,170 49,840 Source: CAISO Queue Feb. 25, 2011 3
Key Challenge: Key Need: Complexity Flexible Resources Greater distribution and variety of resources More variable resources and loads Less predictable resources and loads MW 700 Wind Each day is a different color. PV Solar Cloudy Day vs Clear Day Output 600 500 Day 29 Day 9 400 300 200 Day 5 Day 26 Average 100 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 Source: CAISO Hour 4 Electric Storage is One Type of Flexible Balancing Resource Renewable Resources Flexible Balancing Resources Demand-side Resources Storage Smart Grid Back-up Generation 5
Flexibility Supply Curve Exports? Source: P. Denholm, NREL, 2010; B. Nickell, DOE, 2008 6 Energy Storage: Four Broad Categories of Value Load Leveling Renewables Reliability Ancillary Services 7
Different Storage Technologies Can Play Different Roles http://electricitystorage.org/tech/technologies_comparisons_ratings.htm (logarithmic scale) 8 8 Meeting Utility Scale Needs Energy Storage Technologies Discharge Time (hr) PSH Pumped Storage Hydro CAES Compressed Air EDLC Dbl-layer capacitors Ni-MHNickel-metal hydride Li-Ion Lithium-ion Ni-Cd Nickel-cadmium Na-S Sodium-sulfur VR Vanadium redox L/A Lead-acid Zn-Br Zinc-bromine FW Flywheel Same as prior graph by Electricity Storage Association (converted to normal scale by Rick Miller, HDR DTA) 9 9
PG&E s Storage Project Portfolio Pumped Storage Compressed Air Sodium-Sulfur (NaS) Battery Projects are at various stages of development 10 Helms Pumped Storage More than 25 years of successful operations Courtwright and Wishon reservoirs connected with three motor generators producing 1,212 MW 11
Mokelumne Project Overview Three alternatives would all use the same lower reservoir, Salt Springs, to maximize the use of existing infrastructure. Pumped Storage Project Overview September 2010 12 Mokelumne Project Reservoirs Lower Bear River Reservoir Salt Springs Reservoir 13
Compressed Air Energy Storage (CAES) (1 st generation design) or equivalent 14 CAES in Relation to Tehachapi System Upgrades 4,500 MW of new wind identified CAES 15
CAES Plant Site To Be Near Wind Resources Tehachapi Midway Substation 4,500 MW of new wind generation over the next 4 to 5 years Integration a major concern for CAISO Proposed CAES Site Close to transmission lines Good geologic characteristics Vincent Substation 16 Current area of interest 500 kv 230 kv Midway Substation Midway-Vincent 500 kv 17
Advanced CAES Plant: Design Schematic Second Generation Note: Each Expander can serve each CT in the integrated CAES plant 2009 Electric Power Research Institute, Inc. All rights reserved. 18 Two Battery Projects Office Complex 4 MW / 28 MWh NaS Battery Operational 3Q 2011 Reliability Power quality Islanding Load shaping Ancillary services Frequency regulation Vaca Dixon Solar Plant 2 MW / 14 MWh NaS Battery Operational 3Q 2011 Load shaping Renewable integration Ancillary services 19
Value: Peak Leveling with Islanding Islanding Event Natural Load (MW) Load with Battery (MW) MW Charge Battery Operating Profile Discharge Charge Discharge 12:00 PM 12:00 AM 12:00 PM 20 Value: Load Leveling Natural Load (MW) MW Load with Battery (MW) Battery Operating Profile Charge Charge Discharge Discharge 12:00 PM 12:00 AM 12:00 PM 21
Value: Renewable Stabilization Cloudy PV Output Smoothing of PV Resource Battery Output 22 Value: Frequency Control 4 MW (+/- 2 MW) Regulation Scaled to 250 MW ACE Signal MW Charge Discharge Time (Minutes) 23
Storage Economics Depends on Capturing Multiple High Value Uses High value uses require only small volumes (e.g., fast, short duration frequency control service) Existing resources may capture high value uses Most of storage values are not additive, but optimized (e.g., energy vs. ancillary services ) Estimated Target Market Size and Target Value Analysis* * Source: EPRI s Electricity Energy Storage Technology Options, December 2010. 24 Simultaneous Value Streams 2MW Load Shaping, +/- 2 MW Regulation with Islanding Event Frequency Regulation MW Charge Discharge Load Leveling Time (One Day) Islanding Event 25
Objectives of Battery Projects Technical Ability to meet performance specifications Battery Life Impacts Economics Integration with CAISO Markets Resource and Load bids Ancillary Services Ability to optimize value streams 26