SCE Energy Storage Perspective Building California’s Flexible Grid: The Irvine Smart Grid Demonstration Closing Symposium SCE Energy Storage Perspective Loïc Gaillac SCE, Advanced Energy Storage Manager Southern California Edison

SCE Approach Storage Technology Laboratory Evaluation Validate storage technology performance Create degradation models to optimize system operation (extend life, improve business case) System or Sub-system Laboratory Testing Validate system integration (from a safety and operational performance perspective) Field Demonstration and Pilots Refine deployment and connection processes Validate system performance and reliability in the field System Deployment Extract energy storage system benefits Southern California Edison

SCE Focus Deploy energy storage as a distribution asset Support distribution circuit needs (e.g., lower line loading) When no distribution-function is required, participate in the energy market Enhance energy storage business case Southern California Edison

Storage Distribution Value Measuring, monetizing and capturing storage distribution values still remains a challenge Well Known Values Distribution upgrade deferral Partially Known Values Equipment life extension Voltage support Unknown Values Power quality improvement DER integration enhancement Reactive Power compensation Reliability improvement Other unidentified values Southern California Edison

Overview of SCE’s On-going ES Demonstration and Pilot Activities 1 2 3 4 5 6 7 Tehachapi Storage Project Large-scale Energy Storage (8MW for 4 hours or 32MWh – Q3 2014) Evaluate a utility scale lithium-ion battery’s ability to increase grid performance & integrate wind generation 1 2 Large Distributed Energy Storage (2MW/500kWh unit – Q1 2014) Evaluate containerized Li-ion battery systems in field trials Distributed Energy Storage Integration (DESI) Pilot Program (2MW/4MWh – Q2 2015) Deploy energy storage on the distribution system to solve a challenge or for economic benefit Distribution Optimized Storage (DOS) (1MW/1MWh – 2016) Evaluate aggregated energy storage units on the distribution system with optimized controller Community Energy Storage (CES) (25kW/50kWh – Q3 2013) Evaluate system ability to enhance circuit efficiency, resilience, and reliability Residential Home Energy Storage Unit (RESU) (4kW/10kWh – Q3 2013) Evaluate home storage integration with customer HAN, smart appliances, solar PV, PEV, etc. Large Commercial PLS Program (100kW/500kWh – Q4 2014) Evaluate Energy Storage for Large Commercial Customer Permanent Load Shifting Irvine Smart Grid Demo 3 4 Irvine Smart Grid Demo 5 6 7

TSP Southern California Edison

TSP System Specifications Battery Storage System Li-ion 32MWh usable Manufactured by LG Chem. Power Conversion System (PCS) 9MVA 12kV connected Manufactured by ABB Southern California Edison

TSP Layout 12kV/66kV transformer BESS Building PCS units Southern California Edison

System Configuration How to get 32MWh from 60Wh battery cells x 56 Module Rack Section System Quantity 608,832 10,872 604 4 1 Voltage 3.7 V 52 V 930 V Energy 60 Wh 3.2 kWh 58 kWh 8.7 MWh 32 MWh (AC) Weight 380 g 40 kg 950 kg N/A Southern California Edison

System Validation Challenges Large energy storage systems are modular Comprised of AC and DC subsystems Scaled by adding additional components in series/parallel Multiple manufacturers Requires complex integration Increased likelihood of integration issues Utilities need to assess safety and reliability prior to field deployment Issues with testing large systems in the field Grid/personnel safety Geographic distance Need to exchange significant power at will Hardware/firmware/software problems can take many months to solve Southern California Edison

System Validation Approach: Mini-System Lab Testing Mini-System enables subscale testing in the lab before full-scale operation of the BESS at Monolith Substation Mini-System Full System Footprint 144 ft2 6300 ft2 building Power 60 kW 8 MW Energy 232 kWh 32 MWh Power Conversion System Two Mini-Cabinet Two 40-foot containers Sections 2 4 Banks 32 Racks 604 Modules 72 10,872 Cells 4,032 608,832 Mini-System for Sub-scale Testing Southern California Edison

Mini System at SCE laboratory Site Energy Controller Battery Racks Power Conversion System (PCS) Southern California Edison

TSP Mini-System Testing Key Findings Benefits Discovered and resolved critical safety and operational aspects regarding the battery system and PCS Minimum impact of safety and operational issues, quick to resolve Several iterations of software/firmware upgrades required Significant time and resources saved due to upgrades performed in the lab at subscale level versus full-scale at remote substation location 24/7 operation for more than 4 months prior to full system commissioning yielded feedback to implement many additional functional upgrades System operation and features have been enhanced (optimized control algorithms) Southern California Edison

Remaining Challenges/Gaps Availability of truly grid-ready integrated systems Storage component may be mature, integration into complete turn-key system has not reached full maturity Capturing promised value streams in actual applications & building positive business cases Siting, Siting, Siting Land availability, system footprint Demonstrating required reliability at the system level Integrating with existing utility communication infrastructure & new Smart Grid technologies Validating large systems prior to deployment Availability of standard application definitions and test procedures Southern California Edison