North America's largest battery energy storage online

A California public utility has brought the largest battery energy storage in North America online.  Funded partially by federal stimulus funds, Southern California Edison's Tehachapi Wind Energy Storage Project is designed to demonstrate the effectiveness of large-scale battery storage systems.

Southern California Edison Company is the largest electricity supply company in Southern California.  As part of the U.S. Department of Energy's implementation of the American Recovery and Reinvestment Act of 2009, the utility won funding to develop a major battery energy storage system (or BESS).  The Tehachapi Wind Energy Storage project consists of an array of lithium-ion batteries capable of storing 32 megawatt-hours, deliverable as an 8 megawatt stream of energy for 4 hours.  The LG Chem batteries rely on the same lithium-ion cells installed in battery packs for General Motors’ Chevrolet Volt electric vehicle, and feature 608,832 individual battery cells arrayed in 10,872 battery modules and 604 battery racks.  Along with two 4MW/4.5MVA smart inverters, the project will be housed in a 6,300 square foot facility sited at SCE's existing Monolith substation.

Of the project's $49,956,528 total budget, half will be paid for by SCE, while federal funds will cover $24,978,264.  In return, the project will examine whether and how the battery energy storage system improves grid performance and helps integrate wind and other large-scale variable energy resourced generation.  Project performance will be measured by 13 specific operational uses, most of which either shift other generation resources to meet peak load and other electricity system needs with stored electricity, or resolve grid stability and capacity concerns that result from the interconnection of variable energy resources.  These uses include: providing voltage support and grid stabilization; decreasing transmission losses; diminishing congestion; increasing system reliability; deferring transmission investment; optimizing renewable-related transmission; providing system capacity and resources adequacy; integrating renewable energy (smoothing); shifting wind generation output; frequency regulation; spin/non-spin replacement reserves; ramp management; and energy price arbitrage.  In addition, the project will demonstrate how lithium-ion battery storage can provide nearly instantaneous back-up capacity, minimizing the need for fossil fuel-powered back-up generation.

Between technological advances and a series of recent policy decisions, battery energy storage could be poised for rapid growth.  For example, in 2011 the Federal Energy Regulatory Commission issued Order No. 755, requiring the grid operators in organized markets to compensate battery energy storage systems and other fast-ramping frequency regulation resources based on the actual service they provide.  Last year's Order No. 784 required public utilities to take into account the speed and accuracy of regulation resources such as batteries.  Meanwhile, batteries are hoped to help balance into the grid large amounts of energy from intermittent renewable resources such as solar and wind projects.

After two years, the Tehachapi Wind Energy Storage Project will have completed its initial demonstration run.  Will the project lead to greater deployment of battery energy storage systems in the U.S.?