Once the largest battery grid storage project, Southern California Edison’s 8 megawatt, 32 MW-hour pilot located at its large Tehachapi wind farm was formally decommissioned May 5 by state utility regulators, nine years after it came online.
The Tehachapi Storage Project was launched in 2014 to test how well lithium-ion batteries and smart inverter technologies could integrate intermittent wind energy and improve grid performance. It was initially the largest battery project in North America but was soon overtaken by larger projects.
This renewable storage project at SCE’s Monolith substation in the massive Tehachapi wind energy area cost $57 million. It was funded with $26 million from utility ratepayers, $25 million from the Department of Energy under the American Recovery & Reinvestment Act of 2009, and $1 million from the California Energy Commission. Another $5.3 million was provided by former battery vendor A123.
“It was definitely one of the pathfinders for us,” Mike Gravely, CEC Research & Development supervisor, said of the battery pilot. He told Current this first-generation battery grid storage project, along with several others funded by ARRA and the CEC, led to today’s 3,100 MW of battery storage connected to the state grid. That is far more battery storage than any other state.
“It was gratifying to see how battery storage took off with a hockey stick-like trajectory,” said SCE spokesperson David Song.
The system was built by LG Chem and comprised of 604 battery racks, 10,872 battery modules and 608,832 individual battery cells–the same lithium-ion cells installed in battery packs for General Motors’ Chevrolet Volt, according to Song.
In 2018, SCE told the CPUC the project provided roughly a $500 million benefit.
Parts were swapped out a few times. Advances in battery storage and safety, however, made the system obsolete with SCE unable to find components for its system to accommodate the latest safety technologies, it told the California Public Utilities Commission. It went from an 8 MW project to a 4 MW pilot in June 2020 and then down to 2 MW in March 2021. It was shut down in May of last year on economic grounds.
“Because so much has been learned about Energy Storage safety over the last decade, the current standards for safety in operations, maintenance, and facilities for energy storage resources are notably different than what was considered best practices when [the Tehachapi Storage Project] was built,” according to the CPUC resolution approving the decommissioning. The safety upgrade costs “would overwhelm potential benefits of future operations,” it added.
“We agree that shutting down the Tehachapi Storage Project is appropriate because it is losing money,” said Karin Hieta, Public Advocates Office supervisor, Climate Change Initiative Section. Cal Advocates “worked with SCE to ensure that the costs of shutting down the project are minimized, with any remaining funds going back to ratepayers,” she added.
The CPUC capped the cost of decommissioning the Tehachapi Storage at the $26 million contributed by ratepayers, as urged by Cal Advocates. There is $5.8 million in funds remaining. Any costs above that amount must be sought by SCE through a Tier 3 Advice Letter.
Song said the cost was confidential because it has not yet sought decommissioning bids.
In other news, the CPUC approved Pacific Gas & Electric’s $12 million vehicle to grid project. It entails three pilots: one using homeowners’ electric cars to store power and feed it to the grid and another using commercial fleet vehicles to do the same. A third would use electric vehicles to provide power for a microgrid when the utility invokes public safety power shutoffs to prevent wildfires during wind storms.
Photo: Courtesy of SCE
