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Second eight-hour lithium-ion battery system picked in California long-duration storage procurement


A group representing community energy suppliers in California has made its second long-duration energy storage procurement, with the selected bid once again a lithium-ion battery energy storage system (BESS). 

Seven of the 10 member organisations in CC Power, a Joint Powers Agency collective of Community Choice Aggregator (CCA) groups, banded together to make the procurements. In late January, it announced that a 69MW/552MWh lithium-ion battery project by developer LS Power had been the first selected for a contract from the group’s joint request for proposals (RfP). 

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CC Power said yesterday that members of the Joint Power Agency’s board voted at a special meeting to enter into a contract for Goal Line, a 50MW/400MWh lithium-ion BESS project in development by Onward Energy. 

The eight-hour discharge duration system will be built in Escondido, California, with an expected online date in 2025 — a year earlier than the commissioning date expected for LS Power’s project, called Tumbleweed. 

The procurements are held in response to a requirement from the California Public Utilities Commission (CPUC) that the state’s load-serving entities — including CCAs, investor-owned utilities and municipal utilities and coops — procure sufficient energy to ensure so-called ‘Mid-Term Reliability’ of the energy system. 

In addition to procuring 11.5GW of clean energy resources in the timeframe 2025-2026 to mitigate circumstances including the retirement of natural gas power plants and the Diablo Canyon nuclear power plant, CPUC ordered load-serving entities to procure or contract for at least 1GW of long-duration energy storage.

Bids selected from 9GW of long-duration submissions

CCAs were actually ahead of the curve on this, heard from Girish Balachandran, CEO of one of the participating groups, Silicon Valley Clean Energy (SCVE), in an interview published shortly after the announcement of the contract for Tumbleweed. 

SCVE and other CCAs had, of course, observed the California ‘Duck Curve’ of solar production versus grid demand and how that was changing the pattern of peaks in demand. With the addition of huge amounts of solar, the profile in California has shifted to a ‘net peak’ in nighttime hours.

As the state targets 50% renewable electricity by 2030 and full decarbonisation by 2045, the situation will grow more acute.

CC Power’s original request for information (RfI) on long-duration storage came out in 2020, a year before the CPUC ruling. Seeking eight-hour minimum discharge duration resources of at least 50MW, with a minimum delivery term of 10 years, projects had to be able to come online by 1 June 2026. 

When the CCAs then put out a Request for Offers (RfO), it was responded to by 51 different entities, representing more than 9GW of projects. Girish Balachandran said the diversity of technologies and their ability to meet the duration requirements was “very positive”.

While lithium-ion was picked first — and now also second —  the CEO had said there was a third shortlisted project which was based on an emerging technology. While Balachandran could not disclose what it was, he did refer to bids being received for projects using everything from flow batteries to hydrogen fuel cells, gravity storage, pumped hydro, various thermal storage technologies and more.

California’s energy sector is likely to be contracting for a big mix of energy storage technologies in the coming years, he said. Another CCA, Central Coast Community Energy (CCCE) has signed contracts with three vanadium redox flow battery (VRFB) projects totalling 226MWh, expected to come online in 2026.

Energy storage is already proving its worth in the state. reported yesterday that according to CAISO, California’s main grid and wholesale markets operator, battery storage deployments grew 12-fold on its network in 2021 from 2020 figures.

This enabled the dispatch of around 1GW of energy stored in batteries during the Bootleg wildfire in July 2021, which helped keep the lights on in a tough situation, CAISO president and CEO Elliot Mainzer said.

In the meantime, the Tumbleweed and Goal Line projects between them enable the CC Power member groups to meet their requirement through the CPUC Mid-Term Reliability ruling with lithium-ion. Boards of the individual CCAs will now vote on approvals for Goal Line. 

“This new contract allows the participating members to meet our state-mandated long-duration storage requirements, showing how CCAs are leading the way to advance clean energy in California,” Geof Syphers, chair of the CC Power board and CEO of member group Sonoma Clean Power said. 

California’s government has offered its support to long-duration energy storage with US$380 million of funding available for projects through the 2022-2023 state budget. 

In an article published yesterday on, executives from flow battery companies Invinity Energy Systems and ESS Inc discussed the prospects and use cases for long-duration battery storage.

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