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Batteries at world’s largest solar-plus-storage project supplying California community energy group

Rendering of the Edwards Sanborn project in Kern County, California. Image: Terra-Gen / CPA.

Battery capacity has started to come online at what is claimed to be the world’s largest project to combine solar PV and battery storage at the same site, in California. 

The Edwards Sanborn Solar-plus-Storage facility in California’s Kern County is planned to include 760MW of solar PV and 2,445MWh of battery storage when fully complete. It actually combines both standalone battery storage capacity and batteries directly charged from solar PV. Developer Terra-Gen and its engineering, procurement and construction (EPC) partner Mortenson began construction towards the end of 2020

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Building and financing the project in phases. In August, Terra-Gen said the US$804 million of required financing was complete for the initial phase of 346MWac solar and 1,501MWh of battery storage. The developer’s schedule accounted for the first 735MWh of battery storage to be completed by the end of the third quarter of this year, and the rest of the first phase to be online by Q2 2022. 

The rest will be financed and brought online in 2022 and 2023. Contracts have been signed with numerous off-takers, including coffee and pumpkin spice latte merchant Starbucks, which is purchasing 24MW of solar and 5.5MW of battery storage output from the facility to help provide power for some of its California stores. 

More than 500 unionised workers are already employed at the project, which will require up to 750 workers at the peak of construction.

Also on the list of off-takers is Clean Power Alliance (CPA), one of California’s growing ranks of Community Choice Aggregator (CCA) groups. CPA said earlier this week that it is “receiving 100MW of clean energy storage capacity” from the Edwards Sanborn project. 

Community Choice Aggregators have signed more than 9GWh of California battery capacity contracts

CCAs, able to use the grid infrastructure of the state’s big investor-owned utilities to ensure reliability of supply, offer their member-customers the opportunity to choose where their energy comes from, with many opting for renewable energy. 

Regular readers of this site will have seen several dozen stories in the past year or two of CCAs signing off-take agreements for standalone battery storage and solar-plus-storage projects in the state, with Clean Power Alliance among the most prolific. 

According to the California Community Choice Association (CalCCA), as of 3 November, 2,645.4MW / 9,237.6MWh worth of long-term agreements for energy storage have been signed by the state’s CCAs to date for solar, wind, standalone battery and solar-plus-storage or wind-plus-storage projects. These are shown on a handy chart on the association’s website, including CPA’s 15-year deal for 100MW / 400MWh from Edwards Sanborn.

Sited on land leased from the Edwards Air Force Base and adjacent private land, equipment suppliers to the project include thin-film PV module manufacturer First Solar and two battery providers, LG Energy Solution and Samsung. 

Construction work began on another of the biggest solar-plus-storage projects in California — and therefore the world — in October, at the Daggett project by developer Clearway next to the site of a retired coal and natural gas plant in San Bernadino. CPA is also among the off-takers for that one, as are two other CCAs and two utility companies. Also being built in phases, Daggett will have 482MW of solar PV and 394MW of battery storage when complete.

This article has been amended from its original form to reflect more accurate figures supplied to on CalCCA’s tracking of California battery agreements signed by Community Choice Aggregators.

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