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Terra-Gen puts 129MW/515MWh BESS in operation at California solar PV complex

Terra-Gen continues to expand its footprint in California’s utility-scale energy storage market with the advancement of the Lockhart CL I and CL II Energy Storage System (ESS) projects, reinforcing the state’s grid reliability and resource adequacy framework.



The Lockhart CL I ESS, developed alongside the existing Lockhart solar and battery assets, delivers 69 MW of capacity. It will be complemented by the upcoming Lockhart CL II ESS, which adds a further 59.7 MW. Together, the two projects provide a combined power capacity of 128.7 MW and a substantial energy storage capacity of 515 MWh.


In total, the facilities comprise 164 lithium-ion battery units and benefit from shared infrastructure, including the existing gen-tie line connecting to Southern California Edison’s Kramer Junction Substation, reducing additional grid connection complexity.


The full resource adequacy (RA) capacity of the Lockhart ESS projects has been contracted under two long-term RA agreements with Pacific Gas and Electric (PG&E), underlining the strategic importance of long-duration storage in California’s capacity market.


According to Terra-Gen, construction of the new storage facilities generated over 115 jobs at peak, with workers logging more than 85,000 hours across construction and the transition into operations—highlighting the local economic benefits of large-scale storage deployment.


The Lockhart storage build-out coincides with Terra-Gen’s wider development activities at the site. In December, financing was closed for the Lockhart III & IV solar PV project, a 205 MW development located adjacent to the first two phases. Once complete, the Lockhart complex will reach 160 MW of solar PV capacity across these phases.

Beyond California, Terra-Gen has faced permitting headwinds. Earlier in 2025, a 250 MW / 1,000 MWh BESS project on the US East Coast encountered potential delays after officials in Hurley, New York, requested a temporary suspension of the permitting process from the neighbouring town of Ulster.


In October 2024, Masdar, the Emirati state-owned clean energy group, completed its acquisition of a 50% stake in Terra-Gen from Energy Capital Partners. Following the transaction, Igneo Infrastructure Partners retained its remaining 50% stake.

Terra-Gen is also known for developing Edwards & Sanborn, a landmark solar PV and BESS complex in California featuring 875 MWdc of solar generation and 3,287 MWh of battery storage—the largest combined solar-plus-storage project globally at the time it entered operation in late 2024.




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