California Investor-owned utility (IOU) Pacific Gas & Electric (PG&E) is seeking regulatory approval for a four-project portfolio of hybrid solar and storage resources with over 575MW of battery storage output.
The four off-take agreements were selected by PG&E as part of the utility’s Mid-Term Reliability Request for Offers – Phase 3 (MTR RFO – Phase 3) issued in February 2023 to address grid capacity needs in 2026 and 2027.
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PG&E filed an Advice Letter document (AL 7356-E) with the California Public Utilities Commission (CPUC) on 9 September 2024 detailing the specifics of the four off-take agreements.
Atlas Energy Park: 3.2GW PV and 1.9GW BESS in Arizona
Two of the agreements cover power offtake from separate parts of 174 Power Global’s Atlas Energy Park located in La Paz County, Arizona – namely, the Atlas North 1 + 2 project portions under development through the independent power producer’s (IPP’s) Atlas Solar XII, LLC and Atlas Solar XIII, LLC subsidiaries.
The Power Purchase Agreements (PPA) for the Atlas development both cover 375MW of solar with 225MW/900MWh of lithium-ion battery capacity for a period of 15 years commencing delivery on December 1 2027.
As well as negotiating a PPA with PG&E, the developer has also filed an application for a certificate of environmental compatibility with the Arizona Corporation Commission (ACC) for the construction of a generation tie line to connect the Atlas Solar North project to the grid.
Despite being located in Arizona, the project will connect to the California Independent System Operator (CAISO) grid via the Delaney – Colorado River 500kV transmission line. Hanwha Energy Corporation-owned 174 Power Global has secured a CAISO interconnection agreement for the entire Atlas development covering 3200MW of solar and 1920MW of battery storage capacity (queue no. 1402).
Construction on the northern portion of the Atlas development is expected to commence this year.
PG&E also signs 100MW+ in RA agreements
PG&E has taken big strides this year to bolster its renewable portfolio, including a recent agreement covering RA from a standalone storage project located in Yuma County, Arizona under development by Leeward Renewable Energy (LRE), as reported in Energy-Storage.news last quarter.
The 15-year agreement, which covers 112.5MW/450MWh of storage capacity from LRE’s Sierra Pinta BESS facility, was approved by CPUC in February this year and is expected to commence delivery in June 2025.
Although this PG&E contract only covers storage, the Sierra Pinta BESS shares an interconnection agreement with LRE’s 237.5MW Elisabeth Solar facility connecting to the grid via the Hoodoo Wash 500kV switchyard.
PG&E has also more recently negotiated two long-term resource adequacy agreements with energy settlement (LTRAA w/ES) with developer Terra-Gen covering energy storage capacity from portions of the developer’s Lockhart solar and storage complex located in San Bernardino County, California.
The first agreement, relating to the Lockhart CL ESS IA portion, covers 69MW/276MWh of storage capacity commencing delivery on June 1 2026 for a period of 15 years. The second agreement, relating to the Lockhart CL ESS IIA portion, is identical to the first except it covers a smaller 59.7MW/238.8MWh of BESS capacity.
The Lockhart complex connects to the CAISO grid via Southern California Edison (SCE’s) Kramer Junction 220kV substation.
In an August interview with ESN Premium, PG&E communications principal Paul Doherty discussed the value of energy storage for the utility, including distributed, microgrid and utility-scale systems. PG&E has brought online over 2,300MW of energy storage in the past five years and intends to add more than a gigawatt between now and the end of 2025, Doherty said. PG&E only owns one large-scale BESS and contracts for the rest of its battery capacity from third parties.
Community Choice Aggregator agreement
Meanwhile, Terra-Gen’s Lockhart complex is a multi-phase development that also includes a 45MW/180MWh standalone BESS which commenced operations in April this year.
This portion of the project is contracted with California community choice aggregator (CCA) Peninsula Clean Energy (PCE) under a 15-year Energy Storage Service Agreement (ESSA) covering storage capacity, ancillary services, and resource adequacy at a cost not exceeding US$142 million.
The agreement was executed in 2023 following a 2022 Request for Offers (RFO) issued by PCE seeking standalone storage capacity to meet its procurement requirements.
