Pursuant to the California Environmental Quality Act (CEQA) review process, Imperial County has determined that Avantus’ Big Rock 2 solar and storage complex may have a significant impact on the surrounding environment, and has filed a notice of preparation (NOP), alongside an initial study (IS), of its intentions to carry out a full environmental impact report (EIR).

The NOP and IS were filed September 4, 2024 and outline introductory studies on the potential impacts of the project on the surrounding environment. The public and any interested stakeholders have until October 7, 2024 to submit comments on the report, which the Imperial County Planning and Development Services Department will consider when completing its EIR on the project.

500MW of BESS capacity across four sites

Avantus, through its wholly-owned 90FI 8me, LLC subsidiary, is seeking approval of four separate conditional use permits (CUPs) associated with the construction of its Big Rock 2 complex located southwest of the town of Seeley approximately six miles north of the US/Mexico border.

The proposed area for the project is a mixture of land that has not previously been designated for solar/storage development, and land which Avantus has previously been given the green light to develop in the past. However, permission to develop in these areas, designated under the Laurel 2 North (#21-0014) and Laurel Cluster South (#24-0008) permits, are set to expire at the end of this year.

Across the four use permits, which also includes the Big Rock Cluster North (#24-0006) and South areas (#24-0007), Avantus plans to pair a 500MWac solar farm with up to 500MW of BESS capacity.

Avantus has yet to decide which battery technology it will deploy, but stated that the project could include commercially available lithium or flow batteries complying with Imperial County and national BESS fire standards.

The project is expected to connect to the California Independent System Operator (CAISO)-controlled grid via San Diego Gas & Electric’s (SDG&E’s) Imperial Valley 230kV substation, through the Liebert 230kV switchyard owned by Imperial Irrigation District (IID).

74MW resource adequacy agreement

Earlier this year, California community choice aggregator (CCA) San Diego Community Power (SDCP) signed a five-year offtake agreement with Avantus covering 74MW/296MWh of resource adequacy from the battery storage portion of the developer’s Big Rock 2 project, set to commence delivery in December 2027.

The RA agreement is contingent on Avantus securing a CAISO grid connection for the project which the developer is hoping to secure via a transfer request  – a process whereby developers can transfer CAISO deliverability between resources connecting to the grid via the same point of interconnection.

Under the terms of the agreement, if CAISO grants the full transfer request, SDCP has the option of a full power purchase agreement (PPA) with Avantus from its Big Rock 2 project.

Although specific contract costs weren’t made public, SDCP described the agreement as providing “significant value” and “cost-certainty” to the CCA over the 5-year term.

First phase sold to UK-listed asset manager

As reported by Energy-Storage.news, Avantus sold a portion of the Big Rock complex, known as Big Rock 1, during the first quarter of last year to UK-listed Gore Street Energy Storage Fund (GSF).

GSF has since secured a US$60 million financing package from First Citizens Bank, used to fund the final capital costs of the Big Rock 1 project. The 200MW/400MWh storage facility will utilise 137 AiON-ESS units provided by LS Energy Solutions and is expected to come online by the end of the year.

New majority owner and CEO

Founded in 2009, Avantus is a utility-scale solar and storage developer with a claimed 80 project portfolio comprising 30GWdc of solar and 94GWh of storage capacity. This includes the company’s 2GW hybrid solar and BESS Buttonbush facility located in Kern County, California, as reported by Energy-Storage.news earlier in the year.

It’s been a big year for the company, after global investment firm KKR acquired a majority stake in Avantus in July, which was then followed by a US$522 million development facility arranged by KKR Capital Markets and Sumitomo Mitsui Banking Corporation (SMBC).

Last week, Avantus also announced that it had appointed Cliff Graham as the company’s new chief executive officer (CEO). Prior to joining Avantus, Graham held several senior positions at various prominent independent power producers (IPPS) in the US including 174 Power Global, EDF Renewables and NextEra Energy Resources (NEER).