The Kern County, California hybrid facility will have the capability to generate up to 2GW of solar power co-located with up to 2GW of battery energy storage system (BESS) capacity, spanning approximately 12,875 acres of privately owned land.
The Kern County Planning and Natural Resources Department has informed 260 local agencies of its intention to carry out an environmental assessment of a 2GW solar and battery storage facility being developed by Avantus.
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Under the California Environmental Quality Act (CEQA), Kern County has issued a Notice of Preparation (NOP) soliciting guidance for the creation of a Draft Environmental Impact Report (EIR) which will outline the significant impacts of Avantus’ Buttonbush Solar and Storage facility.
Agencies that received the notice included the California Department of Conservation Division of Land Resource Protection and the Native American Heritage Commission (NAHC) who have both submitted written comments on the scope and content of Kern County’s intended environmental report.
A scoping meeting was held by the Natural Resources Department at Kern County on May 15th 2024 after the NOP was published originally on April 24th 2024. All agencies have until 5pm on May 24th 2024 to submit written comments regarding the proposed environmental report.
Project details
Avantus’ Buttonbush facility is located east of Buttonwillow Raceway Park straddling Interstate Highway 5 on 132 parcels across approximately 12,875 acres of privately owned land in the valley portion of Kern County. The proposed land for the facility is currently under agricultural use and in order for Avantus to construct the project, it will need to obtain 10 Conditional Use Permits (CUPs), 13 Plan Amendments and eight Land Use Contract Cancellations from various local agencies.
The project is being developed under Avantus’ 29SC 8me, LLC subsidiary which follows the developer’s typical business entity naming convention. Up until September 2022, Avantus was known as 8minute Solar Energy.
The Buttonbush project will comprise a solar photovoltaic facility with the capability to generate up to 2GW of alternating current (AC) solar power co-located with a battery energy storage system (BESS) of up to 2GW.
According to the NOP, the BESS will take up no more than 55 acres of the total project site. The battery specifics have yet to be disclosed at this early planning stage but will include “commercially available lithium-ion based or non-lithium ion-based storage technologies.”
Avantus expects to sell the energy produced by the Buttonbush facility under a long-term Power Purchase Agreement (PPA) with a utility or other third-party power offtaker.
CAISO grid interconnection
The facility will connect to the California Independent System Operator (CAISO)-controlled grid via Pacific Gas & Electric’s (PG&E’s) Midway or Ganso substations. Both overhead and underground gen-tie line connections are being considered.
Avantus currently has two active CAISO interconnection queue positions for the Buttonbush facility each including both solar and energy storage capacity. The first position (queue no. 1596) was submitted back in April 2019 and includes 800MW of solar and storage capacity. The second position (queue no. 1987) was submitted to the queue in April 2021 and includes 350MW of capacity for both technologies.
Queue position 1596 was processed as part of CAISO’s Cluster 12 study process and has an expected Commercial Operation Date (COD) in December 2026. The other queue position is being processed as part of CAISO’s Cluster 14 study process and has a later March 2028 expected COD.
An interconnection agreement for the larger of the two positions has been executed between CAISO, PG&E and Avantus whereas an agreement for the second smaller position has yet to be agreed.
Founded in 2009, Avantus is a utility-scale solar and energy storage developer who has historically focused on the southwestern U.S. and California power markets. California is the largest BESS market in the US by deployments.
It was announced in March this year that global investment firm KKR had agreed to acquire a majority stake in Avantus. Following the close of the acquisition, KKR will join existing investor EIG as sole equity investors.
The firm sold another solar and storage project in Kern County, the 500MW/2,000MWh Bellefield project, to utility AES in June 2023. Most large-scale BESS in California are 4-hour systems meaning the Buttonbrush facility could be as large as 8,000MWh.
