How big is Big Rock Solar Farm?

Big Rock Solar Farm has a reported capacity of 200 MW and an energy capacity of 400 MWh. Source: EIA Form 860.

What kind of plant is Big Rock Solar Farm?

Big Rock Solar Farm is a batteries facility in Imperial County, CA, participating in the CAISO market.

Where is Big Rock Solar Farm located?

Big Rock Solar Farm is in Imperial County, CA, inside the CAISO balancing area.

Who operates Big Rock Solar Farm?

Big Rock Solar Farm is operated by Big Rock ESS Assets, LLC according to the EIA generator inventory. Reporting membership does not by itself establish ultimate ownership.

How much electricity does Big Rock Solar Farm generate?

Big Rock Solar Farm reported 134.2 GWh over the twelve months to 2026-06. For a storage plant this is reported gross generation — a discharge proxy, not a cycle count or a conventional capacity factor.

Where does Big Rock Solar Farm connect to the grid?

Big Rock Solar Farm interconnects at Imperial Valley Substation, on the Imperial Irrigation District (IID) system.

How does Big Rock Solar Farm compare to other plants?

By capacity, Big Rock Solar Farm ranks #48 of 962 operating plants of the same technology nationally. It ranks #13 of 248 in CA.

Big Rock Solar Farm — 200 MW battery storage, CA

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Big Rock Solar Farm — 200 MW battery storage, CA · Ask the Grid

Overview

Power / energy: 200 MW / 400 MWh
Reported plant capacity and configuration.
Technology: Batteries
Primary generation technology.
Registry anchor: Plant 64636
Big Rock ESS Assets, LLC · Imperial County · CAISO
Storage duration: 2 hours
Battery subsystem rating.
Operating status: Operating
Big Rock Solar Farm is operating.
Grid connection: Imperial Valley Substation
230 kV · Imperial Irrigation District (IID)
Equipment: 137 containers
Installed equipment documented in public project records.

Profile

Grid role: Grid-scale battery storage providing resource adequacy, ancillary services, and energy shifting/peak support for CAISO.
Grid connection: Imperial Valley Substation · 230 kV · Imperial Irrigation District (IID).
Context: Big Rock was Gore Street Energy Storage Fund’s first investment in California and CAISO and, at acquisition, its largest U.S. acquisition. The 200 MW/400 MWh installation was also described by LS Energy Solutions as its largest energy-storage installation to date and its first for the California ISO.
Physical build: Operational 200 MW / 400 MWh CAISO battery energy-storage site supplied by LS Energy Solutions, comprising 137 AiON-ESS containers. The project source also describes tier-1 lithium-ion batteries and over 1,300 modular 140 kVA AiON-SIS string inverters; each AiON-ESS unit is rated at 1.5 MW and 3.5 MWh.

Structured profile

Reported capacity: 200 MW
Batteries
Energy: 400 MWh
2-hour storage duration
Operating status: operating
Big Rock Solar Farm is operating.
Interconnection: Imperial Valley Substation
230 kV · Imperial Irrigation District (IID)
Location: Imperial County
CAISO

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Units and generators

Operating generator records and technology attributes reported through EIA-860.

Generator	Capacity	Technology	Operation	Status
92JTB	200 MW 200 MW summer	Batteries Electricity used for energy storage · BA	May 2025	Operating

Performance

Monthly EIA generation history and recent market-resource behavior where linked telemetry is available.

Peer context

Technology capacity: 200 MW; Batteries
National rank: #48; of 962 operating peers
CA rank: #13; of 248 operating peers

Monthly generation

Download CSV

Latest 12 months

134.2 GWh

Reported gross generation

Latest report

Jun 2026

EIA-923 monthly filing

Grid and market context

Deterministic links to ERCOT market resources, price records, outage disclosures, queue records, and nearby infrastructure. Candidate joins remain labeled until corroborated.

Nearby substations

HIFLD infrastructure inventory

UNKNOWN308676

IN SERVICE · 230 kV

0.4 km

IMPERIAL VALLEY

Commercial, land, and environmental record

Source-backed project transactions, agreements, land records, permits, and environmental disclosures. Portfolio and adjacent-project facts remain explicitly scoped.

Transactions and agreements

O&M Contract

Jun 6, 2025

CAMS awarded contract by Gore Street to provide comprehensive O&M services for Big Rock BESS in El Centro, California, including preventative and corrective maintenance, remote operations, NERC compliance, cybersecurity monitoring of IT/OT infrastructure. Contract value and duration not disclosed.

Consolidated Asset Management Services · Gore Street Energy Storage Fund plc

Source

Land and environmental record

Battery Installation Permit

Mar 5, 2024

Imperial County Building Permit No. 61777

County March 2024 permit log identifies permit 61777 for installation of 201 MW battery energy-storage facility at 1262 Liebert Road. 2025 County staff report confirms permit 61777 issued for battery facility on Parcel C.

Source

Environmental Review

Aug 13, 2025

CEQA exemption for Lot Line Adjustment No. 00342

County August 13, 2025 lot-line-adjustment resolution states adjustment facilitating IID switchyard and battery facility is exempt from California Environmental Quality Act under Government Code section 15305.

Source

Parcel Adjustment

Aug 13, 2025

Approximately 102.37 acres remaining in Parcel C after lot-line adjustment

County staff report states that approximately 3.63 acres of Parcel C are transferred for switchyard, leaving Parcel C at approximately 102.37 acres for battery storage use. Scope: battery facility footprint only.

Source

Parcel And Lease

Aug 13, 2025

APN 051-350-015, Parcel C; approximately 106 acres; leased from Childers Carolyn TRS

Imperial County's August 13, 2025 lot-line-adjustment staff report identifies APN 051-350-015 (Parcel C) as approximately 106 acres leased by Big Rock ESS Assets, LLC from property owner Childers Carolyn TRS for battery facility and switchyard-related development.

Source

Switchyard Land Transfer

Aug 13, 2025

Approximately 3.63 acres transferred to Imperial Irrigation District for switchyard

Proposed lot-line adjustment transfers approximately 3.63 acres from APN 051-350-015 to adjoining parcel so Imperial Irrigation District can own and operate switchyard serving battery-storage facility. Scope: switchyard land only.

Source

Related parties and identifiers

Parties, market resources, and identifiers tied to this asset, with owner, operator, developer, EPC, compliance provider, and interconnecting entity roles kept separate.

Relationship graph

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AssetFinancierOwner / operatorOrganizationOfftakerContractor

Timeline and sources

Project milestones and public references behind the asset profile.

Project timeline

Feb 17, 2023
Feb 17, 2023
Acquisition AgreedGore Street...
Gore Street Energy Storage Fund plc announced that it had agreed to acquire the 200 MW/400 MWh Big Rock project in Imperial County from Avantus, formerly 8minute. The announcement characterized the project acquisition costs, including capex around closing, development fees, and milestone payments, as approximately $110 million.
Sep 7, 2023

Big Rock Solar Farm

Big Rock Solar Farm

Overview

Profile

Structured profile

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Performance

Peer context

Monthly generation

Grid and market context

Nearby substations

Commercial, land, and environmental record

Transactions and agreements

Land and environmental record

Related parties and identifiers

Relationship graph

Timeline and sources

Project timeline

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Common questions about Big Rock Solar Farm

How big is Big Rock Solar Farm?

What kind of plant is Big Rock Solar Farm?

Where is Big Rock Solar Farm located?

Who operates Big Rock Solar Farm?

How much electricity does Big Rock Solar Farm generate?

Where does Big Rock Solar Farm connect to the grid?

How does Big Rock Solar Farm compare to other plants?

Co-located assets