# Solar Blue

CAISO Batteries, Solar Photovoltaic · https://askthegrid.com/assets/facilities/solar-blue

Solar Blue is a hybrid solar and battery storage facility with 475 MW of EIA-reported total operating capacity and 900 MWh of reported storage energy capacity in Kings County, California, registered as EIA Plant ID 63848. Its grid role is hybrid solar generation with co-located battery storage used for storage arbitrage and frequency regulation.

## Key facts

- Technology: Batteries, Solar Photovoltaic
- Power capacity: 475 MW
- Energy capacity: 900 MWh
- Operating status: operating

## Grid and market context

- ISO/RTO: CAISO
- Balancing authority: California Independent System Operator (CISO/CAISO)
- Substation: Solar Switching Station
- Point of interconnection: Solar Switching Station
- Interconnection voltage: 230 kV

## Source-backed facts

- Identifiers: [{"value":"63848","system":"EIA plant ID"},{"value":"1139","system":"CAISO queue position"},{"value":"SOLBLU_2_WSBSX2","system":"CAISO solar resource ID"},{"value":"SOLBLU_2_WSBBX2","system":"CAISO battery resource ID"},{"value":"ER24-697","system":"FERC docket"}] — Source · confidence: medium
- Identifiers: [{"value":"63848","system":"EIA plant ID"},{"value":"1139","system":"CAISO queue position"},{"value":"SOLBLU_2_WSBSX2","system":"CAISO solar resource ID"},{"value":"SOLBLU_2_WSBBX2","system":"CAISO battery resource ID"},{"value":"ER24-697","system":"FERC docket"}] — db125_source_and_sink · confidence: medium
- Description: Solar Blue is an operating hybrid solar photovoltaic and battery facility in Kings County, California. The plant has two generating units totaling 475 MW. The associated Westlands Solar Blue project has a 250 MW photovoltaic component and a 225 MW storage component, and entered operation in December 2023. — Source · confidence: medium
- Identifiers.1: {"value":"1139","system":"CAISO queue position"} — Source · confidence: high
- Identifiers.2: {"value":"SOLBLU_2_WSBSX2","system":"CAISO solar resource ID"} — db125_source_and_sink · confidence: high
- Identifiers.3: {"value":"SOLBLU_2_WSBBX2","system":"CAISO battery resource ID"} — db125_source_and_sink · confidence: high
- Parties.2: {"relationship":"CEQA lead agency","name":"County of Kings","official_url":"https://www.countyofkingsca.gov"} — Solar Blue Project · confidence: high
- Interconnection: 230-kV substation; transmission/distribution owner Pacific Gas & Electric Co. (PG&E) — Solar Blue Project · confidence: medium
- Site acres: 1895 — Solar Blue Project · confidence: medium
- Construction scope: Operating Solar Blue hybrid facility in Kings County, California: a 250 MW solar photovoltaic generator and a 225 MW battery-storage generator, totaling 475 MW across two generating units. The CEQA scope describes approximately 1,895 acres and a 230-kV substation. A project-specific planning record states that permitted battery-storage units were increased from 84 to 250, covering approximately 9 acres. No exact-asset solar module, inverter, PCS, or OEM model/count was identified. — Solar Blue Project · confidence: medium
- Battery units: 250 — Around Kings County: ‘Wall to Wall’ solar plants on the way - Central California · confidence: medium
- Quality notes: ["The 475 MW total is supported by an EIA-derived plant record, while CAISO records identify approximately 250 MW of photovoltaic capacity and 225 MW of storage; no equipment count is inferred from capacity.","Solar Blue is distinct from Aquamarine, another 250 MW CIM project at Westlands Solar Park that reached commercial operation in 2021–2022.","No retirement, repowering, or later expansion is identified. No third-party acquisition, seller, purchase price, debt financing, tax-equity financing, or construction-loan amount is identified for Solar Blue; the documented September 2025 transaction is an equity contribution into WEPCO rather than identified sale consideration."] — Public Queue Report · confidence: medium
- Quality notes: ["The 475 MW total is supported by an EIA-derived plant record, while CAISO records identify approximately 250 MW of photovoltaic capacity and 225 MW of storage; no equipment count is inferred from capacity.","Solar Blue is distinct from Aquamarine, another 250 MW CIM project at Westlands Solar Park that reached commercial operation in 2021–2022.","No retirement, repowering, or later expansion is identified. No third-party acquisition, seller, purchase price, debt financing, tax-equity financing, or construction-loan amount is identified for Solar Blue; the documented September 2025 transaction is an equity contribution into WEPCO rather than identified sale consideration."] — CIM Group Celebrates Completion and Commercial Operation of Aquamarine, 250-Megawatt Solar Photovoltaic Project within Westlands Solar Park · confidence: medium
- Timeline.0: {"event":"CEQA project definition and permitting","date":"2019-08","detail":"Kings County's CEQA record, received on 2019-08-15, described the Solar Blue Project as a 250 MW solar generating facility on approximately 1,895 acres, to be constructed over an 18-month period beginning in 2020."} — Solar Blue Project · confidence: high
- Timeline.1: {"event":"Planned construction commencement","date":"2020","detail":"The Solar Blue CEQA description called for construction to commence in 2020."} — Solar Blue Project · confidence: medium
- Quality notes.0: The 475 MW total is supported by an EIA-derived plant record, while CAISO records identify approximately 250 MW of photovoltaic capacity and 225 MW of storage; no equipment count is inferred from capacity. — Public Queue Report · confidence: medium
- Quality notes.1: Solar Blue is distinct from Aquamarine, another 250 MW CIM project at Westlands Solar Park that reached commercial operation in 2021–2022. — CIM Group Celebrates Completion and Commercial Operation of Aquamarine, 250-Megawatt Solar Photovoltaic Project within Westlands Solar Park · confidence: high
- Commercial parties.2: {"relationship":"Developer and park owner","name":"CIM Group","detail":"Identified as the owner and developer of Westlands Solar Park, developed in collaboration with Westside Holdings in phases that include Westlands Solar Blue.","official_url":"https://www.cimgroup.com/"} — Westlands Solar Park, California · confidence: medium
- Commercial parties.3: {"relationship":"Development collaborator","name":"Westside Holdings","detail":"Identified as CIM Group's collaborator in the phased development of Westlands Solar Park, including the phase identified as Westlands Solar Blue.","official_url":null} — Westlands Solar Park, California · confidence: medium
- Commercial parties.6: {"relationship":"CEQA lead agency","name":"County of Kings","detail":"Lead agency for the Solar Blue Project's CEQA review and use-permit process.","official_url":"https://www.countyofkingsca.gov"} — Solar Blue Project · confidence: high

## Timeline

- 2019-08 — CEQA project definition and permitting
  Kings County's CEQA record, received on August 15, 2019, described the Solar Blue Project as a 250 MW solar generating facility on approximately 1,895 acres, to be constructed over an 18-month period beginning in 2020.
  Source: Solar Blue Project (https://ceqanet.lci.ca.gov/2019089052/2)
- 2020 — Planned construction commencement
  The Solar Blue CEQA description called for construction to commence in 2020.
  Source: Solar Blue Project (https://ceqanet.lci.ca.gov/2019089052/2)

## Sources

- [Source](https://www.caiso.com/documents/briefing-resourcesavailable-nearterminterconnection.pdf) — caiso.com · tier other
- [db125_source_and_sink](https://www.caiso.com/documents/crrfnmdb125sourceandsinkapnodesfebruary2024monthlyprocess.xlsx) — caiso.com · tier other
- [Solar Blue Project](https://ceqanet.lci.ca.gov/2019089052/2) — ceqanet.lci.ca.gov · tier regulatory
- [Around Kings County: ‘Wall to Wall’ solar plants on the way - Central California](https://centralcalifornia.org/around-kings-county-wall-to-wall-solar-plants-on-the-way/) — centralcalifornia.org · tier other
- [Public Queue Report](https://www.caiso.com/documents/publicqueuereport.xlsx) — caiso.com · tier other
- [CIM Group Celebrates Completion and Commercial Operation of Aquamarine, 250-Megawatt Solar Photovoltaic Project within Westlands Solar Park](https://www.cimgroup.com/press-releases/cim-group-celebrates-completion-and-commercial-operation-of-aquamarine-250-megawatt-solar-photovoltaic-project-within-westlands-solar-park) — cimgroup.com · tier other
- [Westlands Solar Park, California](https://www.power-technology.com/projects/westlands-solar-park/) — power-technology.com · tier other
- [CIM Group Consolidates $1.3B in Solar Assets Into New Investment Vehicle - AltsWire](https://altswire.com/cim-group-consolidates-1-3b-in-solar-assets-into-new-investment-vehicle/) — altswire.com · tier other
- [Curtailed](https://www.caiso.com/documents/curtailed-non-operational-generator-am-report-20251007.xlsx) — caiso.com · tier other

## Data quality

- The 475 MW total is supported by an EIA-derived plant record, while CAISO records identify approximately 250 MW of photovoltaic capacity and 225 MW of storage; no equipment count is inferred from capacity. Solar Blue is distinct from Aquamarine, another 250 MW CIM project at Westlands Solar Park that reached commercial operation in 2021–2022. No retirement, repowering, or later expansion is identified. No third-party acquisition, seller, purchase price, debt financing, tax-equity financing, or construction-loan amount is identified for Solar Blue; the documented September 2025 transaction is an equity contribution into WEPCO rather than identified sale consideration.

---

Canonical page: https://askthegrid.com/assets/facilities/solar-blue

Source: Ask the Grid — https://askthegrid.com/