# Golden Field Solar III, LLC CAISO Batteries, Solar Photovoltaic · https://askthegrid.com/assets/facilities/golden-field-solar-iii-llc Golden Field Solar III, LLC is a hybrid solar and battery storage facility with 339 MW of EIA-reported total operating capacity and 588 MWh of reported storage energy capacity in Kern County, California, registered as EIA Plant ID 63859. Golden Fields Solar III, LLC is the registered plant entity or operator. McCarthy Building Companies built the facility using Wärtsilä GridSolv Quantum equipment. Rosamond Solar Investment LLC, a subsidiary of Clearway Energy, Inc. acquired a 50% interest in the plant from Renew Development HoldCo LLC in 2020. Commercial operation began on January 5, 2021. PG&E DLAP · 230 kV · Southern California Edison (SCE). ## Key facts - Technology: Batteries, Solar Photovoltaic - Power capacity: 339 MW - Energy capacity: 588 MWh - Operating status: operating ## Grid and market context - ISO/RTO: CAISO - Balancing authority: California Independent System Operator (CISO/CAISO) ## Source-backed facts - Owner logo domain: clearwayenergygroup.com — Renewable energy in California - Clearway · confidence: medium - Owner logo domain: clearwayenergygroup.com — Clearway Brings Online Its First Battery Energy Storage Retrofit in California - Clearway Energy · confidence: medium - Description: Golden Field Solar III, LLC is a 339 MW hybrid solar-and-battery power plant in Kern County, California, operating in the CAISO market. The plant comprises a 192 MW solar photovoltaic generator and a 147 MW battery generator; the solar unit began operating in December 2020 and the battery unit in March 2024. The facility is publicly associated with Clearway’s Rosamond Central solar and battery projects. — Clearway Brings Online Its First Battery Energy Storage Retrofit in California - Clearway Energy · confidence: medium - Identifiers.1: {"value":"RCTR","system":"EIA generator ID — solar photovoltaic"} — MBR | Asset Appendix Report - MBR Portal - FERC · confidence: high - Identifiers.4: {"value":"1212","system":"CAISO interconnection resource ID"} — Briefing on Resources available for near term interconnection · confidence: medium - Parties.2: {"relationship":"Public affiliate and BESS owner/equity investor","name":"Clearway Energy, Inc.","official_url":"https://investor.clearwayenergy.com"} — Clearway Brings Online Its First Battery Energy Storage Retrofit in California - Clearway Energy · confidence: high - Parties.2: {"relationship":"Public affiliate and BESS owner/equity investor","name":"Clearway Energy, Inc.","official_url":"https://investor.clearwayenergy.com"} — Clearway Closes Financing and Begins Construction on Utility-Scale Battery Storage Facility - Clearway Energy · confidence: high - Parties.3: {"relationship":"Solar EPC contractor","name":"McCarthy Building Companies","official_url":"https://www.mccarthy.com"} — Clearway Completes Construction on Rosamond Central Solar Project - Clearway Energy · confidence: high - Parties.4: {"relationship":"BESS construction contractor","name":"Rosendin","official_url":"https://www.rosendin.com"} — Clearway Closes Financing and Begins Construction on Utility-Scale Battery Storage Facility - Clearway Energy · confidence: high - Parties.5: {"relationship":"Battery energy-storage system supplier/OEM","name":"Wärtsilä","official_url":"https://www.wartsila.com"} — Clearway Brings Online Its First Battery Energy Storage Retrofit in California - Clearway Energy · confidence: high - Parties.6: {"relationship":"Solar power offtaker","name":"East Bay Community Energy","official_url":"https://ebce.org"} — Clearway Completes Construction on Rosamond Central Solar Project - Clearway Energy · confidence: high - Parties.7: {"relationship":"Solar power offtaker","name":"Clean Power Alliance","official_url":"https://cleanpoweralliance.org"} — Clearway Completes Construction on Rosamond Central Solar Project - Clearway Energy · confidence: high - Parties.8: {"relationship":"Solar power offtaker","name":"City of Palo Alto Utilities","official_url":"https://www.cityofpaloalto.org/Departments/Utilities"} — Clearway Completes Construction on Rosamond Central Solar Project - Clearway Energy · confidence: high - Parties.9: {"relationship":"BESS resource-adequacy offtaker","name":"Southern California Edison","official_url":"https://www.sce.com"} — Clearway Closes Financing and Begins Construction on Utility-Scale Battery Storage Facility - Clearway Energy · confidence: high - Parties.10: {"relationship":"Climate investment and equity investor","name":"HASI","official_url":"https://www.hasifinance.com"} — Clearway Closes Financing and Begins Construction on Utility-Scale Battery Storage Facility - Clearway Energy · confidence: high - Parties.11: {"relationship":"Coordinating lead arranger","name":"NORD/LB","official_url":"https://www.nordlb.com"} — Clearway Closes Financing and Begins Construction on Utility-Scale Battery Storage Facility - Clearway Energy · confidence: high - Parties.12: {"relationship":"Joint lead arranger","name":"CoBank","official_url":"https://www.cobank.com"} — Clearway Closes Financing and Begins Construction on Utility-Scale Battery Storage Facility - Clearway Energy · confidence: high - Parties.13: {"relationship":"Joint lead arranger","name":"Commerzbank","official_url":"https://www.commerzbank.com"} — Clearway Closes Financing and Begins Construction on Utility-Scale Battery Storage Facility - Clearway Energy · confidence: high - Parties.14: {"relationship":"Joint lead arranger","name":"DNB","official_url":"https://www.dnb.no"} — Clearway Closes Financing and Begins Construction on Utility-Scale Battery Storage Facility - Clearway Energy · confidence: high - Parties.15: {"relationship":"Joint lead arranger","name":"Société Générale","official_url":"https://www.societegenerale.com"} — Clearway Closes Financing and Begins Construction on Utility-Scale Battery Storage Facility - Clearway Energy · confidence: high - Parties.16: {"relationship":"Joint lead arranger","name":"Zions Capital Markets","official_url":"https://www.zionsbancorporation.com"} — Clearway Closes Financing and Begins Construction on Utility-Scale Battery Storage Facility - Clearway Energy · confidence: high - Unit configuration: Two generating units: a 192 MW solar photovoltaic generator and a 147 MW, four-hour lithium-ion battery energy-storage generator; total nameplate capacity is 339 MW. — Clearway Brings Online Its First Battery Energy Storage Retrofit in California - Clearway Energy · confidence: medium - Duration hours: 4 — Clearway Brings Online Its First Battery Energy Storage Retrofit in California - Clearway Energy · confidence: high - Power mw: 339 — Clearway Brings Online Its First Battery Energy Storage Retrofit in California - Clearway Energy · confidence: medium - Energy mwh: 588 — Clearway Brings Online Its First Battery Energy Storage Retrofit in California - Clearway Energy · confidence: medium - Product url: https://storage.wartsila.com/technology/gridsolv-quantum/ — Wärtsilä signs contracts to supply energy storage systems for one of the world’s largest solar-plus-storage project portfolios · confidence: medium - Product url: https://storage.wartsila.com/technology/gridsolv-quantum/ — GridSolv Quantum · confidence: medium - Kind: bess — Clearway Brings Online Its First Battery Energy Storage Retrofit in California - Clearway Energy · confidence: medium - Equipment models: [{"manufacturer_domain":"wartsila.com","product_url":"https://storage.wartsila.com/technology/gridsolv-quantum/","count":null,"unit_mw":null,"name":"GridSolv Quantum"}] — Source · confidence: medium - Product family: GridSolv Quantum — Source · confidence: high - Equipment models.0: {"manufacturer_domain":"wartsila.com","product_url":"https://storage.wartsila.com/technology/gridsolv-quantum/","count":null,"unit_mw":null,"name":"GridSolv Quantum"} — Source · confidence: medium - Construction scope: Golden Field Solar III / Rosamond Central is a two-generator hybrid comprising a 192 MW solar PV facility and an adjacent 147 MW / 588 MWh, four-hour lithium-ion BESS. Solar construction was led by McCarthy Building Companies; BESS construction was led by Rosendin, with the storage systems supplied by Wärtsilä. Wärtsilä identifies the storage solution as GridSolv Quantum with the GEMS Digital Energy Platform. No source-backed module, inverter/PCS, battery-unit, or container count was found. — Clearway Brings Online Its First Battery Energy Storage Retrofit in California - Clearway Energy · confidence: medium - Construction scope: Golden Field Solar III / Rosamond Central is a two-generator hybrid comprising a 192 MW solar PV facility and an adjacent 147 MW / 588 MWh, four-hour lithium-ion BESS. Solar construction was led by McCarthy Building Companies; BESS construction was led by Rosendin, with the storage systems supplied by Wärtsilä. Wärtsilä identifies the storage solution as GridSolv Quantum with the GEMS Digital Energy Platform. No source-backed module, inverter/PCS, battery-unit, or container count was found. — Clearway Closes Financing and Begins Construction on Utility-Scale Battery Storage Facility - Clearway Energy · confidence: medium - Product url: https://storage.wartsila.com/technology/gridsolv-quantum/ — Wärtsilä signs contracts to supply energy storage systems for one of the world’s largest solar-plus-storage project portfolios · confidence: high - Product url: https://storage.wartsila.com/technology/gridsolv-quantum/ — Wärtsilä Energy Storage - Leading the energy transition · confidence: high - Kind: bess — Clearway Brings Online Its First Battery Energy Storage Retrofit in California - Clearway Energy · confidence: medium - Description: Golden Field Solar III, LLC is a 339 MW hybrid facility in Kern County, California, consisting of a 192 MW solar photovoltaic generator and a co-located 147 MW battery system. Clearway Energy Group developed and operates the project platform; Clearway Energy, Inc. is the public affiliate associated with the BESS ownership and the solar project’s 50% cash-equity interest. The solar project began operating in December 2020 and was formally announced as commercially operational in January 2021, while the battery expansion began construction in 2023 and reached commercial operations in 2024. Solar output is contracted to East Bay Community Energy, Clean Power Alliance, and City of Palo Alto Utilities; the BESS capacity is contracted to Southern California Edison. — Clearway Brings Online Its First Battery Energy Storage Retrofit in California - Clearway Energy · confidence: medium - Description: Golden Field Solar III, LLC is a 339 MW hybrid facility in Kern County, California, consisting of a 192 MW solar photovoltaic generator and a co-located 147 MW battery system. Clearway Energy Group developed and operates the project platform; Clearway Energy, Inc. is the public affiliate associated with the BESS ownership and the solar project’s 50% cash-equity interest. The solar project began operating in December 2020 and was formally announced as commercially operational in January 2021, while the battery expansion began construction in 2023 and reached commercial operations in 2024. Solar output is contracted to East Bay Community Energy, Clean Power Alliance, and City of Palo Alto Utilities; the BESS capacity is contracted to Southern California Edison. — Clearway Completes Construction on Rosamond Central Solar Project - Clearway Energy · confidence: medium - Quality notes: ["The plant-level 339 MW total comprises 192 MW of solar nameplate capacity and 147 MW of battery nameplate capacity; the BESS is separately described as 147 MW/588 MWh with four-hour duration.","The December 2020 50% equity acquisition and December 2023 BESS transfer are transaction considerations, not construction-financing amounts. Solar debt financing was announced without a disclosed amount, while BESS financing was separately announced at $421 million.","The cited operating records show both generating units operating; no retirement, repowering, or subsequent uprate/derate milestone is identified for this plant."] — Clearway Closes Financing and Begins Construction on Utility-Scale Battery Storage Facility - Clearway Energy · confidence: medium - Commercial parties.1: {"relationship":"Developer and operator; parent platform","name":"Clearway Energy Group, LLC","detail":"Developed and operates the Rosamond Central solar and BESS projects.","official_url":"https://www.clearwayenergygroup.com"} — Clearway Brings Online Its First Battery Energy Storage Retrofit in California - Clearway Energy · confidence: high - Commercial parties.2: {"relationship":"Public affiliate; solar cash-equity investor and BESS owner","name":"Clearway Energy, Inc.","detail":"Acquired a 50% cash-equity interest in the solar project in December 2020 and is identified by Clearway as the public affiliate owning the BESS.","official_url":"https://investor.clearwayenergy.com"} — Clearway Brings Online Its First Battery Energy Storage Retrofit in California - Clearway Energy · confidence: high - Commercial parties.6: {"relationship":"Solar EPC and construction contractor","name":"McCarthy Building Companies","detail":"Led construction of the 192 MW solar project.","official_url":"https://www.mccarthy.com"} — Clearway Completes Construction on Rosamond Central Solar Project - Clearway Energy · confidence: high - Commercial parties.7: {"relationship":"BESS construction contractor","name":"Rosendin","detail":"Led construction of the Rosamond Central BESS.","official_url":"https://www.rosendin.com"} — Clearway Brings Online Its First Battery Energy Storage Retrofit in California - Clearway Energy · confidence: high - Commercial parties.8: {"relationship":"BESS supplier/OEM","name":"Wärtsilä","detail":"Supplied the battery energy-storage systems for the BESS.","official_url":"https://www.wartsila.com"} — Clearway Brings Online Its First Battery Energy Storage Retrofit in California - Clearway Energy · confidence: high - Commercial parties.9: {"relationship":"Solar power offtaker","name":"East Bay Community Energy","detail":"Purchases solar output under a power-purchase agreement; Clearway identified 112 MW associated with the project for EBCE.","official_url":"https://ebce.org"} — Clearway Completes Construction on Rosamond Central Solar Project - Clearway Energy · confidence: high - Commercial parties.10: {"relationship":"Solar power offtaker","name":"Clean Power Alliance","detail":"Purchases solar output under a power-purchase agreement.","official_url":"https://cleanpoweralliance.org"} — Clearway Completes Construction on Rosamond Central Solar Project - Clearway Energy · confidence: high - Commercial parties.11: {"relationship":"Solar power offtaker","name":"City of Palo Alto Utilities","detail":"Purchases solar output under a power-purchase agreement; the project contributes 26 MW to Palo Alto’s portfolio according to the project announcement.","official_url":"https://www.cityofpaloalto.org/Departments/Utilities"} — Clearway Completes Construction on Rosamond Central Solar Project - Clearway Energy · confidence: high - Commercial parties.12: {"relationship":"BESS resource-adequacy offtaker","name":"Southern California Edison","detail":"Purchases the BESS energy-storage capacity under a long-term resource-adequacy agreement.","official_url":"https://www.sce.com"} — Clearway Brings Online Its First Battery Energy Storage Retrofit in California - Clearway Energy · confidence: high - Commercial parties.13: {"relationship":"Solar construction-financing coordinating lead arranger","name":"NordLB","detail":"Served as coordinating lead arranger for the March 2020 solar debt financing.","official_url":"https://www.nordlb.com"} — Clearway Completes Construction Financing on Rosamond Central - Clearway Energy · confidence: high - Commercial parties.14: {"relationship":"Solar construction-financing joint lead arranger","name":"CIT","detail":"Served as a joint lead arranger for the March 2020 solar debt financing.","official_url":null} — Clearway Completes Construction Financing on Rosamond Central - Clearway Energy · confidence: medium ## Timeline - 2020-02 — Solar construction began Construction of the 192 MW Rosamond Central solar project began in February 2020 and was led by McCarthy Building Companies. Source: Clearway Completes Construction on Rosamond Central Solar Project - Clearway Energy (https://www.clearwayenergygroup.com/press-releases/clearway-completes-construction-on-rosamond-central-solar-project/) - 2020-03-11 — Solar construction debt financing closed Clearway closed debt financing for the solar project. NordLB was coordinating lead arranger, while CIT and Zions were joint lead arrangers; the announcement did not disclose the debt amount. Source: Clearway Completes Construction Financing on Rosamond Central - Clearway Energy (https://www.clearwayenergygroup.com/press-releases/clearway-completes-construction-financing-on-rosamond-central/) - 2021-01-05 — Solar commercial operation announced Clearway announced completion of construction and commercial operations for the 192 MW Rosamond Central solar project. Source: Clearway Completes Construction on Rosamond Central Solar Project - Clearway Energy (https://www.clearwayenergygroup.com/press-releases/clearway-completes-construction-on-rosamond-central-solar-project/) - 2023-04 — BESS construction began Construction began on the 147 MW/588 MWh Rosamond Central BESS, designed as a four-hour battery paired with the operating solar farm. Source: Clearway Closes Financing and Begins Construction on Utility-Scale Battery Storage Facility - Clearway Energy (https://www.clearwayenergygroup.com/press-releases/clearway-closes-financing-and-begins-construction-on-utility-scale-battery-storage-facility/) - 2023-07-26 — BESS construction financing closed Clearway closed $421 million of financing for the BESS. The financing consortium included NordLB, CoBank, Commerzbank, DNB, Société Générale, and Zions Capital Markets; HASI and Clearway Energy, Inc. also provided cash equity, with committed tax equity arranged. Source: Clearway Closes Financing and Begins Construction on Utility-Scale Battery Storage Facility - Clearway Energy (https://www.clearwayenergygroup.com/press-releases/clearway-closes-financing-and-begins-construction-on-utility-scale-battery-storage-facility/) - 2024-07-24 — BESS commercial operation announced Clearway announced that the 147 MW Rosamond Central BESS had reached commercial operations. Source: Clearway Brings Online Its First Battery Energy Storage Retrofit in California - Clearway Energy (https://www.clearwayenergygroup.com/press-releases/clearway-brings-online-its-first-battery-energy-storage-retrofit-in-california) ## Sources - [Renewable energy in California - Clearway](https://www.clearwayenergygroup.com/community/california/) — clearwayenergygroup.com · tier other - [Clearway Brings Online Its First Battery Energy Storage Retrofit in California - Clearway Energy](https://www.clearwayenergygroup.com/press-releases/clearway-brings-online-its-first-battery-energy-storage-retrofit-in-california/) — clearwayenergygroup.com · tier other - [MBR | Asset Appendix Report - MBR Portal - FERC](https://mbrweb.ferc.gov/SearchMBRAssetAppendix/AssetAppendixDetails?AssetAppendixId=719) — mbrweb.ferc.gov · tier regulatory - [Briefing on Resources available for near term interconnection](https://www.caiso.com/documents/briefing-resourcesavailable-nearterminterconnection.pdf) — caiso.com · tier other - [Source](https://www.paloalto.gov/files/assets/public/agendas-minutes-reports/reports/city-manager-reports-cmrs/year-archive/2019/mini-packet-id-10213-04.18.2019.pdf?t=58969.3) — paloalto.gov · tier regulatory - [Clearway Completes Construction on Rosamond Central Solar Project - Clearway Energy](https://www.clearwayenergygroup.com/press-releases/clearway-completes-construction-on-rosamond-central-solar-project) — clearwayenergygroup.com · tier other - [Clearway Closes Financing and Begins Construction on Utility-Scale Battery Storage Facility - Clearway Energy](https://www.clearwayenergygroup.com/press-releases/clearway-closes-financing-and-begins-construction-on-utility-scale-battery-storage-facility/) — clearwayenergygroup.com · tier other - [Golden Fields So](https://www.ferc.gov/sites/default/files/2020-06/20200317153707-ER20-840-000.pdf) — ferc.gov · tier regulatory - [Clearway Completes Construction on Rosamond Central Solar Project - Clearway Energy](https://www.clearwayenergygroup.com/press-releases/clearway-completes-construction-on-rosamond-central-solar-project/) — clearwayenergygroup.com · tier other - [Wärtsilä signs contracts to supply energy storage systems for one of the world’s largest solar-plus-storage project portfolios](https://www.wartsila.com/media/news/11-07-2022-wartsila-signs-contracts-to-supply-energy-storage-systems-for-one-of-the-world-s-largest-solar-plus-storage-project-portfolios-3130241) — wartsila.com · tier other - [Source](https://www.wartsila.com/docs/default-source/energy-docs/energy-storage/project-spotlights/eb-eso-casestudy-amer-clearway.pdf?sfvrsn=d7d01243_5) — wartsila.com · tier other - [GridSolv Quantum](https://www.wartsila.com/docs/default-source/power-plants-documents/downloads/specification-sheets/gridsolv-quantum-specification-sheet.pdf) — wartsila.com · tier other - [Wärtsilä Energy Storage - Leading the energy transition](https://storage.wartsila.com/technology/gridsolv-quantum/) — storage.wartsila.com · tier other - [Clearway Brings Online Its First Battery Energy Storage Retrofit in California - Clearway Energy](https://www.clearwayenergygroup.com/press-releases/clearway-brings-online-its-first-battery-energy-storage-retrofit-in-california) — clearwayenergygroup.com · tier other - [Clearway Completes Construction Financing on Rosamond Central - Clearway Energy](https://www.clearwayenergygroup.com/press-releases/clearway-completes-construction-financing-on-rosamond-central/) — clearwayenergygroup.com · tier other - [Clearway Energy, Inc. Third Quarter 2025 Results Presentation](https://investor.clearwayenergy.com/static-files/4f6f3d77-1fa2-4875-82e2-d0499df2e159) — investor.clearwayenergy.com · tier other - [Generator Interconnection Resource ID Report](https://www.caiso.com/documents/generator-interconnection-resource-id-report.xlsx) — caiso.com · tier other ## Data quality - The plant-level 339 MW total comprises 192 MW of solar nameplate capacity and 147 MW of battery nameplate capacity; the BESS is separately described as 147 MW/588 MWh with four-hour duration. Solar debt financing was announced without a disclosed amount, while BESS financing was separately announced at $421 million. The cited operating records show both generating units operating; no retirement, repowering, or subsequent uprate/derate milestone is identified for this plant. --- Canonical page: https://askthegrid.com/assets/facilities/golden-field-solar-iii-llc Source: Ask the Grid — https://askthegrid.com/