# Baldy Mesa Solar & Storage

CAISO Solar Photovoltaic, Batteries · https://askthegrid.com/assets/facilities/baldy-mesa-solar-and-storage

Baldy Mesa Solar & Storage is a hybrid solar and battery storage facility with 225 MW of EIA-reported total operating capacity and 300 MWh of reported storage energy capacity in San Bernardino County, California, registered as EIA Plant ID 66598. AES Clean Energy owns and operates the plant. Contemporary project coverage identified Baldy Mesa as California’s largest DC-coupled solar-plus-storage plant at the time of its October 2024 inauguration.

## Key facts

- Technology: Solar Photovoltaic, Batteries
- Power capacity: 225 MW
- Energy capacity: 300 MWh
- Operating status: operating

## Grid and market context

- ISO/RTO: CAISO
- Balancing authority: CISO (CAISO)
- Substation: Roadway Substation
- Point of interconnection: Roadway Substation
- Transmission owner: Southern California Edison (SCE)
- Interconnection voltage: 115 kV

## Source-backed facts

- Owner logo domain: aes.com — AES | Accelerating the Future of Global Energy · confidence: high
- Description: Baldy Mesa Solar & Storage is an operational 225 MW hybrid solar-and-battery plant in Adelanto, San Bernardino County, California, with two generating units; its first unit came online on May 1, 2024. AES describes the project as 150 MW of solar energy plus 75 MW of battery storage, developed, owned, and operated by AES. Power is delivered to the grid through a five-mile transmission line connected to Southern California Edison’s Roadway Substation. — Baldy Mesa Solar + Storage | AES · confidence: medium
- Identifiers.1: {"value":"BDMSS","system":"EIA generator ID"} — EIA - MBR | Index - FERC · confidence: medium
- Identifiers.2: {"value":"BLDMS","system":"EIA generator ID"} — EIA - MBR | Index - FERC · confidence: medium
- Parties.1: {"relationship":"Developer and operator","name":"AES Clean Energy","official_url":"https://www.aes.com"} — Baldy Mesa Solar + Storage | AES · confidence: medium
- Parties.3: {"relationship":"Interconnecting utility","name":"Southern California Edison","official_url":"https://www.sce.com"} — Baldy Mesa Solar + Storage | AES · confidence: high
- Parties.5: {"relationship":"Project enabler / energy customer","name":"Amazon","official_url":"https://www.aboutamazon.com"} — Amazon is helping decarbonize the grid with AI · confidence: high
- Interconnection: Southern California Edison Roadway Substation via an approximately 5-mile transmission line, including an approximately 5-mile 115 kV gen-tie — Baldy Mesa Solar + Storage | AES · confidence: high
- Interconnection: Southern California Edison Roadway Substation via an approximately 5-mile transmission line, including an approximately 5-mile 115 kV gen-tie — Baldy Mesa Solar Project (California Endangered Species Act Incidental Take Permit No. 2081-2020- 037-06 (ITP)) · confidence: high
- Site acres: 1000 — Source · confidence: medium
- Construction scope: Operational 150 MW solar facility paired with 75 MW / 300 MWh battery storage in Adelanto, San Bernardino County, California. AES developed, owns, and operates the project; Fluence supplied the storage system and bidding software. Power is delivered through a five-mile transmission line to Southern California Edison’s Roadway Substation. The available sources refer to one battery unit but do not provide installed module, panel, inverter, or PCS counts. — Source · confidence: high
- Product url: https://fluenceenergy.com/modular-energy-storage/ — Safe, simple, scalable energy storage technology and systems | Fluence · confidence: medium
- Manufacturer domain: fluenceenergy.com — Accelerating the AI Economy with Battery Storage · confidence: high
- Manufacturer name: Fluence — Accelerating the AI Economy with Battery Storage · confidence: high
- Product url: https://fluenceenergy.com/modular-energy-storage/ — Safe, simple, scalable energy storage technology and systems | Fluence · confidence: medium
- Product url: https://fluenceenergy.com/modular-energy-storage/ — Accelerating the AI Economy with Battery Storage · confidence: medium
- Kind: solar — Baldy Mesa Solar + Storage | AES · confidence: high
- Manufacturer domain: fluenceenergy.com — Accelerating the AI Economy with Battery Storage · confidence: high
- Manufacturer name: Fluence — Accelerating the AI Economy with Battery Storage · confidence: high
- Description: Baldy Mesa Solar & Storage is an operational hybrid facility in Adelanto, San Bernardino County, California, consisting of 150 MW of solar PV and 75 MW of battery storage. AES developed the project and is identified as its owner and operator, with AES Clean Energy listed in FERC records for the 225 MW plant. The facility delivers power through an approximately five-mile transmission line to Southern California Edison’s Roadway Substation. Amazon enabled the project and is the primary purchaser of its energy, while AWS- and Fluence-related software is used to optimize battery dispatch. — Baldy Mesa Solar + Storage | AES · confidence: medium
- Description: Baldy Mesa Solar & Storage is an operational hybrid facility in Adelanto, San Bernardino County, California, consisting of 150 MW of solar PV and 75 MW of battery storage. AES developed the project and is identified as its owner and operator, with AES Clean Energy listed in FERC records for the 225 MW plant. The facility delivers power through an approximately five-mile transmission line to Southern California Edison’s Roadway Substation. Amazon enabled the project and is the primary purchaser of its energy, while AWS- and Fluence-related software is used to optimize battery dispatch. — MBR | Index · confidence: medium
- Quality notes: ["EIA/FERC records identify two generating units: BDMSS at 75 MW and BLDMS at 150 MW; the project-level total is 225 MW.","A 2022 local fact sheet projected commercial operation in the third quarter of 2023, but operational data records the first unit online on 2024-05-01 and the project was reported connected to the grid on 2024-05-21.","Contemporary 2020 reporting identified sPower as the project builder, operator, and owner during development, while AES’s current project page identifies AES as developer, owner, and operator. AES and AIMCo’s 2017 acquisition of sPower was a corporate portfolio transaction, not a separately disclosed Baldy Mesa asset sale.","No expansion, retirement, repowering, or project-specific debt or tax-equity amount is disclosed in the cited project records. The reported $500 easement value is an SCE property transaction, not project financing or sale consideration."] — MBR | Index · confidence: medium
- Quality notes: ["EIA/FERC records identify two generating units: BDMSS at 75 MW and BLDMS at 150 MW; the project-level total is 225 MW.","A 2022 local fact sheet projected commercial operation in the third quarter of 2023, but operational data records the first unit online on 2024-05-01 and the project was reported connected to the grid on 2024-05-21.","Contemporary 2020 reporting identified sPower as the project builder, operator, and owner during development, while AES’s current project page identifies AES as developer, owner, and operator. AES and AIMCo’s 2017 acquisition of sPower was a corporate portfolio transaction, not a separately disclosed Baldy Mesa asset sale.","No expansion, retirement, repowering, or project-specific debt or tax-equity amount is disclosed in the cited project records. The reported $500 easement value is an SCE property transaction, not project financing or sale consideration."] — Source · confidence: medium
- Quality notes: ["EIA/FERC records identify two generating units: BDMSS at 75 MW and BLDMS at 150 MW; the project-level total is 225 MW.","A 2022 local fact sheet projected commercial operation in the third quarter of 2023, but operational data records the first unit online on 2024-05-01 and the project was reported connected to the grid on 2024-05-21.","Contemporary 2020 reporting identified sPower as the project builder, operator, and owner during development, while AES’s current project page identifies AES as developer, owner, and operator. AES and AIMCo’s 2017 acquisition of sPower was a corporate portfolio transaction, not a separately disclosed Baldy Mesa asset sale.","No expansion, retirement, repowering, or project-specific debt or tax-equity amount is disclosed in the cited project records. The reported $500 easement value is an SCE property transaction, not project financing or sale consideration."] — Baldy Mesa Solar Project gains approval for development... · confidence: medium
- Quality notes.0: EIA/FERC records identify two generating units: BDMSS at 75 MW and BLDMS at 150 MW; the project-level total is 225 MW. — MBR | Index · confidence: medium
- Quality notes.1: A 2022 local fact sheet projected commercial operation in the third quarter of 2023, but operational data records the first unit online on 2024-05-01 and the project was reported connected to the grid on 2024-05-21. — Source · confidence: medium
- Quality notes.2: Contemporary 2020 reporting identified sPower as the project builder, operator, and owner during development, while AES’s current project page identifies AES as developer, owner, and operator. AES and AIMCo’s 2017 acquisition of sPower was a corporate portfolio transaction, not a separately disclosed Baldy Mesa asset sale. — Baldy Mesa Solar Project gains approval for development... · confidence: medium
- Quality notes.2: Contemporary 2020 reporting identified sPower as the project builder, operator, and owner during development, while AES’s current project page identifies AES as developer, owner, and operator. AES and AIMCo’s 2017 acquisition of sPower was a corporate portfolio transaction, not a separately disclosed Baldy Mesa asset sale. — Baldy Mesa Solar + Storage | AES · confidence: medium
- Timeline.1: {"event":"Project permitting approval","date":"2020-11","detail":"The City of Adelanto adopted a Mitigated Negative Declaration and granted a Conditional Use Permit for the Baldy Mesa project. Contemporary reporting identified sPower as the project builder, operator, and owner during development."} — Baldy Mesa Solar Project gains approval for development... · confidence: medium
- Timeline.1: {"event":"Project permitting approval","date":"2020-11","detail":"The City of Adelanto adopted a Mitigated Negative Declaration and granted a Conditional Use Permit for the Baldy Mesa project. Contemporary reporting identified sPower as the project builder, operator, and owner during development."} — Source · confidence: medium
- Timeline.4: {"event":"Construction start","date":"2022","detail":"The Adelanto project fact sheet scheduled construction to start in the third quarter of 2022."} — Source · confidence: medium
- Timeline.5: {"event":"FERC market-based-rate filing","date":"2023-03-21","detail":"FERC published a supplemental notice for Baldy Mesa Solar, LLC’s application for market-based-rate authority and related blanket Section 204 authorization request under Docket ER23-1319-000."} — Federal Register :: Baldy Mesa Solar, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for Blanket Section 204 Authorization · confidence: high
- Timeline.6: {"event":"FERC/EIA active plant record","date":"2023-11-01","detail":"FERC’s EIA-indexed record listed AES Clean Energy for Baldy Mesa Solar & Storage, plant code 66598, with generator BDMSS at 75 MW and BLDMS at 150 MW."} — MBR | Index · confidence: medium
- Timeline.8: {"event":"Grid connection reported","date":"2024-05-21","detail":"The project was reported connected to the grid as a 150 MW solar and 75 MW storage facility enabled by Amazon, with AES as developer and owner."} — Baldy Mesa solar + storage project now online and supporting Amazon operations · confidence: medium
- Timeline.9: {"event":"Project inauguration and operating offtake context","date":"2024-10-24","detail":"AES inaugurated Baldy Mesa and adjacent Silver Peak. Coverage described Baldy Mesa as a 150 MW solar PV project with a 75 MW/300 MWh battery, with Amazon as the primary purchaser of energy from the AES projects."} — Renewable hybrid project tied to Amazon PPA reaches commercial operations - DCD · confidence: medium
- Commercial parties.1: {"relationship":"Developer and operator","name":"AES Clean Energy","detail":"FERC’s EIA-indexed record lists AES Clean Energy for plant 66598. AES Clean Energy operates the facility within the AES group.","official_url":"https://www.aes.com"} — MBR | Index · confidence: medium
- Commercial parties.3: {"relationship":"Primary energy purchaser and project enabler","name":"Amazon","detail":"Amazon enabled the project and is identified as the primary purchaser of energy from the AES projects; Amazon’s AWS services support the machine-learning optimization workflow.","official_url":"https://www.aboutamazon.com"} — Amazon is helping decarbonize the grid with AI · confidence: medium
- Commercial parties.4: {"relationship":"Interconnecting utility","name":"Southern California Edison","detail":"Power is delivered through an approximately five-mile transmission line to SCE’s Roadway Substation in Adelanto.","official_url":"https://www.sce.com"} — Amazon signs deals for California solar and battery storage with AES - Energy-Storage.News · confidence: medium
- Commercial parties.5: {"relationship":"Battery and optimization technology provider","name":"Fluence","detail":"AES contracted Fluence for battery-storage solutions within the Amazon portfolio, and Fluence software is identified as supporting Baldy Mesa battery dispatch optimization.","official_url":"https://fluenceenergy.com"} — Baldy Mesa Solar + Storage | AES · confidence: high
- Commercial parties.6: {"relationship":"Predecessor developer during permitting","name":"sPower","detail":"Contemporary 2020 reporting identified sPower as the entity that would build and operate Baldy Mesa and stated that it owned the project during development. sPower later became part of the AES ownership lineage through the 2017 corporate portfolio acquisition.","official_url":null} — Baldy Mesa Solar Project gains approval for development... · confidence: medium
- Substation: Roadway Substation — Source · confidence: high
- Interconnection voltage kv: 115 — SCE 2022 - Annual Progress Report_Final · confidence: medium
- Status date: 2026-08-02 — Baldy Mesa Solar + Storage | AES · confidence: medium
- Transmission owner: Southern California Edison (SCE) — Source · confidence: high
- Resource type: Hybrid solar-plus-storage — CAISO Resource Visibility Template · confidence: medium

## Timeline

- 2020-11 — Project permitting approval
  The City of Adelanto adopted a Mitigated Negative Declaration and granted a Conditional Use Permit for the Baldy Mesa project. Contemporary reporting identified sPower as the project builder, operator, and owner during development.
  Source: Source (https://cms3.revize.com/revize/adelanto/Documents/Services/Community%20Development%20Services/Community%20Development%20Portal/Projects/Alternative%20Energy/Baldy%20Mesa_Fact%20Sheet.pdf)
- 2022 — Construction start
  The Adelanto project fact sheet scheduled construction to start in the third quarter of 2022.
  Source: Source (https://cms3.revize.com/revize/adelanto/Documents/Services/Community%20Development%20Services/Community%20Development%20Portal/Projects/Alternative%20Energy/Baldy%20Mesa_Fact%20Sheet.pdf)
- 2022-04-07 — SCE interconnection easement approval
  The California Public Utilities Commission approved SCE’s request to grant Baldy Mesa Solar, LLC an overhead easement supporting the project’s interconnection. The easement’s appraised value was $500, which was a property transaction rather than project financing or sale consideration.
  Source: Source (https://docs.cpuc.ca.gov/PublishedDocs/Published/G000/M458/K249/458249893.PDF)
- 2023-03-21 — FERC market-based-rate filing
  FERC published a supplemental notice for Baldy Mesa Solar, LLC’s application for market-based-rate authority and related blanket Section 204 authorization request under Docket ER23-1319-000.
  Source: Federal Register :: Baldy Mesa Solar, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for Blanket Section 204 Authorization (https://www.federalregister.gov/documents/2023/03/21/2023-05779/baldy-mesa-solar-llc-supplemental-notice-that-initial-market-based-rate-filing-includes-request-for)
- 2024-05-21 — Grid connection reported
  The project was reported connected to the grid as a 150 MW solar and 75 MW storage facility enabled by Amazon, with AES as developer and owner.
  Source: Baldy Mesa solar + storage project now online and supporting Amazon operations (https://www.solarpowerworldonline.com/2024/05/baldy-mesa-solar-storage-project-now-online-and-supporting-amazon-operations/)

## Sources

- [AES | Accelerating the Future of Global Energy](https://www.aes.com/) — aes.com · tier other
- [MBR | Index](https://mbrweb.ferc.gov/SearchlkpEIA/Index?page=773) — mbrweb.ferc.gov · tier regulatory
- [Baldy Mesa Solar + Storage | AES](https://www.aes.com/sustainability-impact/people-communities/projects/baldy-mesa-solarstorage) — aes.com · tier other
- [Source](https://docs.cpuc.ca.gov/PublishedDocs/Published/G000/M458/K249/458249893.PDF) — docs.cpuc.ca.gov · tier regulatory
- [Amazon is helping decarbonize the grid with AI](https://www.aboutamazon.com/news/sustainability/carbon-free-energy-projects-ai-tech) — aboutamazon.com · tier other
- [Baldy Mesa Solar Project (California Endangered Species Act Incidental Take Permit No. 2081-2020- 037-06 (ITP))](https://ceqanet.lci.ca.gov/2020090176/6) — ceqanet.lci.ca.gov · tier regulatory
- [Source](https://cms3.revize.com/revize/adelanto/Documents/Services/Community%20Development%20Services/Community%20Development%20Portal/Projects/Alternative%20Energy/Baldy%20Mesa_Fact%20Sheet.pdf) — cms3.revize.com · tier other
- [Accelerating the AI Economy with Battery Storage](https://info.fluenceenergy.com/hubfs/Fluence-Data%20Centre%20Brochure-BR-065-01-EN.pdf) — info.fluenceenergy.com · tier other
- [Safe, simple, scalable energy storage technology and systems | Fluence](https://fluenceenergy.com/modular-energy-storage/) — fluenceenergy.com · tier other
- [Draft Initial Study/Mitigated Negative Declaration](https://files.ceqanet.lci.ca.gov/264480-2/attachment/8u4WGIyeQfIVeGNO03DBxryH0ol3LcjF50rXFPz59s76n_o0JSB8vD5us07NAt3_fnjKsTG2acQmUTBB0) — files.ceqanet.lci.ca.gov · tier regulatory
- [Baldy Mesa Solar Project gains approval for development in north Adelanto](https://www.vvdailypress.com/story/news/2020/11/15/baldy-mesa-solar-project-gains-approval-for-development-in-north-adelanto/6299567002/) — vvdailypress.com · tier other
- [Amazon signs deals for California solar and battery storage with AES - Energy-Storage.News](https://www.energy-storage.news/amazon-signs-deals-for-california-solar-and-battery-storage-with-aes/) — energy-storage.news · tier other
- [Federal Register :: Baldy Mesa Solar, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for Blanket Section 204 Authorization](https://www.federalregister.gov/documents/2023/03/21/2023-05779/baldy-mesa-solar-llc-supplemental-notice-that-initial-market-based-rate-filing-includes-request-for) — federalregister.gov · tier regulatory
- [Baldy Mesa solar + storage project now online and supporting Amazon operations](https://www.solarpowerworldonline.com/2024/05/baldy-mesa-solar-storage-project-now-online-and-supporting-amazon-operations/) — solarpowerworldonline.com · tier other
- [Renewable hybrid project tied to Amazon PPA reaches commercial operations - DCD](https://www.datacenterdynamics.com/en/news/renewable-hybrid-project-tied-to-amazon-ppa-reaches-commercial-operations/) — datacenterdynamics.com · tier other
- [SPower Acquisition | AIMCo](https://www.aimco.ca/insights/spower-acquisition) — aimco.ca · tier other
- [AES and AIMCo to Form Leading Renewables Platform | AIMCo](https://www.aimco.ca/insights/aes-and-aimco-to-form-leading-renewables-platform) — aimco.ca · tier other
- [SCE 2022 - Annual Progress Report_Final](https://www.wecc.org/sites/default/files/documents/progress_report/2025/SCE%202025%20APR.pdf) — wecc.org · tier other
- [CAISO Resource Visibility Template](https://www.caiso.com/documents/caiso-resource-visibility-template.xlsx) — caiso.com · tier other
- [AES Energy Projects | Solar, Wind, Storage and More](https://www.aes.com/sustainability-impact/people-communities/projects?view=list&Technology=Solar) — aes.com · tier other

## Data quality

- EIA/FERC records identify two generating units: BDMSS at 75 MW and BLDMS at 150 MW; the project-level total is 225 MW. Contemporary 2020 reporting identified sPower as the project builder, operator, and owner during development, while AES’s current project page identifies AES as developer, owner, and operator. AES and AIMCo’s 2017 acquisition of sPower was a corporate portfolio transaction, not a separately disclosed Baldy Mesa asset sale. No expansion, retirement, repowering, or project-specific debt or tax-equity amount is disclosed in the cited project records. The reported $500 easement value is an SCE property transaction, not project financing or sale consideration.

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