# AES Alamitos LLC

CAISO Natural Gas Steam Turbine · https://askthegrid.com/assets/facilities/aes-alamitos-llc

AES Alamitos LLC is a natural gas-fired power facility with 1,115 MW of EIA-reported nameplate capacity in Los Angeles County, California, registered as EIA Plant ID 315. AES Alamitos LLC owns and operates the plant.

## Key facts

- Technology: Natural Gas Steam Turbine
- Power capacity: 1115 MW
- Commercial operation: 1956
- Operating status: operating

## Grid and market context

- ISO/RTO: CAISO
- Balancing authority: California Independent System Operator (CAISO)
- Substation: SCE Alamitos Switching Station
- Point of interconnection: SCE Alamitos Switching Station
- Transmission owner: Southern California Edison Company
- Interconnection voltage: 230 kV

## Source-backed facts

- Owner logo domain: aes.com — AES | Accelerating the Future of Global Energy · confidence: medium
- Owner logo domain: aes.com — AES Announces Extension Agreement for Southland Legacy Units in California · confidence: medium
- Identifiers: [{"value":"315","system":"EIA plant ID"},{"value":"22148","system":"EIA entity ID"},{"value":"1","system":"EIA generator ID"},{"value":"2","system":"EIA generator ID"},{"value":"3","system":"EIA generator ID"},{"value":"4","system":"EIA generator ID"},{"value":"5","system":"EIA generator ID"},{"value":"6","system":"EIA generator ID"},{"value":"ALAMIT_7_UNIT 1","system":"CAISO market resource ID"},{"value":"ALAMIT_7_UNIT 2","system":"CAISO market resource ID"},{"value":"ALAMIT_7_UNIT 3","system":"CAISO market resource ID"},{"value":"ALAMIT_7_UNIT 4","system":"CAISO market resource ID"},{"value":"ALAMIT_7_UNIT 5","system":"CAISO market resource ID"},{"value":"ALAMIT_7_UNIT 6","system":"CAISO market resource ID"},{"value":"ALAMT1 G","system":"CAISO legacy generator ID"},{"value":"ALAMT2 G","system":"CAISO legacy generator ID"},{"value":"ALAMT3 G","system":"CAISO legacy generator ID"},{"value":"ALAMT4 G","system":"CAISO legacy generator ID"},{"value":"ALAMT5 G","system":"CAISO legacy generator ID"},{"value":"ALAMT6 G","system":"CAISO legacy generator ID"},{"value":"ER98-2185-006","system":"FERC docket"}] — Source · confidence: medium
- Description: AES Alamitos LLC is an independent power producer in Long Beach, Los Angeles County, California, identified by EIA plant ID 315 and entity ID 22148. California Air Resources Board records identify six natural-gas steam-turbine generators at the facility, and CAISO records identify the associated Alamitos Generating Station units as ALAMIT_7_UNIT 1 through ALAMIT_7_UNIT 6. — Source · confidence: medium
- Identifiers.8: {"value":"ALAMIT_7_UNIT 1","system":"CAISO market resource ID"} — Source · confidence: medium
- Identifiers.9: {"value":"ALAMIT_7_UNIT 2","system":"CAISO market resource ID"} — Source · confidence: medium
- Identifiers.10: {"value":"ALAMIT_7_UNIT 3","system":"CAISO market resource ID"} — Source · confidence: medium
- Identifiers.11: {"value":"ALAMIT_7_UNIT 4","system":"CAISO market resource ID"} — Source · confidence: medium
- Identifiers.12: {"value":"ALAMIT_7_UNIT 5","system":"CAISO market resource ID"} — List of Generation Units by Local Capacity Area · confidence: medium
- Identifiers.13: {"value":"ALAMIT_7_UNIT 6","system":"CAISO market resource ID"} — List of Generation Units by Local Capacity Area · confidence: medium
- Identifiers.14: {"value":"ALAMT1 G","system":"CAISO legacy generator ID"} — Source · confidence: medium
- Identifiers.15: {"value":"ALAMT2 G","system":"CAISO legacy generator ID"} — Source · confidence: medium
- Identifiers.16: {"value":"ALAMT3 G","system":"CAISO legacy generator ID"} — Source · confidence: medium
- Identifiers.17: {"value":"ALAMT4 G","system":"CAISO legacy generator ID"} — Source · confidence: medium
- Identifiers.18: {"value":"ALAMT5 G","system":"CAISO legacy generator ID"} — List of Generation Units by Local Capacity Area · confidence: medium
- Identifiers.19: {"value":"ALAMT6 G","system":"CAISO legacy generator ID"} — List of Generation Units by Local Capacity Area · confidence: medium
- Parties.1: {"relationship":"Corporate owner/operator group","name":"The AES Corporation","official_url":"https://www.aes.com/"} — AES Announces Extension Agreement for Southland Legacy Units in California · confidence: medium
- Parties.2: {"relationship":"Former owner","name":"Southern California Edison","official_url":"https://www.sce.com/"} — Source · confidence: high
- Construction scope: Documented AES Alamitos Generating Station scope consists of six natural-gas conventional steam-turbine generating units: Unit 1, 175 MW, in service 1956; Unit 2, 175 MW, 1957; Unit 3, 320 MW, 1961; Unit 4, 320 MW, 1962; Unit 5, 480 MW, 1969; and Unit 6, 480 MW, 1966. The site also has two cooling-water intake structures, two man-made intake canals, and three discharge outfalls. The documented intake equipment includes four traveling screens for Units 1–2 and two traveling screens in each of the separate Unit 5 and Unit 6 screen houses. No exact turbine OEM or model is identified in the cited plant records. — Source · confidence: medium
- Significance: Alamitos was historically a six-unit, 1,950 MW natural-gas steam station and a major Southern California reliability resource. The surviving once-through-cooling units were retained for grid-reliability purposes under a compliance extension through December 31, 2026. — Resolution 2023-0025 · confidence: medium
- Description: AES Alamitos LLC owns and operates the natural-gas-fired Alamitos Generating Station in Long Beach, Los Angeles County. The legacy facility comprised six conventional steam-turbine units that entered service between 1956 and 1969, with a combined rated capacity of 1,950 MW. AES acquired Alamitos in May 1998 as part of a three-station purchase from Southern California Edison; reported consideration was approximately $781 million to $786 million for the portfolio, rather than for Alamitos alone. A separate 1,040 MW Alamitos Energy Center replacement project on part of the site was certified in 2017 and became operational in February 2021; it is distinct from the legacy steam units. — Source · confidence: medium
- Quality notes: ["The reported May 1998 purchase consideration—$781 million in a contemporaneous account and approximately $786 million in a later account—covered three Southern California Edison gas plants, not Alamitos alone.","The $2 billion June 2017 financing was long-term non-recourse construction debt for the broader Southland repowering program; it was not disclosed as the 1998 acquisition price.","The Alamitos Energy Center and Alamitos Battery Energy Storage System are later, separate projects associated with the site and are not added to the legacy steam-station configuration.","The unit chronology is reported as in-service years rather than exact commercial-operation dates."] — AES' Alamitos BESS: Clean Energy Storage Pioneer · confidence: medium
- Timeline.0: {"event":"Legacy unit in-service sequence","date":"1956","detail":"The six legacy steam units entered service in 1956 (Unit 1), 1957 (Unit 2), 1961 (Unit 3), 1962 (Unit 4), 1966 (Unit 6), and 1969 (Unit 5)."} — Source · confidence: high
- Timeline.6: {"event":"Retirement of legacy units","date":"2020","detail":"Units 1, 2, and 6 were retired by December 31, 2020; Units 3, 4, and 5 remained subject to later reliability-related compliance extensions."} — Draft 2026 Report of the Statewide Advisory Committee on... · confidence: medium
- Timeline.8: {"event":"Reliability extension agreement","date":"2023-04-26","detail":"AES announced agreements with the California Department of Water Resources to extend operation of the Alamitos and Huntington Beach once-through-cooling units through 2026."} — AES Announces Extension Agreement for Southland Legacy Units in California · confidence: medium
- Timeline.9: {"event":"Extended compliance date","date":"2026-12-31","detail":"The State Water Resources Control Board resolution extended the compliance date for Alamitos Units 3, 4, and 5 from December 31, 2023, to December 31, 2026."} — Resolution 2023-0025 · confidence: high
- Commercial parties.0: {"relationship":"Owner and operator of the legacy station","name":"AES Alamitos LLC","detail":"Owns and operates the natural-gas-fired Alamitos Generating Station.","official_url":"https://www.aes.com/"} — Source · confidence: high
- Commercial parties.1: {"relationship":"Corporate owner/operator group","name":"The AES Corporation","detail":"Parent corporate group associated with AES Alamitos and the Southland repowering projects.","official_url":"https://www.aes.com/"} — Source · confidence: medium
- Commercial parties.7: {"relationship":"Air-quality regulator","name":"South Coast Air Quality Management District","detail":"Regulates air-quality permitting and compliance for the Alamitos facility in the South Coast Air Basin.","official_url":"https://www.aqmd.gov/"} — AES Announces Extension Agreement for Southland Legacy Units in California · confidence: high
- Commercial parties.8: {"relationship":"Reliability-extension counterparty","name":"California Department of Water Resources","detail":"Signed agreements with AES in 2023 supporting continued operation of eligible Southland once-through-cooling units through 2026.","official_url":"https://water.ca.gov/"} — AES' Alamitos BESS: Clean Energy Storage Pioneer · confidence: high
- Quality notes.2: The Alamitos Energy Center and Alamitos Battery Energy Storage System are later, separate projects associated with the site and are not added to the legacy steam-station configuration. — AES' Alamitos BESS: Clean Energy Storage Pioneer · confidence: high
- Quality notes.3: The unit chronology is reported as in-service years rather than exact commercial-operation dates. — Source · confidence: high
- Interconnection voltage kv: 230 — AES Alamitos Repower Study Report · confidence: medium
- Replacement or repowering: Units 1, 2, and 6 were replaced in part by the 640 MW Alamitos Energy Center combined-cycle project on the same property, which became operational in February 2021. No new repowering capacity is listed for Units 3, 4, and 5; those units are planned for retirement by December 31, 2026. — Source · confidence: medium

## Timeline

- 2017-04-12 — Alamitos Energy Center certification
  The California Energy Commission certified the separate 1,040 MW Alamitos Energy Center project.
  Source: Alamitos Energy Center | California Energy Commission (https://www.energy.ca.gov/powerplant/combined-cycle/alamitos-energy-center)
- 2021-02 — Replacement project operational
  The separate Alamitos Energy Center became operational with a 1,040 MW combined-cycle configuration.
  Source: Alamitos Energy Center | California Energy Commission (https://www.energy.ca.gov/powerplant/combined-cycle/alamitos-energy-center)
- 2023-04-26 — Reliability extension agreement
  AES announced agreements with the California Department of Water Resources to extend operation of the Alamitos and Huntington Beach once-through-cooling units through 2026.
  Source: AES Announces Extension Agreement for Southland Legacy Units in California (https://www.prnewswire.com/news-releases/aes-announces-extension-agreement-for-southland-legacy-units-in-california-301808815.html)
- 2026-12-31 — Extended compliance date
  The State Water Resources Control Board resolution extended the compliance date for Alamitos Units 3, 4, and 5 from December 31, 2023, to December 31, 2026.
  Source: AES Announces Extension Agreement for Southland Legacy Units in California (https://www.prnewswire.com/news-releases/aes-announces-extension-agreement-for-southland-legacy-units-in-california-301808815.html)

## Sources

- [AES | Accelerating the Future of Global Energy](https://www.aes.com/) — aes.com · tier other
- [AES Announces Extension Agreement for Southland Legacy Units in California](https://www.prnewswire.com/news-releases/aes-announces-extension-agreement-for-southland-legacy-units-in-california-301808815.html) — prnewswire.com · tier other
- [List of Generation Units by Local Capacity Area](https://www.caiso.com/documents/list-generationunitsbylocalcapacityarea.pdf) — caiso.com · tier other
- [The AES Alamitos Battery Energy Storage System made history. Here’s why it matters. | AES](https://www.aes.com/energy-insights/aes-alamitos-battery-energy-storage-system-made-history-heres-why-it-matters) — aes.com · tier other
- [Alamitos Energy Center | California Energy Commission](https://www.energy.ca.gov/powerplant/combined-cycle/alamitos-energy-center) — energy.ca.gov · tier regulatory
- [Source](https://www.aqmd.gov/docs/default-source/ceqa/documents/permit-projects/2001/aes-alamitos/appa.pdf) — aqmd.gov · tier regulatory
- [DOCKETED](https://efiling.energy.ca.gov/GetDocument.aspx?tn=201620-8&DocumentContentId=6746) — efiling.energy.ca.gov · tier regulatory
- [Source](https://opc.ca.gov/webmaster/ftp/project_pages/OTC/engineering%20study/Chapter_7A_Alamitos_Generating_Station.pdf) — opc.ca.gov · tier regulatory
- [AES Commissions Alamitos Energy Storage Facility in Long Beach, California](https://blog.fluenceenergy.com/aes-fluence-commission-alamitos-energy-storage-facility-long-beach-california) — blog.fluenceenergy.com · tier other
- [Reliable steam turbines for improved efficiency](https://www.siemens-energy.com/global/en/home/products-services/product-offerings/steam-turbines.html) — siemens-energy.com · tier other
- [Resolution 2023-0025](https://waterboards.ca.gov/board_decisions/adopted_orders/resolutions/2023/rs2023-0025.pdf) — waterboards.ca.gov · tier regulatory
- [AES' Alamitos BESS: Clean Energy Storage Pioneer](https://www.aes.com/energy-insights/aes-alamitos-battery-energy-storage-system-launched-energy-storage-industry-we-know-it-0) — aes.com · tier other
- [Draft 2026 Report of the Statewide Advisory Committee on ...](https://www.waterboards.ca.gov/water_issues/programs/ocean/cwa316/saccwis/docs/2026/saccwis-26dfrpt.pdf) — waterboards.ca.gov · tier regulatory
- [SCE Sells 10 Plants](https://www.power-eng.com/operations-maintenance/sce-sells-10-plants/) — power-eng.com · tier other
- [05-10-23 Q1 2023 Fact Sheet_FINAL](https://www.aes.com/sites/aesvault.com/files/2023-05/Q1%202023%20Fact%20Sheet.pdf) — aes.com · tier other
- [aes-20221231](https://www.sec.gov/Archives/edgar/data/874761/000087476123000010/aes-20221231.htm) — sec.gov · tier regulatory
- [AES Alamitos Repower Study Report](https://efiling.energy.ca.gov/GetDocument.aspx?tn=213941&DocumentContentId=7036) — efiling.energy.ca.gov · tier regulatory
- [Source](https://www.caiso.com/documents/appendix-a-system-data.pdf) — caiso.com · tier other

## Data quality

- The reported May 1998 purchase consideration—$781 million in a contemporaneous account and approximately $786 million in a later account—covered three Southern California Edison gas plants, not Alamitos alone. The $2 billion June 2017 financing was long-term non-recourse construction debt for the broader Southland repowering program; it was not disclosed as the 1998 acquisition price. The Alamitos Energy Center and Alamitos Battery Energy Storage System are later, separate projects associated with the site and are not added to the legacy steam-station configuration. The unit chronology is reported as in-service years rather than exact commercial-operation dates.

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