# Alta Wind Energy Center II

CAISO Onshore Wind Turbine · https://askthegrid.com/assets/facilities/alta-wind-energy-center-ii

Alta Wind Energy Center II is a wind power facility with 150 MW of EIA-reported operating capacity in Kern County, California, registered as EIA Plant ID 57291. Clearway Energy, Inc. is the public owner or developer; Alta Wind II, LLC is the registered plant entity or operator.

## Key facts

- Technology: Onshore Wind Turbine
- Power capacity: 150 MW
- Operating status: operating

## Grid and market context

- ISO/RTO: CAISO
- Balancing authority: CISO

## Source-backed facts

- Description: Alta Wind Energy Center II is a 150 MW operational onshore wind plant in Kern County, California. The plant has one generating unit, AW02, which entered service in January 2011. It operates in the CAISO market under the CISO balancing authority and sells its output to Southern California Edison under a contract listed through 2035. — cwen-20250930 · confidence: medium
- Identifiers.1: {"value":"AW02","system":"EIA generator ID"} — Source · confidence: high
- Parties.3: {"relationship":"Power purchaser / PPA counterparty","name":"Southern California Edison Company","official_url":"https://www.sce.com/"} — cwen-20250930 · confidence: high
- Parties.4: {"relationship":"Wind turbine OEM; Vestas V90 equipment identified for AW02","name":"Vestas","official_url":"https://www.vestas.com/"} — Source · confidence: medium
- Product url: https://www.vestas.com/en/energy-solutions/onshore-wind-turbines — Onshore Wind Turbines | Vestas · confidence: medium
- Significance: Alta Wind Energy Center II is a 150 MW component of the Alta Wind facility, which Clearway describes as North America's largest operating wind facility at 947 MW. The broader Alta Wind development platform comprised eleven interconnected wind projects totaling 1,547 MW. — Source · confidence: medium
- Quality notes: ["EIA and FERC records identify one generating unit, AW02, rated at 150 MW; no equipment count is inferred from capacity.","The $1.2 billion financing applied to Alta units II–V as a group, while the $870 million purchase price and assumed $1.6 billion of non-recourse project financing applied to the broader 947 MW Alta Wind portfolio; neither amount is a plant-specific Alta II valuation.","No separate expansion, retirement, or repowering milestone is reported for Alta II in the cited plant and owner records; the latest identified status remains operational at 150 MW."] — cwen-20251231 · confidence: medium
- Financing summary: Financing for Alta units II–V, the group that included Alta II, was completed in July 2010 for approximately $1.2 billion, with Citibank, Barclays Capital, and Credit Suisse identified as financing parties. This was group-level construction/project financing, not an allocated Alta II amount. Separately, NRG Yield agreed in June 2014 and closed in August 2014 on the acquisition of the broader 947 MW Alta Wind facility from Terra-Gen for $870 million plus assumption of $1.6 billion of non-recourse project financings. Clearway later reported Alta I–V lease-financing arrangements due in 2034 and 2035, without allocating a balance specifically to Alta II. — Alta Wind Energy Center (AWEC), California - Power Technology · confidence: medium
- Timeline: [{"event":"Development-platform acquisition","date":"2008-06","detail":"Terra-Gen Power acquired the Alta Wind Energy Center development platform from Allco Finance Group."},{"event":"First-phase construction","date":"2010-07","detail":"Construction of the first Alta phase, comprising units I–V and including Alta II, began in July 2010."},{"event":"Group construction financing","date":"2010-07","detail":"Approximately $1.2 billion of financing for Alta units II–V was completed; the reported financing covered the four-unit group rather than Alta II alone."},{"event":"Commercial operation","date":"2011-01","detail":"FERC and EIA-linked records identify Alta Wind Energy Center II, generator AW02, as entering commercial operation in January 2011."},{"event":"Acquisition agreement","date":"2014-06-04","detail":"NRG Yield entered into an agreement to acquire the Alta Wind facility from Terra-Gen for $870 million plus assumed non-recourse project financing; the announced transaction covered 947 MW of operating wind capacity."},{"event":"Portfolio acquisition closed","date":"2014-08-12","detail":"NRG Yield completed its acquisition of the Alta Wind facility from Terra-Gen. Alta II was included in the portfolio transaction, but no separate Alta II purchase price was disclosed."},{"event":"Operational status","date":"2026-08-02","detail":"The plant remains identified as an operational 150 MW wind plant with one generating unit, AW02."}] — Source · confidence: medium
- Timeline: [{"event":"Development-platform acquisition","date":"2008-06","detail":"Terra-Gen Power acquired the Alta Wind Energy Center development platform from Allco Finance Group."},{"event":"First-phase construction","date":"2010-07","detail":"Construction of the first Alta phase, comprising units I–V and including Alta II, began in July 2010."},{"event":"Group construction financing","date":"2010-07","detail":"Approximately $1.2 billion of financing for Alta units II–V was completed; the reported financing covered the four-unit group rather than Alta II alone."},{"event":"Commercial operation","date":"2011-01","detail":"FERC and EIA-linked records identify Alta Wind Energy Center II, generator AW02, as entering commercial operation in January 2011."},{"event":"Acquisition agreement","date":"2014-06-04","detail":"NRG Yield entered into an agreement to acquire the Alta Wind facility from Terra-Gen for $870 million plus assumed non-recourse project financing; the announced transaction covered 947 MW of operating wind capacity."},{"event":"Portfolio acquisition closed","date":"2014-08-12","detail":"NRG Yield completed its acquisition of the Alta Wind facility from Terra-Gen. Alta II was included in the portfolio transaction, but no separate Alta II purchase price was disclosed."},{"event":"Operational status","date":"2026-08-02","detail":"The plant remains identified as an operational 150 MW wind plant with one generating unit, AW02."}] — Alta Wind Energy Center (AWEC), California - Power Technology · confidence: medium
- Timeline: [{"event":"Development-platform acquisition","date":"2008-06","detail":"Terra-Gen Power acquired the Alta Wind Energy Center development platform from Allco Finance Group."},{"event":"First-phase construction","date":"2010-07","detail":"Construction of the first Alta phase, comprising units I–V and including Alta II, began in July 2010."},{"event":"Group construction financing","date":"2010-07","detail":"Approximately $1.2 billion of financing for Alta units II–V was completed; the reported financing covered the four-unit group rather than Alta II alone."},{"event":"Commercial operation","date":"2011-01","detail":"FERC and EIA-linked records identify Alta Wind Energy Center II, generator AW02, as entering commercial operation in January 2011."},{"event":"Acquisition agreement","date":"2014-06-04","detail":"NRG Yield entered into an agreement to acquire the Alta Wind facility from Terra-Gen for $870 million plus assumed non-recourse project financing; the announced transaction covered 947 MW of operating wind capacity."},{"event":"Portfolio acquisition closed","date":"2014-08-12","detail":"NRG Yield completed its acquisition of the Alta Wind facility from Terra-Gen. Alta II was included in the portfolio transaction, but no separate Alta II purchase price was disclosed."},{"event":"Operational status","date":"2026-08-02","detail":"The plant remains identified as an operational 150 MW wind plant with one generating unit, AW02."}] — Asset Appendix Report - MBR · confidence: medium
- Quality notes.1: The $1.2 billion financing applied to Alta units II–V as a group, while the $870 million purchase price and assumed $1.6 billion of non-recourse project financing applied to the broader 947 MW Alta Wind portfolio; neither amount is a plant-specific Alta II valuation. — Alta Wind Energy Center (AWEC), California - Power Technology · confidence: high
- Quality notes.2: No separate expansion, retirement, or repowering milestone is reported for Alta II in the cited plant and owner records; the latest identified status remains operational at 150 MW. — cwen-20251231 · confidence: medium
- Timeline.0: {"event":"Development-platform acquisition","date":"2008-06","detail":"Terra-Gen Power acquired the Alta Wind Energy Center development platform from Allco Finance Group."} — Source · confidence: medium
- Timeline.1: {"event":"First-phase construction","date":"2010-07","detail":"Construction of the first Alta phase, comprising units I–V and including Alta II, began in July 2010."} — Alta Wind Energy Center (AWEC), California - Power Technology · confidence: medium
- Timeline.2: {"event":"Group construction financing","date":"2010-07","detail":"Approximately $1.2 billion of financing for Alta units II–V was completed; the reported financing covered the four-unit group rather than Alta II alone."} — Alta Wind Energy Center (AWEC), California - Power Technology · confidence: high
- Timeline.3: {"event":"Commercial operation","date":"2011-01","detail":"FERC and EIA-linked records identify Alta Wind Energy Center II, generator AW02, as entering commercial operation in January 2011."} — Asset Appendix Report - MBR · confidence: high
- Commercial parties.2: {"relationship":"Developer and historical seller","name":"Terra-Gen Power LLC","detail":"Developed the Alta Wind platform and sold the Alta Wind facility to NRG Yield in the 2014 portfolio transaction.","official_url":"https://terra-gen.com/"} — Source · confidence: high
- Commercial parties.4: {"relationship":"Power purchaser and PPA counterparty","name":"Southern California Edison Company","detail":"Alta II's power contract is listed with SCE through 2035.","official_url":"https://www.sce.com/"} — Source · confidence: high
- Commercial parties.5: {"relationship":"Wind turbine OEM","name":"Vestas","detail":"Vestas V90-3.0 MW turbines are identified for Alta units II–V, including the 150 MW Alta II phase.","official_url":"https://www.vestas.com/"} — Alta Wind Energy Center (AWEC), California - Power Technology · confidence: medium
- Commercial parties.6: {"relationship":"Construction/project financing party for Alta units II–V","name":"Citibank","detail":"Identified as a financing party for the approximately $1.2 billion group financing completed for Alta units II–V in July 2010.","official_url":"https://www.citi.com/"} — Alta Wind Energy Center (AWEC), California - Power Technology · confidence: medium
- Commercial parties.7: {"relationship":"Construction/project financing party for Alta units II–V","name":"Barclays Capital","detail":"Identified as a financing party for the approximately $1.2 billion group financing completed for Alta units II–V in July 2010.","official_url":"https://www.barclays.com/"} — Alta Wind Energy Center (AWEC), California - Power Technology · confidence: medium
- Commercial parties.8: {"relationship":"Construction/project financing party for Alta units II–V","name":"Credit Suisse","detail":"Identified as a financing party for the approximately $1.2 billion group financing completed for Alta units II–V in July 2010.","official_url":null} — Alta Wind Energy Center (AWEC), California - Power Technology · confidence: medium
- Commercial parties.9: {"relationship":"Predecessor development-platform owner","name":"Allco Finance Group","detail":"Prior owner of the Alta Wind Energy Center development platform before Terra-Gen acquired it in June 2008.","official_url":null} — Source · confidence: medium
- Resource type: WIND — 2024 Final NQC List · confidence: medium
- Grid role: Non-dispatchable wind generation resource in CAISO. — 2024 Final NQC List · confidence: medium

## Timeline

- 2008-06 — Development-platform acquisition
  Terra-Gen Power acquired the Alta Wind Energy Center development platform from Allco Finance Group.
  Source: Source (https://www.prnewswire.com/news-releases/terra-gen-power-announces-sale-of-alta-wind-to-nrg-yield-261816311.html)

## Sources

- [Asset Appendix Report - MBR](https://mbrweb.ferc.gov/SearchMBRAssetAppendix/AssetAppendixDetails?AssetAppendixId=719) — mbrweb.ferc.gov · tier regulatory
- [cwen-20250930](https://www.sec.gov/Archives/edgar/data/1567683/000162828025049051/cwen-20250930.htm) — sec.gov · tier regulatory
- [Source](https://downloads.regulations.gov/OSHA-H005C-2006-0870-0430/attachment_4.pdf) — downloads.regulations.gov · tier regulatory
- [Alta Wind Energy Center (AWEC), California - Power Technology](https://www.power-technology.com/projects/alta-wind-energy-center-awec-california/) — power-technology.com · tier other
- [Onshore Wind Turbines | Vestas](https://www.vestas.com/en/energy-solutions/onshore-wind-turbines) — vestas.com · tier other
- [Source](https://www.prnewswire.com/news-releases/terra-gen-power-announces-sale-of-alta-wind-to-nrg-yield-261816311.html) — prnewswire.com · tier other
- [Source](https://sec.gov/Archives/edgar/data/1567683/000156768325000007/cwen-20241231.htm) — sec.gov · tier regulatory
- [NRG Yield, Inc. Closes Acquisition of Largest Wind Farm in North America | Clearway Energy, Inc.](https://investor.clearwayenergy.com/news-releases/news-release-details/nrg-yield-inc-closes-acquisition-largest-wind-farm-north-america) — investor.clearwayenergy.com · tier other
- [cwen-20251231](https://www.sec.gov/Archives/edgar/data/1567683/000162828026010952/cwen-20251231.htm) — sec.gov · tier regulatory
- [Source](https://sec.gov/Archives/edgar/data/1567683/000162828025049051/cwen-20250930.htm) — sec.gov · tier regulatory
- [cwen-20240331](https://www.sec.gov/Archives/edgar/data/1567683/000156768324000015/cwen-20240331.htm) — sec.gov · tier regulatory
- [Curtailed](https://www.caiso.com/documents/curtailed-non-operational-generator-am-report-20260131.xlsx) — caiso.com · tier other
- [2026 NQC List](https://www.caiso.com/documents/net-qualifying-capacity-report-for-compliance-year-2026.xlsx) — caiso.com · tier other
- [2024 Final NQC List](https://www.caiso.com/documents/finalnetqualifyingcapacityreportforcomplianceyear2024.xls) — caiso.com · tier other

## Data quality

- EIA and FERC records identify one generating unit, AW02, rated at 150 MW; no equipment count is inferred from capacity. No separate expansion, retirement, or repowering milestone is reported for Alta II in the cited plant and owner records; the latest identified status remains operational at 150 MW.

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