# Alta Wind Energy Center III

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

Alta Wind Energy Center III is a wind power facility with 150 MW of EIA-reported operating capacity in Kern County, California, registered as EIA Plant ID 57292. Clearway Energy, Inc. is the public owner or developer; Alta Wind III, LLC is the registered plant entity or operator. The facility interconnects at Windhub Substation at 230 kV.

## Key facts

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

## Grid and market context

- ISO/RTO: CAISO
- Balancing authority: CISO
- Substation: Windhub Substation
- Point of interconnection: Windhub Substation
- Transmission owner: Southern California Edison Company
- Interconnection voltage: 230 kV

## Source-backed facts

- Owner logo domain: clearwayenergygroup.com — Electric Matters - A | Federal Energy Regulatory Commission · confidence: medium
- Owner logo domain: clearwayenergygroup.com — Wind farms and wind energy benefits in the US · confidence: medium
- Identifiers: [{"value":"57292","system":"EIA plant ID"},{"value":"AW03","system":"EIA generator ID"},{"value":"CISO","system":"Balancing authority"},{"value":"CAISO","system":"ISO/RTO market"},{"value":"Alta Wind 3","system":"CAISO market-resource name"},{"value":"EL10-62-000","system":"FERC docket"}] — Curtailed · confidence: medium
- Description: Alta Wind Energy Center III is an operational 150 MW onshore wind plant in Kern County, California, with one generating unit identified as AW03. Its first unit entered service on February 1, 2011, and the plant participates in the CISO balancing authority and CAISO market. The plant's power purchase agreement is with Southern California Edison through 2035. — cwen-20241231 · confidence: high
- Parties: [{"relationship":"Legal project entity and operator","name":"Alta Wind III, LLC","official_url":"https://www.clearwayenergygroup.com/"},{"relationship":"Parent portfolio owner","name":"Clearway Energy, Inc.","official_url":"https://www.clearwayenergygroup.com/about/"},{"relationship":"Developer","name":"Terra-Gen Power, LLC","official_url":"https://terra-gen.com/"},{"relationship":"Asset management and operations-and-maintenance provider","name":"Terra-Gen Operating Company","official_url":"https://terra-gen.com/"},{"relationship":"EPC / balance-of-plant contractor for Alta II–VI, including Alta III","name":"Blattner","official_url":"https://www.blattnercompany.com/"},{"relationship":"Wind turbine OEM","name":"Vestas Wind Systems","official_url":"https://www.vestas.com/"},{"relationship":"Power purchase agreement counterparty","name":"Southern California Edison","official_url":"https://www.sce.com/"}] — Terra-Gen Power Announces Sale of Alta Wind to NRG Yield · confidence: medium
- Parties: [{"relationship":"Legal project entity and operator","name":"Alta Wind III, LLC","official_url":"https://www.clearwayenergygroup.com/"},{"relationship":"Parent portfolio owner","name":"Clearway Energy, Inc.","official_url":"https://www.clearwayenergygroup.com/about/"},{"relationship":"Developer","name":"Terra-Gen Power, LLC","official_url":"https://terra-gen.com/"},{"relationship":"Asset management and operations-and-maintenance provider","name":"Terra-Gen Operating Company","official_url":"https://terra-gen.com/"},{"relationship":"EPC / balance-of-plant contractor for Alta II–VI, including Alta III","name":"Blattner","official_url":"https://www.blattnercompany.com/"},{"relationship":"Wind turbine OEM","name":"Vestas Wind Systems","official_url":"https://www.vestas.com/"},{"relationship":"Power purchase agreement counterparty","name":"Southern California Edison","official_url":"https://www.sce.com/"}] — Power plant profile: Alta Wind Project, US · confidence: medium
- Parties: [{"relationship":"Legal project entity and operator","name":"Alta Wind III, LLC","official_url":"https://www.clearwayenergygroup.com/"},{"relationship":"Parent portfolio owner","name":"Clearway Energy, Inc.","official_url":"https://www.clearwayenergygroup.com/about/"},{"relationship":"Developer","name":"Terra-Gen Power, LLC","official_url":"https://terra-gen.com/"},{"relationship":"Asset management and operations-and-maintenance provider","name":"Terra-Gen Operating Company","official_url":"https://terra-gen.com/"},{"relationship":"EPC / balance-of-plant contractor for Alta II–VI, including Alta III","name":"Blattner","official_url":"https://www.blattnercompany.com/"},{"relationship":"Wind turbine OEM","name":"Vestas Wind Systems","official_url":"https://www.vestas.com/"},{"relationship":"Power purchase agreement counterparty","name":"Southern California Edison","official_url":"https://www.sce.com/"}] — Alta Wind I Owner Lessor C, et. al. v. United States · confidence: medium
- Parties: [{"relationship":"Legal project entity and operator","name":"Alta Wind III, LLC","official_url":"https://www.clearwayenergygroup.com/"},{"relationship":"Parent portfolio owner","name":"Clearway Energy, Inc.","official_url":"https://www.clearwayenergygroup.com/about/"},{"relationship":"Developer","name":"Terra-Gen Power, LLC","official_url":"https://terra-gen.com/"},{"relationship":"Asset management and operations-and-maintenance provider","name":"Terra-Gen Operating Company","official_url":"https://terra-gen.com/"},{"relationship":"EPC / balance-of-plant contractor for Alta II–VI, including Alta III","name":"Blattner","official_url":"https://www.blattnercompany.com/"},{"relationship":"Wind turbine OEM","name":"Vestas Wind Systems","official_url":"https://www.vestas.com/"},{"relationship":"Power purchase agreement counterparty","name":"Southern California Edison","official_url":"https://www.sce.com/"}] — cwen-20241231 · confidence: medium
- Identifiers.4: {"value":"Alta Wind 3","system":"CAISO market-resource name"} — Curtailed · confidence: medium
- Parties.1: {"relationship":"Parent portfolio owner","name":"Clearway Energy, Inc.","official_url":"https://www.clearwayenergygroup.com/about/"} — cwen-20241231 · confidence: medium
- Parties.2: {"relationship":"Developer","name":"Terra-Gen Power, LLC","official_url":"https://terra-gen.com/"} — Terra-Gen Power Announces Sale of Alta Wind to NRG Yield · confidence: medium
- Parties.3: {"relationship":"Asset management and operations-and-maintenance provider","name":"Terra-Gen Operating Company","official_url":"https://terra-gen.com/"} — Terra-Gen Power Announces Sale of Alta Wind to NRG Yield · confidence: medium
- Parties.4: {"relationship":"EPC / balance-of-plant contractor for Alta II–VI, including Alta III","name":"Blattner","official_url":"https://www.blattnercompany.com/"} — Alta Wind I Owner Lessor C, et. al. v. United States · confidence: medium
- Parties.5: {"relationship":"Wind turbine OEM","name":"Vestas Wind Systems","official_url":"https://www.vestas.com/"} — Power plant profile: Alta Wind Project, US · confidence: medium
- Parties.6: {"relationship":"Power purchase agreement counterparty","name":"Southern California Edison","official_url":"https://www.sce.com/"} — cwen-20241231 · confidence: high
- Product url: https://www.vestas.com/content/dam/vestas-com/global/en/sustainability/reports-and-ratings/lcas/LCA_V902MW_version1.pdf.coredownload.inline.pdf — Life Cycle Assessments · confidence: medium
- Description: Alta Wind Energy Center III is an operational 150 MW onshore wind plant in Kern County, California, with one EIA generating unit identified as AW03. Clearway Energy’s asset table lists Alta III as 100%-owned, with commercial operation in February 2011 and a Southern California Edison power-purchase agreement expiring in 2035. Terra-Gen developed and constructed the project after acquiring the Alta Wind development platform from Allco Finance in June 2008; NRG Yield later acquired the Alta Wind I–V, X, XI and Realty portfolio from Terra-Gen in August 2014, and NRG Yield changed its name to Clearway Energy in August 2018. Alta III uses Vestas V90/3.0 MW turbines and participates in the CISO balancing authority and CAISO market. — cwen-20251231 · confidence: medium
- Description: Alta Wind Energy Center III is an operational 150 MW onshore wind plant in Kern County, California, with one EIA generating unit identified as AW03. Clearway Energy’s asset table lists Alta III as 100%-owned, with commercial operation in February 2011 and a Southern California Edison power-purchase agreement expiring in 2035. Terra-Gen developed and constructed the project after acquiring the Alta Wind development platform from Allco Finance in June 2008; NRG Yield later acquired the Alta Wind I–V, X, XI and Realty portfolio from Terra-Gen in August 2014, and NRG Yield changed its name to Clearway Energy in August 2018. Alta III uses Vestas V90/3.0 MW turbines and participates in the CISO balancing authority and CAISO market. — Terra-Gen Power Announces Sale of Alta Wind to NRG Yield · confidence: medium
- Timeline: [{"event":"Alta Wind platform acquisition","date":"2008-06","detail":"Terra-Gen acquired the Alta Wind Energy Center development platform from Allco Finance, establishing the predecessor development ownership for the later Alta III project."},{"event":"Alta II–V construction financing","date":"2010-07-23","detail":"Terra-Gen closed a $1.2 billion financing package for Alta Wind II–V, the four-project 570 MW phase that included Alta III. Proceeds were designated to fund construction, which was expected to begin immediately."},{"event":"Alta II–V turbine delivery and commissioning","date":"2010-10","detail":"Delivery and commissioning of the Vestas turbines for Alta Projects II–V were scheduled to begin in October 2010."},{"event":"Commercial operation","date":"2011-02-01","detail":"EIA data identifies Alta III’s first unit, generator AW03, as entering service on February 1, 2011."},{"event":"Portfolio sale agreement","date":"2014-06-04","detail":"Terra-Gen announced a purchase-and-sale agreement with NRG Yield for its 947 MW Alta Wind I–V, X, XI and Realty projects."},{"event":"Portfolio acquisition completed","date":"2014-08-12","detail":"NRG Yield completed its acquisition of 100% of the Alta Wind Asset portfolio from Terra-Gen for $870 million plus assumption of $1.6 billion of non-recourse project financings."},{"event":"Owner name change","date":"2018-08-31","detail":"NRG Yield changed its corporate name to Clearway Energy, Inc.; the Alta Wind portfolio remained within the successor company’s asset base."},{"event":"Latest reported operating configuration","date":"2025-12-31","detail":"Clearway’s latest owner filing continues to list Alta III at 150 MW rated and net capacity, 100% ownership, February 2011 commercial operation, and Southern California Edison as counterparty through 2035."}] — Terra-Gen Power Announces Sale of Alta Wind to NRG Yield · confidence: medium
- Commercial parties: [{"relationship":"Legal project entity and operator","name":"Alta Wind III, LLC","detail":"Project company and operating entity for the 150 MW Alta III plant; EIA identifies it as the operator.","official_url":"https://www.clearwayenergygroup.com/"},{"relationship":"Current portfolio owner","name":"Clearway Energy, Inc.","detail":"Successor owner of the Alta Wind portfolio following NRG Yield’s August 2018 name change; Clearway’s filings list Alta III as 100%-owned.","official_url":"https://www.clearwayenergygroup.com/about/"},{"relationship":"Developer, predecessor owner and seller","name":"Terra-Gen Power, LLC","detail":"Developed and constructed Alta III, acquired the Alta Wind development platform from Allco Finance in June 2008, and sold the Alta Wind portfolio to NRG Yield in August 2014.","official_url":"https://terra-gen.com/"},{"relationship":"Predecessor platform owner and seller to Terra-Gen","name":"Allco Finance","detail":"Transferred the Alta Wind Energy Center development platform to Terra-Gen in June 2008; the company later became Clearway Energy, Inc.","official_url":"https://investor.clearwayenergy.com/"},{"relationship":"Power-purchase agreement counterparty","name":"Southern California Edison","detail":"Counterparty for Alta III’s long-term power-purchase agreement, listed by Clearway with contract expiration in 2035.","official_url":"https://www.sce.com/"},{"relationship":"Wind-turbine OEM","name":"Vestas Wind Systems","detail":"Supplied the V90/3.0 MW turbines used at Alta III; the Alta II–V financing announcement identifies Vestas-American Wind Technology as the manufacturer for the 190 turbines ordered for the four-project phase.","official_url":"https://www.vestas.com/"},{"relationship":"Leveraged-lease purchaser and financing party","name":"Citibank, N.A.","detail":"Committed to purchase the Alta II–V projects at the start of commercial operations and lease them back to Terra-Gen; Citibank also participated in the credit facilities.","official_url":"https://www.citigroup.com/"},{"relationship":"Book-running manager and lender","name":"Barclays Capital","detail":"Acted as a joint book-running manager for the pass-through certificate issuance and participated in the Alta II–V credit facilities.","official_url":"https://home.barclays/"},{"relationship":"Administrative agent and lender","name":"Crédit Agricole Corporate and Investment Bank","detail":"Served as administrative agent for the Alta II–V construction financing and participated in the lender group.","official_url":"https://www.credit-agricole.com/"}] — cwen-20251231 · confidence: medium
- Commercial parties: [{"relationship":"Legal project entity and operator","name":"Alta Wind III, LLC","detail":"Project company and operating entity for the 150 MW Alta III plant; EIA identifies it as the operator.","official_url":"https://www.clearwayenergygroup.com/"},{"relationship":"Current portfolio owner","name":"Clearway Energy, Inc.","detail":"Successor owner of the Alta Wind portfolio following NRG Yield’s August 2018 name change; Clearway’s filings list Alta III as 100%-owned.","official_url":"https://www.clearwayenergygroup.com/about/"},{"relationship":"Developer, predecessor owner and seller","name":"Terra-Gen Power, LLC","detail":"Developed and constructed Alta III, acquired the Alta Wind development platform from Allco Finance in June 2008, and sold the Alta Wind portfolio to NRG Yield in August 2014.","official_url":"https://terra-gen.com/"},{"relationship":"Predecessor platform owner and seller to Terra-Gen","name":"Allco Finance","detail":"Transferred the Alta Wind Energy Center development platform to Terra-Gen in June 2008; the company later became Clearway Energy, Inc.","official_url":"https://investor.clearwayenergy.com/"},{"relationship":"Power-purchase agreement counterparty","name":"Southern California Edison","detail":"Counterparty for Alta III’s long-term power-purchase agreement, listed by Clearway with contract expiration in 2035.","official_url":"https://www.sce.com/"},{"relationship":"Wind-turbine OEM","name":"Vestas Wind Systems","detail":"Supplied the V90/3.0 MW turbines used at Alta III; the Alta II–V financing announcement identifies Vestas-American Wind Technology as the manufacturer for the 190 turbines ordered for the four-project phase.","official_url":"https://www.vestas.com/"},{"relationship":"Leveraged-lease purchaser and financing party","name":"Citibank, N.A.","detail":"Committed to purchase the Alta II–V projects at the start of commercial operations and lease them back to Terra-Gen; Citibank also participated in the credit facilities.","official_url":"https://www.citigroup.com/"},{"relationship":"Book-running manager and lender","name":"Barclays Capital","detail":"Acted as a joint book-running manager for the pass-through certificate issuance and participated in the Alta II–V credit facilities.","official_url":"https://home.barclays/"},{"relationship":"Administrative agent and lender","name":"Crédit Agricole Corporate and Investment Bank","detail":"Served as administrative agent for the Alta II–V construction financing and participated in the lender group.","official_url":"https://www.credit-agricole.com/"}] — Terra-Gen Power Announces Sale of Alta Wind to NRG Yield · confidence: medium
- Commercial parties.1: {"relationship":"Current portfolio owner","name":"Clearway Energy, Inc.","detail":"Successor owner of the Alta Wind portfolio following NRG Yield’s August 2018 name change; Clearway’s filings list Alta III as 100%-owned.","official_url":"https://www.clearwayenergygroup.com/about/"} — cwen-20251231 · confidence: high
- Commercial parties.2: {"relationship":"Developer, predecessor owner and seller","name":"Terra-Gen Power, LLC","detail":"Developed and constructed Alta III, acquired the Alta Wind development platform from Allco Finance in June 2008, and sold the Alta Wind portfolio to NRG Yield in August 2014.","official_url":"https://terra-gen.com/"} — Terra-Gen Power Announces Sale of Alta Wind to NRG Yield · confidence: high
- Commercial parties.3: {"relationship":"Predecessor platform owner and seller to Terra-Gen","name":"Allco Finance","detail":"Transferred the Alta Wind Energy Center development platform to Terra-Gen in June 2008. — Terra-Gen Power Announces Sale of Alta Wind to NRG Yield · confidence: high
- Commercial parties.5: {"relationship":"Power-purchase agreement counterparty","name":"Southern California Edison","detail":"Counterparty for Alta III’s long-term power-purchase agreement, listed by Clearway with contract expiration in 2035.","official_url":"https://www.sce.com/"} — cwen-20251231 · confidence: high
- Commercial parties.7: {"relationship":"Leveraged-lease purchaser and financing party","name":"Citibank, N.A.","detail":"Committed to purchase the Alta II–V projects at the start of commercial operations and lease them back to Terra-Gen; Citibank also participated in the credit facilities.","official_url":"https://www.citigroup.com/"} — Terra-Gen Power Announces Closing of $1.2 Billion Construction Financing and Wind Turbine Order - EnergyTrend · confidence: high
- Commercial parties.8: {"relationship":"Book-running manager and lender","name":"Barclays Capital","detail":"Acted as a joint book-running manager for the pass-through certificate issuance and participated in the Alta II–V credit facilities.","official_url":"https://home.barclays/"} — Terra-Gen Power Announces Closing of $1.2 Billion Construction Financing and Wind Turbine Order - EnergyTrend · confidence: medium
- Timeline.0: {"event":"Alta Wind platform acquisition","date":"2008-06","detail":"Terra-Gen acquired the Alta Wind Energy Center development platform from Allco Finance, establishing the predecessor development ownership for the later Alta III project."} — Terra-Gen Power Announces Sale of Alta Wind to NRG Yield · confidence: medium
- Timeline.2: {"event":"Alta II–V turbine delivery and commissioning","date":"2010-10","detail":"Delivery and commissioning of the Vestas turbines for Alta Projects II–V were scheduled to begin in October 2010."} — Terra-Gen Power Announces Closing of $1.2 Billion Construction Financing and Wind Turbine Order - EnergyTrend · confidence: medium
- Timeline.4: {"event":"Portfolio sale agreement","date":"2014-06-04","detail":"Terra-Gen announced a purchase-and-sale agreement with NRG Yield for its 947 MW Alta Wind I–V, X, XI and Realty projects."} — Terra-Gen Power Announces Sale of Alta Wind to NRG Yield · confidence: high
- Prior owner: Terra-Gen Power, LLC — Terra-Gen Power Announces Sale of Alta Wind to NRG Yield · confidence: medium
- Substation: Windhub Substation — Source · confidence: medium

## Timeline

- 2008-06 — Alta Wind platform acquisition
  Terra-Gen acquired the Alta Wind Energy Center development platform from Allco Finance, establishing the predecessor development ownership for the later Alta III project.
  Source: Terra-Gen Power Announces Sale of Alta Wind to NRG Yield (https://www.prnewswire.com/news-releases/terra-gen-power-announces-sale-of-alta-wind-to-nrg-yield-261816311.html)
- 2010-07-23 — Alta II–V construction financing
  Terra-Gen closed a $1.2 billion financing package for Alta Wind II–V, the four-project 570 MW phase that included Alta III. Proceeds were designated to fund construction, which was expected to begin immediately.
  Source: Terra-Gen Power Announces Closing of $1.2 Billion Construction Financing and Wind Turbine Order - EnergyTrend (https://www.energytrend.com/news/20100723-394.html)
- 2010-10 — Alta II–V turbine delivery and commissioning
  Delivery and commissioning of the Vestas turbines for Alta Projects II–V were scheduled to begin in October 2010.
  Source: Terra-Gen Power Announces Closing of $1.2 Billion Construction Financing and Wind Turbine Order - EnergyTrend (https://www.energytrend.com/news/20100723-394.html)

## Sources

- [Electric Matters - A | Federal Energy Regulatory Commission](https://www.ferc.gov/electric-matters) — ferc.gov · tier regulatory
- [Wind farms and wind energy benefits in the US](https://www.clearwayenergygroup.com/projects/wind-energy/) — clearwayenergygroup.com · tier other
- [Curtailed](https://www.caiso.com/documents/curtailed-non-operational-generator-am-report-20260120.xlsx) — caiso.com · tier other
- [cwen-20241231](https://www.sec.gov/Archives/edgar/data/1567683/000156768325000007/cwen-20241231.htm) — sec.gov · tier regulatory
- [Terra-Gen Power Announces Sale of Alta Wind to NRG Yield](https://www.prnewswire.com/news-releases/terra-gen-power-announces-sale-of-alta-wind-to-nrg-yield-261816311.html) — prnewswire.com · tier other
- [Power plant profile: Alta Wind Project, US](https://www.power-technology.com/marketdata/power-plant-profile-alta-wind-project-us/) — power-technology.com · tier other
- [Alta Wind I Owner Lessor C, et. al. v. United States](https://www.novoco.com/public-media/documents/trial-order-alta-wind-retc-071026.pdf) — novoco.com · tier other
- [Source](https://www.caiso.com/documents/august5_2010lgiabetweeniso_sce_andaltaentitiesindocketno_er10-2122-000.pdf) — caiso.com · tier other
- [Life Cycle Assessments](https://www.vestas.com/en/sustainability/environment/lifecycle-assessments) — vestas.com · tier other
- [Terra-Gen Power Announces Closing of $1.2 Billion Construction Financing and Wind Turbine Order - EnergyTrend](https://www.energytrend.com/news/20100723-394.html) — energytrend.com · tier other
- [cwen-20251231](https://www.sec.gov/Archives/edgar/data/1567683/000162828026010952/cwen-20251231.htm) — sec.gov · tier regulatory
- [Announced Resource Retirement and Mothball List posted](https://www.caiso.com/notices/announced-resource-retirement-and-mothball-list-posted) — caiso.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
- [2026 NQC List](https://www.caiso.com/documents/net-qualifying-capacity-report-for-compliance-year-2026.xlsx) — caiso.com · tier other

## Data quality

- The $870 million sale consideration and assumption of $1.6 billion of non-recourse project financings were disclosed for the 947 MW Alta Wind portfolio, not as an Alta III-specific allocation. The $1.2 billion July 2010 financing covered Alta Wind II–V collectively, including Alta III, and should not be treated as standalone Alta III debt. The latest owner asset table available in the evidence continues to list Alta III at 150 MW and 100% ownership, with no separate project-specific expansion, retirement, or repowering milestone identified.

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Canonical page: https://askthegrid.com/assets/facilities/alta-wind-energy-center-iii

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