# Diablo Canyon

CAISO Nuclear · https://askthegrid.com/assets/facilities/diablo-canyon

Diablo Canyon is a nuclear power facility with 2,323 MW of EIA-reported nameplate capacity in San Luis Obispo County, California, registered as EIA Plant ID 6099. Pacific Gas & Electric Co. is the registered plant entity or operator. The plant's generating configuration is nuclear facility with two Westinghouse pressurized-water reactor (PWR) units. Commercial operation began on May 7, 1985.

## Key facts

- Technology: Nuclear
- Power capacity: 2323 MW
- Operating status: operating

## Grid and market context

- ISO/RTO: CAISO
- Balancing authority: California Independent System Operator (CAISO/CISO)
- Substation: Diablo Canyon substation
- Point of interconnection: Diablo Canyon substation
- Transmission owner: Pacific Gas and Electric Company (PG&E)
- Interconnection voltage: 500 kV

## Source-backed facts

- Owner logo domain: pge.com — Nuclear Power | PG&E · confidence: medium
- Identifiers: [{"value":"6099","system":"EIA plant ID"},{"value":"14328","system":"EIA utility ID"},{"value":"1","system":"EIA generator ID"},{"value":"DIABLO_7_UNIT 1","system":"CAISO resource ID"},{"value":"DIABLO_7_UNIT 2","system":"CAISO resource ID"},{"value":"50-275","system":"NRC docket"},{"value":"50-323","system":"NRC docket"},{"value":"DPR-80","system":"NRC facility operating license"},{"value":"DPR-82","system":"NRC facility operating license"},{"value":"NRC-2023-0192","system":"NRC proceeding docket"}] — 2026 Generation · confidence: medium
- Identifiers: [{"value":"6099","system":"EIA plant ID"},{"value":"14328","system":"EIA utility ID"},{"value":"1","system":"EIA generator ID"},{"value":"DIABLO_7_UNIT 1","system":"CAISO resource ID"},{"value":"DIABLO_7_UNIT 2","system":"CAISO resource ID"},{"value":"50-275","system":"NRC docket"},{"value":"50-323","system":"NRC docket"},{"value":"DPR-80","system":"NRC facility operating license"},{"value":"DPR-82","system":"NRC facility operating license"},{"value":"NRC-2023-0192","system":"NRC proceeding docket"}] — This is a modified version of the EIA... · confidence: medium
- Identifiers: [{"value":"6099","system":"EIA plant ID"},{"value":"14328","system":"EIA utility ID"},{"value":"1","system":"EIA generator ID"},{"value":"DIABLO_7_UNIT 1","system":"CAISO resource ID"},{"value":"DIABLO_7_UNIT 2","system":"CAISO resource ID"},{"value":"50-275","system":"NRC docket"},{"value":"50-323","system":"NRC docket"},{"value":"DPR-80","system":"NRC facility operating license"},{"value":"DPR-82","system":"NRC facility operating license"},{"value":"NRC-2023-0192","system":"NRC proceeding docket"}] — Evaluation Report of Load Serving Entities' Compliance... · confidence: medium
- Identifiers.0: {"value":"6099","system":"EIA plant ID"} — This is a modified version of the EIA... · confidence: medium
- Identifiers.1: {"value":"14328","system":"EIA utility ID"} — This is a modified version of the EIA... · confidence: medium
- Identifiers.3: {"value":"DIABLO_7_UNIT 1","system":"CAISO resource ID"} — Evaluation Report of Load Serving Entities' Compliance... · confidence: high
- Identifiers.4: {"value":"DIABLO_7_UNIT 2","system":"CAISO resource ID"} — Evaluation Report of Load Serving Entities' Compliance... · confidence: high
- Identifiers.7: {"value":"DPR-80","system":"NRC facility operating license"} — Federal Register :: Pacific Gas and Electric Company; Diablo Canyon Nuclear Power Plant, Units 1 and 2; License Renewal and Record of Decision · confidence: high
- Identifiers.8: {"value":"DPR-82","system":"NRC facility operating license"} — Federal Register :: Pacific Gas and Electric Company; Diablo Canyon Nuclear Power Plant, Units 1 and 2; License Renewal and Record of Decision · confidence: high
- Commercial operation date: 1985-05-07 — Diablo Canyon 1 · confidence: medium
- Commercial operation date: 1985-05-07 — The History of the Diablo Canyon Power Plant · confidence: medium
- Product url: https://westinghousenuclear.com/new-plants/ap1000-pwr/ — AP1000® Pressurized Water Reactor · confidence: medium
- Manufacturer domain: westinghousenuclear.com — AP1000® Pressurized Water Reactor · confidence: medium
- Product family: Westinghouse pressurized water reactor (PWR) — Diablo Canyon Power Plant · confidence: medium
- Product family: Westinghouse pressurized water reactor (PWR) — AP1000® Pressurized Water Reactor · confidence: medium
- Manufacturer name: Westinghouse — Diablo Canyon Power Plant · confidence: high
- Financing summary: In September 2022, California SB 846 authorized up to $1.4 billion from the General Fund to the Department of Water Resources for loans to the licensed Diablo Canyon operator to facilitate continued operation. The legislation permitted loans totaling up to $1.4 billion, including up to $350 million under initial loan agreements. This was extension-of-operations financing, not sale consideration. The retrieved records do not disclose a purchase price or original construction project-financing structure; a reported $11.556 billion construction cost in 2007 dollars is a cost estimate rather than a financing amount. — Bill Text - SB-846 Diablo Canyon powerplant: extension of operations. · confidence: medium
- Financing summary: In September 2022, California SB 846 authorized up to $1.4 billion from the General Fund to the Department of Water Resources for loans to the licensed Diablo Canyon operator to facilitate continued operation. The legislation permitted loans totaling up to $1.4 billion, including up to $350 million under initial loan agreements. This was extension-of-operations financing, not sale consideration. The retrieved records do not disclose a purchase price or original construction project-financing structure; a reported $11.556 billion construction cost in 2007 dollars is a cost estimate rather than a financing amount. — (Non-Proprietary Information) Direct Transfer of Facility Operating Licenses for Diablo Canyon Power Plant, Units 1 and 2. · confidence: medium
- Commercial parties.2: {"relationship":"Construction completion contractor","name":"Bechtel Power Corporation","detail":"NRC records identify Bechtel project-completion responsibilities including design engineering, procurement services, construction completion, and preoperational testing.","official_url":"https://www.bechtel.com/"} — "QA Program,Bechtel Power Corp,Diablo Canyon Project." · confidence: high
- Commercial parties.3: {"relationship":"Integrated services and operations-and-maintenance supplier","name":"Fluor Corporation","detail":"Fluor provides site services, facility maintenance, strategic and station projects, engineering services, and outage services at Diablo Canyon.","official_url":"https://www.fluor.com/"} — Diablo Canyon Integrated Services Supplier · confidence: high
- Commercial parties.4: {"relationship":"Extension-loan administrator","name":"California Department of Water Resources","detail":"SB 846 authorized the Department of Water Resources to receive up to $1.4 billion from the General Fund and lend the funds to the Diablo Canyon operator for continued operations.","official_url":"https://water.ca.gov/"} — Bill Text - SB-846 Diablo Canyon powerplant: extension of operations. · confidence: high
- Quality notes.1: The $1.4 billion amount was authorized as a California extension-of-operations loan administered through the Department of Water Resources; it is not sale consideration or disclosed original construction financing. — Bill Text - SB-846 Diablo Canyon powerplant: extension of operations. · confidence: high
- Quality notes.2: The documented expansion was an NRC-approved Unit 1 reactor-core power uprate in 2000. No separate repowering project is identified. — Diablo Canyon Unit 1 Approved Power Uprate Application Information | Nuclear Regulatory Commission · confidence: high
- Timeline.1: {"event":"Unit 1 construction permit and construction start","date":"1968-04-23","detail":"The Unit 1 construction permit, CPPR-39, was issued on April 23, 1968, the date recorded as the start of Unit 1 construction."} — Diablo Canyon 1 · confidence: high
- Timeline.2: {"event":"Unit 2 construction permit and construction start","date":"1970-12-09","detail":"The Unit 2 construction permit was issued on December 9, 1970, with construction beginning in early 1971."} — Diablo Canyon 2 · confidence: high
- Timeline.5: {"event":"Unit 1 power uprate","date":"2000-10-26","detail":"The NRC issued Amendment No. 143 approving PG&E’s Unit 1 reactor-core thermal-power uprate application; the application had been submitted on December 31, 1999."} — Diablo Canyon Unit 1 Approved Power Uprate Application Information | Nuclear Regulatory Commission · confidence: high
- Timeline.9: {"event":"Planned retirement announced","date":"2016-06","detail":"PG&E announced plans to close Diablo Canyon when the then-current NRC licenses expired in 2024 and 2025."} — Nuclear Power | PG&E · confidence: high
- Timeline.10: {"event":"California extension legislation and loan authorization","date":"2022-09-02","detail":"California enacted SB 846, directing PG&E to seek continued operation through October 31, 2030 and authorizing up to $1.4 billion in extension-of-operations loans through the Department of Water Resources."} — Bill Text - SB-846 Diablo Canyon powerplant: extension of operations. · confidence: high
- Timeline.11: {"event":"License-renewal application","date":"2023-11-07","detail":"PG&E submitted its application to the NRC for renewal of the Diablo Canyon operating licenses."} — Federal Register :: Pacific Gas and Electric Company; Diablo Canyon Nuclear Power Plant, Units 1 and 2; License Renewal and Record of Decision · confidence: high
- Timeline.12: {"event":"NRC renewed operating licenses","date":"2026-04-02","detail":"The NRC issued renewed Facility Operating Licenses DPR-80 and DPR-82. Public reporting states that the renewals authorize Unit 1 to operate until November 2, 2044 and Unit 2 until August 26, 2045."} — NRC approves Diablo Canyon license renewal, extension · confidence: high
- Status detail: Operating. Unit 1 began extended operations in November 2024 and Unit 2 began extended operations on August 27, 2025, superseding the earlier planned 2024/2025 retirements. California law authorizes operation through 2030; the NRC issued renewed federal licenses on April 2, 2026, extending the federal license terms to 2044 for Unit 1 and 2045 for Unit 2, but operation beyond 2030 requires further state legislative action. — Diablo Canyon Enters Full Extended Operations | PG&E · confidence: medium
- Operating status: operating — Diablo Canyon Enters Full Extended Operations | PG&E · confidence: high

## Timeline

- 1985-05-07 — Unit 1 commercial operation
  Unit 1 began commercial operation on May 7, 1985.
  Source: Source (https://www.pge.com/assets/pge/docs/about/pge-systems/PGE-DCL-23-002.pdf)
- 1986-03-13 — Unit 2 commercial operation
  Unit 2 began commercial operation on March 13, 1986.
  Source: Source (https://www.pge.com/assets/pge/docs/about/pge-systems/PGE-DCL-23-002.pdf)
- 2000-10-26 — Unit 1 power uprate
  The NRC issued Amendment No. 143 approving PG&E’s Unit 1 reactor-core thermal-power uprate application; the application had been submitted on December 31, 1999.
  Source: Diablo Canyon Unit 1 Approved Power Uprate Application Information | Nuclear Regulatory Commission (https://www.nrc.gov/reactors/operating/licensing/power-uprates/pwr-stretch/diablo-canyon-pu)
- 2001-09-20 — Proposed bankruptcy-plan ownership restructuring
  PG&E and PG&E Corporation filed a Chapter 11 reorganization plan under which operating authority would be transferred to Electric Generation LLC and ownership of the two-unit generating asset would be assigned to its wholly owned subsidiary, Diablo Canyon LLC.
  Source: (Non-Proprietary Information) Direct Transfer of Facility Operating Licenses for Diablo Canyon Power Plant, Units 1 and 2. (https://www.nrc.gov/docs/ML0217/ML021750017.pdf)
- 2002-01-17 — NRC notice of proposed transfer
  The NRC published notice of consideration of the proposed transfer of Diablo Canyon’s facility operating licenses from PG&E to Electric Generation LLC and Diablo Canyon LLC.
  Source: Federal Register, Volume 67 Issue 12 (Thursday, January 17, 2002) (https://www.govinfo.gov/content/pkg/FR-2002-01-17/html/02-1211.htm)
- 2016-06 — Planned retirement announced
  PG&E announced plans to close Diablo Canyon when the then-current NRC licenses expired in 2024 and 2025.
  Source: Nuclear Power | PG&E (https://www.pge.com/en/about/pge-systems/nuclear-power.html)

## Sources

- [Nuclear Power | PG&E](https://www.pge.com/en/about/pge-systems/nuclear-power.html) — pge.com · tier other
- [2026 Generation](https://www.eia.gov/nuclear/generation/xls/usreact26.xlsx) — eia.gov · tier regulatory
- [This is a modified version of the EIA ...](https://downloads.regulations.gov/EPA-R06-OAR-2014-0754-0008/attachment_102.pdf) — downloads.regulations.gov · tier regulatory
- [Evaluation Report of Load Serving Entities' Compliance ...](https://www.caiso.com/documents/evaluationreportofloadservingentitiescompliancewith2022resourceadequacyrequirements.pdf) — caiso.com · tier other
- [Federal Register :: Pacific Gas and Electric Company; Diablo Canyon Nuclear Power Plant, Units 1 and 2; License Renewal and Record of Decision](https://www.federalregister.gov/documents/2026/04/06/2026-06641/pacific-gas-and-electric-company-diablo-canyon-nuclear-power-plant-units-1-and-2-license-renewal-and) — federalregister.gov · tier regulatory
- [Diablo Canyon Integrated Services Supplier](https://www.fluor.com/projects/operations-maintenance-nuclear-power-plant) — fluor.com · tier other
- [Source](https://www.nrc.gov/docs/ML1720/ML17206A065.pdf) — nrc.gov · tier regulatory
- [Diablo Canyon 1](https://world-nuclear.org/nuclear-reactor-database/details/Diablo-Canyon-1) — world-nuclear.org · tier other
- [The History of the Diablo Canyon Power Plant](https://diablocanyonpanel.org/history-of-dcpp/) — diablocanyonpanel.org · tier other
- [AP1000® Pressurized Water Reactor](https://westinghousenuclear.com/new-plants/ap1000-pwr/) — westinghousenuclear.com · tier other
- [Source](https://www.pge.com/assets/pge/docs/about/pge-systems/PGE-DCL-23-002.pdf) — pge.com · tier other
- [NRC approves Diablo Canyon license renewal, extension](https://www.ans.org/news/2026-04-03/article-7906/nrc-approves-diablo-canyon-license-renewal-extension/) — ans.org · tier other
- [Diablo Canyon Unit 1 Approved Power Uprate Application Information | Nuclear Regulatory Commission](https://www.nrc.gov/reactors/operating/licensing/power-uprates/pwr-stretch/diablo-canyon-pu) — nrc.gov · tier regulatory
- [Bill Text - SB-846 Diablo Canyon powerplant: extension of operations.](https://leginfo.legislature.ca.gov/faces/billNavClient.xhtml?bill_id=202120220SB846) — leginfo.legislature.ca.gov · tier regulatory
- [(Non-Proprietary Information) Direct Transfer of Facility Operating Licenses for Diablo Canyon Power Plant, Units 1 and 2.](https://www.nrc.gov/docs/ML0217/ML021750017.pdf) — nrc.gov · tier regulatory
- [Diablo Canyon 2](https://world-nuclear.org/nuclear-reactor-database/details/Diablo-Canyon-2) — world-nuclear.org · tier other
- [Federal Register, Volume 67 Issue 12 (Thursday, January 17, 2002)](https://www.govinfo.gov/content/pkg/FR-2002-01-17/html/02-1211.htm) — govinfo.gov · tier regulatory
- ["QA Program,Bechtel Power Corp,Diablo Canyon Project."](https://www.nrc.gov/docs/ML1634/ML16340C626.pdf) — nrc.gov · tier regulatory
- [2024-2025 TRANSMISSION PLAN](https://www.caiso.com/documents/iso-board-approved-2024-2025-transmission-plan.pdf) — caiso.com · tier other
- [Diablo Canyon Power Plant, Units 1 and 2](https://www.nrc.gov/docs/ML2120/ML21207A199.pdf) — nrc.gov · tier regulatory
- [Governor Newsom welcomes approval of Diablo Canyon license renewals, delivering on California’s commitment to a clean and reliable grid | Governor of California](https://www.gov.ca.gov/2026/04/02/governor-newsom-welcomes-approval-of-diablo-canyon-license-renewals-delivering-on-californias-commitment-to-a-clean-and-reliable-grid/) — gov.ca.gov · tier regulatory
- [Diablo Canyon Enters Full Extended Operations | PG&E](https://www.pge.com/en/newsroom/currents/future-of-energy/diablo-canyon-enters-full-extended-operations-.html) — pge.com · tier other

## Data quality

- The NRC approved that proposed transfer in June 2003, but later official records identify PG&E as the owner and operator, so it should not be treated as a completed arm’s-length sale. The documented expansion was an NRC-approved Unit 1 reactor-core power uprate in 2000. No separate repowering project is identified. PG&E’s official regulatory correspondence gives Unit 2’s commercial-operation date as March 13, 1986; that date is used despite a conflicting secondary historical reference that gives 1987.

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