Watson Cogeneration
ARCO Products Co-WatsonLos Angeles County
Watson Cogeneration is a natural gas-fired power facility with 405 MW of EIA-reported nameplate capacity in Los Angeles County, California, registered as EIA Plant ID 50216. ARCO Products Co-Watson is the registered plant entity or operator. Marathon Petroleum identifies the Watson cogeneration plant as the largest cogeneration facility in California; its refinery page states that the plant produces approximately 400 MW. Commercial operation began on April 1, 1988.
Mapped infrastructure geometry associated with this asset.
Natural Gas Fired Combined Cycle
Watson Cogeneration is operating.
66 kV · Southern California Edison (SCE)
EIA plant 50216 · Inventory for Sep 2026.
| Generator | Technology | Status | Power (MW) | Energy (MWh) |
|---|---|---|---|---|
| GN91 | Natural Gas Fired Combined Cycle | Operating | 82 | Unknown |
| GN92 | Natural Gas Fired Combined Cycle | Operating | 82 | Unknown |
| GN93 | Natural Gas Fired Combined Cycle | Operating | 82 | Unknown |
| GN94 | Natural Gas Fired Combined Cycle | Operating | 82 | Unknown |
| GN95 | Natural Gas Fired Combined Cycle |
Similar plants ranked by technology, capacity, and distance.
Current generator records and technology attributes reported through EIA-860.
| Generator | Capacity | Technology | Operation | Status |
|---|---|---|---|---|
| GN91 | 82 MW 82 MW summer | Natural Gas Fired Combined Cycle CT | Mar 1988 | Operating |
| GN92 | 82 MW 82 MW summer | Natural Gas Fired Combined Cycle CT | Feb 1988 | Operating |
| GN93 | 82 MW 82 MW summer | Natural Gas Fired Combined Cycle CT | Jan 1988 | Operating |
| GN94 | 82 MW 82 MW summer | Natural Gas Fired Combined Cycle CT | Dec 1987 | Operating |
| GN95 | 38.5 MW | |||
Monthly EIA generation history and recent market-resource behavior where linked telemetry is available.
Deterministic links to ERCOT market resources, price records, outage disclosures, queue records, and nearby infrastructure. Candidate joins remain labeled until corroborated.
Source-backed project transactions, agreements, land records, permits, and environmental disclosures. Portfolio and adjacent-project facts remain explicitly scoped.
Parties, market resources, and identifiers tied to this asset, with owner, operator, developer, EPC, compliance provider, and interconnecting entity roles kept separate.
Drag organizations to explore the network. Select a node to pin its details and available page link.
Project milestones and public references behind the asset profile.
The California Energy Commission certified the original Watson Cogeneration Project under docket 85-AFC-01.
CAISO
CAISO · Los Angeles County
| Operating |
| 38.5 |
| Unknown |
| GN96 | Natural Gas Fired Combined Cycle | Operating | 38.5 | Unknown |
|---|
| GN97 | Natural Gas Fired Combined Cycle | canceled_or_postponed | 94.2 | Unknown |
|---|
Monthly generation is reported through EIA-923. Capacity factor uses the current EIA nameplate capacity and is shown only for complete calendar years.
Portfolio membership follows the latest EIA-860 reporting entity. It does not imply ultimate ownership.
EIA-860 lists generator GN94, generator GN96 with this operating date.
EIA-860 lists generator GN93 with this operating date.
EIA-860 lists generator GN92, generator GN95 with this operating date.
EIA-860 lists generator GN91 with this operating date.
The original project began commercial operation.
The CEC approved construction of a new 45-MW fifth-train addition.
The CEC approved Application for Certification 09-AFC-01C for an additional fifth train; the project was later terminated at the owner’s request.
California Energy Commission records upstream ownership change. NRG Energy acquired Edison Mission Energy assets, including interest in Watson Cogeneration. Source does not disclose consideration allocated to Watson.
The CEC officially terminated the 09-AFC-01C fifth-train project at the owner’s request.
The CEC docketed a Watson Cogeneration petition to amend the project; the filing stated that the proposed changes would not affect compliance and would have no significant environmental impacts.
Answered from the published record above. Questions whose inputs this profile does not carry are omitted rather than estimated.
Watson Cogeneration reports 405 MW natural gas of operating nameplate capacity. These technology ratings do not establish a common export limit. Source: EIA Sep 2026.
Watson Cogeneration is a Natural Gas Fired Combined Cycle facility in Los Angeles County, CA, participating in the CAISO market.
Watson Cogeneration is in Los Angeles County, CA, inside the CAISO balancing area.
Watson Cogeneration is operated by ARCO Products Co-Watson according to the EIA generator inventory. Reporting membership does not by itself establish ultimate ownership.
Watson Cogeneration reported 2,383.3 GWh over the twelve months to 2026-07. Figures are net generation as filed to EIA-923.
Watson Cogeneration interconnects at SCE Hinson Substation, on the Southern California Edison (SCE) system.
By capacity, Watson Cogeneration ranks #329 of 540 operating plants of the same technology nationally. It ranks #24 of 64 in CA.
Plants within 25 km, nearest first, regardless of technology. Proximity is straight-line distance between mapped plant coordinates; it does not by itself establish a shared point of interconnection.