Marathon Bay Area Cogen
Natural gas power plant in Contra Costa County, California. 113.5 MW of nameplate capacity across 3 generators, operated by Tesoro Marketing & Refining Co. LLC (Martinez).
Also known as Foster Wheeler Martinez · EIA plant 10342
Analyst: free account, 1 question a day.
Key facts
- Capacity
- 113.5 MWNameplate
- Generators
- 3 operatingEIA-860M, August 2026
- Operating since
- February 1987First generator online
- Operator
- Tesoro Marketing & Refining Co. LLC (Martinez)EIA operator ID 65130
- Grid
- CAISOBalancing authority CISO
- Price nodes
- 1 CAISO nodeResource nodes with prices
- Location
- Contra Costa County, CA38.0244, −122.0589
- EIA plant ID
- 10342EIA plant page
Data as of EIA-860M August 2026 (published 2026-09-24). Capacity is nameplate, not live output.
How much power Marathon Bay Area Cogen produces
Free · EIA-923Net generation, 2025
585 GWh
585,121 MWh, final. 11 of 12 months reported
Capacity factor, 2025
64.3%
2024: 69.2%
January to July 2026
346 GWh
Provisional
Range, 2015 to 2024
479.5–752.4
GWh a year. Low 2022, high 2016
| Year | Net generation, MWh | Capacity factor | Months reported |
|---|---|---|---|
| 2000 | 758,383 | Not reported | 12 of 12 |
| 2001 | 774,028 | Not reported | 12 of 12 |
| 2002 | 837,070 | Not reported | 12 of 12 |
| 2003 | 799,709 | Not reported | 12 of 12 |
| 2004 | 776,834 | Not reported | 12 of 12 |
| 2005 | 735,165 | Not reported | 12 of 12 |
| 2006 | 675,424 | Not reported | 12 of 12 |
| 2007 | 791,121 | Not reported | 12 of 12 |
| 2008 | 808,936 | Not reported | 12 of 12 |
| 2009 | 744,495 | Not reported | 12 of 12 |
| 2010 | 766,445 | 77.1% | 12 of 12 |
| 2011 | 809,464 | 81.4% | 12 of 12 |
| 2012 | 792,256 | 79.5% | 12 of 12 |
| 2013 | 739,924 | Not reported | 12 of 12 |
| 2014 | 774,724 | 77.9% | 12 of 12 |
| 2015 | 742,361 | 74.7% | 12 of 12 |
| 2016 | 752,411 | 75.5% | 12 of 12 |
| 2017 | 742,365 | 74.7% | 12 of 12 |
| 2018 | 673,306 | 67.7% | 12 of 12 |
| 2019 | 691,779 | 69.6% | 12 of 12 |
| 2020 | 581,854 | 58.4% | 12 of 12 |
| 2021 | 519,934 | 52.3% | 12 of 12 |
| 2022 | 479,547 | 48.2% | 12 of 12 |
| 2023 | 624,226 | 62.8% | 12 of 12 |
| 2024 | 689,814 | 69.2% | 12 of 12 |
| 2025 | 585,121 | 64.3% | 11 of 12 |
| 2026 (provisional, partial year) | 345,873 | 59.9% | 7 of 7 |
* 2026 covers January to July and is provisional. Capacity factor is net generation divided by nameplate capacity times the hours of each reported month.
Power prices and basis
Free account · CAISOEmissions
Free · EPA CAMPDNo EPA emissions units are linked to this plant.
Water use
Free · EIA-923 cooling, USGSNo EIA cooling-water record for this plant in 2024.
Generators
Free · EIA-860M| Generator | Technology | Nameplate MW | Online since |
|---|---|---|---|
| TG1 | Natural Gas Fired Combined Cycle | 40.0 | February 1987 |
| TG2 | Natural Gas Fired Combined Cycle | 40.0 | February 1987 |
| TG3 | Natural Gas Fired Combined Cycle | 33.5 | February 1987 |
Ownership and offtake
ProOwnership and offtake are part of Pro
Owners and their shares, parent companies, and power purchase agreements with their buyers. EIA-860M lists Tesoro Marketing & Refining Co. LLC (Martinez) as the operator, which is not always the owner.
Modeled data
ProPro adds modeled values for this plant. Everything above stays free.
Generation potential vs reported
Monthly potential at seasonal net capability, next to EIA-923 output. Shows how much of the plant's capability was used.
300 analyst questions a month, plus MCP
Query Marathon Bay Area Cogen and 14,224 other projects from Claude or your own tools. Free accounts get 1 question a day.
Power plants near Marathon Bay Area Cogen
Questions about Marathon Bay Area Cogen
How much power does Marathon Bay Area Cogen produce?
Marathon Bay Area Cogen reported 585,121 MWh (585 GWh) of net generation in 2025, a 64.3% capacity factor on 113.5 MW of nameplate capacity. From January to July 2026 it reported 346 GWh, which is provisional. 11 of 12 months were reported for 2025.
Where is Marathon Bay Area Cogen?
Marathon Bay Area Cogen is in Contra Costa County, California, at 38.0244, −122.0589. It is in the California Independent System Operator balancing area (CISO).
Who operates Marathon Bay Area Cogen?
EIA-860M for August 2026 lists Tesoro Marketing & Refining Co. LLC (Martinez) as the operator (EIA operator ID 65130). The operator is not always the owner.
When did Marathon Bay Area Cogen start operating?
Its first generator began operating in February 1987, according to EIA-860M.
Does InfraMap have power prices for Marathon Bay Area Cogen?
Yes. InfraMap has CAISO day-ahead and real-time prices at 1 price node linked to Marathon Bay Area Cogen, with the hub price and node-to-hub basis. Prices are free with an InfraMap account; pricing node names are part of InfraMap Pro.
Sources
- EIA-860 2025 (final) and EIA-860M August 2026: plant, generators, capacity, operator and location
- EIA-923 monthly net generation, 2000 to July 2026 (2026 provisional)
- CAISO day-ahead and real-time prices; node and hub assignments as of 2026-10-05
- Plant names from OpenStreetMap, © OpenStreetMap contributors (ODbL)
Page updated 2026-10-04 from the InfraMap data build. Methodology · Data sources · EIA plant page