Data last collected:
PowerPlantFactsEvidence report · prepared 19 October 2026https://powerplantfacts.com/entity/10342
EIA plant 10342
Martinez · Contra Costa · CA
Marathon Bay Area Cogen
Operated by Tesoro Marketing & Refining Co. LLC (Martinez)
Published location
Where is Marathon Bay Area Cogen?
This locator uses the coordinates in the approved source record. It shows geographic context, not a site boundary, safety zone or property-risk area.
38.024400, -122.058900
Open the interactive map ↗Map data © OpenStreetMap contributors
Capacity is not generation. Nameplate MW describes equipment; annual MWh describes recorded output. Proposed and retired units are not added to operating capacity.
Equipment mix
Operating capacity by technology
Grouped from this plant’s represented generator records. Use the CA plant index for regional peers.
See the evidence
Electricity output across the year
Monthly net generation shows the seasonal shape of this plant's represented output. A negative value is retained when the source reports net consumption.
157,551
248,507
358,999
452,792
553,420
659,179
759,866
858,853
961,265
1062,926
1154,445
1262,011
MWh net generation · 2024 final edition · EIA 923 represented operating rows. 12 of 12 supplied rows shown; 0 missing values omitted. Months with no reported numeric value are omitted, not treated as zero.
Read the chart as a table
| Record | MWh net generation |
|---|---|
| 1 | 57,551 |
| 2 | 48,507 |
| 3 | 58,999 |
| 4 | 52,792 |
| 5 | 53,420 |
| 6 | 59,179 |
| 7 | 59,866 |
| 8 | 58,853 |
| 9 | 61,265 |
| 10 | 62,926 |
| 11 | 54,445 |
| 12 | 62,011 |
2024 monthly net generation
| Month | Net generation |
|---|---|
| 1 | 57,551 MWh |
| 2 | 48,507 MWh |
| 3 | 58,999 MWh |
| 4 | 52,792 MWh |
| 5 | 53,420 MWh |
| 6 | 59,179 MWh |
| 7 | 59,866 MWh |
| 8 | 58,853 MWh |
| 9 | 61,265 MWh |
| 10 | 62,926 MWh |
| 11 | 54,445 MWh |
| 12 | 62,011 MWh |
Operating generators
| ID | Technology | Fuel | MW | Status |
|---|---|---|---|---|
| TG1 | Natural Gas Fired Combined Cycle | NG | 40 | OP |
| TG2 | Natural Gas Fired Combined Cycle | NG | 40 | OP |
| TG3 | Natural Gas Fired Combined Cycle | NG | 33.5 | OP |
Continue exploring
Similar-capacity plants in the same state
Identity, technology and limitations
EIA plant ID
10342
Sector
IPP CHP
Water source
Wells
Data edition
2024-final
Use this record
Questions this evidence can answer
01What exactly is this record?
Use the name, place, date and identifiers above to confirm that you have the right Marathon Bay Area Cogen power plant: capacity and generation | PowerPlantFacts record.
02What does the evidence establish?
Read the reported values with their units, coverage dates and source notes. Keep observed facts separate from estimates or interpretation.
03What should I verify next?
Follow the primary-source links and check the limitations before using this evidence for a decision, comparison or citation.
A closer look at Marathon Bay Area Cogen
Variation in the published months
Across 12 numeric monthly generation entries, 10 has the highest recorded value (62,926 MWh) and 2 the lowest (48,507 MWh). Their difference is 14,419 MWh. Missing months have not been treated as zero.
Reading the MW column
In the 3 numeric rows displayed in this table, MW ranges from 33.5 (TG3) to 40 (TG1, TG2). The difference is 6.5 in the column's stated units. This summary covers the displayed rows and retains the table's period and scope.
Generator capacity in different operating conditions
| Generator ID | Technology | Nameplate MW | Summer MW | Winter MW | Minimum load MW |
|---|---|---|---|---|---|
| TG1 | Natural Gas Fired Combined Cycle | 40.0 | 35.0 | 37.0 | 29.0 |
| TG2 | Natural Gas Fired Combined Cycle | 40.0 | 35.0 | 37.0 | 29.0 |
| TG3 | Natural Gas Fired Combined Cycle | 33.5 | 33.5 | 33.5 | 5.0 |
EIA-860 2024 final source. Ratings describe capacity, not actual generation or availability. Missing ratings are not zero.
Source: US Energy Information Administration Form EIA-860 2024 plant and operable-generator workbooks; archive 2024. US EIA-authored information is generally public domain; cite EIA, preserve third-party exceptions, changes and no-endorsement context. Source-specific derived data.