Mariposa Energy Project
Alameda County, California · EIA plant ID 57483 · Operator: Diamond Generating Corporation
Nameplate200MWSummer 200 MW
Generators4in service
Net generation39GWh12 mo to Aug 2026
Capacity factor2%gas/coal/oil units, summer MW
Heat rate10,286Btu/kWhfossil units, electric fuel, HHV
First online2012Runs as peaking
The 12-month figures include preliminary EIA-923 months, which EIA revises. Final data runs through Dec 2025.
Monthly net generation
EIA-923, all units at the plant. Net of station use; storage can go negative.
FinalPreliminary
Capacity factor by year
Net MWh ÷ (summer MW × hours), gas/coal/oil units. Each year uses that year's EIA-860 ratings; the hollow dot is the latest 12 months.
Heat rate by year
Electric fuel MMBtu × 1000 ÷ net MWh (Btu/kWh, HHV), fossil units only; CT + CA counted as one combined-cycle block.
Annual data table
| Year | Net GWh | Capacity factor | Heat rate (Btu/kWh) |
|---|---|---|---|
| 2012 | 27.9 | 6.3% | 10,551 |
| 2013 | 77.9 | 4.5% | 10,775 |
| 2014 | 99.7 | 5.7% | 10,881 |
| 2015 | 82.9 | 4.7% | 10,570 |
| 2016 | 85.6 | 4.9% | 10,779 |
| 2017 | 136.3 | 7.8% | 10,913 |
| 2018 | 112.2 | 6.4% | 10,952 |
| 2019 | 90.8 | 5.2% | 11,028 |
| 2020 | 104.3 | 5.9% | 11,256 |
| 2021 | 91.3 | 5.2% | 10,317 |
| 2022 | 94.6 | 5.4% | 10,232 |
| 2023 | 87.7 | 5.0% | 10,182 |
| 2024 | 93.4 | 5.3% | 10,148 |
| 2025 | 29.1 | 1.7% | 10,303 |
Generators
EIA-860 (annual) with EIA-860M updates through Sep 2026. EIA-923 reports generation by plant, prime mover and fuel, not by unit, so unit-level output isn't shown.
| Gen ID | Technology | Prime mover | Nameplate MW | Summer MW | Online | Status | Planned retirement | OEM / model |
|---|---|---|---|---|---|---|---|---|
| CTG1 | Natural Gas Fired Combustion Turbine | GT | 49.9 | 49.9 | Oct 2012 | Operating | — | coming soon |
| CTG2 | Natural Gas Fired Combustion Turbine | GT | 49.9 | 49.9 | Oct 2012 | Operating | — | coming soon |
| CTG3 | Natural Gas Fired Combustion Turbine | GT | 49.9 | 49.9 | Oct 2012 | Operating | — | coming soon |
| CTG4 | Natural Gas Fired Combustion Turbine | GT | 49.9 | 49.9 | Oct 2012 | Operating | — | coming soon |
Owner / operator
Operator: Diamond Generating Corporation. Ownership shares by in-service nameplate MW (EIA-860 Schedule 4; units not listed there are wholly owned by the operator).
| Diamond Generating Corporation | 100.0% | 200 MW |
Nearby plants
Within 80 km.
| Sand Hill C | — | 2.2 km |
| Diablo Wind LLC | 18 MW | 3 km |
| Golden Hills North Wind Energy Center | 46 MW | 3.3 km |
| Sand Hill B | — | 3.8 km |
| Sand Hill A | — | 5.1 km |
| Buena Vista Energy LLC | 38 MW | 6 km |