Donnells
Tuolumne County, California · EIA plant ID 415 · Operator: Oakdale&South San Joaquin Irrigation D.
Nameplate72MWSummer 72 MW
Generators1in service
Net generation233GWh12 mo to Dec 2025
Capacity factor37%hydro units, summer MW
Heat rate—thermal plants only
First online1957
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), hydro 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.
Heat rate applies to fuel-burning (thermal) units only.
Annual data table
| Year | Net GWh | Capacity factor | Heat rate (Btu/kWh) |
|---|---|---|---|
| 2001 | 215.7 | 34.2% | — |
| 2002 | 311.2 | 49.4% | — |
| 2003 | 272.9 | 43.3% | — |
| 2004 | 288 | 45.5% | — |
| 2005 | 343.5 | 54.5% | — |
| 2006 | 417.1 | 66.1% | — |
| 2007 | 175.3 | 27.8% | — |
| 2008 | 220.2 | 34.8% | — |
| 2009 | 229.4 | 36.4% | — |
| 2010 | 209 | 33.1% | — |
| 2011 | 345.9 | 54.8% | — |
| 2012 | 205 | 32.4% | — |
| 2013 | 208 | 33.0% | — |
| 2014 | 134.6 | 21.3% | — |
| 2015 | 143.1 | 22.7% | — |
| 2016 | 347.2 | 54.9% | — |
| 2017 | 434.4 | 68.9% | — |
| 2018 | 129.2 | 20.5% | — |
| 2019 | 302.3 | 47.9% | — |
| 2020 | 196.9 | 31.1% | — |
| 2021 | 158.1 | 25.1% | — |
| 2022 | 203.6 | 32.3% | — |
| 2023 | 347.7 | 55.1% | — |
| 2024 | 219.2 | 34.6% | — |
| 2025 | 233.4 | 37.0% | — |
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 |
|---|---|---|---|---|---|---|---|---|
| H1 | Conventional Hydroelectric | HY | 72 | 72 | Jun 1957 | Operating | — | coming soon |
Owner / operator
Operator: Oakdale&South San Joaquin Irrigation D.. Ownership shares by in-service nameplate MW (EIA-860 Schedule 4; units not listed there are wholly owned by the operator).
| Oakdale&South San Joaquin Irrigation D. | 100.0% | 72 MW |
Nearby plants
Within 80 km.
| Beardsley | 10 MW | 6.2 km |
| Spring Gap | 6 MW | 9.5 km |
| Sand Bar Power Plant | 16 MW | 12.2 km |
| Spicer Meadow Project | 6 MW | 16.4 km |
| Stanislaus | 82 MW | 31.7 km |
| Salt Springs | 42 MW | 32.2 km |