Marshalltown Generating Station
Marshall County, Iowa · EIA plant ID 58236 · Operator: Interstate Power and Light Co
Nameplate709MWSummer 668 MW
Generators5in service
Net generation2,732GWh12 mo to Aug 2026
Capacity factor47%gas/coal/oil units, summer MW
Heat rate6,562Btu/kWhfossil units, electric fuel, HHV
First online2017Runs as baseload
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) |
|---|---|---|---|
| 2017 | 1,307.6 | 30.3% | 7,199 |
| 2018 | 3,028.8 | 53.3% | 7,059 |
| 2019 | 3,761.1 | 62.8% | 6,736 |
| 2020 | 2,677.2 | 46.2% | 7,009 |
| 2021 | 1,921.7 | 33.1% | 7,294 |
| 2022 | 2,724 | 46.9% | 7,176 |
| 2023 | 3,582 | 62.7% | 6,586 |
| 2024 | 3,498.9 | 59.8% | 6,468 |
| 2025 | 3,177.9 | 54.5% | 6,619 |
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 |
|---|---|---|---|---|---|---|---|---|
| BESS1 | Batteries | BA | 0.3 | 0.3 | Oct 2020 | Operating | — | coming soon |
| CTG1 | Natural Gas Fired Combined Cycle | CT | 222.7 | 222.6 | Apr 2017 | Operating | — | coming soon |
| CTG2 | Natural Gas Fired Combined Cycle | CT | 222.7 | 222.2 | Apr 2017 | Operating | — | coming soon |
| PV1 | Solar Photovoltaic | PV | 2.6 | 2.6 | Feb 2020 | Operating | — | coming soon |
| STG1 | Natural Gas Fired Combined Cycle | CA | 260.5 | 220.4 | Apr 2017 | Operating | — | coming soon |
| CC1 | Natural Gas Fired Combined Cycle | CC | 870 | 646 | planned Apr 2017 | not_current | — | coming soon |
Owner / operator
Operator: Interstate Power and Light Co. Ownership shares by in-service nameplate MW (EIA-860 Schedule 4; units not listed there are wholly owned by the operator).
| Interstate Power and Light Co | 100.0% | 709 MW |
Nearby plants
Within 80 km.
| Marshalltown | 189 MW | 1.2 km |
| Alliant SBD 9107 JBS USA | 11 MW | 2.5 km |
| Vienna Wind Farm | 150 MW | 15.2 km |
| Laurel Wind Farm | 123 MW | 18.5 km |
| State Center | 7 MW | 24.2 km |
| Salt Creek Wind | 169 MW | 32.7 km |