Marshalltown
Marshall County, Iowa · EIA plant ID 1068 · Operator: Interstate Power and Light Co
Nameplate189MWSummer 157 MW
Generators3in service
Net generation20GWh12 mo to Dec 2025
Capacity factor1%gas/coal/oil units, summer MW
Heat rate12,924Btu/kWhfossil units, electric fuel, HHV
First online1978Runs as peaking
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) |
|---|---|---|---|
| 2001 | 21 | 1.5% | 14,080 |
| 2002 | 11.9 | 0.8% | 14,259 |
| 2003 | 20.2 | 1.4% | 13,759 |
| 2004 | 18.5 | 1.3% | 14,012 |
| 2005 | 46.9 | 3.2% | 14,166 |
| 2006 | 28.6 | 2.0% | 15,512 |
| 2007 | 54.6 | 3.7% | 13,728 |
| 2008 | 9.7 | 0.7% | 15,656 |
| 2009 | 13.3 | 0.9% | 14,498 |
| 2010 | 17.8 | 1.3% | 14,349 |
| 2011 | 14.1 | 1.0% | 14,505 |
| 2012 | 30.1 | 2.7% | 14,301 |
| 2013 | 18.3 | 1.4% | 14,707 |
| 2014 | 9.7 | 0.7% | 13,403 |
| 2015 | 2.2 | 0.1% | 17,675 |
| 2016 | 3.1 | 0.3% | 16,230 |
| 2017 | 17.9 | 1.2% | 11,780 |
| 2018 | 30.8 | 2.0% | 9,154 |
| 2019 | 29.9 | 2.0% | 5,793 |
| 2020 | 48.7 | 3.3% | 7,948 |
| 2021 | 88.1 | 6.0% | 7,389 |
| 2022 | 71.9 | 5.0% | 21,067 |
| 2023 | 122.1 | 13.3% | 15,544 |
| 2024 | 79 | 5.8% | 14,234 |
| 2025 | 20.3 | 1.5% | 12,924 |
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 |
|---|---|---|---|---|---|---|---|---|
| 1 | Natural Gas Fired Combustion Turbine | GT | 63 | 51.2 | Jun 1978 | Operating | — | coming soon |
| 2 | Natural Gas Fired Combustion Turbine | GT | 63 | 52.1 | Jun 1978 | Operating | — | coming soon |
| 3 | Natural Gas Fired Combustion Turbine | GT | 63 | 53.2 | Jul 1978 | Operating | — | 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% | 189 MW |
Nearby plants
Within 80 km.
| Marshalltown Generating Station | 709 MW | 1.2 km |
| Alliant SBD 9107 JBS USA | 11 MW | 3.3 km |
| Vienna Wind Farm | 150 MW | 14.2 km |
| Laurel Wind Farm | 123 MW | 19.2 km |
| State Center | 7 MW | 25.3 km |
| Salt Creek Wind | 169 MW | 31.5 km |