Marshalltown Generating Station
Natural gas power plant · Marshall County, Iowa
Nameplate capacity
709 MW
Rank in Iowa
#4
of 305 plants
In service since
2017
April 2017
Details
- Primary fuel
- Natural gas
- Technology
- Natural Gas Fired Combined Cycle
- Operator
- Interstate Power and Light Co
- County
- Marshall County
- Generating units
- 5
- Share of state capacity
- 2.85%
- Rank among natural gas plants in Iowa
- #1 of 42
- EIA plant code
- 58236
Generating units
| Unit | Technology | Nameplate | Summer | Online | Status |
|---|---|---|---|---|---|
| STG1 | Natural Gas Fired Combined Cycle | 261 MW | 220 MW | 2017 | Operating |
| CTG1 | Natural Gas Fired Combined Cycle | 223 MW | 223 MW | 2017 | Operating |
| CTG2 | Natural Gas Fired Combined Cycle | 223 MW | 222 MW | 2017 | Operating |
| PV1 | Solar Photovoltaic | 2.6 MW | 2.6 MW | 2020 | Operating |
| BESS1 | Batteries | 0.3 MW | 0.3 MW | 2020 | Operating |
Nameplate is the maximum rated output; summer capacity is what the unit can reliably deliver on a hot day, which is typically lower.
Similarly sized plants in Iowa
| Louisa | Coal | 812 MW |
| Ottumwa | Coal | 726 MW |
| George Neal South | Coal | 696 MW |
| Emery Station | Natural gas | 603 MW |
About this data
From EIA’s inventory of operable generators, May 2026 release. Capacity is nameplate — the maximum rated output of the equipment, not what the plant actually generates over a year, which depends on how often it runs. A 709 MW solar plant and a 709 MW nuclear plant have the same entry here and produce very different amounts of electricity.
“In service since” is the earliest in-service date among the units still listed, so a site rebuilt around newer equipment can read as younger than the site itself. All Iowa power plants · What Iowa actually generates