4th largest plant in Iowa · 494th nationally
Marshalltown Generating Station is a natural gas power plant in Iowa with a nameplate capacity of 709 MW. It generates roughly 3.6M MWh per year — enough to power about 341,139 average U.S. homes.
Its capacity factor of 58% puts it in the middle range — running steadily but not full-time. At 882 lb CO₂/MWh, its emission rate sits above the national grid average of roughly 800 lb/MWh.
Ghost bars are each month's theoretical maximum (709 MW nameplate × hours in the month). Filled bars are actual net generation reported to EIA Form 923. The gap between them is capacity factor made visible.
| Plant Name | Marshalltown Generating Station |
|---|---|
| Operator | Interstate Power And Light Co |
| City | Marshalltown |
| County | Marshall County |
| State | Iowa |
| ZIP | 50158 |
| Coordinates | 42.04333, -92.87278 |
This plant highlighted in navy-ringed pin; other generators within 25 miles shown as fuel-colored dots.
| ID | Technology | Fuel | Capacity | Status | Online |
|---|---|---|---|---|---|
| STG1 | Natural Gas Fired Combined Cycle | Natural Gas | 261 MW | Operating | 2017 |
| CTG1 | Natural Gas Fired Combined Cycle | Natural Gas | 223 MW | Operating | 2017 |
| CTG2 | Natural Gas Fired Combined Cycle | Natural Gas | 223 MW | Operating | 2017 |
| PV1 | Solar Photovoltaic | Solar | 2.6 MW | Operating | 2020 |
| BESS1 | Batteries | Battery | 0.3 MW | Operating | 2020 |
| CO₂ | 1.6M metric tons |
|---|---|
| SO₂ | 8 metric tons |
| NOₓ | 101 metric tons |
| CO₂ Rate | 882 lb/MWh |
Annual totals and CO₂ rate reported by EPA eGRID for 2023. Reference averages are approximate U.S.-wide figures from the same dataset.
| NERC Region | MRO |
|---|---|
| Balancing Authority | Midcontinent Independent Transmission System Operator, Inc.. |
Natural gas plants are the workhorse of the modern grid. Combined-cycle units achieve very high efficiency and can ramp up and down quickly to balance variable renewables. They emit roughly half the CO₂ per MWh of coal and far less of other pollutants, but they still release upstream methane during fuel extraction.