Marshalltown Generating Station
Interstate Power and Light CompanyMarshall County
Marshalltown Generating Station is located at 2115 East Nevada Street, Marshalltown, Marshall County, Iowa. Interstate Power and Light Company owns and operates the plant under the Alliant Energy trade name. The EIA plant record comprises CTG1 and CTG2 natural-gas combined-cycle combustion turbines, STG1 combined-cycle steam turbine, PV1 solar photovoltaic generation, and BESS1 battery storage. The principal gas block comprises two Siemens SGT6-5000F gas turbines each rated 222.7 MW, two Nooter/Eriksen heat-recovery steam generators, and one Siemens SST6-5000 steam turbine rated 260.5 MW, for a combined-cycle subtotal of 705.9 MW. The EIA-listed solar and battery units add 2.6 MW and 0.3 MW, respectively. Total plant nameplate capacity is 708.8 MW.
Mapped infrastructure geometry associated with this asset.
EIA plant 58236 · Inventory for Aug 2026.
| Generator | Technology | Status | Power (MW) | Energy (MWh) |
|---|---|---|---|---|
| BESS1 | Batteries | Operating | 0.3 | 0.6 |
| CTG1 | Natural Gas Fired Combined Cycle | Operating | 222.7 | Unknown |
Similar plants ranked by technology, capacity, and distance.
Operating generator records and technology attributes reported through EIA-860.
| Generator | Capacity | Technology | Operation | Status |
|---|---|---|---|---|
| BESS1 | 0.3 MW 0.3 MW summer | Batteries Electricity used for energy storage · BA | Oct 2020 | Operating |
| CTG1 | 222.7 MW 222.6 MW summer | Natural Gas Fired Combined Cycle Natural Gas · CT | Apr 2017 | Operating |
| CTG2 | 222.7 MW 222.2 MW summer | Natural Gas Fired Combined Cycle Natural Gas · CT | Apr 2017 | Operating |
| PV1 | 2.6 MW 2.6 MW summer | Solar Photovoltaic Solar · PV | Feb 2020 | Operating |
| STG1 | 260.5 MW |
Monthly EIA generation history and recent market-resource behavior where linked telemetry is available.
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Source-backed project transactions, agreements, land records, permits, and environmental disclosures. Portfolio and adjacent-project facts remain explicitly scoped.
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Project milestones and public references behind the asset profile.
Interstate Power and Light Company filed applications with the Iowa Utilities Board seeking regulatory approval for construction of the proposed Marshalltown Generating Station. The filings were for a generation siting certificate (docket GCU-2012-0001) and ratemaking principles (docket RPU-2012-0003).
| CTG2 | Natural Gas Fired Combined Cycle | Operating | 222.7 | Unknown |
|---|
| PV1 | Solar Photovoltaic | Operating | 2.6 | Unknown |
|---|
| STG1 | Natural Gas Fired Combined Cycle | Operating | 260.5 | Unknown |
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Monthly generation is reported through EIA-923. Capacity factor uses the current EIA nameplate capacity and is shown only for complete calendar years.
| Largest reported plants | Capacity | State | |
|---|---|---|---|
| Ottumwa | 725.9 MW | IA | |
| Marshalltown Generating StationCurrent | 708.8 MW | IA | |
| Emery Station | 602.8 MW | IA | |
| Upland Prairie | 299.3 MW | IA | |
| Burlington (IA) | 290.8 MW | IA | |
| Wever Solar (150MW) | 249 MW | IA | |
| Whispering Willow North | 201.3 MW | IA | |
| Golden Plains | 199.8 MW | IA |
Portfolio membership follows the latest EIA-860 reporting entity. It does not imply ultimate ownership.
View full reporting portfolioAlliant Energy's Iowa utility issued the Full Notice to Proceed for construction of Marshalltown Generating Station. Construction was underway and KBR was selected as the engineering, procurement, and construction contractor. Commercial operation was expected in Q2 2017.
EIA-860 lists generator CTG1, generator CTG2, generator STG1 with this operating date.
EIA-860 lists generator PV1 with this operating date.
EIA-860 lists generator BESS1 with this operating date.
Alliant Energy announced plans for the Bobcat Energy Center, a planned 720 MW natural-gas generating facility adjacent to the existing 650 MW Marshalltown Generating Station. Both facilities will operate together.
Answered from the published record above. Questions whose inputs this profile does not carry are omitted rather than estimated.
Marshalltown Generating Station reports 0.3 MW battery storage + 705.9 MW natural gas + 2.6 MW solar of operating nameplate capacity. These technology ratings do not establish a common export limit. Source: EIA Aug 2026.
Marshalltown Generating Station is a Solar Photovoltaic, Batteries, Natural Gas Fired Combined Cycle facility in Marshall County, IA, participating in the MISO market.
Marshalltown Generating Station is in Marshall County, IA, inside the MISO balancing area.
Marshalltown Generating Station is operated by Interstate Power and Light Co according to the EIA generator inventory. Reporting membership does not by itself establish ultimate ownership.
Marshalltown Generating Station reported 3,006.7 GWh over the twelve months to 2026-07. Figures are net generation as filed to EIA-923.
By capacity, Marshalltown Generating Station ranks #179 of 540 operating plants of the same technology nationally. It ranks #1 of 4 in IA.
Plants within 25 km, nearest first, regardless of technology. Proximity is straight-line distance between mapped plant coordinates; it does not by itself establish a shared point of interconnection.