Award-Winning Power Generation Balances Natural Gas, Solar Energy and Battery Storage at a Single Site 

Marshalltown Generating Station is one of the nation’s most efficient power plants. The 650 megawatt natural gas-fired combined cycle facility generates environmentally responsible power for more than half a million homes, and interconnects with an adjacent 2.5 megawatt solar photovoltaic generation facility and a 500 kilowatt-hour battery energy storage system. 

After developing a longstanding relationship working with Alliant Energy, we were brought in as owner’s engineer, overseeing the Marshalltown Generating Station project from the ground up.  

Marshalltown Generating Station is one of the most sustainable and affordable power plants in Iowa’s history. It’s designed to integrate with regional wind resources, and with a ramp rate of 50 megawatts per minute the station can quickly adjust to variable wind conditions. Replacing several less efficient, smaller and older generating units with the latest energy technology, the combined cycle facility emits less than half the carbon dioxide, two-thirds less nitrogen oxides, and roughly 99% less sulfur dioxide and mercury than traditional coal-fired plants.  

Our sustainability team guided the effort for the project to achieve Envision® Platinum Verification — the highest level awarded under the Envision Rating System for sustainable infrastructure implementation. With a 7-acre nature path and more than 63 acres of restored prairie and pollinator habitat, the site encourages nature to flourish.