Marshalltown is the site of our first battery connected directly to a utility-scale solar field. Online since 2020, the battery sits next to our Marshalltown Solar Garden and our Marshalltown Generating station. The 2.55-megawatt (MW) battery fully charges in two hours and can power nearly 200 homes for two hours.
In 2025, we announced plans for a large battery energy storage system (BESS) in Marshalltown adjacent to our original site. We expect to begin constructing the 175-MW facility in 2027. When complete, the Marshalltown BESS will be able to power more than 140,000 homes for four hours on a single charge.
How does battery storage work?
Battery storage systems charge from the grid when energy demand is low or directly from wind or solar projects when excess renewable energy is abundant. They discharge energy when demand increases, such as on hot summer or cold winter days. The ability to capture and store energy to use when needed improves the overall benefit of renewable resources.
