Alliant Energy has put into service a battery which forms part of its Marshalltown Solar Garden, consisting of more than 9,500 solar panels.

This pilot project combines solar power and a battery to generate, store and deliver electricity to customers.

The Marshalltown Solar Garden sits next to Alliant Energy’s Marshalltown Generating Station, one of the most efficient natural-gas-fired facilities in the country.

“This solar-battery combination allows us to provide our customers with solar power during the day and night. The solar field adds power to the grid when the sun is shining and then our battery allows our customers to continue using this renewable energy resource in the evening when the sun isn’t shining.”

Terry Kouba, president Alliant Energy Iowa.

The 2.55-MW AC solar system in Marshalltown can power nearly 400 homes. With full sun, the solar panels can also fully charge the 548kWh battery within two hours. When discharged, the battery can power nearly 200 homes for two hours. The solar garden became operational in mid-February and the battery was just put into service this week.

The company has three battery sites in Iowa, and each is being used to pilot different combinations of solar power and energy storage technology. The Marshalltown battery is the company’s first battery that’s directly connected to a utility-sized solar field.

The battery in Wellman provides resiliency and reliability in a rural area with an abundance of customer-owned solar systems. Similarly, the battery in Decorah will be used as an “electron bank” to manage capacity on a circuit instead of rebuilding it.