More than 9500 solar panels now generate clean energy at Alliant Energy's new Marshalltown Solar Garden. 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. Both energy sources are part of the company's diverse energy mix, helping Alliant Energy to continue providing reliable and cost-effective energy to its customers.
"This solar-battery combination allows us to provide our customers with solar power during the day and night," said Terry Kouba, president, Alliant Energy Iowa. "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."
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 548-kWh 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 put into service in October.
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.
In 2003, Alliant Energy built its first solar system in Iowa at the Indian Creek Nature Center in Cedar Rapids. In 2015, the company added additional solar panels to increase Indian Creek's capacity. Alliant Energy has two Dubuque solar gardens, which have been generating clean energy for customers since 2017.