More than 9,500 solar panels now generate clean energy at Alliant Energy’s new Marshalltown Solar Garden in Marshalltown, Iowa. This pilot project combines solar power and battery storage to generate, store and deliver electricity to customers.
Marshalltown Solar Garden. Alliant Energy
The Marshalltown Solar Garden sits next to Alliant Energy’s Marshalltown Generating Station, a natural-gas-fired facility. Both energy sources are part of the company’s energy mix, helping Alliant Energy to continue providing 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-MWac 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 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 + storage technology. The Marshalltown battery is the company’s first 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 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.
News item from Alliant Energy
“The company has three battery sites in Iowa, and each is being used to pilot different combinations of solar + storage technology. The Marshalltown battery is the company’s first 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.”
The specific design use of these sites is interesting. With the solar PV only plant into energy storage with a natural gas plant just a little way from the energy storage facility, one might be able to operate the solar PV and energy storage, then add interconnection to the natural gas plant to use off peak times of the night to take natural gas generation and store it for the bottom of the next days “duck curve” in the early morning hours before solar PV is making good generation. It is also possible to increase hours of storage in these energy storage facilities and be able to use the asset for different control schemes to make money off of the asset for longer hours of the day.