Work has begun on Alliant Energy's battery project in Decorah

Crews have started working on a new electricity battery-storage project in Decorah, jointly supported by Alliant Energy, the US Department of Energy and the Iowa Economic Development Authority.

The battery storage project was approved for Decorah because the one electric circuit that serves the community will start to reach capacity as more customer-owned renewables are added. Until now, energy companies have had to either upgrade the grid in a community, which is expensive, or restrict the number of solar arrays that could be added in one area. Using battery storage to meet this challenge gives utilities a different option.

The project is supported in part by a $250,000 cost-share from the U.S. Department of Energy and a $200,000 grant from the Iowa Economic Development Authority. Alliant Energy is leasing the site of the project from the City of Decorah. Sandia National Laboratories is providing technical support for the project and will collect operational data.

The 2.5-megawatt, 2.922-megawatt-hour battery will serve as an "electron bank" to store excess solar power. It will store energy generated when the sun is most powerful and then release it in the evening, when demand for electricity peaks. It will also provide valuable insight into the challenges of providing reliable and affordable electricity in areas with a concentration of customer-owned solar. Lessons learned from the Decorah pilot will inform similar, future battery projects.

The Decorah energy storage project is expected to be complete and in service by the end of 2020