KNOXVILLE, Iowa (AP) — MidAmerican Energy says it’s installing a battery system that could store enough power to serve around 900 Iowa homes for four hours. The Des Moines Register reports that Chicago-based Invenergy will install the system, housed in two truck-size steel containers, at a MidAmerican Energy substation in Knoxville. The lithium-iron phosphate system is expected to begin operating by the end of December. Officials say it will let MidAmerican store for later use energy produced when the winds are blowing and the sun is shining.

Mike Fehr is MidAmerican Energy vice president of resource development, and he says large scale energy storage has the potential to provide several benefits. It is still in the development stage, “and the economic feasibility on a larger scale is being assessed as well.”