Capacity or output derived by a municipality from a project not then required by the municipality may be sold or exchanged by the municipality, for such consideration, for such period, and upon such other terms and conditions as may be determined by the parties to any other municipality, improvement district, federal or state political subdivision or agency, or other person, which other municipality, improvement district, federal or state political subdivision or agency, or other person owns an electric system or electric system facilities whether operated by it, or by a person under a franchise, lease, or other agreement.