Minn. Stat. § 216B.244: NUCLEAR PLANT CAPACITY REQUIREMENTS.

A reactor unit at a nuclear power electric generating plant that has an annual load capacity factor of less than 55 percent for each of three consecutive calendar years must be shut down and cease operating no later than 500 days after the end of the third such consecutive calendar year. For the purposes of this section, "load capacity factor" means the ratio between a reactor unit's average load and its peak load.