Solar power in Minnesota has been increasing, as the cost of photovoltaics has decreased. In 1983 Minnesota adopted a net metering rule which allows customers generating up to 40 kW to use net metering, with the kilowatt hour surplus rolled over each month, or optionally credited at the retail rate.
In May 2013, the Minnesota legislature adopted a mandate on investor-owned utilities in the state that requires them to produce 1.5% of their electricity from solar power by 2020 with the bill also raising the state's cap on net metering from 40 kW to 1 MW. This mandate is in addition to the state's renewable portfolio standard of 25% by 2025 and it's estimated that affected utilities will have to add 450 MW of solar by 2020 to comply with the 1.5% requirement.
Minnesota's largest solar array is the 600 kW array on the roof of the Minneapolis Convention Center, but a 2 MW array is being constructed in Slayton, as well as a 1.1 MW array in Bloomington. In January 2015, Ecolab announced it would be going 100% solar powered by purchasing power from community solar gardens to be built by SunEdison. Ecolab's share of the power would be 16MW, more than the amount of solar power in the state at the time of the announcement. If completely subscribed the solar gardens could provide up to 200MW. The Marshall Solar Energy Project is a proposed 62 MW solar farm that would be built on 500 acres near Marshall, Minnesota.
A 2012 estimate suggests that a typical 5 kW system will pay for itself in about 10 years. With incentives, a $25,000 system can be installed for a cost after the first year of $8,064, and will generate a profit of over $24,000 over its 25-year life.