Maine’s original Renewable Resource Portfolio Requirement was passed as part of the state’s 1997 electric utility restructuring law. In 1999, Maine’s Public Utility Commission (PUC) adopted rules requiring each electricity provider to supply at least 30% of their total electric sales using electricity generated from eligible renewable and certain energy efficiency resources.

Eligible Technologies

Eligible facilities include those up to 100 megawatts (MW) in capacity that use fuel cells, tidal, solar, wind, geothermal, hydro, biomass, or municipal solid waste in conjunction with recycling. Electricity generated by efficient combined heat and power (CHP) facilities and other systems that qualify as “small power production facilities” under the federal Public Utility Regulatory Policies Act of 1978 (PURPA) also are eligible.

Since 1999, the renewable portfolio standard (RPS) has been amended several times and two separate classes designated. Class II includes existing renewables, which are eligible to meet the 30% requirement described above. Class I is composed of new renewables that have come on-line after September 1, 2005. Unlike Class II, municipal solid waste facilities and CHP facilities are not eligible for Class I, and there are more stringent hydropower qualifying requirements. In addition, new wind installations may exceed 100 MW.  In 2017, Maine extended the 10% Class I requirement to year 2022. In 2019, this was further increased to the following requirements.

Tracking Registry: NEPOOL-GIS