Renewable Portfolio Standard

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. At the time of passage, the required percentage of renewable energy was actually lower than the existing percentage supplied. In 2019 Governor Mills signed legislation (L.D. 1494) that increased Maine’s renewable portfolio standard (RPS) to 80% by 2030 and set a goal of 100% by 2050. In addition, the bill requires the Maine Public Utilities Commission (MPUC) to procure long-term contracts for new clean energy generation, which may be paired with advanced energy storage. In order to ensure this procurement creates significant economic benefits for Maine, the procurement weighs bids with a 70% consideration towards benefits to ratepayers (i.e. price) and 30% towards proven benefits to the economy. 

In 2023, Governor Mills called for accelerating the state’s goal to 100% clean electricity by 2040. To support this goal, the Governor’s Energy Office is conducting a planning effort to achieve this goal.

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 three classes designated. Class I is composed of new renewables that came online after September 1, 2005. Class IA are Class I resources other than those that for at least 2 years have not operated or were not recognized by ISO-NE as a capacity resource and, after September 1, 2005, resumed operations or was then recognized by ISO-NE. Class II includes existing renewables, which are eligible to meet the 30% requirement described above. 

Unlike Class II, municipal solid waste facilities and CHP facilities are not eligible for Class I, and there are more stringent hydropower qualifying requirements.

Requirements

The schedule for Class I is as follows:

• 1% for the period from 1/1/2008 to 12/31/2008

• 2% for the period from 1/1/2009 to 12/31/2009

• 3% for the period from 1/1/2010 to 12/31/2010

• 4% for the period from 1/1/2011 to 12/31/2011

• 5% for the period from 1/1/2012 to 12/31/2012

• 6% for the period from 1/1/2013 to 12/31/2013

• 7% for the period from 1/1/2014 to 12/31/2014

• 8% for the period from 1/1/2015 to 12/31/2015

• 9% for the period from 1/1/2016 to 12/31/2016

• 10% for the period from 1/1/2017 to 12/31/2022 and each year thereafter

The schedule for Class IA is as follows:

• 2.5% for the period from 1/1/2020 to 12/31/2020

• 5% for the period from 1/1/2021 to 12/31/2021

• 8% for the period from 1/1/2022 to 12/31/2022

• 11% for the period from 1/1/2023 to 12/31/2023

• 15% for the period from 1/1/2024 to 12/31/2024

• 19% for the period from 1/1/2025 to 12/31/2025

• 23% for the period from 1/1/2026 to 12/31/2026

• 27% for the period from 1/1/2027 to 12/31/2027

• 31% for the period from 1/1/2028 to 12/31/2028

• 35% for the period from 1/1/2029 to 12/31/2029

• 40% for the period from 1/1/2030 to 12/31/2030 and each year thereafter

Thermal Renewable Energy Credits: 

Each competitive electricity provider must, in addition to meeting the other portfolio requirements, demonstrate in a manner satisfactory to the commission that it has purchased thermal renewable energy credits in an amount at least equal to the following percentages of its portfolio of supply sources for retail electricity sales in this State:

• For calendar year 2020, 0.4%;
•  For calendar year 2021, 0.8%;
•  For calendar year 2022, 1.2%;
• For calendar year 2023, 1.6%;
• For calendar year 2024, 2%;
• For calendar year 2025, 2.4%;
•  For calendar year 2026, 2.8%;
• For calendar year 2027, 3.2%;
•  For calendar year 2028, 3.6%;
• For calendar year 2029, and each year thereafter, 4%.

Multiplier

A 300% multiplier is applied to the output of a municipal solid waste-fueled generator in conjunction with recycling that has obtained a solid waste license from the state’s Department of Environmental Protection. The multiplier is repealed starting in 2027.

Compliance

The PUC has approved the use of NEPOOL Generation Information System (GIS) certificates (which are similar to renewable energy certificates, or RECs) to satisfy the portfolio requirement. GIS certificates are awarded based on the number of kilowatt-hours (kWh) of eligible electricity generated. GIS certificates used to meet the Class I and Class IA standards may not also be used to satisfy the Class II standard.

The PUC sets an alternative compliance payment (ACP) that utilities may pay instead of satisfying the standard by procuring GIS certificates. Current ACP rates are found in the PUC’s annual RPS reports. 

Legislation enacted in 2011 (Public Act 413) required the PUC to study the renewable portfolio standard. The results were published in January 2012 in the comprehensive report, MPUC RPS Report 2011 - Review of RPS Requirements and Compliance.

Further legislation (Public Law 321) was enacted in 2023, directing the Governor's Energy Office to report on the status and impacts of the RPS by April 2024, and then every three years thereafter in coordination with the PUC.