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An arrow graphic shows that Maine's renewable portfolio standard is set at 40% in 2017.

Carve-out: None (community multiplier)
Tracking system: New England Power Pool Generation Information System (NEPOOL-GIS)

Additional requirement: 10% for Class I (New Resources) by 2017.
1.5 credit multiplier for qualifying community-based renewable energy projects.

Maine has a 40% Renewable Portfolio Standard (RPS), with a 1.5 credit multiplier for qualifying community-based renewable energy projects. There is an additional requirement of 10% Class I renewable resources (new renewable installations). Maine-based nonprofits, community action programs, quasi-municipal corporations, and school administrative units may be eligible for grants from the Efficiency Maine Trust.

Latest Updates

  • In January 2017, the Maine Public Utilities Commission approved to decrease the net metering rate by 10 percent each year and remaining at the rate for 15 years, effective January 1, 2018. Existing customers and projects installed before 2018 will keep the current net metering rate for up to 15 years.

Net Metering

Maine's net metering policy (called "net energy billing") applies to all utilities. Legislation passed in 2015 requires the Maine Public Utilities Commission (MPUC) to work with a stakeholder group to establish a long-term policy alternative to net metering. The MPUC approved a measure to move the rate structure from net metering to a buy-all, sell-all scheme for projects installed after December 31, 2017. Under this rate structure, customers sell all of the solar energy they generate at one rate and buy all the energy they consume from the utility at a higher rate. The credit they receive for power generated will decrease by 10 percent each year over 10 years. Existing customers and systems installed before 2018 will stay on the old structure for up to 15 years.

System size limit: Investor Owned Utilities (IOUs) are required to provide net metering for facilities up to 660 kW and municipal and cooperative utilities are required to offer the incentive for systems up to 100 kW.

Aggregate cap: Not addressed

Credit: Net excess generation is credited at the retail rate. Systems installed after 2017 will be credited at a rate that decreases by 10 percent every year.

RECs: Not addressed

Meter aggregation: Allowed


Maine's tiered interconnection policy applies to transmission and distribution utilities, based on the size of the facility. Systems are required to meet IEEE and UL standards. Insurance requirements vary based on the size of the facility. Inverter-based facilities not exceeding 1 MW and non-inverter-based facilities up to 50 kW do not require insurance. All other facilities are required to have liability insurance ranging from $1 million to $3 million in coverage depending on the facility's rated capacity.

System size limit: Not specified

Liability insurance: Not required for systems <1 MW; varies by system size and/or type for other systems

External disconnect switch: Not required

Third Party Ownership

Third party solar power purchase agreements are allowed in Maine.

Community Solar

Maine requires IOUs to offer virtual net metering to "shared ownership" customers. The state allows up to 10 meters to receive virtual net-metering credits from a single eligible facility. Subscribers must have an actual ownership stake in the system, effectively excluding customers from leasing options.

Maine has a community-based renewable energy program in 2009 for projects with a net-generating capacity of up to 10 MW and that are majority-owned (at least 51 percent) by one or more qualifying local owners. The net generating capacity of all program participants is capped at 50 MW. The participants can select either the renewable energy credit multiplier or a long-term contract. All projects entering a long-term contract with a utility need to become operational before 2019. There is a cap of 10 MW of net generation capacity for the renewable energy credit multiplier.

State Incentive Programs

Program Administrator Incentive
Efficiency Maine Trust Maine Public Utilities Commission Maine-based nonprofits, community action programs, quasi-municipal corporations, and school administrative units may be eligible for grants for demonstration projects.
Property Assessed Clean Energy (PACE) financing Local authorities PACE allows property owners to repay loans for solar PV projects through a special assessment on the property over a specified loan term. Maine has authorized local governments to offer PACE financing.

Utility Incentive Programs

Please check local utilities for midscale solar incentives.


The list below provides some resources for each type of policy or program. Please reference and contact relevant authorities and local utilities for the most up-to-date and accurate information on state and utility policies and incentive programs.

Renewable Portfolio Standard

Net metering and interconnection

Community Solar