Net Energy Billing (Maine)

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Last modified on February 12, 2015.

Rules Regulations Policies Program

Place Maine

Name Net Energy Billing
Incentive Type Net Metering
Applicable Sector Agricultural, Commercial, Industrial, Institutional, Low-Income Residential, Multi-Family Residential, Nonprofit, Residential, Schools
Eligible Technologies Biomass, CHP/Cogeneration, Fuel Cells, Fuel Cells using Renewable Fuels, Geothermal Electric, Hydroelectric, Municipal Solid Waste, Photovoltaics, Small Hydroelectric, Small Wind, Solar Thermal Electric, Tidal Energy, Wind
Active Incentive Yes

Implementing Sector State/Territory
Energy Category Renewable Energy Incentive Programs
Aggregate Capacity Limit No limit specified
Applicable Utilities All utilities

Meter Aggregation Allowed
Net Excess Generation Credited to customer's next bill at retail rate; granted to utility at end of 12-month billing cycle

REC Ownership Not addressed

System Capacity Limit 660 kW for IOU customers; 100 kW for muni and co-op customers (munis and co-ops may voluntarily offer net energy billing for systems up to 660 kW)

Date added to DSIRE 2000-01-01
Last DSIRE Review 2013-01-16

References DSIRE[1]


All of Maine's electric utilities -- investor-owned utilities (IOUs), consumer-owned utilities (COUs), which include municipal utilities and electric cooperatives -- must offer net energy billing for individual customers. Furthermore IOUs are required to offer net metering for shared ownership customers, while COUs may offer net metering to shared ownership customers at their discretion. "Shared ownership" allows for community net metering, where several people invest in an eligible system and are therefore allowed to benefit (see below for more information). IOUs are required to offer net metering to eligible facilities with capacity limits up to 660 kilowatts (kW). COUs are required to offer net metering to customer-generators up to 100 kW, but, they are authorized to offer net metering to eligible facilities with capacity limits up to 660 kW at their discretion.

Net metering is available to owners of eligible, qualified facilities, including facilities generating electricity using fuel cells, tidal power, solar, wind, geothermal, hydroelectric, biomass, generators fueled by municipal solid waste in conjunction with recycling, and eligible combined heat and power (CHP) systems. It should be noted that the CHP systems must meet efficiency requirements in order to qualify for net metering: micro-CHP 30 kW and below must achieve combined electrical and thermal efficiency of 80% or greater, and micro-CHP 31 kW to 660 kW must achieve combined efficiency of 65% or greater.

Net excess generation (NEG) is credited to the following month for up to 12 months; after the end of a 12-month period, any remaining NEG is granted to the utility with no compensation for the customer. At its own expense, a utility may install additional meters to record purchases and sales separately. There is no limit on the aggregate amount of electricity generated by net-metered customers. However, a utility must notify the PUC if the cumulative capacity of net-metered facilities reaches 1.0% of the utility's peak demand.

Shared ownership customers must maintain ownership interest in an eligible facility. These customers share the responsibilities and costs of the facility and resulting proportional benefits. Up to 10 meters can be net metered against a single eligible facility. The shared ownership customers must designate one contact person to serve as the liaison between the owners and utility.


Net metering has been available in Maine from 1987 to 1998 for owners of qualified combined heat and power (CHP) systems and from 1987 until April 30, 2009 for owners of other small power-production facilities with a maximum capacity of 100 kilowatts (kW). When Maine's legislature enacted restructuring legislation that provided for retail competition beginning March 1, 2000, the Maine Public Utilities Commission (PUC) amended the state's net-metering rules to make the rules consistent with changes to structure of the electric industry. The rules were modified to address issues related to existing contracts that extend beyond March 1, 2000.

However, in addressing net-metering arrangements that took effect after the onset of retail access, the PUC decided that new rules would be more appropriate than the regulations already in place for cogeneration and small power-production facilities. Thus, the PUC issued new net-metering rules that apply to the resources and technologies defined in the state's restructuring legislation: fuel cells, tidal power, solar, wind, geothermal, hydroelectric, biomass, and generators fueled by municipal solid waste in conjunction with recycling. CHP was not eligible at that time. It was also clarified that net energy billing was exempt from sales or use tax with respect to the sale or delivery of kilowatt hours of electricity to net energy billing customers as defined by the Public Utilities Commission for which no money is paid to the electricity provider or to the transmission and distribution utility (see MRSA Title 36, §1760, sub-§80).

The PUC issued an order amending net metering early 2009 in order to allow shared ownership, subject to legislative approval. In April 2009, Gov. John Baldacci signed LD 336, authorizing the final adoption of the rule, further amending it to include high efficiency micro-combined heat and power systems as eligible to net meter and to participate in the new shared ownership net metering opportunities and increasing the capacity limit from 500 kW (as in the proposed rules) to 660 kW.

Incentive Contact

Contact Name Mitchell Tannenbaum
Department Maine Public Utilities Commission

Address #18 State House Station

Place Augusta, Maine
Zip/Postal Code 04333
Phone (207) 287-3831


Authorities (Please contact the if there are any file problems.)

Authority 1: CMR 65-407-313

Date Enacted 12/10/1998 (subsequently amended)

Authority 2: Resolve, Chapter 20, 124th Legislature
Date Effective 2009-04-30
Date Enacted 2009-04-30

Authority 3: 35-A MRSA §3209-A
Date Effective 2011-06-08
Date Enacted 2011-06-08

  • Incentive and policy data are reviewed and approved by the N.C. Solar Center's DSIRE project staff.[1]


  1. 1.0 1.1  "Database of State Incentives for Renewables and Efficiency (DSIRE)"