The Maine Public Utilities Commission (PUC) issued a request for information (RfI) for the development of transmission infrastructure and qualified renewable energy generation projects to transmit electricity from Northern Maine to the ISO New England (ISO-NE) system.
During its 2021 session, the Legislature enacted an ‘Act to Require Prompt and Effective Use of the Renewable Energy Resources of Northern Maine, P.L. 2021, Chapter 380 (Act)’. The purpose of the Act was to “remove obstacles to the use of and to promote development of the substantial renewable energy resources in northern Maine.” The Act directs the PUC to approve a contract or contracts for selected transmission infrastructure and generation proposals. During its 2023 session, the Legislature made several amendments to the Act in P.L. 2023 c. 660.
As detailed in the RfI, the PUC is requesting that interested entities provide information concerning and comment on both the Northern Maine procurement and recent developments that will impact such procurement on or before June 2, 2025, with supplemental comments permitted through September 30, 2025. Given these recent developments, the PUC is also requesting that potential bidders submit either new or revised Indication of Interest forms on or before June 2, 2025.
ISO-NE had also issued a request for proposals (RfP) on March 31, 2025 to address the region’s longer-term transmission needs to enable the interconnection of at least 1,200 MW of onshore wind in northern Maine. The grid operator wants to upgrade the transmission system between this area and the demand centers in southern New England.
The RfP process was developed in collaboration between the ISO and regional stakeholders, allowing the states to request that the grid operator pursue transmission investment that is grounded in the evaluation of broad regional benefits and consumer interests. The RfP was issued at the direction of the New England States Committee on Electricity (NESCOE), as previously, NE lacked a mechanism to enable the ISO to procure transmission at the states’ request.
NESCOE’s request includes a list of needs that all proposals must address. These include increasing the amount of power that can flow across the Maine–New Hampshire and Surowiec–South transmission interfaces, and developing new infrastructure around Pittsfield, Maine, that could accommodate the interconnection of 1,200 MW of land-based wind.
The request is in accordance with Phase 2 of the longer-term transmission planning (LTTP) process. LTTP was initiated in response to the ‘NE States’ Vision for a Clean, Affordable, and Reliable 21st Century Regional Electric Grid’, a document issued in 2020 that called on the ISO to incorporate LTTP in its regional system planning process.
Much of the framework of the RfP is drawn from the ISO’s 2050 Transmission Study, part of Phase 1 of the LTTP. The study identified high-likelihood concerns and associated transmission system upgrade costs that may be driven by the states’ pursuit of policy goals to reduce carbon emissions. The RfP also targets a key area of future need identified in this study – seeking transmission solutions to strengthen the connection between northern and southern NE, and unlock additional affordable generation resources located in Maine.
The ISO will assess proposals based on various factors, including cost benefit to the region and additional evaluation priorities identified by NESCOE. The former will provide updates on the process, as appropriate, through the Planning Advisory Committee.
The deadline for bids by qualified transmission project sponsors is September 30, 2025. After evaluation by the ISO, a preferred solution may be selected by NESCOE as early as September 2026. A strong preference will be given to proposals with an in-service date on or before December 31, 2035, or as close as possible, according to the RfP.
The NE states have agreed to share the costs of these transmission investments, following an analysis by ISO-NE comparing project costs with reliability benefits and cost savings that the upgraded transmission would provide to the region.
Massachusetts officials, including the governor, noted that this first competitive RfP for longer-term transmission investments has been a long-term goal of the NE states. It is hoped to address the long-standing constraints on the NE power system and integrate new, affordable, onshore wind resources in the coming years.
In May 2024, with broad support from regional stakeholders, ISO-NE submitted a proposal to the Federal Energy Regulatory Commission (FERC) to implement this new regional transmission procurement process. In July 2024, FERC approved the new rules and, in December 2024, NESCOE sent a formal request to ISO-NE to develop an RfP for issuance this year.