Preferred regional longer-term transmission solution moves on to next steps

The regional effort to address the New England power system’s longer-term transmission needs has taken its next step forward, with cost allocation finalized for the preferred solution ISO New England selected in connection with the 2025 request for proposals (RFP).

The ISO issued the RFP at the direction of the New England States Committee on Electricity (NESCOE). The allocation follows the default methodology set in the ISO’s governing tariff, and will spread the costs across the six New England states based on their share of peak electricity demand.

The preferred solution, submitted by Central Maine Power and Eversource, would upgrade the transmission system between northern Maine, where land-based wind generation is expected to increase, and more populous regions of southern New England, where demand for electricity is highest.

The six proposed solutions to the RFP underwent rigorous technical review by the ISO. Proposals that passed preliminary analysis were also evaluated for their benefits versus cost to the region, and the preferred solution’s forecasted financial benefits outweighed its costs. Updates throughout the process have been provided through the Planning Advisory Committee (PAC).

Central Maine Power and Eversource will now submit an executed agreement to proceed with the solution. The ISO also plans to initiate a “lessons learned” review of the RFP process at the PAC by the end of 2026.