Around 20 substations near New England's coastline may be suitable for interconnecting 1,200 MW of offshore wind without new or upgraded transmission infrastructure, according to ISO New England's recently published 2050 Transmission Study: Offshore Wind Analysis. The report also highlights the importance of holistic planning and coordination between states in the construction of offshore wind within the existing transmission system.
Stakeholders requested the offshore wind analysis as a follow-up to the foundational 2050 Transmission Study, published in early 2024. Further screening found that around 9,600 MW of offshore wind may be able to interconnect in New England and operate simultaneously without major transmission upgrades or significant curtailment. The analysis examined 50 potential interconnection points within 20 miles of the coastline, and simulated the regional transmission system under a variety of electrical demand conditions in which all potential wind farms operated at full output. And while the study refers to these potential interconnected resources as offshore wind, the electricity injections studied could also represent batteries, solar, or any other resource type.
The 2050 Transmission Study: Offshore Wind Analysis also found that locating some offshore wind interconnection further south than was assumed in the initial study could reduce necessary upgrades and their associated costs, but not eliminate them entirely. Specifically, interconnecting more offshore wind along the Boston-area coastline rather than along the Maine coastline could significantly lower transmission infrastructure costs. Connecting offshore wind closer to demand centers would decrease the amount of power expected to flow between northern New England and southern New England, which would also reduce strain on the transmission system.
The study performed only thermal steady-state analysis, which is one type of high-level screening the ISO uses to evaluate whether generators can reliably interconnect to the existing transmission system. When proposals for actual generators are submitted to the ISO's Interconnection Request Queue, their feasibility is evaluated using the more comprehensive analysis of ISO-NE Interconnection Studies. Results from these studies would likely reduce the number of viable substations further.
High-level studies like the 2050 Transmission Study: Offshore Wind Analysis help the region form a more comprehensive picture of what options may be available to ensure a reliable clean energy transition.
