Tie line added to ISO-NE website, app

Data related to the New England Clean Energy Connect (NECEC) tie line now appears on the ISO New England website and mobile app as transmission owners prepare to begin active power testing.

NECEC joins 13 other interconnections to neighboring power systems. Imports over the tie lines supplied about 9% of the electricity consumed in New England in 2024.

NECEC will be used to import up to 1,200 megawatts of electricity from Canada. During testing, however, electricity may flow in either direction.

ISO New England presents NECEC data on the iso-ne.com homepage, the ISO Express dashboard, and the ISO to Go mobile app (users will need to update the app to see the changes).

• NECEC is represented on the homepage Price Map by a line pointing to northwestern Maine. The line becomes an arrow when imports are flowing. There’s a similar display in ISO to Go.
• The ISO Express LMP Map displays the new interface as a line or arrow, depending on whether it’s active, along with its associated day-ahead and real-time locational marginal prices.
• A purple line on the ISO Express External Interfaces Graph represents the volume of imports over NECEC throughout each operating day. Historical data is retained for roughly three years.
• Imports from NECEC are also factored into the “Net Imports” category in the Resource Mix charts on the homepage, app, and ISO Express.

The 145-mile transmission line stretches from the Canadian border to a substation in Lewiston, Maine, where the electricity it carries will be injected into the New England grid. The project grew out of renewable energy legislation passed in Massachusetts in 2016. It was built and will be maintained by a subsidiary of Avangrid, but ISO New England has operational control over the line in its role as a regional transmission organization.