The agreements by Avangrid and the New England system operator are intended to make way for trial operations of the project in September.

The grid operator’s latest load forecast projects 3.4% lower peak winter demand this year than previously forecasted, with the difference increasing to 5.5% by 2030.

The advocacy group argues that ISOs lack the legal authority to collect tariffs, which are the responsibility of U.S. Customs and Border Protection.