Donald Jessome, head of TDI, says the deal was reached after 15 months of closed-door negotiations and will shape how the underwater line is laid under Lake Champlain and the Hudson River.
The project still needs state and Federal permits before going forward. And one environmental group in the Adirondack Park is still questioning whether burying the cable under the bed of Lake Champlain would violate the state Constitution.
Adirondack Wild's David Gibson sent a letter to state officials last week saying that "a very strong legal argument can be made" that Lake Champlain's bed is forest preserve. If so, that means that no human structures could be built without a constitutional amendment.
The project faces another potential hurdle, a soft market.
TDI's Jessome says his company isn't discouraged by the fact that electricity rates have slumped in recent year.
If the project does clear those regulatory hurdles, the new transmission line would feed enough electricity to New York City to power roughly a million homes.
Jessome says the company has already spent $25 million developing the line. He hopes to see the cable completed by 2016.