Newfoundland and Labrador has reached a tentative deal with Quebec over power flowing from the Churchill Falls hydroelectric plant that could reap hundreds of billions of dollars over the next five decades.

Newfoundland and Labrador signed a historic MOU on Thursday, to terminate and replace the 1969 Upper Churchill Contract, develop Gull Island and expand the capacity of the Churchill Falls plant. The deal will result in more than $225 billion in total revenue for NL over the life of the agreements.

Officials from both provinces have been trying to negotiate a new deal surrounding the Churchill Falls hydroelectric plant in Labrador. The current agreement, signed in 1969, is widely considered as lopsided in Quebec’s favour.