HALIFAX -- A regulatory hearing in Nova Scotia considering an undersea hydro cable from the Muskrat Falls project started today with proponents and critics clashing on whether it is the cheapest alternative for electricity.

James Smellie, the lawyer for the Emera (TSX:EMA) subsidiary, Nova Scotia Power Maritime Link Inc., told the Nova Scotia Utility and Review Board that the $1.5-billion subsea connection is the most affordable source of energy over the next four decades.

A spokesman for the provincial Department of Energy said the power from Muskrat Falls is the only alternative before the board that meets the government's goals to reduce greenhouse gas emissions.

But John Merrick, the province's consumer advocate, said Nova Scotia would be better off not locking into one project for 35 years.

He said the price for electricity from Muskrat Falls is largely based on the cost of constructing the 180-kilometre link, and it's likely this will be more costly than other sources of power.

Nelson Blackburn, the small business advocate, said in his presentation that it's clear the deal will benefit Emera but it hasn't been proven to be the cheapest long-term source of energy for customers.

The hearings are scheduled for the next two weeks.