Nalcor will borrow $5 billion over 40 years to pay for Muskrat. In December, the project closed on a federal loan guarantee and a successful bond issuance. The hydropower station is scheduled to start producing electricity in 2017.

But that is too late, say Dunderdale's political opponents and other critics of Muskrat Falls. Lorraine Michael, leader of the province's New Democratic Party, said it was disturbing to hear Nalcor and Dunderdale say that, because of an aging infrastructure, the province might have to accept the use of rolling blackouts during peak periods while waiting for electricity from Muskrat Falls.

O'Neill says Hydro has invested,since 2002, almost $500 million in system upgrades to support both safe operations and system reliability, including millions of investment in the Holyrood plant and transmission lines.

"In the province of Newfoundland and Labrador, the demand for electricity is growing, and we need a new source of electricity [such as Muskrat Falls] to meet this need," O'Neill says.