Nova Scotia is now exporting power to Newfoundland.
Electricity is being carried via the new Maritime Link, two 170-kilometre subsea cables laid across the Cabot Strait last year.
The link will eventually send power to Nova Scotia from the Muskrat Fall hydro project in Labrador. But with Muskrat Falls delayed, Newfoundland and Labrador Hydro, a subsidiary of Nalcor Energy, is importing power.
Nalcor says the imports will save up to $50,000 a day at peak demand times in the colder months, offsetting more expensive fuel burned at its Holyrood generating station.
"Today marks a significant change to our island electricity grid and the way we deliver energy to our island electricity customers," Nalcor said in a statement Tuesday.
"We now have the ability to import energy over the Maritime Link that is cheaper than burning oil to generate power at Hydro's Holyrood plant -- meaning Hydro can use less oil."
The $1.6 billion Maritime Link -- which connects Newfoundland to the North American energy grid for the first time -- was laid last year and first tested in December. It also includes almost 50 kilometres of overland transmission in Nova Scotia and more than 300 kilometres of overland transmission in Newfoundland.
The 500-megawatt link will eventually carry power from the Muskrat Falls hydro project in Labrador, where construction is running two years behind schedule and $4 billion over budget, to Nova Scotia consumers. It was supposed to start producing power later this year, but first power is now expected late in 2019.
Another power line, the Labrador-Island Transmission link, is expected to come online in June or July, offering other options for cheaper power.