Weekend cold snap nearly overloaded N.S. electricity grid

When Collin Bagnell flicked on the lights in his house Sunday morning, they emitted only a glow.

“That’s when I switched over to the generator,” he said. 

Bagnell, who lives in Lake Charlotte on Nova Scotia's Eastern Shore, said the flow of electricity coming into his house was unusually weak, reaching 190 out of a possible 240 volts.

And Bagnell wasn’t alone. As temperatures dipped well into the minus double digits in Nova Scotia over the weekend, lights dimmed and appliances were sluggish for some Nova Scotia Power customers as the grid strained to meet high demand.

Matt Drover, Nova Scotia Power’s senior director of energy delivery, said these effects were the result of local distribution lines approaching capacity and technicians manually reducing the load to protect the rest of the grid. But effects were not widespread, he said.

The utility asked customers to reduce their electricity use, and Drover said that helped to prevent severe impacts. Further strain could have resulted in controlled blackouts across the system — a practice called load shedding.

“We collaborated very closely to import energy from both New Brunswick and Newfoundland,” Drover said in an interview.

“The addition of that, as well as all of our customers being very mindful of the energy they used over the weekend, definitely all helped to create a situation where we didn't have system-wide impacts,” Drover said.

At some points on Saturday, Nova Scotia was sending electricity to Newfoundland and Labrador through the Maritime Link because that province was down a generating station. But Drover said the electricity flow reversed on Sunday as N.L. Hydro’s generation rebounded.

Drover said periods of high demand that strain electricity grids are becoming more common across North America as people have been installing heat pumps, other forms of electric heating systems and electric vehicle chargers.

“We’re really focused on making sure the grid is able to withstand that additional usage,” he said, pointing to the ongoing construction of new grid-scale batteries and an additional transmission line to New Brunswick.

Wayne Groszko, an energy research scientist at the Nova Scotia Community College, said grid capacity is part of the solution, but so is managing demand.

“What we'll see with this in the future is really going to depend on how we set up our electricity systems and … what opportunities we give electricity users to make the timing of their electricity consumption more flexible.”

Groszko said users need to be educated and incentivized to shift some of their energy usage to off-peak times. He gave the example of water heaters, which typically activate every time the tap is turned to hot, even if there's already plenty of hot water in the tank.