Maritime Electric initiated an emergency power outage on Prince Edward Island Thursday, cutting off power to some business customers in order to prevent a blackout.

Kim Griffin - custom

Cold weather and low winds came together to prevent Maritime Electric from meeting P.E.I. electricity demand for about two hours on Thursday, said spokeswoman Kim Griffin. (CBC)

"We have what is called an overload protection scheme, and it's basically a computer system that makes sure we're protecting our system," said Maritime Electric spokeswoman Kim Griffin.

"We also had some other challenges with freezing, so we weren't able to get our generation up as quickly as we wanted to. So normally we can supply that with our on-Island generation, and we had no wind last night. We had a couple of factors that made it a challenge."

The surge in demand between 5 p.m. and 7 p.m. was much higher than anticipated. Not cutting off power selectively could have led to an Island-wide blackout.

The businesses that were cut off are under agreements with the utility that allow them to be shut off during periods of peak load. Some residential customers also lost power.

The extreme cold on Thursday was a factor in the load on the electricity grid, said Griffin. More Island households have been switching to electric heat, she said.

With winds picking up Friday, allowing the Island's wind turbines to take up some of the load, and warmer temperatures, the utility is not expecting further problems.

Griffin said Thursday's peak load before the shutdown may have been the highest in Island history, but the utility is still going over the numbers.