Rotating power outages affected electricity customers today after a grid alert was issued by the Alberta Electric System Operator.
During an afternoon press conference on April 5, AESO said it couldn’t say how many outages took place, since they are handled by distribution facilities, but confirmed the entire province was affected.
"It was not just Calgary and Edmonton,” said Marie-France Samaroden, AESO vice president of grid reliability operations. “Rotating outages, and the load shed that occurs, is done pro rata across the entire province.”
The load shed directive took place from 8:53 to 9:16 a.m. and called on transmission and distribution partners to shed 250 megawatts of load, she said.
Just after 9 a.m., Enmax said on X, formerly Twitter, that a number of communities in Calgary could see power disruptions lasting about 30 minutes.
Over two dozen communities in the city were affected, but by 9:26 a.m., Enmax said power had been restored to all affected customers.
The rotating outages took place following the grid alert that was issued at 6:49 a.m. due to “tight supply,” AESO said.
The grid alert was ended at 11 a.m.
“It is truly a combination of many things that occurred that got us into the rotating outage situation,” Samaroden said.
Wind generation in the morning was 900 megawatts lower than expected and a natural gas generator unexpectedly went offline at 8:49 a.m., resulting in an additional loss of 400 megawatts of power, she said.
Generators can commonly be taken offline for maintenance at this time of year, there’s always uncertainty with forecasts and operational issues do occur, she said.
“Those were the factors that led to the situation that we're in,” she said. “Those are mechanical things that happen, and that's outside of our control.
"We are looking to improve our forecasts as best as we can. However, the reality is, is that we can't control the wind and the sun, and so we do our best to forecast and have mitigation measures in place."
A brief grid alert was also called by AESO on April 3, due to unexpected generation loss, but it was ended after less than an hour.
Information on the AESO website says that during a grid alert, consumers are asked to reduce their electricity use to help mitigate the possibility of more serious emergency measures being taken to balance the system, which can include rotating power outages.
