At 3:52 p.m. Wednesday, the Alberta Electric System Operator issued a Level 2 alert, meaning that reserves were being used to supply energy requirements and that load management procedures had been implemented. The alert ended at 6:06 p.m.
"This is due to unplanned generator outages, low wind and a reduction of import capability," the agency said in a post to social media. "Supply is tight but still meeting demand."
AESO spokesperson Mike Deising said the intertie with Saskatchewan had tripped off, and an issue on the British Columbia side of the border meant the province couldn't import power.
"There are no blackouts … this just means we're using our reserve power, and that's a standard procedure we'll deploy," he said.
AESO had asked that people reduce their energy consumption between 4 and 7 p.m., which is typically when peak use occurs.
Deising said the system was several hundred MWs away from needing to move to an alert Level 3, which is when power is cut off to some customers in order to keep the system operating. Deising said Level 2 alerts are fairly rare and occur every few years. The last Level 3 alert was in 2013.
According to the supply and demand report on AESO's website, the load on the grid at 5 p.m. was 10,643 MW.
That's down significantly from last week, when a heat wave pushed demand to record highs on the grid, with loads in the 11,700 MW range.
A heat warning was issued Wednesday for Edmonton and surrounding areas shortly before 4 p.m., with temperatures above 29 C expected over the next three days.