Hot weather pressures Alberta's electricity grid, with 2 'rare' alerts this month

Alberta's energy grid was running on reserves on Wednesday, for the second time in a week according to the Alberta Electric System Operator.

Alberta's energy grid was running on reserves for hours on Wednesday

A Level 2 energy alert was issued by AESO late Wednesday afternoon. (Evelyne Asselin/CBC)

Alberta's energy grid was forced to run on reserves twice in one week, an issue that is supposed to be rare, according to the Alberta Electric System Operator.

At 4:46 p.m. Wednesday, AESO 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 7:34 p.m.

"This is due to unplanned loss in generation. Reserves are balancing the power system. Supply continues to meet demand," the agency said in a post to social media. An AESO spokesperson was unavailable for further comment on Wednesday.

The system operator's website stated that the load on the grid was 11,228 MW, and that two generating stations, Battle River and Sundance, were offline. It also appeared that a tie-line to Saskatchewan was down, based on the system report. 

Extreme weather taxing the grid

It was the second Level 2 alert issued in one week. Last Wednesday, an AESO spokesperson said Level 2 alerts usually only occur every few years. The last Level 3 alert was in 2013. Alert Level 3 is when power is cut off to some customers in order to keep the system operating. 

Joel Macdonald, managing partner with, said it's "very rare" to see two Level 2 alerts back-to-back.

"We typically only see one every couple of years. Typically Alberta sees peak grid demand in the wintertime, and these alerts are tied to extreme cold periods," he said. "I'm no scientist by any stretch of the imagination, but we're seeing extreme weather events across the globe, we're seeing them across Alberta, and it's really taxing our grid supply."

The alert comes alongside another wave of hot weather, with temperatures in the 30 C range in much of the province on Wednesday. 

In June, a heat wave pushed demand to record highs on the grid, with loads in the 11,700 MW range. 

"I think new standards and tolerances are probably going to have to be investigated. Just like Texas wasn't ready for the extreme cold, you know, maybe we have to plan for more extreme heat events," Macdonald said, referring to a cold snap this winter that killed dozens and saw roughly half of the U.S. state without power.

Macdonald said if extreme heat events like this continue, it could see a larger proportion of the population buying and running air conditioners for comfort and health reasons — increasing demand further.

"You know how many Albertans have air conditioning right now? Maybe 30, 40 per cent … so, will the grid be able to keep up to the pace of what we'll see here for air conditioning installation in the next year or two?"

AESO had asked that people reduce their energy consumption between 4 and 7 p.m., which is typically when peak use occurs. 

"Unfortunately, grid supplies are inelastic, meaning we can only create so much generation," Macdonald said. "We can actually reduce our our demand. We can choose not to run our dishwashers and we can choose not to run our laundry … those minor things on the residential side would help quite a bit."

The projected power pool price was also at the maximum of $999/MWh. 

Macdonald said Alberta's maximum price is much lower than Texas, where during the winter storm some saw power bills in the thousands. 

But, he said for customers on a floating rate it might be worth to consider switching to fixed. 

"These weather events are causing incredibly high bills," he said.

Alberta's hot weather is projected to last until at least Saturday, with a brief respite before temperatures rise again on Sunday.


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