Because of extremely cold temperatures, Alberta’s electrical grid was in such peril of falling into rotating outages on Jan. 13 that the provincial government urged people to turn off even their bathroom fans, among other things.
Turning off kitchen or bathroom ventilation fans; delaying the use of washers, dryers, and dishwashers; unplugging vehicle block heaters; and even using a laptop instead of a desktop computer were all suggested to relieve the pressure on the grid.
With temperatures again well below -30 C in many parts of the province, as well as its neighbours in Saskatchewan and Montana, the Alberta Electric System Operator (AESO) issued its second Grid Alert in two days at 3:30 p.m., on Saturday, Jan. 13.
Natural Gas and Some Coal Kept the Lights On
The vast bulk of Alberta’s power generation was being drawn from natural gas and some coal, with nearly every fossil fuel-fired generating unit running flat out. A notable exception was H.R. Milner Generating Station, which was producing only around one-tenth to one-quarter of its 300-megawatt capacity. That was the unit whose lack of operation the day before was one of the reasons Alberta had a grid alert on Jan. 12. Other reasons included the bitter cold driving demand and near total lack of wind and solar generation.
Wind power throughout the supper hour remained around the 90 to 130 megawatt range, or 2 to 3 percent of installed capacity. Only eight of Alberta’s 45 wind farms were producing any power at 5:54 p.m. Most were shut down because temperatures below -30 C run the risk of brittle behaviour of materials, meaning components could shatter.
Contingency Reserve Razor Thin
Generally speaking, power needs to be consumed at the instant it’s produced. There is very little in the way of grid-scale storage in Alberta’s electrical grid, although the province has built 10 grid-scale batteries totalling 190 megawatts capacity. All of that capacity would come into play Saturday evening.Grid operators must maintain a small amount of excess capacity at all times, known as a “dispatched contingency reserve” (DCR). The North American Electric Reliability Corporation standard is to maintain at least 4 percent DCR. That’s because if the DCR runs out, all sorts of bad things happen, with voltage drops and frequency variance which then can lead to cascading brownouts, including additional power-generating units tripping off and whole areas going without power.
With demand hovering around 11,800 megawatts, 4 percent would have been around 472 megawatts DRC. Instead, for the better part of an hour, the DCR was 20 megawatts, or 0.1 percent.
As the supper hour went on, and contingency reserves flatlined, 9 of Alberta’s 10 grid-scale batteries were called into service. Three had been providing low levels of output—4 or 5 megawatts each—for the 6 o’clock hour, the pattern they had been exhibiting since Dec. 20. But the other six 20 megawatt batteries were put online as well, an exceptionally rare occurrence.
This is a main part of their purpose. Usually they are listed on the dispatched contingency reserve, but rarely called upon, even when wind and solar power flatline. This time, it was all but one of the batteries on deck. They were at times providing 126 megawatts of power to the grid. Even with nine batteries being drawn upon, there were still only 20 megawatts of contingency reserve left on the board from the strained natural gas generation.
At this time, hydro capacity was running full out. Alberta almost always keeps at least 100 megawatts of hydro capacity in reserve, but at 5:54 p.m., all 401 megawatts of hydro available were producing to the grid. (While Alberta has a theoretical maximum capacity of 894 megawatts of hydro, that depends on all dams being full, and southern Alberta has been experiencing pronounced dry conditions of late.)
Alert System Activated
A call went out from the Alberta Electric System Operator and the Government of Alberta to conserve power immediately.Around that time, an emergency alert was pushed to all cellphones in the province, as well as on TV screens. It stated: “This is an Alberta Emergency Alert issued by the AEMA. This alert is in effect for AB. Extreme cold resulting in high power demand has placed the Alberta grid at a high risk of rotating power outages this evening. Albertans are asked to immediately limit their electricity use to essential needs only.
“Turn off unnecessary lights and electrical appliances. Minimize the use of space heaters. Delay use of major power appliances. Delay charging electrical vehicles and plugging in block heaters. Cook with microwave instead of stove. For more info vising the Alberta Electric System Operator website.”
Screenshots of the alert soon flooded Albertans’ social media.
The press release said:
“Currently, the AESO projects the Alberta grid will face a 100 to 200 MW shortfall of electricity during peak evening hours. Immediate power conservation could make a significant difference in reducing overall system demand, currently at approximately 12,000 MW. To put these numbers into perspective, tonight the City of Calgary will be drawing approximately 1,650 MW of electricity, and, if rotating outages are implemented, will need to reduce power by approximately 50 MW.
“Rotating outages mean that some power will be temporarily out in different parts of the province until sufficient generation returns to the grid or power demand declines enough that the AESO can rebalance supply and demand.
“In the event of a rotating outage, the AESO directs Distribution Facility Owners (DFOs), such as municipalities, to reduce power on a pro-rata basis across the province. Outages will occur simultaneously across Alberta. Critical facilities such as hospitals, fire, police and first responders are not included in rotating outages. Each DFO manages rotating outages at their level. Each rotating outage is expected to last approximately 30 minutes at a time and could be implemented shortly.”
Alberta Premier Danielle Smith subsequently put the request to Albertans to cut electricity use where possible.
At that point, Saskatchewan was already giving Alberta all it could, with SaskPower sending 153 megawatts, pretty much the maximum Saskatchewan ever supplies Alberta, from over a year of observations.
On various social media, Saskatchewan Premier Scott Moe posted a screenshot of the Alberta alert that went out to cellphones in that province, saying, “SaskPower is providing 153 MW of electricity to AB this evening to assist them through this shortage. That power will be coming from natural gas and coal-fired plants, the ones the Trudeau government is telling us to shut down (which we won’t).”
Emergency Alert Worked
In the half hour after the alert went out, power production did not rise, but the load dropped by roughly 400 megawatts. Those 400 megawatts showed up on the beleaguered dispatched contingency reserve, which rose to around 405 megawatts. That, in turn, put the province close to its required 4 percent.It wasn’t so much production increased as demand dropped as the populace responded to the alert.
Five hours and 10 minutes after the grid alert was declared, it ended, at 8:40 p.m., according to the AESO’s event log.
Later that night, the AESO put out a press release thanking Albertans.
“The province-wide response to the call for energy conservation was tremendous,” said Mike Law, president and CEO of the AESO. “On behalf of the AESO, I would like to extend my thanks to all Albertans who responded to the call for action, which ensured we didn’t have to progress to rotating outages, keeping our grid up and running for all Albertans.”
And while Alberta endured grid alerts two days in a row, it’s not over.
“With extremely cold temperatures forecast through tomorrow, the AESO requests that Albertans continue to conserve energy during the peak demand period from 4 p.m. to 7 p.m.,” AESO said.
