SaskPower better prepared than Texas when it comes to cold weather

But our wind turbines shut down at -30 C

As of Thursday morning, Feb. 18, SaskPower continued to supply American power companies with 175 megawatts of power through our interconnect to their grid along our southern border.

According to SaskPower spokesperson Joel Cherry, speaking from Regina, that’s about as much as we’re able to send. We have one interconnect from Saskatchewan to the United States, located south of the Boundary Dam Power Station, near Estevan. 

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The United States is still dealing with the impacts of a “polar vortex” that brought Texas, in particular, to its knees. Wind turbines there froze up, and natural gas infrastructure, built more to handle temperatures in the +40C range, lacks the insulation to deal with severe cold, resulting in freeze-ups that have reduced gas flow for both heating and power generation in the most energy-rich state in that nation.

Over the past few weeks, Saskatchewan has endured its own cold snap, but this is par for the course for SaskPower. The Crown utility has a total system power generation capacity of 4,893 megawatts, if everything was running at 100 per cent. On Feb. 11, it was producing a peak of 3,722 megawatts. 

Saskatchewan’s wind turbines are better adapted for the cold than those in Texas, for example. But even they have their limitations. Our wind turbines shut down when the ambient temperature (not the windchill rating) is -30 C.

Cherry said, “Typically when you have temperatures that low, there's not a ton of wind anyway. But during the cold period we've experienced here, when the temperature is below -20 but above -30, we were still getting some productivity out of those turbines.

“There was the occasional instance of them having to shut down because the temperature was below -30, and there have been times, of course, where we had low output just because there's been low winds.”

He noted that in the southwest portion of the province, temperatures have come up above -30 C, during the day, at least, and wind power was generated. But they dropped below that in the evenings.

“It depended on the day whether we had any wind or not, so the winds were kind of more of a factor here than the temperatures,” he said. “It’s usually during the day when you have higher winds, in any case.”

Asked how our wind production has been during the cold snap, Cherry replied, “During the last two weeks, SaskPower’s hourly averaged wind power production was 86 megawatts, out of a total capacity of 241 megawatts. For comparison, the average wind production for SaskPower’s wind farms during the past two winters (December-March) has been 92 megawatts. Wind facilities do have a lower output during periods of extreme cold because they tend to coincide with lower winds.

“It’s important to note that this is the expected operation of these facilities. As you know wind is an intermittent power source reliant on weather conditions and so there will necessarily be periods of low output. The emissions-free power generated by these facilities helped to keep our grid stable and reliable during the cold weather, and SaskPower is satisfied with their performance.”

He also pointed out, “It is an intermittent source, so you're never going to be getting 100 per cent of the theoretical capacity out of them unless you have perfect wind conditions at all times which is not the case, even in a windy place like Saskatchewan.”

The bulk of Saskatchewan’s power generating capacity is thermal, from burning coal and natural gas.

“Over the last couple of weeks, our grid has been quite stable. There hasn’t been any risk of outages because of lack of capacity. All of our major units are available,” he said. 

The new Chinook Power Station, which is natural gas-fired, was down briefly in late January, before the cold snap happened. “Throughout the cold, we’ve had most of our units running, definitely. We haven’t had all them running at all times. But our system plan is to account for this sort of conditions, the weather. And so we’ve been optimizing our utilization of our units.

Asked if SaskPower is susceptible to a power grid crash like what’s happened with Texas, which has its own grid, separate from the rest of the continent’s major power grids, Cherry explained that Texas’s infrastructure is not built to accommodate this sort of cold weather, whereas ours is optimized to meet cold conditions. 

“Our units are designed to be protected from the cold. They have stuff down there, like generating units, that are pretty much exposed to the elements. Ours are largely indoors,” Cherry said.

He added that most of Saskatchewan’s home heating is by natural gas, and our homes are well-insulated. 

SaskPower has its own insulated, self-sufficient grid, with interconnects to its neighbours as part of a larger grid. Cherry said, “We always make sure we have enough contingency built into the system, so that even if our largest single facility went down, we'd have enough power to cover everyone off. Those are the sorts of things we take into account, when we're planning.

“And if we got to the point where we didn't think we had adequate capacity to have that contingency in the system, to make sure we were certainly able to keep the grid stable, and to meet the needs of all of our customers here, we would cut off those exports. But because, right now, the grid is stable, and we have our units all available, we're able to meet the need here and export some of that power south.”

SaskPower has itself, in recent years, had to import power from its neighbours due to our own issues. Cherry noted that in December, 2018, frost on our powerlines meant a widespread blackout. We brought in power at that time. And more recently, we’ve exported power to Alberta as needed, although not nearly as much as is currently going to the United States.

“We’ve been a net exporter for a little while now,” Cherry said. 

And that power isn’t free, either. Cherry said it is all done with the economics in mind.

Some of those economics are the price of natural gas, and the carbon tax applied to natural gas and coal, as coal “is more heavily exposed to the carbon tax” due to being a higher emission fuel source.

Currently there is a 200-megawatt wind farm under construction just outside of Assiniboia. That wind farm, which will have up to 59 wind turbines, is expected to be completed this year.

The Golden South Wind Energy Facility is being built by Potentia Renewables Inc. on 34,000 acres of leased agricultural land. Peak workforce during construction is expected to be 220 people, and 10 full-time staff will operate it, according to Potentia’s website. SaskPower will be buying its power through a power purchase agreement.

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