Unit 4 to remain on standby for another year

By David Willberg

SaskPower has announced another stay of permanent retirement for Unit 4 at the Boundary Dam Power Station (BD4).

SaskPower spokesman

Joel Cherry said BD4 will be kept in a “lay-up status” until March 31, 2024, or until the

Great Plains Power Station goes into service.

“We want to make sure we have that extra power when we need it, as we have [previously],” said Cherry. “We’ve used it [BD4] intermittently since it was first put to standby at the end of 2021.”

Unit 4 was taken offline in December 2021, follow-

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ing SaskPower’s decision in July 2018 to not retrofit the conventional coal-fired unit with carbon capture and storage technology, as it had done with Unit 3 at Boundary Dam. But SaskPower kept BD4 available for a few months in case it was needed to provide baseload power for the hottest days of the summer or the coldest days of the winter.

The Crown Corporation announced last spring that it would keep BD4 as a powerproducing option through March 31, 2023.

Now it is extending BD4’s life by another year.

From April 1, 2022, to March 31, 2023, Cherry said BD4 operated for 3,315 hours, which is equivalent to about 138 days, or about 38 per cent of the year.

“Our system continues to grow. There’s just more demand for power from our customers. We’ve also had some severe weather events. We’ve had planned and unplanned outages at other facilities where BD4 was useful to come in and backstop that. It was on a case-by-case, situational basis where we would use that facility,” said Cherry.

If SaskPower has advanced notice, it takes about two days to bring BD4 back into service, Cherry said, but typically it will take anywhere from two to seven days. It’s a large piece of equipment, so it’s not as simple as flipping a switch or pressing a button, he said.

Bringing Unit 4 back online involves readying systems for operation. This would include checking equipment, filling systems and working with Westmoreland Mining LLC for coal deliveries.

“We undergo similar processes when any unit is returned to service, for example after planned or unplanned outages,” said Cherry.

Great Plains, a natural gas plant, will be located in the Moose Jaw area. The 360-megawatt facility is expected to begin operation next year, although Cherry said he doesn’t have a specific date.

“If it comes on later than

March 31, we would extend BD4 longer, until the [Great Plains] power station is online,” said Cherry. Once Great Plains does come online, BD4 will be permanently retired, he said. “That facility [BD4] was built to add to our system in 1970, so it’s at the end of its life, and it’s only going to be useful for so much longer. So, once we have the additional baseload power from Great Plains available, we’ll retire BD4.”

Meanwhile, Unit 5 at Boundary Dam, which is scheduled to come offline at the end of 2024, will be on standby until “at least” the end of 2027, Cherry said. That is when Unit 6 at Boundary Dam is scheduled to come offline, unless it is retrofitted with CCS technology.

SaskPower is not expecting any changes to staff once BD4 is offline permanently or BD5 shifts to standby, Cherry said.