ESTEVAN - SaskPower is hopeful that the start of a new year will mean a return to more consistent operations at the carbon capture and storage (CCS) facility at the Boundary Dam Power Station.
The CCS facility captured a total of 442,126 tonnes of CO2 last year, despite a couple of shutdowns in the capture island. Unit 3 at Boundary Dam was able to remain online for most of the year.
The CCS facility performed very well in the first five months of the year. It was online at least 90 per cent of the time from February to May, and eclipsed a milestone in late March, with four million tonnes of CO2 captured since it came online in October 2014.
It was offline for a few weeks in June and July for a scheduled maintenance shutdown, with replacement of the packing where CO2 is captured. It was a fairly large job, said Howard Matthews, the vice-president of power production with SaskPower, and he credited everyone involved.
“We were really happy with the performance of CCS coming out of that. We saw a really good capture,” said Matthews.
Shortly after the facility returned to service, it was knocked offline for nearly three months due to a compressor motor failure.
A few weeks after it returned to service, a CO2 cooler leak on the main compressor struck.
Matthews said the cooler leak was unrelated to the motor failure.
“They’re both really unusual, almost random events,” Matthews said in an interview with the Mercury. “If you go back to the earlier failure on the compressor, it was a failure with an internal component of the compressor motor itself.”
The motor is a large, 20,000-horsepower unit that should run for many years without having to be taken apart. Matthews said it was a failure of an internal component, and it has occasionally happened at other plants.
“The compressor is driven by this large, 20,000-horsepower motor, and has many stages to it, and then between some of the stages, you actually have to cool the gas, because as you compress it, it heats up.”
The failure of the cooler was also unusual.
“One of the challenges of course, with this installation was even just finding it. It was not an easy thing to find. And then to find it and to find the repair strategy, it’s hard to describe in words. You almost have to see a picture of the size and the number of tubes this heat exchange would have.”
The Crown corporation thought they had found the leak, and brought the facility back online from Dec. 1-9, and parts of Dec. 10 and 25, but then it had to go back offline again.
“We noticed another leak, and then we had to come off and go through a similar process again to find the leak,” said Matthews.
A root cause analysis is ongoing for the cooler issue, but the initial investigation shows the failure had nothing to do with the CCS process. It could have happened at any one of their coolers at any SaskPower facility.
It was unfortunate to have it happen at CCS so close to the motor failure, Matthews said.
SaskPower is in the final stages of completing the repair, returning the cooler to service and starting up the facility again. It is expected to be online this week.
Matthews is confident that SaskPower has resolved the issues.
“Knowing the technicians involved in this, they certainly put their heart and soul into this,” he said. “They’ve put their best effort into trying to locate the problem here and get it fixed, like they do in all of their work.”
The plan is to run with very good outputs for the CCS facility for the next few months. SaskPower has been completing some work in the facility while it was offline, and the next shutdown isn’t scheduled until October.
Unit 3, meanwhile, has been performing quite well during the cold winter months, Matthews said.
SaskPower set two power usage records during the recent cold snap, and the system performed quite well, Matthews said. But it did not necessitate Unit 4 at Boundary Dam coming back online. That unit was retired on Dec. 1, 2021.
“It’s available for us if the system needs it,” said Matthews. “We could start it back up again. It would take a number of days to do so, but actually we went through this cold snap and as I mentioned with those two record peaks that we had, we didn’t have to restart BD4. It came off according to plan, and it will probably stay off.”
It will still be available to SaskPower for a few more months, but only if one of its units is scheduled to come offline for a considerable period of time.