How Basin Electric's power plant professionals prepared and performed during the February energy emergency

As cold weather rolled into the Upper Great Plains in early February, electricity was essential, keeping homes warm and systems running. This is how people keep power plants running.

man in front of power plant
Michael Hessman is the only employee stationed at Spirit Mound Station, a fuel oil-based peaking power plant near Vermillion, South Dakota.

Blockbuster week

For 11 years now, Michael Hessman has proudly worn the label, “Maytag repairman,” as the only employee at Basin Electric’s Spirit Mound Station, located near Vermillion, South Dakota.

Spirit Mound is a peaking power plant, meaning it runs about a dozen times a year, usually during periods of extreme hot or cold weather. It uses fuel oil, and while there is capacity on site to hold up to 8 million gallons of the fuel, Spirit Mound rarely stores more than 1 million gallons because it takes quite a few run hours to use that fuel up.

Early in February, Hessman put in an order for more fuel oil, something he only had done only twice before: in 2008 and 2019. “We were getting day-ahead calls, which never happens,” he says, meaning he was getting notice from Basin Electric marketing that he would likely need to be ready to run the next day.

“I’m usually the last guy they call, or the most expensive guy they call.”

The oil arrives on the plant site via the NuStar Energy Pipeline, a multi-use pipeline near the plant. Sara Erhardt, Basin Electric buyer, says a supplier near Sprit Mound has access to the pipeline, but “We’re at the mercy of the correct product flowing through that pipeline when we need it, and whether that product has already been allocated to somebody else,” Erhardt says. Since another product was already in the pipeline, the Feb. 9 order wasn’t available to arrive until Feb. 17.

Learning of the pipeline delay, Hessman realized additional oil would be needed prior to the pipeline delivery. “Well, the cold snap was coming. So on Feb. 13, that Saturday, we had conference calls to talk through, how can we get fuel to these units without shutting down?” Hessman says. “We ended up lining up truckloads of fuel to come in on Valentine’s Day.”

Hessman slept at the plant overnight and called in help from Deer Creek Station, Basin Electric’s nearest power plant located in Brookings County, South Dakota, to help with offloading the fuel. “We did 10 truckloads on Valentine’s Day. We had run out of fuel on Saturday, so we went into an outage. We were in contact with marketing and ran through our plan. Each day for the next three days, we received the fuel, burned it, and then put the plant in outage until the next morning when we got more fuel. It was 12-hour shifts,” Hessman says.

Each Spirit Mound unit will use 6,000 gallons of fuel oil an hour, to generate 120 megawatts total. Each truckload holds about 7,200 gallons.

While the truckloads of oil bridged the gap, Spirit Mound Station was headed for a blockbuster week. Erhardt says the plant originally ordered 400,000 gallons on the pipeline. Mid-morning on Feb. 17, she was asked for an additional 400,000 gallons.

“So within a five-hour timeframe, we went from getting 400,000 gallons to getting 800,000 gallons. We always want to help in any way we can,” Erhardt says. “There were lots of phone calls, lots of communication, you drop everything and put it on the back burner until you get it to a place where you know it’s going to work. It worked out because they had the fuel and the pipeline was available. There are a lot of factors that come into play when you are expediting something.”

All told, Hessman says it took about 27 hours to bring in the 800,000 gallons of fuel. Erhardt says between the truckload deliveries and the pipeline, slightly more than 958,000 gallons of fuel oil were delivered Feb. 14-18.

“We try to keep very good relationships with the facilities of course, but also with our vendors and their employees, because when times like this come up, we’re not their only customer,” Erhardt says. “They need to get fuel to other places as well, and they do their very best. But their hands are tied sometimes too, and I think good working relationships with vendors we use help so much, especially in times like this.”

To understand how unusual this February was, “There are years I didn’t run this station at all. Since we’ve been in SPP (Southwest Power Pool), I run about once a month, way less in 2020 due to COVID and not needing as much power,” Hessman says. “This February, I used 835,000 gallons. That’s the same amount I used in the past eight or nine years.”

woman with computer
Sara Erhardt buys fuel for Spirit Mound Station, among other duties, and says good relationships with vendors are key to getting what’s needed quickly.

Moisture and cold

Cold weather can cause issues in the unlikeliest of places.

Take coal cars, for example.

“Coal, especially lignite, has a pretty high inherent moisture content. Then, you have the snow or moisture in the air that contributes,” says Joe Leingang, Basin Electric superintendent of fuel and transportation. “At Leland Olds Station, we take pretty extraordinary measures to minimize that problem. We have liners in the coal cars and they use chemical release agents. But just the same, we sometimes have as high as a 15% carryback. So think of that, you’re shipping, you’re paying freight on 15% of the tons, or 15 tons per car, twice, sometimes three times. …
“At Laramie River Station, it’s a little bit better because of the lower inherent moisture content in the coal. Also, the climate is more temperate in Wyoming with lower humidity rates,” Leingang says. “But once the coal gets on the stockpile and it’s been sitting there for a while, or if there’s any moisture in the air, that becomes a problem there as well.”

Leingang says it’s the operator’s preference to take coal straight from the coal cars into the power plants, rather than try to take it off the coal stockpile.

“They can get the coal off the stockpile, but it’s just a whole lot tougher situation,” he says. “There needs to be a lot of manual intervention, overtime hours in the coal yard, the coal needs to be crushed, which is harder on equipment.”

man in power plant
Clyde Moch, Basin Electric superintendent of operations for North Dakota, Wyoming, and Montana distributed generation, at Lonesome Creek Station near Watford City, North Dakota.

Prepared for the cold

Operators at Basin Electric’s natural gas-fueled peaking plants begin preparing for cold snaps well before winter. Because these plants don’t run all the time and are valued for their quick start-up times, extra care goes into the planning.

In the fall, operators check and blow out water systems that won’t be used through the winter, and check all heat tracing and insulation, according to Joe Fiedler, Basin Electric manager of distributed generation. “As the temperatures get subzero, we’ll monitor our heat trace circuits. We have automatic alarms on a lot of those circuits, so we know if any have failed and we get it repaired,” he says.

Fiedler says operators will run lube oil systems, for example, because the lube oil tanks are heated. “We can limit the unit’s output to minimum and keep them running. It’s much better to keep fluids circulating than it is to shut them down and let them get cold, and then try to restart at -25 degrees. It’s just much better if we can keep those warm oils circulating.”

Finally, the operators use another trick that many non-plant operators might be familiar with. “We also have water systems that we’ll automatically recirculate, so it’ll push the fluid through the systems and then back to the tanks. That way there is water flowing through the lines every once in a while, like every four hours,” Fielder says. “It’s like if you have ever lived in a trailer house – if you leave your faucet dripping, it’s less likely to freeze up.”

The prep work is similar at the coal-based power plants. “Going into the fall season, we go through and check all our heaters by making sure they cycle on and off and are heating. In some areas we bring in spare heaters to keep things from freezing,” says Troy Tweeten, Basin Electric senior vice president of Operations.

“Up here, we are a little more prepared for the cold, compared to down south, like in Texas. The issue they have there is that their boilers aren’t even enclosed, so they don’t even have an option to keep heat in the building.”

Cooperative-wide, Basin Electric operators saw early on that with new peaking plants, additional winterization was necessary.

“We put enclosures around the water system at Pioneer Generation Station. That wasn’t in the original design, but after freezing up a winter or two, we decided that was the only way we could ensure that when it got really cold we wouldn’t freeze these systems up. Sometimes heat tracing and insulation aren’t enough,” Fiedler says. “We built a whole building around the HRSG (heat recovery steam generator) at Deer Creek Station because the first winters they had so many things freezing up. There’s been a fair amount of money stuck into winterization at these sites over the past couple years, and for the most part, we’ve done very well. … We’ve been making improvements so that when we hit events like this we aren’t sitting like Texas was, with days of being frozen.”

Fiedler says several of the operators at the peaking plants are cooperative members and knew every megawatt was important during the energy emergency. “You have local co-ops starting to make calls to customers and telling them, ‘You could be without power for several hours,’ and “Prepare by having water on hand,’” Fiedler says.

“It starts to hit home when it’s happening in your backyard.”

Decision and future planning

In 2020, several major power plant outages were postponed due to safety concerns related to the COVID-19 global pandemic. In addition to not wanting to bring hundreds of workers from various states onto Basin Electric’s plant sites, the cooperative also didn’t want to potentially overwhelm local hospitals or clinics.

The work done during outages is meant to keep power plants operating with minimal issues for several years. During the energy emergency, some plants did face trouble with coal ash and tube leaks, but operators were able to keep the plants online until the emergency was over.

“Postponing the outages from 2020 because of COVID and not having all the contractors there to do that work, did make us take on a little more risk. … We did make it through the cold spell without seeing any of the impacts of the delayed outages from 2020. All of the events at Dry Fork, Laramie River Station Units 2 and 3 – none of those issues would have been related to any issues from delaying the outages. Even though there were tube leaks on LRS Unit 2, that unit wasn’t scheduled for an outage until next year. So, that issue was just a coincidence,” Tweeten says. “Yes, you do get those tube leaks that come up every now and then, but the ash problems, those were unexpected, just the kinds of things that happen due to coal quality and how the boiler is firing. It’s funny, you’d think it was problems related to the delay on the 2020 outages, but it wasn’t.”

Tweeten says he is proud of his operators for keeping the units operating when they were needed most.

“Even though it took more work to get the ash cleaned out of the boilers at Dry Fork Station and Laramie River Station Unit 3, or fixing the tube leaks at Laramie River Unit 2, we needed those plants to stay online when that power was needed the most and we were able to do that,” he says.

Basin Electric has been exploring the possibility of extending outage cycles to four years, rather than the current three-year cycle. In North Dakota, a boiler inspection is required by law every three years, but could be completed during a minor outage.

Tweeten says the events of February’s energy emergency haven’t changed his thinking on a longer outage cycle. “As far as trying to extend outages to a four-year cycle, it doesn’t necessarily impact the events that happened in this cold weather event,” he says. “The reason I say that is we do preparation work during the outages no matter how long they are to make it to the next outage. So when we are on a three-year cycle, we are trying to make it to three years. So we will initially have to do more repairs up front to stretch it to a four-year cycle. For example, we may have to do extra pad welding on boiler tubes to stretch them to a four-year cycle. Also, we may be able to do other work during shorter outages (one to two weeks) in the shoulder months to keep up reliability.”

Tweeten says the Operations department has meetings planned to go over the event and talk through next steps. “We have a protocol meeting in May and we’ll review what went good and what went bad,” he says. “We want to document everything we saw happen during this cold weather spell and prevent some of these things from happening again. To try to keep the lights on.”

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