Trains, trucks, cars and conveyors make Great River Energy’s Coal Creek Station near Underwood, North Dakota, look like a giant model of perpetual motion.
Built in the late 1970s, the power plant is North Dakota’s largest. It consists of two units – both rated at 550 megawatts. Unit 1 began producing power in 1979 and Unit 2 in 1980. Together, they provide much of the electricity that is sold by Great River Energy to 28 electric distribution cooperatives that serve about two-thirds of the geographic area of Minnesota.
“The idea was to build a power plant adjacent to the lignite fields in North Dakota to supply electricity to Minnesota cooperatives,” said John Bauer, the director of North Dakota generation for Great River Energy.
The power travels more than 400 miles by direct current (DC) transmission lines from Coal Creek Station to a large substation just west of the Twin Cities. There, the power is converted from DC to alternating current (AC) where it travels to distribution cooperatives serving about 1.7 million people.
About 8 million tons of lignite coal comes from the Falkirk Mine, owned and operated by The Falkirk Mining Company, a subsidiary of North American Coal Corporation, every year. The coal is not only used to generate electricity, but also steam from the plant is sold to the neighboring Blue Flint Ethanol Plant, which is partially owned by Great River Energy.
“The ethanol plant is a low-cost producer since it doesn’t need its own boiler,” Bauer said. “In addition, Coal Creek Station can also supply water and share other services with Blue Flint making it one of the most cost-effective ethanol producers in the Upper Midwest.”
Fly ash collected in the electro-static precipitators at Coal Creek Station is hauled away by truck and train to ready-mix concrete companies in the Upper Midwest. The fly ash is a replacement for Portland cement and is in demand throughout the region because it makes the concrete more flowable, stronger and easier to finish.
The fly ash has another benefit. It reduces the need to make cement which saves on costs and the environment.
“Every ton of fly ash we sell reduces the amount of carbon dioxide produced because a kiln is not being fired up to make the cement,” Bauer said. He noted that Coal Creek Station sells practically all the fly ash it produces.
Trains not only haul away fly ash, they also haul away coal that has been beneficiated through Great River Energy’s patented DryFiningTM process. By using waste heat, the coal is dried, which increases its BTU value. Some of the dried coal is hauled by covered train cars from the Coal Creek Station to the Spiritwood Station east of Jamestown.
Trains can also be found hauling corn to the ethanol plant and hauling away ethanol, which is blended with gasoline for transportation fuel. The Blue Flint Ethanol plant is located just east of the power plant and has been operating for the past 10 years.
With all this activity, Coal Creek Station is one of the most efficient plants in North Dakota and one of the cleanest. Bauer says that reducing emissions from the power plant has been a continuous process improvement for the employees at the plant.
When originally built, the desulfurization system could scrub 60 percent of the unit’s flue gas. Through upgrades, that percentage has now climbed to allow scrubbing of more than 90 percent. In addition, the plant has also reduced its nitrous oxides and mercury emissions – keeping the plant well within its permitted limits.
Bauer attributes the success of the plant to an employee culture that empowers workers to constantly look for new ways to be more efficient and cleaner.
“As we transition to a younger work force, we see few bumps in the road,” Bauer said. “The newer employees have a lot of energy and our culture gives them the ownership required to constantly be looking for ways to do things better.”