Antelope Valley Station (AVS), north of Beulah, North Dakota, stands out among Basin Electric Power Cooperative’s fleet of electric generation resources for several reasons – size, dependability and location. The plant is located next to the largest lignite mine in the United States and the nation’s only synfuels plant that turns lignite into synthetic natural gas and nine other valuable products.
“Antelope Valley Station is a very affordable and reliable generation source,” said Chad Edwards, plant manager at AVS. “We are part of a $4 billion industrial complex that includes the Freedom Mine and the Great Plains Synfuels Plant. We share resources with each other that help our efficiency and keeps our costs down.”
Built in the early 1980s, the 900-megawatt plant first began producing power in 1984. A rule of thumb is that one megawatt of capacity produces enough electricity to serve 800 customers. Thus, AVS has the capacity to serve nearly three-quarters of a million homes and businesses — more customers than are found in North Dakota.
Antelope Valley is also the largest single supplier of electricity to Basin Electric’s membership, which spans nine states and 141 member cooperatives, who in turn serve 3 million end-use consumers. Basin Electric is part owner of the Laramie River Station in Wyoming – which is larger – but Basin Electric’s share in the Wyoming plant is smaller than Antelope Valley Station.
Transmission lines connected to Antelope Valley Station run in all directions with two of them running to major substations in South Dakota and another two heading toward western North Dakota’s oil fields and towns.
Antelope Valley uses about 6 million tons of coal a year. The coal is purchased from the neighboring Freedom Mine, which is owned by The Coteau Properties Company, a wholly owned subsidiary of North American Coal Corporation. The mine sends coal to the nearby gasification plant where they accept chunks of coal appropriate for the gasification process and send the smaller coal pieces or “fines” over to Antelope Valley where they are pulverized further into fine powder consistency required at the plant.
Edwards credits the plant’s availability and reliability to several factors including its design, the dedicated workforce and the regularly scheduled outages that allow for maintenance and upkeep.
“The employees at this plant are amazing. Of the 202 employees who work here, there are still 54 people who have worked here since the plant began operations in 1984,” Edwards said. “However, many are now reaching retirement age and are being replaced so we have another 28 employees who weren’t even born when the plant was built.”
The plant has always been environmentally compliant. Original equipment included a baghouse to remove particulates and a scrubber to remove sulfur dioxide from the flue gases. Basin Electric has more recently added over-fire air systems to both units to reduce the formation of nitrogen oxides. The cooperative also built a tandem system with two silos to reduce mercury. One system uses absorbents such as activated carbon and a second uses a liquid solution that allows the mercury to be captured in the baghouse. The two systems work together to ensure the plant is compliant with EPA’s mercury standards for lignite-based power plants.
The control systems to run the plant have also been updated to keep Antelope Valley running more efficiently, which reduces the amount of coal used to generate electricity.
“The original controls were vintage equipment for the 1980s but as computer technology evolved, it made sense to remove the old analog controls and replace them with an integrated digital system that keeps the plant’s multiple systems operating together instead of as separate units,” Edwards added.
Antelope Valley is also known for one other thing – tours. Students and teachers of all ages along with members of various electric distribution cooperatives throughout the Dakotas, Minnesota and Montana come annually to tour the station.
“We run a very clean plant – both inside and out,” Edwards said. “People who tour the plant get a much better understanding of how electricity is produced and delivered to their homes so they can keep their phones charged and their appliances running every day for many years.”