Dakota Gas carbon capture: Improving the environment and the bottom line

Both advocates and adversaries of coal are familiar with the term “carbon capture.” Finding a way to capture carbon dioxide (CO2) emissions from coal-based generation facilities is the biggest hope for continuing to keep this reliable fuel source in the energy portfolio. There are projects of all kinds trying to find efficient and effective ways of capturing carbon, but it’s something the Great Plains Synfuels Plant has already been doing for more than 20 years.

On Nov. 10, 2020, the Beulah, North Dakota, plant reached the milestone of capturing 40 million metric tons of CO2. The Synfuels Plant is one of the world’s largest carbon capture facilities, capturing about 2 million metric tons of CO2 each year.

Carbon dioxide pipeline
Carbon dioxide is captured at the Synfuels Plant and sent via pipeline to Canada.

This environmental initiative isn’t just economical; it also generates revenue. Recovered from the coal gasification process, the CO2 is captured by washing the synthetic natural gas in the plant’s Rectisol unit. The captured CO2 is then transported near Weyburn, Saskatchewan, Canada, and is used in the oil fields for enhanced oil recovery.

Dakota Gas and its Canadian subsidiary, Souris Valley Pipeline Ltd., operate a 205-mile CO2 pipeline to transport the carbon dioxide from the Synfuels Plant to Saskatchewan. The first CO2 was sent to Canada in October 2000.

“This has been a great revenue stream for Dakota Gas, and it has provided our Canadian customers with the ability to drastically improve the life and productivity of their oil fields, all while providing an environmental benefit by permanently and safely sequestering carbon dioxide underground,” says Dale Johnson, Dakota Gas vice president and Synfuels Plant manager.

Dakota Gas’ project was the first commercial-scale project to capture CO2 from a coal plant and transport it for beneficial use. CO2 from power plants is typically very wet and diluted with nitrogen and oxygen and requires further processing, but the Synfuels Plant’s process results in a CO2 stream that is dry and 96% pure, so no additional processing is needed. The Synfuels Plant’s unique gasification operations and CO2 capture and transport continue to draw worldwide attention and serve as a model for the next generation of carbon capture.

Dakota Gas is also exploring the possibility of a Section 45Q sequestration project at the Synfuels Plant. The 45Q legislation is a tax credit designed to stimulate investment in technology that allows for the addition of equipment to capture CO2 from new and existing facilities. The project promotes capturing even more CO2 for underground sequestration, enhancing coal’s quest to be a more environmentally friendly energy source.

Three years ago, the Synfuels Plant Gas also started processing a higher-purity liquefied beverage-grade CO2 stream from the plant’s fertilizer production facility. This process provides many options for the CO2 product. Some of the beneficial uses of liquid beverage-grade CO2 include treating water at municipal water treatment facilities, beverage carbonation, and industrial purposes, including oil and gas fracking, which is a technique of pumping pressurized carbon dioxide into wells to shatter the rock and push out more oil and gas.

Most recently, Dakota Gas sold liquefied CO2 to the North Dakota Department of Health to be used for its dry ice machine to preserve the quality of COVID-19 vaccines.

Additionally, the Synfuels Plant’s beverage-grade CO2 has played a key role in North Dakota’s well-being for 2020, helping statewide water treatment plants during a shortage.

“We continuously look for new opportunities to create valuable products from North Dakota lignite, and it is exciting when we can do this while reducing our carbon footprint,” Johnson says.