January 3, 2024 - About two years out from almost closing its doors, North Dakota's largest coal-fired power plant is making a new large investment.

Rainbow Energy Center last month expanded a partnership between Utah-based Eco Material Technologies and Coal Creek Station, which Rainbow purchased in 2022. The plant will now be recycling three of its main waste streams.

Eco Material has been working with the Underwood-based Coal Creek Station for the past three decades to recycle fly ash. Now, bottom ash and calcium sulfite -- two other waste materials from coal combustion -- will be treated for future uses.

Rainbow last summer received a $42.5 million loan through North Dakota's Clean Sustainable Energy Authority -- an advisory board to the regulatory Industrial Commission, which is composed of the governor, attorney general and agriculture commissioner. The total project cost will be $85 million, according to the loan application.

The federal Environmental Protection Agency last spring proposed denying an alternative liner for one of Coal Creek Station's ash ponds due to concerns that it was not sturdy enough to prevent leaks of coal residuals into groundwater. The state Department of Environmental Quality had previously approved the liner, but the EPA began to regulate coal residuals disposals as well in 2015. State officials earlier this year expressed concern that rejection of the alternative liner could shut down the plant for three years because an existing facility would have to be rebuilt.

A representative for Rainbow declined comment in response to Tribune questions on whether the agreement with Eco has anything to do with, or could affect, the proposed EPA proposed order on the liner. The EPA website for the case does not indicate whether a final decision has been made.

Concrete and Wallboard

Around 400,000 tons of bottom ash from Coal Creek will go to concrete mixes annually for the next 25 years. This will replace around 20-25% of portland cement mixes used for concrete. Cement production accounts for about 7% of climate-warming carbon dioxide emissions globally, according to the Global Cement and Concrete Association, an industry group.

The concrete mixes will be marketed to projects for bridges, roads and buildings in North Dakota, Minnesota and Wisconsin. Fly ash recycled at Coal Creek has been going toward similar uses.

Around 150,000 tons of Coal Creek's calcium sulfite waste will go toward synthetic gypsum, which will mostly be marketed for wallboard, a construction material. Gypsum can also be used as a fertilizer. 

The project will not just keep new waste out of landfills, it will be recovering old waste as well, Eco Material CEO Grant Quasha told the Tribune.

"(Landfilled coal waste) is an environmental problem, and rather than trying to monitor it and hope nothing goes wrong, what we (say) is, 'It's much better if you dig it out, clean it up, and put it into infrastructure,'" he said.

Coal Creek is the second power plant where Eco Material will help recycle all three waste streams. The first was in Texas.

Quasha said construction will begin this spring, and the project should be up and running in around 1½ years. It is expected to create 20 full-time jobs.

'Fully Circular' 

Rainbow's vision for the plant is for it to be "fully circular," either using or capturing all of its waste materials.

For years, Coal Creek has provided the Blue Flint Ethanol plant -- its next-door neighbor -- with waste heat for ethanol refining and grain drying. Rainbow has also been developing plans for handling another source of waste from Coal Creek, CO2 emissions.

The federal Energy Department in May awarded the University of North Dakota Energy and Environmental Research Center a $38 million grant to help Rainbow deploy a carbon capture project at Coal Creek.

North Dakota has been investing heavily in carbon capture to keep its emissions-heavy industries such as coal and ethanol alive in the face of new regulations and market standards.

Opponents argue the technology is costly and unproven in its ability to capture the necessary CO2 to meet emission reduction goals.

Quasha said he believes Rainbow will be successful in deploying carbon capture, though Eco Material is not involved in that effort. Eco Material's goal is to put all the waste it can to good use, whether or not carbon capture proves successful, he said.

"Eventually the plant's not going to be around forever even if it invests in carbon capture and sequestration; that's why part of this project is harvesting where we take stuff that's been thrown away before and we can bring it back in," said Quasha. "So long-term these facilities can theoretically be used past (operation)."