New Environmental Protection Agency regulations are driving energy companies to search for alternate ways of reducing the pollutant gas CO2, and some University of Wyoming professors are working to store it underground.
The pressure management project is part of a large seven-year research project involving several professors. A team lead by the UW Carbon Management Institute is focusing its efforts on one possible Wyoming storage site, said Kipp Coddington, director of the institute.
“We have great confidence and data for the Rock Springs Uplift, and since it’s already a well-characterized storage reservoir — perhaps one of the best characterized reservoirs in the United States — we are quite happy to continue to pursue opportunities there,” he said.
The Rock Springs Uplift is a massive formation that is a possible site for storing CO2 produced from coal-fired power plants, said Scott Quillinan, senior hydrogeologist.
“The Rock Springs Uplift itself is a huge structure in southwestern Wyoming — something in the order of 50 miles by 100 miles,” he said. “It could take many, many years of all of Wyoming’s CO2 emissions.”
While space for billions of tons of CO2 could be available, it is currently occupied by brine, a very salty water, Quillinan said.
“The pore space is already filled with salty water — if you force (CO2) in, you’re going to elevate the pressures in the formation and fracture the rock,” he said. “You don’t want to fracture the rock.”
The institute’s research, paid for by a $1.9 million grant from the U.S. Department of Energy, is meant to figure out how to keep the pressure equal throughout the entire process, requiring the removal of some of the brine, Quillinan said.
“For pressure management, you have to get that water to the surface, and once that water’s at the surface, it has to be managed,” he said. “You can’t just make the Great Salt Lake in Rock Springs.”
This is where the water desalination treatment comes into play, Coddington said. Bringing huge amounts of salt water to the surface is not very useful, and transforming it into potable water is almost necessary.
“I think finding the technology to desalinate water economically and efficiently might be more challenging than the CO2 injection,” he said. “But it’s really a win-win if this all proves out.”
The Rock Springs Uplift lies directly underneath the Jim Bridger Power Plant — the largest producer of CO2 in Wyoming, Quillinan said.
“One thing looking at very seriously is treating water to point where it could be used at the Jim Bridger Power Plant,” he said. “It could supply it with half of the total water.”
If a process is found to easily desalinate water for this project, it could be modified and applied elsewhere, Coddington said.
“In theory, if this technology pans out at a subsurface storage site, there’s no reason you couldn’t do it from the Pacific Ocean,” he said. “There might be some input differences — (desalinating brine) won’t be like just taking water out of the ocean — but in theory, the technology could be put to use elsewhere.”
UW’s years of work and characterization of the Rock Springs Uplift helped it be selected by the Department of Energy along with four other institutions for the first phase of a carbon capture, utilization, and storage research project, Coddington said.
“Because we have a lot of existing data of the Rock Springs Uplift from the prior work that we’ve done, we have a nice head start on the analysis,” he said. “We’re under some deadline to publish some of our work late next year.”
Grants of up to $30 million could accompany a phase two study, which moves from concepts to fieldwork, Quillinan said.
“Phase two is moving forward to demonstration, where we would be actively injecting brine, not CO2, to increase pressure to see if it can be standardized,” he said.