Event: Steven Bryant, engineering professor at The University of Texas at Austin, will present new research at the ninth annual International Conference on Greenhouse Gas Control Technologies that examines a unique storage method in carbon sequestration that eliminates the risk of CO2 escaping via buoyancy.
When: Nov. 19, about 9:30-10 a.m. EST
Where: Omni Shoreham Hotel, 2500 Calvert St. NW, in Washington, D.C. The research will be presented during “Technical Session 7E – Novel Options for Geological Storage” in Congressional A+B Room of the hotel.
Background: The standard approach to carbon capture and storage involves extracting CO2 from a fossil-fuel burning power plant, compressing and transporting the captured carbon dioxide and injecting the compressed CO2 into a deep underground formation.
The biggest risk associated with geologic carbon-dioxide sequestration is that the CO2, which is less dense than water, will escape from the storage formation through buoyancy. But Bryant, who directs the Geological CO2 Storage Research Project at The University of Texas at Austin, believes he and his team have a novel solution.
Instead of injecting the compressed CO2 directly into a deep underground formation, Bryant offers this alternative: drill wells in the deep, salt-water filled formation, pump out the salt water, dissolve the carbon dioxide into the salt water in a mixing tank at the surface, and then inject the CO2 –laden water back into the same formation. The CO¬2-laden water is much denser than compressed CO2, and slightly denser than the original brine. Thus, it will have no tendency to rise toward the earth's surface, in contrast to compressed CO2, which is buoyant under typical storage conditions.
“Our idea is the equivalent of injecting carbonated water. This process has several advantages, but the most important is that it eliminates the risk of sequestered carbon dioxide escaping from the storage formation,” Bryant says. “Our work shows that this alternative process does cost more than the standard approach, but not prohibitively more. In essence, the incremental cost can be regarded as the price of risk reduction. This is an important consideration because all stakeholders will want the greatest assurance of secure storage for the lowest cost.
