As climate change continues to accelerate, many scientists are increasingly worried that the world will not be able to reduce its reliance on fossil fuels quickly enough to meaningfully avert worst-case scenarios. Carbon capture and storage (CCS) technologies, which would remove carbon dioxide from the atmosphere and store it have been hotly discussed and prototyped as an additional method of drawing down the greenhouse gas concentration in the atmosphere; however, to date, they have never been successfully scaled up for production use. Now, a researcher in the University of Texas at Austin’s Bureau of Economic Geology has applied the power of supercomputing to investigate how CCS technology can be optimized for scale-up.
CCS typically works by capturing carbon dioxide emissions from, say, a coal plant, then injecting the captured gas into porous rock, where it can be held for long periods of time. The researcher—Sahar Bakhshian—was investigating which factors determined how much carbon dioxide could be stored in a rock deposit. “Our research is basically trying to characterize geologic settings suitable for storage and exploring the way we inject CO₂ to make sure it’s safe, effective and poses no threat to people or groundwater resources,” Bakhshian said in an interview with Aaron Dubrow of the Texas Advanced Computing Center (TACC).
To do this, she ran micrometer-level computational fluid dynamics simulations that studied the gas injection into the digitally recreated rocks from a CCS test site in Mississippi. “We tried different scenarios—using different injection rates and fluid-rock properties—to determine how the properties affect what percentage of injected CO₂ can ideally be trapped by the dissolution mechanism,” Bakhshian said.
This work was done on Frontera, the 23.5-Linpack petaflops Dell system that has served as TACC’s flagship supercomputer since 2019. Frontera ranked 13th on the most recent Top500 list of the world’s most powerful publicly ranked supercomputers. “Computational fluid dynamics techniques are essential for this field, to better screen suitable target reservoirs for carbon dioxide storage, and predict the behavior of carbon dioxide plumes in these reservoirs,” she said.
Bakhshian found that there were two crucial controlling factors for determining the carbon dioxide capacity of porous rock. First, wettability, which represents how carbon dioxide molecules stick to the exposed surface of the rock. Second, the speed of the carbon dioxide injection.
Bakhshian is hopeful that this research will help advance CCS technologies—which have largely been stymied by cost and siting concerns—on the road to viability. “It’s safe and effective,” said Bakhshian. “And computing will help us find economical ways to achieve this goal.”
To learn more about this research, read the reporting from TACC’s Aaron Dubrow here.