Research by University of Illinois scientists with the Center for Geologic Storage of CO2 could have planetary implications while also producing benefits close to home.
Initiated last year through a 4-year, $10 million grant from the U.S. Department of Energy, the center is part of a collaborative network that includes three other Energy Frontier Research Centers in Illinois and 28 others across the country.
The Urbana center's mission is to conduct "use-inspired basic research" to help better understand the location and distribution of carbon dioxide after it is pumped into the subsurface of the Earth for storage.
Carbon dioxide is a greenhouse gas produced as a byproduct of respiration and by the burning of fossil fuels and industrial manufacturing processes. Increasing levels of CO2 are considered a primary cause of global warming.
Scott Frailey, a senior reservoir engineer at the Illinois State Geological Survey and the center's director, said scientists at the center already have field data from several previous storage test projects.
But the current project is focused on research that addresses uncertainty identified in these test projects, which could lead to modeling accuracy and ultimately more scientific clarity about CO2 storage, particularly for implementing CO2 storage on a commercial scale.
"We have had five unique and diverse field injection projects and we are asking, 'What are some of the things that we were unable to predict?’" Frailey said.
The current research is centered at a project site in Decatur, Illinois. The carbon dioxide, a byproduct of an Archer Daniels Midland Company ethanol-production plant, is captured before it is released into the atmosphere and then compressed and dehydrated before being pumped under an impermeable shale caprock and into a brine-saturated sandstone reservoir called the Mount Simon Sandstone.
The result of the process is a clear, harmless, slow-moving plume of buoyant carbon dioxide. The CO2 is less dense than the brine and eventually dissolves over geologic time.
The scientists, using seismic and other monitoring methods to track the carbon dioxide released 7,000 feet underground, are recording the pressure and saturation of the 1-million-metricton CO2 plume – pumped in over a three-year period – to find out how the plume interacts with rock and where and how quickly it migrates.
Data is being collected down to even the pore-scale and molecular levels, the makeup of each differing level affecting the flow of the carbon dioxide differently – as well as scientists' predictions about the flow's path.
The center’s 52 members from across the U.S. and Norway are focusing on geomechanics, geophysics, multiphysics flow and transport, and geological characterization and modeling. Their goal is to produce a flood of papers on the CO2 storage process.
"If we are to predict where it will flow and how it (the CO2) interacts with the features below the surface, we have to know more about the features, about the sedimentary architecture," said Edward Mehnert, a senior geohydrologist at the ISGS and a member of the center’s multiphysics flow and transport team.
Another aim of the center is an improved understanding about the suspected cause and effect of microseismic activity that can result from pressure changes during CO2 injection.
Frailey said researchers so far have found that, oddly enough, the prevalence of microseismicity occurs when injection is temporarily halted. They don't know why yet.
Frailey said the center's discoveries will hopefully lead to practical commercial CO2 industry uses that benefit the environment.
"We're using basic science solutions to find uncertainties and to discover new technology and research that can be applied to real-world challenges," he said. "As we get a better description of the geology, we can get a better understanding of how it (the CO2 and geologic properties) all interacts."
Frailey said the work could lead to improved methods for storing carbon dioxide, with implications ranging from atmospheric to economic. He said those methods could be used as cleaner, alternative fuel sources are developed.
Frailey said if the technology existed to effectively and safely store carbon underground, the impact could even be felt on the Illinois coal and oil industry by helping to further reduce the environmental effect of using fossil fuels.
"Illinois is very rich in coal, we just haven't been able to use it compared with other U.S. coals until recently," Frailey said.
Frailey said another benefit is purely scientific, as the center has worked hard to bring scientists and students from disparate backgrounds to help solve the CO2 storage challenge. He said the federal funding guidelines demand it – and he feels it helps push the boundaries of the research.
"We've tried to bring in people who don't normally work together," he said. "We're continuing to reach out and to build relationships and foster collaboration. We're looking at this from all aspects and may be asking scientists to get out of their ‘single PI, single institute’ comfort zones."
The ISGS is a part of the U. of I.'s Prairie Research Institute. Participating faculty members from the U. of I. also include James L. Best, a professor of geography and geographic information science; Bruce Fouke, a professor of geology; and Albert J. Valocchi, a professor of civil and environmental engineering. The U.S. Department of Energy's Office of Science, Basic Energy Sciences is funding the Center for Geologic Storage of CO2.
Participating GSCO2 institutions:
- Bureau of Economic Geology
- Illinois State Geological Survey
- National Technology Energy Laboratory
- NORSAR
- Schlumberger
- SINTEF
- University of Illinois at Urbana-Champaign
- University of Notre Dame
- University of Southern California
- University of Texas at Austin
- Wright State University