WHAT TO DO WITH CARBON DIOXIDE EMISSIONS FROM COAL-FIRED UTILITIES? GEOLOGIC SEQUESTRATION INVESTIGATIONS OF THE MIDWEST REGIONAL CARBON SEQUESTRATION PARTNERSHIP

Carbon dioxide (CO₂) emissions have increased with industrialization in the last century. Coal-fired power plants are among the largest point sources of CO₂ emissions. There is growing concern these emissions are contributing to global warming. The U.S. Department of Energy is investigating technologies and methods for reducing CO₂ emissions. One approach being explored is geologic sequestration, which is the injection of CO₂ into subsurface reservoirs where there is sufficient permeability, depth, and confinement to allow safe injection of large volumes of CO₂. Depleted oil and gas fields, unmineable coal beds, organic-rich shales, and saline water-bearing formations have all been identified as potential repositories for CO₂. This will not be practical everywhere and the types of reservoirs used will vary across the nation. The Midwest Regional Carbon Sequestration Partnership (MRCSP), one of seven regional carbon dioxide sequestration partnerships funded by the U.S. Department of Energy, conducted an initial (Phase I) geologic assessment of the CO₂ storage potential in the seven-state region of Indiana, Kentucky, Maryland, Michigan, Ohio, Pennsylvania, and West Virginia. Geologically, this region includes the Michigan basin, Cincinnati and Kankakee arches, the northern and central Appalachian basin, and a portion of the eastern coastal plain. Physical and chemical data on numerous geologic units in these provinces were collected. Nine potential deep saline reservoirs and five regional seal (cap rock) intervals were mapped, as were all oil and gas fields. Deep coal beds cumulative thickness was also mapped. Digital geologic databases, maps, and calculations were created to evaluate various sequestration technologies, aid in pilot study site-selection decisions, and estimate available CO₂-sequestration capacities. Presently, in Phase II of the project, preparations are being made for pilot test injections of small amounts of CO₂ in several parts of the region to better assess the sequestration potential of reservoirs mapped in Phase I. Although this analysis was performed specifically to examine the geologic capacity for carbon sequestration, the products from this investigation will have wide-ranging applications in many industries and the public sector for years to come.