Siting Coal-Fired Power Plants in a Carbon-Managed Future; the Importance of Geologic Sequestration Reservoirs
Greb, S.F., Nuttall, B.C., Solis, M.P., Parris, T.M., Drahovzal, J.A., Eble, C.F., Harris, D.C., Hickman, J.B, Lake, P.D., Overfield, B., and Takacs, K.G.
Kentucky Geological Survey, University of Kentucky, Lexington, KY
In a carbon-managed future, coal gasification technology will be used to produce electric power and hydrogen from coal with near-zero emissions. CO2 will likely be captured and sequestered in the subsurface. This is important, because existing power plants are not sited based on the potential reservoir space near the plant. If the economics of reducing carbon emissions require sequestration in the future, then existing siting factors will have to be coupled with geologic criteria to determine optimal plant locations. To illustrate future potential in Kentucky, the locations of existing power plants, suitable water sources, and seismic risk were combined to delineate an energy and power infrastructure area. Within this area, potential geologic reservoirs were defined. In Kentucky, depleted oil and gas reservoirs and deep saline aquifers (permeable sandstones and carbonates) are sequestration possibilities where they occur at depths in excess of 2,500 feet. Because of their adsorptive properties, coals and organic shales are options at shallower depths, but still need to be both below drainage, and the level of surface fracturing. In all cases, potential reservoirs must have an adequate seal to prevent leakage of sequestered CO2, and capacity and injectivity volumes of at least 1 million tons of CO2 /year for 30 years, a standard set for a FutureGen gasification plant. These limitations result in variable potential across the energy and infrastructure area. More information about reservoir permeability, heterogeneity, structural closure, water chemistry, mineralogy, and other geologic factors are needed to better calculate injectivity and actual storage volumes.