Scientific American ... comment "The One-Stop Carbon Solution" (Scientific American, 11/2013) suggests sequestration of coal plant emissions by "soda-streaming" CO2 into brine and injecting the brine into wells. The pressurized brine forced into the substrata in turn forces methane to be released into return wells drilled for the purpose. Anywhere else it would be called fracking -- tapping even more CO2 and the spew from burning methane!
Why go to absurd lengths to support continued environmental terror by the commodities industrial complex? CO2 sequestration is commodities hokus pokus and a waste of good investment and research money. Why produce the CO2 in the first place? Geothermal EGS can tap the heat beneath our feet virtually anywhere on earth -- and within a few decades could replace virtually all commodity/CO2-based (coal, oil, gas, nuclear ...) electricity generation.
Instead of coal plant enhancement, why not adapt generating equipment on-site to geo requirements and feed the grid through the plant's existing connection. Instead of wells for injecting chemicals, drill wells that extract geothermal heat directly. With much less complexity, replace coal-burning with the unlimited heat of the earth. As geothermal power generation becomes feasible, not just on geyser strata or "rings of fire", savings from elimination of commodities-associated externalities* together with long-term operational savings make a practical, long-term financial case with enormous environmental benefit.