Subsurface sequestration of CO₂ in the U.S: Is it money best spent?

The continuously decreasing average coal rank (heating value), inadequate investment, and ever stricter air-emission controls have caused the average efficiency of electricity generation from coal in the U.S. to plummet to a mere 32% by the year 2008. The U.S. gas-fired powerplants are 30% more efficient than the coal-fired ones, with average efficiency of 43% in 2008. Replacing each 1,000 MW_e generated by an average coal-fired powerplant with an average gas-fired powerplant would avoid today 7 million tonnes of CO₂ emissions, 1.2 million tonnes of toxic ash, and significant issues with water contamination. The parallel upgrades to the more efficient supercritical steam turbines would decrease current emissions by up to 50% (from the current average plant efficiency of 32% to over 45%). The CO₂ captured in the new combined-cycle powerplants might be used to enhance oil recovery in local fields, where feasible. The CO₂ enhanced oil recovery (EOR) can never become the main sink for the gigantic CO₂ volume generated each year by electric powerplants. Currently, EOR could absorb only 1% of that volume.