EIA: “On July 7, 2011, the Environmental Protection Agency (EPA) released the final version of the Cross-State Air Pollution Rule (CSAPR). The CSAPR is intended to reduce emissions of sulfur dioxide (SO2) and nitrogen oxides (NOx) from power plants in the eastern half of the United States by imposing state-level caps on emissions and facilitating a limited interstate cap-and-trade program. There are several possible strategies for reducing SO2 and NOx emissions from coal-fired power plants: plant owners can use lower sulfur coal in their boilers, run the plants with higher emissions less often, retire plants without emissions controls and run other plants, or install emissions control equipment—primarily, flue gas desulfurization units (FGD, or scrubber) for SO2 and selective catalytic reduction (SCR) units for NOx. The CSAPR’s SO2 limits apply to 23 states. Total coal-fired electric generating capacity in these states is 250 GW, or 76% of the national total. Approximately 45% of these plants already had FGD scrubbers in 2009, with installations planned for an additional 5%. FGD scrubbers remove SO2 from post-combustion flue gas through the use of an alkaline solution.”