Air Quality Compliance: Latest Costs for SO2 and NOx Removal (effective coal clean-up has a higher–but known–price tag)

Editor Note: Robert Peltier, Ph.D., PE, is editor-in-chief of POWER magazine. His bio is at the end of this post.

Environmental retrofits at coal plants have experienced costs greater than estimated by the Energy Information Administration. That is the bad news. The good news is:

• There are no significant technical problems with flue gas desulphurization (FGD) or selective catalytic reduction (SCR) technologies.  Utilities are not buying “serial number one” so the performance or compliance risk is negligible.  Completion risk for any project also appears to be minimal.
• The costs to construct either technology are reasonably well understood so that project capital cost estimates should be on the money.
• The cost escalation (updated below) during the boom is now subsiding.

The overall result is that the “dirtiest” power plants have been and are being cleaned up to current stringent air-emission standards via the Clean Air Act and other pollution regulation.…

Cleaned-Up Coal: Technology Improvements, Low-Sulfur Resources Are Winning the Day against Air Pollution

Air quality from America’s coal plants have been improving for decades, even before Congress passed the Clean Air Act of 1970. And since 1970, the six so-called criteria pollutants have declined significantly overall and in the generation of electricity, even though coal-fired generation has increased by more than 180 percent.[i] (The “criteria pollutants”—those for which the EPA has set criteria for permissable levels—are carbon monoxide, lead, sulfur dioxide [SO2], nitrogen oxides [NOx], ground-level ozone, and particulate matter [PM]).

Specifically, total SO₂ emissions from coal-fired plants were reduced by about 40 percent between 1970 and 2006, and NO_x emissions were reduced by almost 50 percent between 1980 and 2006. On an output basis, the percent reduction is even greater, with SO₂ emissions (in pounds per megawatt-hour) almost 80 percent lower, and NO_x emissions 70 percent lower.