Environmental Technology

The technology to achieve these standards does not exist, so how can the standards be mandatory and not just aspirational? Certainly there is an urgent need, in view of the well-documented toxicity of mercury in the environment. But EPA and DOE need to be frank about what is available. I saw a lot about the dangers of mercury -- but very little about mercury control technology -- in the recent EPA announcement.

Consider that a utility boiler has a flow rate of 4,050,000 dscm (dry standard cubic meters) per hour, which is about 40,000 cubic feet per second of hot and dirty flue gas. Mixing chemicals into this stream to capture microscopic quantities of mercury vapor is not going to work. Membranes are not going to work either. Injection of activated carbon has the disadvantage of significantly increasing the amount of particulate matter requiring storage and disposal.

The EPA report of 1997 found:

"Control technologies designed for control of pollutants other than mercury (e.g. acid gases and particulate matter) vary in their mercury-removal capability, but in general achieve reductions no greater than 50 percent."

and

"Mercury capture is mass-transfer limited in utility flue gas streams due to the low mercury concentrations in the extremely high volumes of flue gas."

See p. 31 of the pdf.

Mandates unsupported by any technology are worse than futile because they might result in blackouts as condemned coal plants go offline with nothing to replace them.