Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: MONDAY, May 17, 1993 TAG: 9305170269
SECTION: EDITORIAL PAGE: A4 EDITION: METRO
SOURCE: KARL A. SENSE
DATELINE: LENGTH: Medium
Years ago, as a young research engineer at a tin smelter in Texas, I was able to observe firsthand the terrible destruction wreaked on the environment by stack emissions containing sulfur oxides. The smelter had been in operation only a few years, but already a sharply defined swatch of destruction had impacted on homes and vegetation downwind of it. This was due to the sulfur oxide emissions. Lawsuits against the government-operated smelter ensued.
The United States government recognizes the enormous damage that can result from stack emissions containing even small amounts of sulfur. To meet this problem head-on, the federal government enacted the 1970 Clean Air Act, which restricts the emission of sulfur oxides to 1.2 pounds-per-million BTU of energy derived from burning coal. This means that utilities must burn coal having less than 1 percent sulfur. Unfortunately, Southwest Virginia coal does not meet this requirement since it has a sulfur content of about 2.5 percent, and maybe as high as 3 percent.
However, even the use of 1 percent sulfur coal does not ensure that federal standards are met. To protect humans and the environment, the United States government has (as of 1984) set the following primary federal standards for sulfur dioxide concentrations in the effluent:
The maximum average 24-hour concentration of 365 micrograms per cubic meter is not to be exceeded more than once per year.
The maximum average annual concentration is 80 micrograms per cubic meter.
A secondary federal standard is that the maximum average three-hour concentration that is not to be exceeded more than once a year is 1,300 micrograms per cubic meter.
However, even with these stringent regulations, there is no assurance that the cumulative effect over a number of years does not have serious consequences. In general, to meet federal standards, a utility must employ a combination of burning low-sulfur coal, coal-cleaning before burning, and removal of sulfur oxides after combustion by such means as scrubbing. (However, even the reliability of scrubbers is controversial as far as meeting the stringent emissions standards is concerned.) It is quite obvious that the construction of a coal-fired power plant is not a simple mom-and-pop endeavor.
According to his letter, Boucher seems to promote the construction of coal-fired power plants as the need for more power arises. In light of the above, this is the worst-possible scenario. Not only is such a scheme very inefficient but it is not viable, because of the problem of control of sulfur oxide emissions to meet federal standards.
The only sensible solution lies in the construction of a large power plant, which not only can be operated more efficiently than a bunch of smaller power plants but whose sulfur emissions can be limited much more readily to comply with federal standards.
Furthermore, more advanced concepts such as fluidized bed combustion may become a reality much more quickly in a large plant. A very promising concept for a large plant is magnetohydrodrynamic energy conversion. Such a system results in substantial improvement in overall energy-conversion efficiency because of the elimination of steam turbines, as well as reduction of sulfur oxide emission and particulate matter.
As stated, the main problem regarding power plants in Southwest Virginia is the high sulfur content of Southwestern coal. One way this could be solved is by the use of coal having less than 1 percent sulfur. However, most of this coal is found in the western United States, such as the Rocky Mountain region.
AUTHOR Karl A. Sense, who is a retired physicist in the space program in California, now lives in Galax.
by CNB