I am not sure of the source of the data since it is not given on NET's Web site. But, there are extensive data on the EPA's Web site (www.epa.gov), including a 15-page report that states in the summary and conclusions section: "The reduction at any individual plant ranges from 0 to 98 percent dependent on coal type, control technology type, and other unquantified factors.

"A very limited set of short term full-scale trials of activated carbon injection have been carried out as described in this white paper. These trials do not cover a representative range of control technology-fuel combination that would be required to demonstrate the widely achievable levels of Hg [mercury] control that might be achieved in a cost effective manner. Furthermore, they represent short-term (four- to nine-day) continuous operation and do not address all of the operational issue and residue impacts that may be associated with commercial operation. Therefore, these technologies are not currently commercially proven to consistently achieve high levels of Hg control on a long-term basis."

Plants designed to burn sub-bituminous and lignite coals have trouble with mercury reduction. With sufficient research and development and demonstration of representative technologies, many systems can get emissions down by 90 to 95 percent by 2015, per the EPA.

But, sub-bituminous and lignite coals will require advanced absorbing materials and special oxidizing systems, needing more R&D to optimize mercury control approaches even before testing in full scale systems. All coal plants are different, and the 90 percent reduction by 2008 is unrealistic based on EPA data. A more realistic time frame is 2015 for all plants, which should be the standard.

Michael P. Siklosi

Bar Harbor