MEIC Negotiates a Mercury Control Agreement for the Hardin Generating Station

In January 2005, MEIC filed an administrative appeal of the air quality permit issued to Rocky Mountain Power (RMP) for the Hardin Generating Station (HGS). RMP wants to build a 116-megawatt coal-fired power plant near Crow Agency. MEIC appealed the permit issued by the Montana Department of Environmental Quality because of its concerns about the mercury emissions from the plant.

Mercury is a potent neurotoxin that has been linked in scientific studies to many diseases and developmental problems, ranging from autism in children to heart disease in men. Coal-fired power plants are the largest source of mercury emissions in the United States. In Montana, warnings have been issued for every water body in the state, advising certain people to minimize or eliminate fish consumption due to mercury contamination.

MEIC is committed to preventing coal-fired power plants from continuing to emit this toxin. The permit that DEQ issued in December 2004 contained mercury emission limits so weak as to be meaningless. In its application, RMP had submitted data on the mercury content of the coal it intended to use. The permit allowed the company to emit 27% more mercury than its uncontrolled emissions would contain. So MEIC appealed.

MEIC was not the only party to file an appeal. Three individuals from Crow Agency—Bill and Mari Eggers, and Tracy Small—also appealed, citing concerns about mercury, sulfur dioxide, and particulates, among other things. In addition, RMP appealed, saying the permit “establishes a [mercury] emission limitation where significant uncertainty exists whether this limitation can be achieved.” The company’s appeal expressed similar concerns about the achievability of the emissions limitations for sulfur dioxide and particulates. A July 2005 hearing was scheduled before the Board of Environmental Review for the three appeals.

The parties have been negotiating in an attempt to resolve their differences prior to the Board hearing. Those discussions have now resulted in an agreement between the three appellants and DEQ. The Board approved the agreement in May 2005.

The agreement allows the HGS to be a test facility for mercury controls during the first three years of its operation. Sometime in that period RMP must install a mercury control technology known as activated carbon injection (or a similarly effective technology approved by DEQ). After the mercury removal equipment has operated for 18 months, DEQ will establish a final emission limit for mercury based on what the equipment has been shown to be capable of achieving. In exchange for being the first coal-fired power plant in Montana to install mercury control equipment, HGS will receive slightly less stringent emission standards for particulates and sulfur dioxide for the 18-month period. After that, the plant must comply with the more stringent standards DEQ will set in the final permit. This provides RMP the flexibility it believes it needs to bring the plant to full operating status.

Activated carbon injection systems are the technology of choice for mercury control for coal-fired power plants. Tests have shown them to be effective at controlling more than 90% of the mercury emissions at many plants around the country. Whether HGS can achieve such a high level of mercury control remains to be seen. However, the agreement requires it to do the best job it can of controlling its mercury emissions, and DEQ is supposed to set a final emission limit that reflects what the test results show is possible.

This agreement is a significant step forward in controlling mercury emissions from coal-fired power plants in Montana, and perhaps around the country. If a relatively small plant in Montana burning western coal—from which mercury removal is supposed to be more difficult—can install and operate effective mercury control equipment, all plants should be able to do so.

IN THE NEWS

• DEQ seeks $484,800 penalty for air violations at Hardin Plant (posted on Aug. 22, 2007, by the Associated Press)