For Immediate Release
May 31, 2002

Contact: Bill Skewes, WUA608-231-6814

MILWAUKEE - Mercury deposition in most areas of the state would decline by less than five percent even if emissions from the state's power plants were completely eliminated. That is a key finding from the "Wisconsin Mercury Deposition Case Study" conducted by Atmospheric and Environmental Research, Inc., managed by the Electric Power Research Institute, and sponsored by the Wisconsin Utilities Association (WUA). WUA announced these findings today and is requesting that the Wisconsin Department of Natural Resources (DNR) consider this information as it determines state mercury reduction requirements.

Last year, the DNR proposed rules that would require the state's major utilities to reduce mercury emissions from coal-fueled power plants by 30, 50 and 90 percent over five, 10 and 15 years, respectively. WUA supports reductions of 10 and 40 percent over five and 10 years, respectively, for these affected sources.

"We think it's a good idea to reduce the level of mercury in the environment and we support reasonable state rules for reducing mercury from coal-fueled power plants," said Bill Skewes Executive Director of the Wisconsin Utilities Association. "However, this case study shows that there would be limited environmental benefit achieved from the DNR's proposal. We think it is important that utility customers be informed of the level of environmental improvement that can realistically be accomplished by the state-only rules."

The "Wisconsin Mercury Deposition Case Study" simulated the transport, chemical, and physical transformations of mercury emissions using detailed chemical, meteorological, precipitation, and geographic data. The model simulations focused on the upper Midwestern and Northeastern United States. The DNR's inventory of in-state sources of mercury emissions was a primary input to the model. The DNR estimates that slightly less than one third of mercury released in the state comes from Wisconsin's coal plants.

The principal modeling result is that mercury deposition in Wisconsin declines by one to four percent, even when the state's coal plant emissions are completely eliminated.
These results are based on comparing modeling simulations with and without Wisconsin
utility emissions of mercury included. The model was verified using actual mercury deposition data measured through the Mercury Deposition Network (MDN). Four of the 30 MDN monitors are located in Wisconsin.

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These findings are consistent with a study conducted by the U.S. Environmental Protection Agency (EPA) in the mid 1990's that estimated that less than seven percent of mercury emissions from large coal-fueled utility boilers is deposited within 50 kilometers of the facility and a study funded by the Lake Michigan Air Directors Consortium (LADCO) released this year. LADCO is a consortium comprised of the DNR and other state air regulatory agencies of the upper Midwest. The LADCO study estimated that utility sources in Wisconsin contribute one to five percent of mercury deposition. Both studies employed the most recent EPA models of mercury deposition then available.

Model performance for the current modeling simulations was considered very good. The simulations did, however, over-predict the amount of mercury being deposited in Wisconsin compared to the measured data from the MDN monitors. Therefore, the estimates contained in the current modeling are likely to represent an upper limit on the contribution of local and regional sources to mercury deposition in Wisconsin.

Utilities say that they would like their customers and state policy-makers to be more informed of the science behind this environmental issue.

"Decision makers need to have a more realistic understanding of how much of the mercury in Wisconsin lakes comes from the state's coal plants. We hope the DNR will review this data and use it in the rule-making process," said Skewes. "The final rules must achieve an acceptable balance among environmental, energy and economic objectives and impacts."

The proposed mercury control actions are intended to reduce in-state mercury deposition, and ultimately mercury levels in the state's fish. Much of the support for the rule has been based on the potential to reduce state mercury fish advisories.

Although the study did not specifically evaluate the direct impact that reducing in-state mercury reductions would have on state fish advisories, since the expected reduction in the level of mercury deposited to lakes is so low, no reduction in fish advisories is anticipated.

The Wisconsin Utilities Association (WUA) represents the state's investor-owned power providers before the Legislature and state regulatory agencies.

• Wisconsin Mercury Deposition Case Study - Summary of Results