Wisconsin's Mercury Rule and Revisions

The mercury rule was revised in 2008. Links to supporting documents related to the Board's action are listed below.

Rule Summary

90% reduction by 2015: Under the proposed mercury rule, large coal-fired power plants must either meet a 90% mercury emission reduction or limit the concentration of mercury emissions to 0.0080 pounds of mercury per gigawatt-hour by January 1, 2015.

Multi-pollutant option: Large coal-fired power plants also have the option of choosing a multi-pollutant alternative. The multi-pollutant alternative requires the affected power plants to achieve nitrogen oxides (NOx) and sulfur dioxide (SO2) reductions beyond those currently required by federal and state regulations. Under the multi-pollutant approach, an additional six years is allowed to achieve the 90% mercury emission reduction standard. Further, under that option, interim mercury reduction provisions are established. The affected power plants must meet either a 70% mercury emission reduction or a mercury emission concentration of 0.0190 pounds per gigawatt-hour by January 1, 2015. Beginning January 1, 2018, an 80% mercury emission reduction or an emission concentration limit of 0.0130 pounds of mercury per gigawatt-hour must be achieved. By January 1, 2021, a 90% mercury emission reduction or an emission concentration limit of 0.0080 pounds of mercury per gigawatt-hour is required.

Mercury Rule Factsheet