The Case for Coal Rank Subcategorization to Regulate Mercury Emissions

摘要

Much has been written and discussed about the EPA's decision to regulate utility Hg emissions based on coal rank—bituminous, subbituminous, or lignite. Some have argued that a one-size-fits-all regulatory approach would be more appropriate. However, in its final rulemaking for CAMR, EPA recognized that to effectively and efficiently regulate Hg emissions, the rule must take into consideration the chemistry of the respective coal type. Hg emissions from coal-fired power plants come in three distinct forms—oxidized, particulate-bound, and elemental—and coal rank determines the relative proportions of these forms in total Hg emissions. Coal rank-based allocation of Hg emissions budgets will result in a regulatory approach that effectively and efficiently addresses the controllability of Hg emissions and their environmental impacts .