Super emitters in the United States coal-fired electric utility industry: comparing disproportionate emissions across facilities and parent companies

Environmental disproportionality research shows extreme differences in the production of environmental harm by what would seem to be similar producers. Although researchers have studied disproportionality among individual facilities in a given place or within a given industry, few assess such patterns at the corporate level. We conduct a disproportionality analysis of the generation of CO₂ emissions in the United States coal-fired electric utility industry between 2010 and 2015, comparing emissions distributions across two levels: individual facilities and groups of facilities owned by distinct parent companies. Although facility-based disproportionality patterns are largely attributable to the amount of electricity a power plant generates, this proxy for size does less to explain disproportionality patterns at the parent company level: we find that a small group of parent companies generates a disproportionate share of the industry’s total emissions, even when accounting for each company’s relative contribution to the electric grid. We find that disproportionality patterns are temporally stable within both groups. These findings suggest that researchers should consider how disproportionality among pollution producers may differ depending on the unit of analysis.