Existing power plants are the nation’s largest single source of carbon emissions. In the absence of comprehensive federal climate change, EPA is forging ahead with power plant controls through § 111(d) of the Clean Air Act. This article focuses on one critical consideration: the ancillary impacts of carbon controls on associated co-pollutants, like sulfur oxides, particulates, nitrogen oxides, and mercury. The article focuses on an array of regulatory options, including both “inside-the-fence” reductions at power plants and “outside-the-fence” measures that reduce power sector emissions, like renewable energy and consumer energy efficiency. The article then evaluates the co-pollutant consequences of several regulatory options in terms of their distributional impacts, stringency, transformative potential, capacity to generate real (rather than “paper”) results, and their capacity to generate actual reductions from the power sector. The article then uses this framework to evaluate a narrow proposal for limited reductions as well as EPA’s proposed § 111(d) rule, released June 2, 2014.

Although environmental justice concerns have focused on the potential adverse distributional consequences of cap-and-trade programs, the article reveals that distributional outcomes under all of the likely regulatory options are highly uncertain, and that other factors, like stringency, and the ability to take a system-wide approach that fosters stringency, are likely to be the most important factors for maximizing co-pollutant benefits. By taking a system-wide approach, EPA’s proposed § 111(d) takes an essential step toward transformative power sector changes. Still unclear, however, is whether the state targets EPA established in its proposal will trigger the degree of change needed to maximize both GHG and co-pollutant reductions.