Questions and Answers on the EPA's Legal Authority to Set "System Based" Carbon Pollution Standards for Existing Power Plants under Clean Air Act Section 111(d)

In his June 25, 2013, Climate Action Plan and an accompanying memorandum, President Obama directed the Environmental Protection Agency (EPA) to use Section 111 of the Clean Air Act to curb carbon pollution from new and existing power plants. Power plants are the nation’s largest source of the heat-trapping pollution that drives dangerous climate change, and there are no federal limits on their emissions.

In December 2012, NRDC proposed a flexible, "system based" plan for cutting dangerous carbon pollution from the nation’s existing power plants.8 Our proposal responds to the urgent threat of climate change and offers overwhelming benefits at reasonable cost. Using the same power sector modeling tools used by the EPA and the power industry, NRDC projects that our plan will achieve a 26 percent reduction in power sector CO2 emissions by 2020, compared with 2005 levels, with climate protection and public health benefits worth $26 to 60 billion in 2020, at a reasonable cost of $4 billion. This paper addresses frequently asked questions about implementing a system-based approach to power plant standards under Section 111(d).