Power plants are a major source of carbon emissions in the US. The EPA is working on controlling these emissions through the Clean Air Act. They are looking at how reducing carbon emissions can also affect other pollutants like sulfur oxides and mercury. Different options are being considered, including changes within power plants and promoting renewable energy. The focus is on factors like fairness, effectiveness, and the potential for real results. The EPA's proposed rule aims to make significant changes in the power sector, but it's uncertain if it will be enough to reduce both greenhouse gases and other pollutants.