The Clean Power Plan (CPP) was a landmark Obama-era environmental regulation proposed by the U.S. Environmental Protection Agency (EPA) in June 2014 and finalized on August 3, 2015. It aimed to reduce carbon dioxide emissions from existing fossil fuel-fired power plants by 32% from 2005 levels by 2030, while also cutting other pollutants like soot and smog that harm public health. The plan established state-specific goals based on the 'best system of emission reduction' (BSER), incorporating four building blocks: improving efficiency at coal plants, shifting generation to natural gas, expanding low- or zero-emitting renewable energy sources, and enhancing energy efficiency programs. States had flexibility to develop their own implementation plans, either individually or in multi-state collaborations, with options for rate-based or mass-based emissions limits. If states failed to submit compliant plans, the EPA could impose federal plans to ensure reductions.

The CPP was designed to accelerate the transition to clean energy, projecting benefits including up to 3,600 prevented premature deaths, 90,000 fewer childhood asthma attacks, and the creation of tens of thousands of jobs in renewables by 2030. It included incentives like the Clean Energy Incentive Program for early investments in renewables and energy efficiency in low-income communities, and safeguards for grid reliability during emergencies. However, the plan faced significant opposition from industry groups, coal-dependent states, and Republican lawmakers, who argued it would raise energy costs, harm jobs in fossil fuel sectors, and infringe on state authority. It was legally challenged by states including South Carolina, leading to a Supreme Court stay in 2016, and the Trump administration repealed it in 2019 via the Affordable Clean Energy rule, though efforts to replace or reinstate similar measures continued under subsequent administrations.

As one of the first major U.S. initiatives to regulate greenhouse gas emissions from the power sector under the Clean Air Act, the CPP influenced global climate efforts, aligning with the 2015 Paris Agreement. Its repeal and replacement highlighted partisan divides on climate policy, with supporters emphasizing health, economic, and environmental gains, while critics focused on reliability risks and economic burdens, as assessed in reports by organizations like NERC.