On 3 August 2015, U.S. President Barack Obama released the final rule of the Clean Power Plan (CPP), which regulates greenhouse gas emissions from existing power plants. The Environment Protection Agency has set average CO2 emission performance rates for electric utilities in each state, which will have until 2018 to report to the federal government on how they intend to comply. States have considerable flexibility in how to comply.  The three building block options are: increased power plant efficiency, fuel switch from coal plants to natural gas plants, and more renewable electricity generation. States also have the option of converting their emission rate targets to mass based targets and joining with other states through a cap and trade scheme like the Regional Greenhouse Gas Initiative (RGGI) in the northeastern and mid-Atlantic States. Compliance plans must be implemented no later than 2022. For states that do not submit plans, the EPA will impose an implementation plan. With the CPP, the EPA aims for a 32% reduction in electricity sector emissions by 2030 compared to 2005 levels.

Power plants make up a third of the U.S.’ national greenhouse gas (GHG) emissions. Meeting the CPP targets would result in a 6% reduction in national emissions and will play an important role in reaching the national emissions reduction target of at least 26% by 2025 compared to 2005 levels. However, various companies and states have already announced their intention to challenge the CPP in court. The result of the 2016 national presidential election would also play a role in the final impact of the CPP.