text: Clean Power Plan: In June 2014, the EPA proposed a rule to control greenhouse gases from existing power plants, known as the Clean Power Plan. The unprecedented rule would regulate the entire electric industry, rather than on a source-by-source basis as had been EPA's practice for 40 years. As such, the proposed Clean Power Plan would grossly expand EPA's authority into the states' traditional authorities. For 80 years, States have overseen retail electricity markets shielded from federal intrusion. The Clean Power Plan would radically alter this arrangement, which dates from the New Deal, such that state authority would now fall under the thumb of EPA approval. In addition to posing grave federalism concerns, the rule would be the most expensive regulation ever imposed on the power sector, costing between $41 billion and $73 billion per year.