The Affordable Clean Energy (ACE) repeals the Clean Power Plan (CPP). The CPP aimed to reduce emissions from the power sector by 32% below 2005 levels by 2030, by setting targets for each state individually. The ACE rule limits the scope of the plan to reduce emissions inside the fence at individual power plants, for example through efficiency measures or carbon capture and storage technologies and gives states the ability to set their own rules. The rule is under at least two legal challenges: one by a group of 23 State Attorneys General and six large cities and one by a group of major power utilities