What is EPA's Affordable Clean Energy ACE Rule?
EPA has proposed a new rule for greenhouse gas emissions at power plants called the Affordable Clean Energy Rule (ACE) Rule.
EPA has proposed a new rule for greenhouse gas emissions at power plants called the Affordable Clean Energy Rule (ACE) Rule. This rule is a replacement for the controversial Clean Power Plan (CPP) Rule.
⚡ TL;DR — The ACE Rule shifts power to states to set their own greenhouse gas emission reduction standards for existing coal plants. Federal standards replaced by state-by-state flexibility. If you operate a facility with air emissions, compliance landscape just got more fragmented.
The CPP Rule was developed by the Obama Administration, and it put some definite limits in place to reduce greenhouse gas emissions at power plants. The rule created quite a bit of controversy and EPA was taken to court by a number of parties. The Trump Administration and EPA put the CPP on hold in order to review it for potential repeal and replacement. The new ACE Rule is the result of this review.
⚠️ The Problem — State-level rules create complexity. What passes in one state may not in another. Facilities operating across state lines now need to track multiple standards. Regulatory uncertainty makes long-term planning difficult. You need state-specific guidance before your next permit renewal.
With the new ACE Rule, EPA hands over greater power to the states to set their own limits. According to EPA, ACE will reduce greenhouse gas emissions through four actions:
Defines a “Best System of Emission Reduction”, for existing power plants based on heat rate efficiency improvements; Provides states with an example list of technologies that may be used in their rules to establish standards of performance; Updates the New Source Review permit program to further encourage efficiency improvements; and, Puts the regulation in Clean Air Act section 111(d) to give states time to develop their own plans.
Opponents of the original CPP Plan say that while limiting greenhouse gas emissions is very important, the makeup of the CPP Plan went too far. It would create burdensome regulation and a tremendous negative economic impact. Coal industry advocates are happy with the ACE Rule in that it will save coal industry jobs. Also, giving the responsibility back to the states will allow states to customize their rules for the conditions and economies around them.
Critics of the new ACE Rule say the new regulations will not nearly reduce the emissions the CPP would have. There is some fear it’ll allow states to write less strict regulations that the power companies will be able to get around. Other say the new rule appears to be an appeasement to the coal industry.
EPA says that replacing CPP with ACE will save $400 million in net benefits and $400 million in compliance burden, will still reduce greenhouse gas emissions, and may reduce carbon dioxide emissions even as much as 33-34% from 2005 which is even more than what CPP projected.
The ACE Rule is available for comment and there will be a public hearing scheduled. The D.C. Circuit Court will also have to determine if it is a suitable replacement for the CPP rule, which is still on hold with the court.
Most facilities operating under air permits don’t track how state-level ACE implementation will change their compliance roadmap. If your state adopts stricter efficiency requirements, your facility may need equipment upgrades or operational changes. We help map what ACE means for your specific operation and your state’s likely approach.
Which EPA environmental air regulations apply to your facility? iSi can help determine what applies and help you get the paperwork completed!
💰 Typical planning cost: $2,000–$4,000 for state-level air permit analysis and compliance roadmapping. Non-compliance with new state ACE rules can cost $10,000–$50,000+ per violation depending on facility type.
Frequently Asked Questions
Q: What is the EPA’s Affordable Clean Energy (ACE) Rule?
The EPA’s Affordable Clean Energy (ACE) Rule regulates greenhouse gas emissions from existing coal-fired power plants under Clean Air Act Section 111(d). The rule replaced the controversial Clean Power Plan and allows states to develop their own emission reduction plans rather than requiring federal standards. The ACE Rule emphasizes heat rate efficiency improvements and gives states flexibility in setting emission standards.
Q: What are the key differences between the ACE Rule and the Clean Power Plan?
The Clean Power Plan (CPP) established federal emission reduction standards that were prescriptive and controversial, while the ACE Rule devolves authority to states to establish their own emissions standards. The ACE Rule focuses on heat rate efficiency improvements for existing plants, whereas CPP used a broader range of strategies. This state-flexibility approach was intended to reduce regulatory burden and economic impact.
Q: How does the ACE Rule help power plants reduce greenhouse gas emissions?
The ACE Rule encourages emission reductions through four mechanisms: defining “Best System of Emission Reduction” based on heat rate efficiency, providing states with example technologies for emission reduction, updating New Source Review permitting to encourage efficiency improvements, and allowing states time to develop their own emission plans. State plans can include technology improvements, maintenance optimization, and operational efficiency changes.
Q: Does the ACE Rule apply to facilities other than power plants?
No, the ACE Rule specifically regulates existing fossil fuel-fired power plants under EPA authority. Other facilities with air emissions are governed by different EPA rules including New Source Performance Standards (NSPS), Prevention of Significant Deterioration (PSD), and Title V permitting requirements based on facility-specific operations and emissions profiles.
Need help understanding your state’s air compliance requirements? Contact iSi Environmental for a same-day quote, or explore our EPA services to see how we can help your facility.
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