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Attorney General William Tong



Coalition of 29 States, Counties and Cities Charges Trump EPA’s “Dirty Power” Affordable Clean Energy (ACE) Rule Violates Clean Air Act While Propping Up Dirty, Expensive Coal Power and Undercutting Clean, Renewable, and Affordable Energy

(Hartford, CT) – Attorney General William Tong joined a coalition of 22 states and 7 local governments today in announcing a lawsuit challenging the U.S. Environmental Protection Agency's "Dirty Power" rule.

The ACE rule replaced the Clean Power Plan, the first-ever nationwide limits on one of the largest sources of climate change pollution – existing fossil-fueled power plants. The EPA’s rule rolls-back these limits and will have virtually no impact on these emissions, prolonging the nation’s reliance on polluting, expensive coal power plants and obstructing progress of states toward clean, renewable, and affordable electricity generation.

"I believe in science. Climate change is real and if we do nothing to curb our reliance on fossil fuels we are dooming future generations and our planet. The Dirty Power rule is a craven, political attempt to protect Trump's toxic allies in the fossil-fuel industry from the change we all know is urgently required. Trump and his Big Pollution friends need to stop prolonging this inevitable shift, and start truly investing in clean, renewable and affordable power," said Attorney General Tong.

Besides ignoring the science of climate change – the text of the ACE rule barely mentions climate change, much less recognize the dire threat it poses to people’s health, the economy, and the environment – the rule disregards requirements of the federal Clean Air Act. The Clean Air Act requires that limits on air pollutants, such as greenhouse gases, must be based on the emissions reductions achievable through the “best system of emission reduction.” However, in the “Dirty Power” rule, EPA has ruled out as such a “best system” the most cost-effective, proven, and successful approach to controlling greenhouse gas emissions: shifting from coal-fueled generation to less carbon-intensive generation.

Unlike the Clean Power Plan, which was modeled after successful state programs that require cleaner energy generation, the ACE rule turns a blind eye to these programs. For example, the 10-state (New York, Connecticut, Delaware, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, Rhode Island, and Vermont) Regional Greenhouse Gas Initiative (RGGI), a market-based cap-and-trade program, has proven to be an effective, cost-efficient model for reducing power plant emissions of climate change pollution. Power plants in the participating RGGI states have cut their emissions by more than 50 percent, and between 2015 and 2017, these states saw $1.4 billion of net positive economic activity and the creation of 14,500 new jobs – all while maintaining reliability of service and holding the line on electricity rates.

In fact, the “Dirty Power” rule goes so far as to prohibit states from participating in cap-and-trade programs means of complying with the requirements of the Clean Air Act.

Significantly, the “best system of emission reduction” used by the Trump EPA in the “Dirty Power” rule – equipment upgrades at coal power plants – will reduce emissions by only 0.7 percent more by 2030 than having no rule at all, according to EPA’s own analysis. Further, EPA found that emissions of one or more of three pollutants – carbon dioxide (CO2), nitrogen oxides (NOx), and sulfur dioxide (SO2) – will increase in 18 states in 2030 compared to no “Dirty Power” rule.

The differences in benefits provided by the Clean Power Plan compared to the Trump “Dirty Power” rule are substantial, as reflected in the table below using the agency’s own calculations when it finalized the two rules:

“Dirty Power”Rule

(ACE Rule)

Clean Power Plan

Pollutant Reductions by 2030

CO2 (million tons)





SO2 (thousand tons)





NOx (thousand tons)





Benefits by 2030($ millions)*



Costs by 2030($ millions)*



Net Benefits by 2030

($ millions)*



* 3% Discount Rate; ACE rule in 2016 dollars and Clean Power Plan in 2011 dollars.

Sources: Regulatory Impact Analysis for the Repeal of the Clean Power Plan, and the Emission Guidelines for Greenhouse Gas Emissions from Existing Electric Utility Generating Units, EPA-452/R-19-003 (June 2019); Regulatory Impact Analysis for the Clean Power Plan Final Rule, EPA-452/R-15-003 (August 2015).

The implications of the “Dirty Power” rule’s failure to achieve virtually any reductions in power plant emissions are extensive. The International Energy Agency estimates that climate change pollution from the U.S. power sector must be reduced by 74 percent by 2030 below 2005 levels for the U.S. to be able to achieve the goal of limiting worldwide temperature increase to less than 2 degrees Celsius. By the EPA’s own estimates, the “Dirty Power” rule falls woefully short of hitting this target with a projected reduction of only 35 percent from 2005 levels. Of that, only roughly one percent is attributable to the impact of the “Dirty Power” rule and 34 percent attributable to market factors.

Assistant attorneys general Scott Koschwitz and Matt Levine, Head of the Environment Department, assisted the Attorney General in this matter.

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