New Environmental Protection Agency rules cutting back on the amount of carbon emissions from power plants would cost the economy more than $50 billion per year through 2030, according to a U.S. Chamber of Commerce report that amounts to one of the first salvos in the upcoming war over the rules.

The report comes as the EPA is preparing to announce the first-ever greenhouse gas emission regulations for the 1,600 power plants that account for 40 percent of the nation’s carbon emissions. It signals a tortuous path for the Obama administration that likely will force the courts to decide the fate of the rule that is the centerpiece of President Obama‘s climate strategy.