According to an Arizona State University study led by Senior Sustainability Scientist Kevin Gurney, federal data on power-plant carbon dioxide emissions is significantly flawed.

Power plants are responsible for roughly 40 percent of carbon dioxide emissions nationwide. Inaccurate data concerning these emissions undermines the federal Clean Power Plan, which is designed to strengthen the clean-energy trend by setting a national limit on the carbon pollution produced by power plants.

“This policy relies on the achievement of state-level CO2 emission-rate targets,” write the study's authors. “When examined at the state level, we find that one-third of the states have differences that exceed 10 percent of their assigned reduction amount. Such levels of uncertainty raise concerns about the ability of individual states to accurately quantify emission rates in order to meet the regulatory targets.”