As the United States Environmental Protection Agency (EPA) stands poised to issue the final rule on reducing carbon emissions from existing power plants, states are considering how to incorporate energy efficiency into their compliance plans. As part of their annual meeting, the Association for Environmental Studies and Sciences asked Jim Lazar to address a recent paper by John Laitner showing the cost-effectiveness and job creation potential of a 20-percent energy efficiency target. Mr. Lazar expands on Mr. Laitner’s study, positing that including both the carbon value of energy efficiency and a modest level of non-energy benefits increases the optimal energy efficiency level to 25 percent, and would produce enough carbon savings to meet the entire reduction mandate under the EPA’s Clean Power Plan.