On January 25, 2016, the Supreme Court decided several energy cases consolidated under the heading Federal Energy Regulatory Commission v. Electric Power Supply Association. These cases concern a practice called “demand re­sponse,” in which operators of wholesale markets pay electricity consumers for commitments not to use power at certain times. In the regulation challenged here, the Federal Energy Regulatory Commission (FERC) required those market operators, in specified circumstances, to compensate the two services equivalently—that is, to pay the same price to demand response providers for conserving energy as to generators for making more of it. The U.S. Court of Appeals for the D.C. Circuit vacated this regulation, however, holding it beyond the FERC’s authority under the Federal Power Act as well as arbitrary and capricious, for failure to justify adequately a potential windfall to demand response providers. -- The Supreme Court granted certiorari on two questions: (1) Does the Federal Power Act permit FERC to regulate these demand response transactions at all, or does any such rule impinge on the States’ residual authority? (2) Even if FERC has the requisite statutory power, did FERC fail to justify adequately why demand response providers and electricity producers should receive the same compensation? -- By a vote of 6-2, the Court reversed the judgment of the D.C. Circuit and remanded the case, holding that (1) FERC did possess adequate regulatory authority under the Federal Power Act; and (2) FERC’s decision to compensate demand response providers at locational marginal price was not arbitrary and capricious. Justice Kagan delivered the opinion of the Court, in which the Chief Justice and Justices Kennedy, Ginsburg, Breyer, and Sotomayor joined. Justice Scalia filed a dissenting opinion in which Justice Thomas joined. Justice Alito was recused from this case. -- To discuss the case, we have James Coleman, who is assistant professor at the University of Calgary, Faculty of Law and Haskayne School of Business.