Does the prohibition against retroactive rate increases set forth in Section 206(a) of the Federal Power Act foreclose a judicially created exception authorizing a retroactive rate increase (surcharge)?

QUESTIONS PRESENTED Does the prohibition against retroactive rate increases, Ark. La. Gas Co. v. Hall, 453 U.S. 571 (1981), FPC v. Tenn. Gas Trans. Co., 371 U.S. 145, 152-53 (1962), set forth in Section 206(a) of the Federal Power Act, 16 U.S.C. § 824e(a) (2012), “mean what it says,” City of Anaheim v. FERC, 558 F.3d 521, 523 (D.C. Cir. 2009) (Kavanaugh, J.), and foreclose a judicially created exception authorizing a retroactive rate increase (surcharge)? Subsumed within this question are the related questions — (a) Does the D.C. Circuit’s reliance on general “enabling” language, authorizing “necessary or appropriate” actions, to confer on a regulatory agency a power that unambiguous operative statutory language expressly denied, exceed the statutory limitations imposed on the agency’s delegated powers? (b) As a matter of statutory construction, may “negative implication” be relied upon to confer on a regulatory agency powers which this Court’s precedents found to be expressly denied to the agency in clear and unambiguous operative statutory language? And (c) Does the D.C. Circuit’s reliance on a highly disfavored form of statutory construction, which was not advanced by FERC in support of the orders under review (and, indeed, was first raised on brief by intervenors before the Court of Appeals), violate this Court’s holding in SEC v. Chenery Corp., 332 U.S. 194 (1947), that judicial review of agency orders is confined to the grounds relied upon by the agency? (i)