Mobile–Sierra doctrine.The principle that the Federal Energy Regulatory Commission may not grant a rate increase to a natural-gas producer unless the producer’s contract authorizes a rate increase, or unless the existing rate is so low that it may adversely affect the public interest (as by threatening the continued viability of the public utility to continue its service).United Gas Pipe

Line Co. v. Mobile Gas Serv. Corp., 350 U.S. 332, 76 S.Ct. 373 (1956); Federal Power Comm’n v. Sierra Pac. Power Co., 350 U.S. 348, 76 S.Ct. 368 (1956). — Also termed Sierra–Mobile doctrine. [Cases: Gas 14.4(1).]

[Blacks Law 8th]