15 U.S.C. § 717x

(a) Determination of entitlement (1) For purposes of determining the natural gas entitlement of any local distribution company under any curtailment plan, if the Commission revises any base period established under such plan, the volumes of natural gas which such local distribution company demonstrates— (A) were sold by the local distribution company, for a priority use immediately before the implementation of conservation measures, and (B) were conserved by reason of the implementation of such conservation measures, shall be treated by the Commission following such revision as continuing to be used for the priority use referred to in subparagraph (A). (2) The Commission shall, by rule, prescribe methods for measurement of volumes of natural gas to which subparagraphs (A) and (B) of paragraph (1) apply. (b) Conditions, limitations, etc. Subsection (a) shall not limit or otherwise affect any provision of any curtailment plan, or any other provision of law or regulation, under which natural gas may be diverted or allocated to respond to emergency situations or to protect public health, safety, and welfare. (c) Definitions For purposes of this section— (1) The term “conservation measures” means such energy conservation measures, as determined by the Commission, as were implemented after the base period established under the curtailment plan in effect on November 9, 1978 . (2) The term “local distribution company” means any person engaged in the transportation, or local distribution, of natural gas and the sale of natural gas for ultimate consumption. (3) The term “curtailment plan” means a plan (including any modification of such plan required by the Natural Gas Policy Act of 1978 [ 15 U.S.C. 3301 et seq.] ) in effect under the Natural Gas Act [ 15 U.S.C. 717 et seq.] which provides for recognizing and implementing priorities of service during periods of curtailed deliveries.