Page:United States Reports 502 OCT. TERM 1991.pdf/615

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Cite as: 502 U. S. 437 (1992)

457

Opinion of the Court

tempted to achieve it by “the illegitimate means of isolating the State from the national economy.” Philadelphia v. New Jersey, supra, at 627. The State embellishes this argument somewhat when suggesting that, by requiring the utilities to supply 10% of their needs for fuel from Oklahoma coal, which because of its higher sulfur content cannot be the primary source of supply, the State thereby conserves Wyoming’s cleaner coal for future use. We have no reason to doubt Wyoming’s unrebutted factual response to this argument: Reserves of low sulfur, clean-burning, sub-bituminous coal from the Powder River Basin are estimated to be in excess of 110 billion tons, thus providing Wyoming coal for several hundred years at current rates of extraction. Reply Brief for Wyoming 9, n. 4 (citing Geological Survey of Wyoming, Guidebook of the Coal Geology of the Powder River Basin, Public Information Circular No. 14, p. 126 (1980)). In any event, this contention, which is raised for the first time in Oklahoma’s brief on the merits, finds no support in the records made in this case. See Hughes v. Oklahoma, 441 U. S., at 337–338, and n. 20; cf. Maine v. Taylor, 477 U. S., at 148–149. Oklahoma argues more seriously that the “saving clause” of the Federal Power Act, 16 U. S. C. § 824(b)(1),13 which reserves to the States the regulation of local retail electric rates, makes permissible the Act’s discriminatory impact on the movement of Wyoming coal in interstate commerce. Oklahoma argues that it “has determined that effective and helpful ways of ensuring lower local utility rates include 1) reducing over-dependence on a single source of supply, a single 13

“The provisions of this subchapter shall apply to the transmission of electric energy in interstate commerce and to the sale of electric energy at wholesale in interstate commerce, but except as provided in paragraph (2) shall not apply to any other sale of electric energy or deprive a State or State commission of its lawful authority now exercised over the exportation of hydroelectric energy which is transmitted across a State line.” 16 U. S. C. § 824(b)(1).