A private benefit can still be condemnation's "public use."

Even though the federal government would get only 10 percent of the power transmitted from a public-private power line in Central California, that is still a "public use" for the purpose of allowing a taking under the Fifth Amendment. That's the ruling of the Ninth Circuit Court of Appeal in the case of U.S. v. 14.02 Acres of Land More or Less in Fresno County 2008 WL 4684092. Relying primarily upon Kelo v. City of New London (2005) 545 U.S. 469 and Haw. Hous. Auth. v. Midkiff (1984) 467 U.S. 229 the Court acknowledged that it is unconstitutional under Kelo for the government to take private property simply to transfer it directly to another private party. But in this case the Court was following the principal from those cases that: “It is only the taking's purpose, and not its mechanics that matters in determining public use.” The taking of the land here was to provide power transmission by the federal Western Area Power Administration. The Court declined to step into the legislative decisionmaking that authorized the transmission line improvements, but reference was made to California's power blackouts in recent years as motivating the project. The decision notes that the WAPA will retain ownership of both the land from the taking as well as transmission improvements constructed... This is unlikely to be the case that will one day be before the U.S. Supreme Court that addresses Kelo's outstanding question: then what exactly is a "private-to-private" transfer by taking that would be prohibited?