December 19, 2011. Duke Energy Corp. and American Transmission Co. have bought a $3.5 billion powerline project that would bring wind energy from Wyoming to California and the U.S. Southwest. Duke-American Transmission Co., a joint venture of the companies, bought the 950-mile (241-kilometer) Zephyr Power Transmission project from Pathfinder Renewable Wind Energy LLC, Charlotte. Pending regulatory approval, the project is expected to be completed in 2020 and will be able to send 3,000 megawatts of power from wind farms in Wyoming to demand centers in California and the U.S. Southwest. Zephyr will be built alongside a wind farm Pathfinder is developing near Chugwater, Wyoming. The 500 kilovolt high-voltage direct-current project, which Pathfinder bought in July from TransCanada Corp. (TRP), will run from Chugwater and end in the Eldorado Valley south of Las Vegas.