In the U.S., a substantial portion of the best wind and solar resources are far from where most of the nation’s electricity is consumed. That fact has spurred development of new transmission lines to efficiently and cost-effectively move large volumes of wind and solar power long distances.

For example, Clean Line Energy Partners, Houston, is in various stages of developing five wind-focused transmission projects, most of which will move power from the Great Plains—where winds are strongest and most reliable—to the energy-hungry Midwest, Southeast and West Coast (see map).

Clean Line President Michael Skelly says moving renewable power to market is “an age-old problem. They needed a transmission line to deliver power from the first hydroelectric project at Niagara Falls to Buffalo” in the 1890s, he says, adding that major transmission lines also were needed to move energy from the Hoover Dam to Los Angeles.

Virtually all U.S. transmission lines use alternating current (AC), but Clean Line’s projects will use direct current (DC), which reduces energy losses over long distances. In the 1960s, the Pacific DC Intertie was developed to efficiently move up to 3,100 MW of hydroelectric power from the Pacific Northwest to Southern California (blue line on map).

Skelly says that Clean Line is furthest along in developing its proposed $2-billion Plains & Eastern transmission project, which, by decade’s end, will be moving up to 4,000 MW of wind power to a location near Memphis from the Oklahoma Panhandle. From there, existing AC lines will deliver the wind power to utilities in the mid-South and Southeast.

Developers in Oklahoma, Kansas and Texas already want to feed wind power into Plains & Eastern’s western end, Skelly says, and utilities to the east are working toward deals to buy and receive that power. Quanta Services, Clean Line’s construction adviser on the project, expects to begin construction in 2017.

“We’re also working on the Grain Belt Express and Rock Island projects,” says Skelly, referring to DC projects that, by the early 2020s, will move wind power to the Midwest from western Kansas and northwestern Iowa, respectively. Clean Line’s other projects—Centennial West and Western Spirit—will move wind and solar power to the West.

Clean Line is not alone. Pattern Energy has been developing Southern Cross, a proposed DC line that is designed to run 400 miles to eastern Mississippi from Texas.