There are few wind turbines west of the Missouri River in South Dakota, and some experts say a lack of transmission lines is the main reason. 

A group of energy consultants is raising money to study a potential project that could change that. The $9 billion transmission line would unite the eastern and western power grids of the U.S. with a line traversing southern South Dakota.

The Power from the Prairie project would connect the two U.S. grids (which both have a footprint in South Dakota) with a 4,000-megawatt electric transmission line. That’s enough electricity to power around 4 million homes, according to Robert Schulte, the project’s president and principal at Schulte Associates, an energy consulting firm in North Carolina. He spoke with the South Dakota Wind Energy Association and South Dakota Renewable Energy Association about the project on Sept. 29 in Sioux Falls.