Terms of the agreement were not made public. Houston-based Clean Line says the 720-mile-long (1,158km) Plains and Eastern is the first overhead HVDC transmission project in the US in more than 20 years, and the nation’s largest clean energy infrastructure venture.

Last March, the US Department of Energy (DOE) approved the project, designated a preferred route and agreed to participate in its development. Plains and Eastern is the furthest advanced of four planned HVDC transmission projects that would carry wind energy.

Construction