The key regulatory hurdle was cleared when the Federal Energy Regulatory Commission granted approval for the sale of capacity on the 1,200-mile (1,900-kilometre) overhead direct-current transmission line.
When operational, the project is intended to deliver up to 3.5GW of wind-generated energy from western Kansas to energy consumers in Missouri, Indiana and Illinois.
Clean Line is a utility based in Kansas and Indiana. It received an order from the Kansas Corporation Commission in November 2013, granting it a permit to construct a 595-mile Kansas section of the line.
The transmission line has now been granted authorisation to negotiate bilateral agreements with generators for all of the line's capacity.
"Generator interconnection to the Grain Belt Express will be subject to the requirements of the project's open access transmission tariff," the company said in a statement.
The company has already announced preferred supplier agreements with ABB, Hubbell Power Systems and General Cable.
While there are still other permitting approvals to be granted, including construction consent from states other than Kansas, the company believes the line could be operating as early as 2018.
Kansas has the eight highest installed wind capacity among US states, with 2.9GW in the ground. It already generates 19% of its power from wind. By contrast, Missouri only generates 1.3% of its electricity from wind.