The requests, which are all from wind developers, are around four and a half times the line's capacity of 3.5GW.
The Grain Belt Express Clean Line is a 1,200-kilometre direct current transmission line between projects in Kansas and markets in Missouri, Illinois and Indiana.
There was a lot of interest in Missouri. Clean Line said ten respondents had submitted requests for a combined 3GW to deliver wind power to the state.
Last year, the Grain Belt Clean Line transmission line was granted approval to sell its services to wind farm operators in Kansas at negotiated rates.
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 960-kilometre Kansas section of the line.