The approval means the line's developer, Clean Line Energy, can begin negotiating with potential customers. The line will connect projects in wind rich northern Texas, western Oklahoma and southwest Kansas to Tennessee and Arkansas.
It is expected to come into operation in 2017.
The line will be able to carry 3.5GW. FERC has granted Clean Line the authority to negotiate rates and subscribe up to 75% of the line's transmission capacity to anchor tenants. The remainder will be offered on the same terms through an open season process.
Speaking about the approval, Oklahoma Energy Secretary Michael Ming said: "This approval from FERC is a great step towards developing Oklahoma’s low-cost clean energy resources. The Plains and Eastern Clean Line will create jobs, while enabling billions of dollars of investments in Oklahoma’s clean energy industry."