After years of rejection, court battles and delays, a four-state transmission line that would connect western Kansas wind farms to the eastern power grid gained approval from the Missouri state agency that regulates public utilities. With the Grain Belt Express projected to cross properties of 570 Missouri landowners, the Missouri Landowners Alliance and Eastern Missouri Landowners Alliance said they plan to appeal the Public Service Commission’s order to the Missouri Court of Appeals, according to the opposition’s attorney Paul Agathen.Though far from the last step, Wednesday’s unanimous vote by the five PSC commissioners in favor of granting the Grain Belt Express a certificate of conveniency and need -- giving it the ability to acquire property through eminent domain -- is the furthest the project has come in its quest to stretch a transmission line more than 200 miles through eight northern Missouri counties.