its not an efficient enough process to be financially viable yet.

maybe in a few years it will improve with technology or the price of oils will go up enough to make it viable that way.

Its a good idea if it can be made as a truley renewable process. If it needs shit loads of electric from the grid powered by coal and oil fired power stations (now that we a nuclear paranoid despite nuclear being the only sensible medium term stop gap) then its not as green just moving the carbon emissions to a different place.

same with the prius and other electric cars and hybrids. If the electric fuelling them isnt green then its pointless.