The problem with alternative sources for the grid is that none of them is 100% all the time (even windmills near the North Sea, as Denmark has found out). Our grid needs 100% all the time.
However, if one could use the excess that alternative sources produce to JUST produce this fuel—where the plant doesn’t need 100% power all the time...it could be an excellent way to store the extra energy that alternatives produce, when they are running...
If they can make a plant that produces NOT attached to the grid, than great! Even if, as stated above solar or other sources have low-efficiency rates, so what? If it can all go into oil production...with no drain on the grid for the rest of us—than a major new source of energy-storage (THE issue for alternative energy) may be upon us.
Not very good with economics. Tying capital up in inefficient production makes for a very expensive product. And turning expensive electricity via a further inefficient process only worsens the losses.