Google tackled this problem with all the vigour you'd expect, they were right out there at the jagged edge. A few years ago they ran up the white flag conceding defeat. They saw no way the energy return over energy input would be more than two.
I'd have a shilling or two to say Google has some pretty smart cookies working on this. Smarter than me and thee.
Note that the industrial processes involved cannot tolerate intermittent power supplies so you need regular base load power forever because it will take that long to build a renewable grid. Like the light on the hill, or the end of the rainbow, it is always out of reach.
