"[I]t's . . . possible that some innovation will come along and make [other energy storage] ideas obsolete, the way the personal computer came along and more or less made the typewriter unnecessary. Cheap hydrogen could do that for storing electricity. . . . We could use electricity from a solar or wind farm to create hydrogen, store the hydrogen as a compressed gas or in another form, and then put it in a fuel cell to generate electricity on demand. [This] would solve the location problem; . . . although you can't ship sunlight in a railcar, you can turn it into fuel first and then ship it any way you like."