Solar thermal fuels convert light to heat -- someday . . .

If you skip the liquid part, the technology to convert sunlight into usable fuel has been around (and used) for many millennia. Growing up, we heated our house with solar energy...slightly indirectly, using wood as an intermediary storage medium.

That's not to suggest that this isn't a cool and technology being developed, nor one that has the potential to be of significant value, of course.