There's a technology called - battery. Some hold energy for quite a while. And the article mentions Rwanda. If the prime market is this huge continent, then you might be able to use the sun to augment the "other energy source".

I think it's interesting to notice that most (I try hard not to write all) comments so far seem to be armchair designer style. It's like 'build the next toilet' is a new bike shed.

Yeah, I'm skeptical as well, but assuming that the scientists are full of .. err - just want to grab the money and have no clue what they are talking about seems weird to me..