Electricity from renewable sources available 24/7 now, or soon

Could solar energy power the entire electric grid even though the sun is only up, in any given place, an average of 12 hours a day?

Yes. It would be expensive to build solar power plants across every time zone, and interconnect them so that the sun would always be up somewhere over the electric grid, but it could, theoretically, be done.

Projects that seem like that type of science fiction are being developed. Companies in the United Kingdom and Morocco are working on a system that will export electricity generated by a combination of solar and wind power from the Moroccan desert to Great Brit...