Why aren't we only using solar power?

Solar power is cheaper and more sustainable than our current coal-fueled power plants, so why haven't we made the switch? The real culprits here are the clouds, which make solar power difficult to control. Alexandros George Charalambides explains how solar towers and panels create electricity and how scientists are trying to create a system that can function even under cloud cover. [Directed by Richard O'Connor, narrated by Addison Anderson].