Another option for a hydrogen economy is ammonia. Ammonnia contains hydrogen and works better with metal and is being shipped around the world. The process of manufacturing ammonia is a dirty one at the moment, though.

This video is about the pollution involved with producing ammonia. There are more pollution problems -NOx is emitted when ammonia is used as a fuel. https://en.wikipedia.org/wiki/NOx

Using hydrogen and ammonia seem to be ideas that need to be worked out.