I think the downside for hydrogen storage is the inefficiency of electrolysis. Last time I looked at it, you lose about 50% of the energy when making hydrogen.

I think the downside for hydrogen storage is the inefficiency of electrolysis. Last time I looked at it, you lose about 50% of the energy when making hydrogen. The plus side is that the fuel cell side is very efficient. It'd be practical to have hydrogen split from water at a large scale at solar farms or at existing power plants, and delivered to homes as backup power. (like propane?)