A problem with renewable energy sources like wind and solar is that a wind or solar farm might have a rated capacity of many megawatts, but there is no guarantee that times of demand will exactly coincide with times of supply.

Hydrogen is easily produced by the hydrolysis of water, and could be achieved cheaply by using this spare capacity whenever it occurs. Thus all electrical energy companies could improve profitability by setting up hydrogen production facilities.

@Petter Electricity storage for off-hour use will mostly be batteries. Time will tell, but I doubt hydrogen will be used for that purpose at all.

@EdEarl Not for Off peak storage. That's not what I meant.
For use in fuel cell equipped motor vehicles. This technology, given plentiful, cheap hydrogen, would be a most attractive option, allowing electric hybrid cars to carry much smaller batteries, yet have an extended range.

@Petter Time will tell, but I think H2 manufacture and storage will never be less expensive than battery storage of electricity, for any purpose.