In the below link they claim to be able to now extract hydrogen...

In the below link they claim to be able to now extract hydrogen from water simply using a dye-sensitized photoelectrosynthesis cell rather than external power. This obviously would be good for fuel cells as each house would require a fuel cell for generating electricity at night



http://www.pennenergy.com/articles/pennenergy/2014/02/unc-researchers-harness-solar-power-during-day-for-use-at-night.html