Well this is good point, but this way you can negate anything
What I was thinking about is that water could be broken into hydrogen and oxygen by electrolysis—a photoelectrochemical cell (PEC) process which is also named artificial photosynthesis. Research aimed toward developing higher-efficiency multijunction cell technology is underway by the photovoltaic industry.
Here's process description from public source:
Electrolysis of water
Hydrogen can be made via high pressure electrolysis or low pressure electrolysis of water. In current market conditions, the 50 kWh of electricity consumed to manufacture one kilogram of compressed hydrogen is roughly as valuable as the hydrogen produced, assuming 8 cents/kWh. The price equivalence, despite the inefficiencies of electrical production and electrolysis, is due to the efficiency of direct conversion of fossil fuels to produce hydrogen, rather than burning fuel to produce electricity. However, this is of no help to a hydrogen economy, which must derive hydrogen from sources other than the fossil fuels it is intended to replace.
Here's a working storage http://en.wikipedia.org/wiki/Hydrogen_Challenger
High pressure electrolysis is the electrolysis of water by decomposition of water (H2O) into oxygen (O2) and hydrogen gas (H2) by means of an electric current being passed through the water. The difference with a standard electrolyzer is the compressed hydrogen output around 120-200 Bar (1740-2900 psi). By pressurising the hydrogen in the electrolyser the need for an external hydrogen compressor is eliminated, the average energy consumption for internal compression is around 3%.