Electrolysis of water - Hydrogen

If water is so plentiful in Nature, why to not use its electrolysis in industry to obtain hydrogen?

 

[Astronuc]

If water is so plentiful in Nature, why to not use its electrolysis in industry to obtain hydrogen?

Electricity costs money and at the moment it is much cheaper to produced hydrogen from natural gas, light oil or coal, with only 4% by electrolysis.

See - http://www.eere.energy.gov/hydrogenandfuelcells/production/prod_methods.html

See also - http://www.bellona.no/en/energy/hydrogen/report_6-2002/22869.html [Broken]

http://en.wikipedia.org/wiki/Hydrogen_economy (seems the some of the info came from DOE)