Hydrogen can also be generated by electrolysis of water by using extra electricity generated by wind and / or solar collection to be stored for burning in power plants when those collection systems have lulls especially for solar at night, of course. (green.blogs.nytimes.com)
In 2006, a study for the IEEE showed that for hydrogen produced via electrolysis of water: «Only about 25 % of the power generated from wind, water, or sun is converted to practical use.» (bluebird-electric.net)
«New catalyst for hydrogen production is a step toward clean fuel: Carbon - based nanocomposite with embedded metal ions yields impressive performance as catalyst for electrolysis of water to generate hydrogen.» (sciencedaily.com)