An excerpt from the article I referenced:
Hydrogen isn't there for the taking. The most common and cheapest place to get hydrogen is from natural gas, by mixing it with steam heated to 750 to 1,000 degrees Celsius. A two-step reforming process yields not only hydrogen, at a projected cost of $4 to $5 a kilogram (equivalent in chemical-energy content to a gallon of gasoline), but also carbon dioxide, a greenhouse gas. The world's most abundant reserves of natural gas happen to be found in the Middle East. The economics and the environmental attributes of the process could be improved by using waste heat from nuclear power plants to warm up the steam, but no one's doing that yet.
Hydrogen can also be extracted by sending electrical current through water, degrading it into hydrogen and oxygen. It is a well-developed process, but it <u>takes 50 kilowats of juice</u> worth $2.50 or more, to produce a kilogram of hydrogen. Nowadays incremental demand for electricity is met with natural-gas-burning power plants that also produce carbon dioxide. The energy-guzzling does not stop there. <u>It takes mountains of energy to compress and transport hydrogen.</u> Author Romm calculates it would take 25 truckloads of hydrogen to match the energy contained in one truckload of gasoline. Donald Anthrop, professor emeritus of environmental studies at San Jose State University, concludes, in a recent white paper: <u>"A transition from gasoline to hydrogen would nearly double net greenhouse gas emissions attributable to passenger vehicles."</u>
Yes, speeddemon, the use of hydrogen as a fuel produces only water vapor as a result but hydrogens production has many unwanted byproducts! This would be an "unintended consequence similar to that which is now occurring with the production of lower sulpher gasoline... many refineries now have piles and piles of sulphur that are unsalable and piling up and also blowing into the atmosphere.