> > And completely pollution free! > > Afaik burning hydrogen in air is not good. You get ammonia, nitric > oxides, hno3 ... And let's not forget about the _production_ of the hydrogen, it's not like we can just suck it out of the air. The only current LARGE scale production method is to reform natural gas - this process not only takes energy (high temp operation) but also produces more CO2 than burning the natural gas directly. (all of the carbon is converted to CO2 plus the energy needed to heat the reaction) Electrolysis is fine, until you consider where the electricity comes from. Sure PV panels can make electricity without emitting unpleasant byproducts, until you consider the processes used to make them. It's been a while since I've done the research, but the last numbers I seen indicated that a PV cell would have to operate for something like 100 years to recoup 'real' costs competing with current utility rates. ('real' costs remove the effect of various tax incentives and industry subsidies) Sure utility rates are going to rise during that time, which does alter those calculations. But if utility rates do rise, so will the cost to manufacture PV cells. Of course you could use Nuke, but we know how much everybody loves that idea. And recall that Hydrogen is the smallest of all the elements, when compressed it leaks right through the sides of the tank. The best tanks currently available have about a thirty day half life. Yes Hydrogen does have more energy per unit mass, but compressed Hydrogen has about 1/4 the energy per volume of liquid hydrocarbon fuels. So to maintain a comparable range, a Hydrogen automobile will need a fuel tank four times as large as they currently have, plus it needs to be a stronger tank because it has to hold compressed gas- so it'll be heavier. And yes, you can store Hydrogen as a cryogenically cooled liquid, but maintaining those temperatures takes some energy too. And what about safety? Since hydrogen is odorless and colorless, it'd be necessary to add an artificial scenting agent so people can detect leaks, right? (they already add methyl mercaptan (CH3SH) to natural gas and propane) Problem is even in _extremely_ small concentrations sulfur will destroy the proton exchange membrane in a fuel cell in a matter of hours. In fact at this point there are NO suitable odorants to use in hydrogen systems. There are _serious_ flaws in the proposed "Hydrogen Future", and nobody seems to be talking about them. They might be solvable, but I'm not holding my breath. -Denny -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist