I read this thread mainly for entertainment.

I should take this advice.

Yawn................

Boring...........

I'l stick to beleiving the chemistry and laws of physics thank you................

thought id bring this back up now that the japenese are doing exactly what is being discussed here :hippy:

Genepax Water Car photo

Water-Powered Cars
Like clockwork, every time oil prices shoot up journalists scramble for stories about energy, and a few water-powered cars and perpetual motion machines always make it through. That's what happened with the Genepax Water-Powered Car featured on Reuters (and then a bit too uncritically on TreeHugger, but also on many other green sites like Environmental Leader, Celcias, etc).

How this Water Car Probably Works
One thing that helps fuel the conspiracy rumors surrounding water cars is that the media run these segments where they show "water cars" actually driving around, and it all seems to work, and then we never hear about them again. People figure that Big Oil (or the Illuminati, whatever) is suppressing the technology. The reality is more mundane: It is actually possible to make a car look like it runs on water without breaking the first law of thermodynamics. The way it's usually done is with metal hydrides. These react with water to produce hydrogen, which is then used to power the car. But since these hydrides will deplete with time, they need to be replaced and so they are actually the fuel, not the water. And you can be sure that more energy will go into producing them than will be taken out, making them an energy carrier, just like a battery.

Genepax Water-powered Car photo

Water Cars Create False Hopes and Real Apathy
There is a real danger in widely reporting these stories without debunking them, or at least being cautious to say that the "water car" is probably not doing what it claims it does until rigorous proof of the contrary.

The danger is that it creates false hopes, which then turn into real apathy. Either people believe that there's a solution to all our energy problems "coming real soon now", and so there's no need to worry and make efforts. And the people who've been around longer end up disillusioned and frustrated because they've been promised "water cars" for decades and it never comes, so they think that there's a big worldwide conspiracy against it (and somehow none of the dozens of "inventors" and "engineers" who worked on these projects were able to put the technical information on the internet).

The Bottom Line on Water Cars
As Carl Sagan used to say, extraordinary claims require extraordinary evidence. The next time you hear about a water car, remember that and don't get your hopes up too quickly.

Yep - it's pretty much as I suspected. In a follow-up interview the president of the company revealed that the "membrane electrode assembly" is a porous material coated with a metal that is oxidized by water, releasing hydrogen. In other words, the car does not require "only water and air" - it also need the electrode assembly replaced as fast as it's used up.

Let's see if I can put some numbers to this:

Energy density of hydrogen is 141.9 MJ/kg, or 284 kJ/mol H2
Energy density of gasoline is 47 MJ/kg, or 37 MJ/L

So, to replace one litre of gasoline requires around 260g of hydrogen, which works out to 130 moles (H2=2g/mol)

Now, taking magnesium (as the most generous option out of the metals they listed), the hydrogen liberation reaction would be:

Mg + H2O --> MgO + H2.

In other words, you need one mole of Mg to liberate one mole of H2. So, to liberate the H2 equivalent of a litre of petrol would require... drumroll please...

3.1 kg of magnesium.

Now, fuel-cell based hybrids are slated to achieve much better fuel efficiency than gasoline engines, but are still likely to need the equivalent of ~10L gasoline storage to achieve any realistic range. That's 31 kilograms of magnesium, and that's before the support structure (I'm guessing at least equal weight) is taken into account. You'd be refuelling your car with a freaking crane!

as soon as i purchase better metals ill post some pictures

once we have near free electricity (come on fusion) then hydrogen will be a good power source. Cuz then it wouldn't matter how much electricity it would cost to produce. we could just keep pumping it out.

that is the real key to an hydrogen economy.