FYI, there is another thread going on right now in the “Great Debates” forum on the assertion that “Hydrogen-powered cars won’t solve the problem,” or something like that (I haven’t yet learned how to insert thread-to-thread links).
Just open up the thread, and copy&paste the address into the reply box for this thread.
IAAChemical Engineer, and IMHO biomass is the best solution. Alcohol-based fuel can be produced from organic waste, be it sewage, grass clippings, rotten meat, or whatever. The engines that can use it are fundamentally similar to the ones that exist today, so there’s no big technological barrier to overcome. As has been said above, you can already get the stuff in Europe, and the American auto companies are starting to experiment with it. I know Ford has a “flex-fuel” vehicle that can run on gasoline, an alcohol-based fuel called E85 (ethanol based), or a mixture of the two. GM probably has something similar.
Don’t underestimate flexibility: it’s going to be many years before any alternative fuel becomes widely available, and you don’t want to be tethered to the one gas station that sells the fuel you need.
Ficer67: No one doubts that hydrogen can be electrolyzed with solar power. Hell, you can do it with a watch battery. Just not very much.
I wasn’t claiming that the electrolysis was impossible, just that it was impractical. You can’t put enough solar cells on a car to generate a significant amount of hydrogen. And you’d never recover the cost in cells and maintenance of them.
A good solar panel in direct sunlight can generate maybe 100 watts per square meter. The absolute best solar powered vehicles we have today are the vehicles that enter the Sunrayce competitions. They are built with very large, flat areas loaded with solar cells, and they can generate 1,000-1,500 watts of electricity. On a realistic vehicle, maybe you could generate 200-300 watts of power in direct sunlight, if you were willing to cover the entire roof, hood, and trunk with solar cells.
Let’s say we need 50hp on average for our car. That’s roughly 40 kW of power.
Electrolyzing hydrogen is not 100% efficient. In a real-world system, call it 50%. Actually, with all the other losses in the system it’d probably be worse than that.
So, you’d have to leave your car in direct sunlight for 20-40 hours in order to be able to drive it for one hour. Assuming your solar panels are sparkly clean, the wiring is new, etc.
Of course, most people park their cars in garages, or in areas where they are covered or in shade most of the time. Leave it out in the sun, and you suffer additional damage to the vehicle. And a moving vehicle is not a very hospitable place for rather fragile solar cells.
It’s just not a practical idea. If you really wanted to power your car with solar, it would make more sense to install an electrolyzer in your home, cover your roof in solar cells, and then transfer the hydrogen to your car at home. Even then, it’s a pretty low efficiency way to do things, and it would be a very expensive way to travel.
Well, it sorta doesn’t matter, because in my surfing for cites, I have come to find that the fuel cells which will probably be put into commercial vehicles are not going to run on pure hydrogen, but probably ethanol or methanol.
I had an idea that I could put up a windmill, solar, and wire an exercise bike to electrolysize water into Oxygen and Hydrogen. Each device would cover for the others in the event that, there was no wind, or no sun, or I was lazy. But it looks like I am going to have to move to a farm and run a still.