why do people think that a hydrogen vehicles are dangerous when fuel cells convert water into electricity?

Answer 1

they fear what they do not understand. Yes Hydrogen is explosive, but so is gas. However, Hydrogen is lighter than air, this means if it leaks, it goes up and away from people. Gas fumes are heavier than air and stay low where a person would really get hurt. The by product of burning hydrogen is water. Not poisons like gasoline. But the biggest problem is that we have "polititicians" who's pockets are being lined by the oil companies.

Answer 2

It's difficult to store....

The most practical way at present is to use high pressure cylinders. These are heavy and bulky, and would only give you about 200 or 300 miles of range at best.

The cylinders themselves are pretty durable, but the valve stems and regulators are far from it. If the stem broke off in an accident, 3000 psi of hydrogen could turn a 70 lb tank into an unguided missile. Dealing with highly pressurized gas is probably the biggest risk.

Hydrogen is no more explosive, flammable, or dangerous than gasoline is. You see burned out cars on the news all the time.....

This is just to give you an example.

Another problem with hydrogen, is though fuel cells are pretty efficient when compared to internal combustion engines, actually producing, storing, transporting, and distributing the hydrogen is far from it. Such "down the line" losses mean that at best, fuel cells only offer modest improvements in net energy economy.

Most current methods of producing hydrogen involve either electricity, or burning fossil fuels directly. So basically you are just burning the fossil fuels at the hydrogen plant instead of in your car...

If you are going to use fuel cells to generate electricity to run you car, why not just run it off of batteries instead?

Squeezing 200 or 300 miles out of a lithium battery pack is a FAR easier technical feat, than building an entire "hydrogen infrastructure." The technology to make excellent, extremely reliable electric cars is here today, not 20 or 30 years from now! Neither hydrogen nor gasoline even come close to the "down the line" efficiency of an electric car. (charging you car at home would cost two or three dollars of electricity at most..!)http://www.teslamotors.com/index.php

So, why all the hype about hydrogen? When enourmous technical issues, "down the line efficiency", and simple practicality threaten to sink it in dry dock?

Turns out, most of the initiative, support, funding, and lobbying for hydrogen research comes from, (you guessed it...) the petroleum industry. They are pretty intimidated by the fact that in 20 or 30 years, the rising cost of oil is going to force them into obsolescence (any economist will tell you this...) They are really just looking for a lucrative replacement for gasoline, that lets them keep their stock options....

Done ranting for now
~W.O.M.B.A.T.

Answer 3

I think it's just the hydrogen storage itself. It has to be stored in some sort of pressurized vessel.