Set me straight about hydrogen power

[Muffloj]

    Dont get me wrong im all for any power system that minimises negative affects on the environment but i do have one hangup about hydrogen power.

    What happens to the water in the process?  Where did it go? How much water does it take to run a car? how much water would it take to run the world?

    That raises the question where does water come from? Does Earth get more water. What happens if we start using up all the water?

    I like water. I drink lots of water(i think its in my beer isnt it) but i also think im gonna give it all back.  All of it eventualy.  So set me straight i may be seeing this wrong, but if im lookin at it any kind of right i would rather have to clean up  after pollution than have nothing to clean it up with.

 Just a thought electrons in action

[zmoz]

As soon as it's burned, the hydrogen turns back into the same amount of water that it was before. Steam is the exhaust from a fuel cell.

[tecker]

  You reckon your gona get some funky water after It's all been cracked and re bonded

several million times .that's a valid point I think nature has us covered this time but It's worth a look  I 'll look around so should you . I do know that under test water doesn't bond with any of the elements of the surrounding materials in the processes

of lab extraction .But whose to say it wouldn't make a little h2 or a little more 02

 which would be a problem .   My brown's gas torch hasn't made me sick  internal combustion may cause some trouble .I'll check it out .I'm a water drinker also and takegreat pains to get the good stuff.

[JW]

Im not so sure you would get all the water back, I feel this way because fuel cells are not 100% efficient. Some of the hydrogen will be undoubtly lost(converted) to heat(maybe as much as 40%). But this is a real though one to nail down, since pem fuel cells need humidity injected into them to work best. The water content in the humidity would accumulate with the water thats produced in the fuel cells exhaust.

 Once I get the chance, Id like to convert five gallons of water to hydrogen then run it thru a fuel cell. Then collect the water from the fuel cell exhaust and see how it measures up. I suspect youd have less water, after its said and done, probably even with the humidity factor. If you did somehow get "all" the water back, while compensating for the humidity(you should have more water than you started with) the most likely you have broken some law of thermodynamics.

-JW

[DngrDave]

From the considerable amount that I've read on the subject the general consensus is that running fuel cells on hydrogen will actually clean up the environment.  In it's purest form water H2O is two hydrogen molecules and one Oxygen molecule bonded together by shared electrons.  Now comes the tricky part... when you release hydrogen and oxygen by method of electrolysis what you're doing is "injecting" extra electrons into the water.  So the H and the O in the H2O no longer have to share, and the bond is broken.  

When you then run the hydrogen through a fuel cell it strips the electrons off the hydrogen, the oxygen in the air then shares it's electrons with the hydrogen molecule and water is formed... absolutely pure water that is.  The water is in fact so pure that it will not conduct electricity.

As a side note, when you're splitting the water with electrolysis, the impurities in the water work against you.  So if hydrogen cars ever do hit the market you'll probably see some method of capturing that water vapor hit with them... it would become the best available source for pure water.

One other thing... PEM fuel cells don't have to run on pure hydrogen.... www.plugpower.com is trying to get theirs to run reliably on natural gas or propane.  GMC also ran a concept S-10 pickup on propane although this ran through a catalytic converter... it was 28% more efficient than just burning the propane if my memory is correct.  It all comes down to stripping electrons from molecules.  Hydrogen works well because it's easy to make, and when you run it through a fuel cell you get a beneficial byproduct.  But it's just a transportation media you still have to get that energy from somewhere else, solar, wind, hydro-electric, nuclear or fossil fuels.  

[finnsawyer]

It might not hurt to lose some water from this planet.  Some years ago it was reported that the Earth was being bombarded by bus sized snowballs from space.  When they hit the atmosphere they poof into clouds.  An estimate was given as to how many tons were involved.  I did a calculation at the time (I've forgotten the numbers) and over the last four billion years this process would have very nicely accounted for the total water on the planet.  I haven't heard any more about this, though.  A misfire or are we headed for a water world?

As far as the fuel cells are concerned, if any hydrogen escapes it will tend to rise through the atmosphere.  On the way up it will be bombarded by various energies which will tend to cause it to bind with oxygen to form water.  Little if any of it will reach space just as it is today.  Earths gravity is sufficient to keep the atmosphere from escaping.  We truly live in a "golden" zone.