Alternate fuels?

Question

Is this dumb for me to say? Can't you just make a machine that has hydrogen fuel cells with an electrolysis machine. So the process would just repeat over and over again with using no more than the original amount of water. OR IS THIS COMPLETLY WRONG?

Answer 1

You are correct that you could use electrolysis to convert water to hydrogen and oxygen and then the products from the fuel cell would be water that you could then reuse.  

The problem is that neither electrolysis nor fuel cells are 100% efficient.  Even if they were, you would be consume the exact same amount of energy through the electrolysis process that you got out of the fuel cell.  Since they are not 100% efficient, you will actually just be making a machine that will use energy - not generate any.

It is a good thought though.  Just remember that energy can't be created - it has to come from somewhere.  The electrolysis process takes electrical energy and converts it to chemical potential energy that is stored in the hydrogen and oxygen.  The fuel cell then takes that chemical potential energy and converts it to electricity which is then converted to mechanical energy.

Answer 2

The short answer is Yes; water could be used over and over.  But that is not the issue.  The issue is that electrolytic production of hydrogen is expensive: it requires vast quantities of energy.  Most industrial hydrogen is made from natural gas, which is also expensive -- but a bit less so.

Answer 3

Well a good idea, well where do you get current to get electrolysis done, if you say the fuel cell, i would say the power generated by the fuel cell is not sufficient as such you can completely convert water back to hydrogen and oxygen...

So the concept fails.:-(