[Alex Mair]

Alex Mair asked the Naked Scientists:
   
Quick question, assume in the future all cars are run on hydrogen.

The only biproduct is water. I'm guessing the oxygen from the water comes from the atmosphere. So will this upset the balance?

Regards, Alex Mair,



What do you think?

[Geezer]

Hello Alex,

As long as the hydrogen was produced by separating water into hydrogen and oxygen, there would be no net change in oxygen.

[litespeed]

Geezer - You wrote: "As long as the hydrogen was produced by separating water into hydrogen and oxygen, there would be no net change in oxygen." Wrong.

Each and every source of hydrogen I have ever heard of requires energy in order to collect, produce, package, compres, and distribute the stuff.  After which it is burned into water from ambient oxygen. The entire cycle is powered, in large part, by fossil fuels.

[Geezer]

Geezer - You wrote: "As long as the hydrogen was produced by separating water into hydrogen and oxygen, there would be no net change in oxygen." Wrong.

Each and every source of hydrogen I have ever heard of requires energy in order to collect, produce, package, compres, and distribute the stuff.  After which it is burned into water from ambient oxygen. The entire cycle is powered, in large part, by fossil fuels.

Litespeed,

It seems you are unaware that water can be separated into hydrogen and oxygen by electrolysis. The energy to drive this process could be provided by any number of nonfossil energy sources.

When the hydrogen is consumed it converts back into water. Where is the net change in oxygen, or didn't you understand the question?

[litespeed]

Geezer - We are just pondering technicalities. The question posed does not stipulate how the electrolysis will be accomplished.  However, ALL currently 'so called' reneuable sources are HEAVILY dependent, and often subsidized with fossil fuels. Nuclear power could not exist without fossil fuels. Wind turbines are MADE out of the stuff.

And it gets worse.  Ethanol production for maize has already been accused of causing food riots in places like Egypt. The entirety of the 21st century will be run almost entirely on fossil fuels. Hell, even using all these fossile fuels we will not get one nuke plant on line till at least 2030.

Till then, China, I believe, is constructing one large coal plant per week. It just a fatct.....

[Geezer]

Litespeed,

The question was very specific, and the answer you gave was incorrect. If you want to start a new topic, feel free but please do not use this topic as your personal soapbox.

[thedoc]

We discussed this question on our Nanostructures show

We put this question to Professor Stephen Bennington from ISIS at the Rutherford Appleton Laboratory...

It shouldn’t do because it’s recycling it. So I mean you're taking water, you split it up into hydrogen and oxygen, and then you recombine them again in your car. So, the net effect is zero. Water vapour is different perhaps because if you're using these things to power jets up in the high atmosphere and then you're depositing water vapour up there, and that’s a greenhouse gas. So we have to think carefully about those problems. It’s probably not a problem, but it could be.

Click to visit the show page for the podcast in which this question is answered. Alternatively, [chapter podcast=2713 track=10.06.20/Naked_Scientists_Show_10.06.20_6548.mp3] listen to the answer now[/chapter] or [download as MP3]