What effect will Hydrogen Fuel Cells have on the Hydrological (Water) Cycle?

[TarkinLarson]

So, there's all this talk about hydrogen fuel cells being what cars will run on in the future.

If all cars transferred from internal combustion to fuel cell what would the effect be on the earths water system? I know it's a (mostly) closed system but would there be less water in the ground, sea or lakes? Would there be more water in the air as vapour. How much water vapour would be released every day, month or year? Would this effect cloud formation or rain? Would taking the water from the sea cause extra salinity?

Or am I getting this all wrong and the amount of energy we get from hydrogen so great and it's so efficient that we won't actually use that much water?

[magnemoe]

So, there's all this talk about hydrogen fuel cells being what cars will run on in the future.

If all cars transferred from internal combustion to fuel cell what would the effect be on the earths water system? I know it's a (mostly) closed system but would there be less water in the ground, sea or lakes? Would there be more water in the air as vapour. How much water vapour would be released every day, month or year? Would this effect cloud formation or rain? Would taking the water from the sea cause extra salinity?

Or am I getting this all wrong and the amount of energy we get from hydrogen so great and it's so efficient that we won't actually use that much water?

Amount of water used would not have any effect on the water cycle, it would hardly have any effect on water supply even as the use is low compared with other water use, remember gas stations get gas by trucks.

[AngelLestat]

You can use sea water to get hydrogen without extra complications, but even if you use potable water there is not difference, the amount is nothing compared to the amout of water we use for irrigation or different industrial process.

[pincushionman]

Remember that in combustion (burning of hydrocarbons; what we do now), the products are both carbon dioxide AND water vapor. So the water vapor output may not be as different as you think, especially compared to natural evaporation worldwide.

As for "water in the ground," that all depends on how you get your hydrogen. Industrial hydrogen production is from methane, not from electrolyzed groundwater.

[SeaDog]

On a global scale it doesn't matter, but on local scales, it might. One should also have the entire life cycle in mind, and remember that many common types of power generation do have an impact on water supplies. Yet another example of how efficient transports may be more important than alternative fuels.

[TarkinLarson]

On a global scale it doesn't matter, but on local scales, it might. One should also have the entire life cycle in mind, and remember that many common types of power generation do have an impact on water supplies. Yet another example of how efficient transports may be more important than alternative fuels.

Cheers. Ok I thought I might be going a bit too far with it.

I wonder if the local effects might include increased humidity in cities.

Then again I completely forgot that water vapour is a product of combustion so I bet the difference is negligible.

[lajoswinkler]

Even if the cars run on it in the future, which is a pipedream, it will have negligible effect.

We actually spend (destroy) plenty of water in basic chemical industry by reacting it with various stuff.