If all vehicles used hydrogen fuel cells & emitted only water vapor, what would be the impact on environment?

Question

Would all the extra water have harmful effects? Global cooling? More rain? Increased urban humidity?

Answer 1

It would be reflected in a net increase in greenhouse gasses and other pollutants such as mercury.

The most significant greenhouse gas is water vapor. We just don't talk about it because it is not usually considered to be an athropogenic (from man) issue. It is to some extent, such as the evaporated vapor from water cooling towers, but we concentrate on others that we directly control, such as carbon dioxide.

When we switch to electric or fuel cell power, we are only switching places where the energy is generated from under the hood to remote power generation, which uses coal and oil for the most part. These are not very clean sources. Coal provides most of our atmospheric mercury.

Fuel cells convert hydrogen to energy and water. You have to add more energy to water to turn it back to hydrogen, because you have to account for losses in electricity generation and transmission, and the hydrogen production.

Answer 2

Unfortunately, there are no production-model fuel cell vehicles and so no calculations can be done on how much water vapor will increase if everyone drove a fuel cell car. If anything, water vapor increases global warming so a global cooling is not likely to happen because we use hydrogen fuel cells.

The #1 benefit of using hydrogen is the elimination of tailpipe carbon dioxide emissions. Other yahoo answers have been there and done that.

The #2 benefit of using hydrogen that few people talk about is the TOTAL ELIMINATION OF SMOG. There are no emissions of nitrogen oxides which are the precursors to unhealthy ozone smog. Coal power plants do not produce the same kind of pollution that makes ozone so this is a very big benefit that people overlook. Smog is the #1 air pollution problem in cities and will be completely eliminated once everyone drives hydrogen fuel cell cars.

Answer 3

I once heard or read about someone trying to imagine what environmental consequences might result from very widespread use of hydrogen. There were some, but I don't recall what they were. They had mostly to do with the inevitable leaking of some of the hydrogen into the air without being burned, and what effect that would have on the atmosphere. Also, water vapor is a much more powerful greenhouse gas than carbon dioxide. The point of the exercise was to point out that EVERYTHING we do has consequences and that people who yell and scream that we are all stupid and should just do X or Y obvious thing to save the environment and make the world perfect (there sure a lot of people like that posting in Yahoo! Answers), are themselves stupid.

Answer 4

Hydrogen gasoline cells are noticeably costly and don't final long.  that's a miles larger difficulty than their effluent. Water vapor is the biggest greenhouse gasoline (on universal) by weight, yet basically bills for type of 0.5 the completed greenhouse result (often interior the tropics, little or no on the poles - because of the fact of this AGW warms the poles lots greater effective than something of the earth).  additionally, water vapor basically lasts approximately 9 days interior the ambience until now it precipitates out as rain or snow.  including or subtracting water vapor has an rather small impact on climate; the movers and shakers are the failings which stress the quantity of water which keeps to be, how lots varieties severe clouds vs. low clouds vs. vapor, etc.

Answer 5

We would have some warming too, but not "green house gases".
The dirty little secret is how to fabricate the Hydrogen.... there you may get extra CO2, warming... etc

We probably wouldn't have extra rain or water in the global atmosfere, because we would be making H2 out of H2O to beguin with...

But yes, in the big cities we may have fog, extra rain, humidity, air borne deseases (many bacterias travel great in humid air...)