I assume also that RayChuang88 is being facetious. It is hard not to be when discussing anything relating to the massive global warming fraud currently being perpetuated.
The problem that I have with fuel cells is that even after who knows how many billions of dollars that have been spent over the last twenty or so years, there is still nothing on the market that is marketable to your average consumer. Fuel cells are in theory very scalable. So I am not just talking cars; I mean for replacement of batteries in other applications as well. When could reasonably conclude that with the massive amount of research taxpayers by now should be receiving some sort of benefit... but just like so many other pie in the sky concepts we are always “two or three” years away from some type of break through. So at this point I have become highly skeptical of any technology that is hyped only in journals that are highly subsidized by a highly subsidized research organizations.
If you look for fuel cells on Amazon you won’t find anything other than a few science fair kits and a cell phone battery charger. By the time you buy all the pieces you need to actually use the “charger” it will cost you hundreds of dollars to get something that is far less functional than a lithium ion based cell phone charger that costs less than $20. And this is approximately the same situation currently with other fuel cell powered products currently available to consumers. It is almost all hype.
http://www.plugpower.com/customer/whos-using-gendrive/
While it's obvious that air will be way cleaner (since we're not spewing out carbon monoxide, sulfur dioxide, unburned hydrocarbons and particulates), we want to make sure several million cars spewing out pure water vapor in an urban area doesn't create unintended local climate effects.