With hydrogen fuel, wouldn't putting all that water vapor, a greenhouse gas, into the atmosphere contribute to anthropogenic climate change? Plus storing hydrogen might be dangerous. If someone was to get into a serious car crash with a tank of hydrogen on board, that could create quite an explosion.
Any water vapor coming from such an exhaust would likely be like a bit of steam or fog. It might raise the humidity, and cause more frequent rains....which would be a good thing in the Western US., but it would certainly be far less damaging to the environment than any other fuel sources.
Yes, it might be dangerous in a major collision....depending upon how the fuel tank was built and located. But then, even gas and diesel can cause major fires/explosions in a wreck.
At any rate, current technology and plans to replace fossil fuels are mostly "speculation", and would require massive infrastructure investments, etc., to become reality....and decades to fully accomplish.
The current "plans" to transition to EV's are quite "optimistic", IMO. EV's would be practical if/when they have a range of 250+ miles, and can be recharged in just a few minutes. And, we would need half a million charging stations, to avoid dozens of vehicles waiting in line to recharge. Then, we would need a lot more electric generating resources....wind, solar, nuclear, etc., to provide the increased electrical demand.
Then, too, most EV's seem to be powered from Lithium batteries....most of which seems to be supplied by China....another thing that would put us as the mercy of that regime....unless there is some huge resource of that element in the U.S. that is Not being mined. And, apparently Lithium batteries have their own "risk" of overheating and burning...everything from Tesla's to laptop PC's.
Bottom line, IMO...EV's are great, but we are a LONG way from such a transition.
