It occurs to me that before we boldly stride into the world of hydrogen-powered cars, we should consider the potential environmental impacts, both positive and negative.
The obvious ones:
A benefit would be that car exhausts would be mostly water vapor, which could make city living a lot more pleasant.
On the other hand, it will take much more electricity than we’re now generating to separate the hydrogen for use as fuel. If we use coal-fired plants, this will mean an increase in air pollution produced by those plants. (Will this be offset by the reduced auto emissions?) If we use nuclear energy, we’ll have a lot more nuclear waste to store.
What about less-obvious consequences? Will releasing water vapor into the atmosphere on a large scale via car exhausts have a noticeable effect on the weather? Increased rainfall? More severe weather? A greenhouse effect?
And surely some hydrogen will be lost to the atmosphere during the separating process and the fueling process. What happens to hydrogen released into the atmosphere? Does it drift into the stratosphere never to return? And what would be the cumulative effect if we are separating hydrogen out of water and then losing some of that hydrogen into the atmosphere? Increased oxygen levels here at ground level? Would that be a good thing or a bad thing?
Any other environmental issues we need to think about?
(And for the record, I’m not someone who’s just out looking for environmental issues to gripe about. I just want to consider all the ramifications of a hydrogen economy before we take that leap.)
As I mentioned in a GQ thread on this, Scientific American’s TV show spoke of getting a lot of the hydrogen from crude oil but it didn’t explain what we were going to do with the left over carbon and sulfur. LOTS of leftover carbon and sulfur. Or how this was going to reduce our dependence on foreign oil. Just didn’t seem fully thought out.
Scientists can’t even come to an agreement on how much impact the internal combustion engine has had on the environment and the global climate - What are the odds they’ll find accord on the impact of hydrogen powered vehicles?
I suspect this isn’t much of an issue. The H2O released can be though of as the same H2O that was destroyed to produce the H (and O) that fueled the car. So this effect should be not much more worrisome than setting a sprinkler out on your lawn.
A good question that I’ve never seen addressed. If every car in the US we’re turned into a fuel cell powered auto overnight, I’d think that would be a lot of water vapor released into the air. Water is a green house gas, and in the form of clouds it also has the opposite effect, it reflects sunlight back out into space.
Of course there’s already a lot of water vapor in the air, so the amount produced by a few million extra fuel cells might actually be trivial, but I’ve never seen where someone has actually crunched the numbers.
Presumably the water destroyed to make the water used to make the hydrogen was sitting in a lake somewhere (and even if we get it from hydrocarbons, I can’t imagine that will effect the total amount of H2O on the planet that much). When its released out of your exhaust it will be a vapour though, presumably this will have some effect on the total amount of water vapor in the air, at least in big cities.
Suppose you put a storage mechanism on the car instead of just releasing the water as exhaust. Then you could legislate the follow-through, either by having people use it as drinking water or by having curbside pickup for it to be dumped back in the lakes. Would this be practical? How much water would such a car produce per minute? Per hour?
I’m sure that if there are unavoidable minute hydrogen leaks, and if some of that hydrogen eventually escapes our atmosphere, it will barely be measurable versus the effects of the solar wind (in both replenishing and stripping the atmosphere,) and the addition of more hydrogen via dust.
On the other hand, if there were lots of big big hydrogen leaks, I still don’t think it would make much of a difference, but you never know.
But it’s quite possible that we wouldn’t even be able to get rid of our hydrogen even if we tried. After all, it took us decades/centuries to raise the CO[sub]2[/sub] content of our atmosphere by a fraction of 1% (of total air content), and the world’s oceans contain enough water vapour to fill the world’s atmosphere many times over.
In any event, later in the thread someone points out that hydrogen cars would produce on the order of 0.008 gal of water per mile, which is LESS than regular cars.
I’m going to show my ignorance here. Yes, I know gasoline is explosive when it is “carbureted” or whatever the word is (I’m electrical, not mechanical). But, there is something about hydrogen in cars, driven by cell phone talking, newspaper reading, drunk drivers that scares the hell out of me. Maybe it’s the old film of the Hindenburg zeppelin. Also, would the process of extracting hydrogen be efficient enough to give us any sort of “energy saving”?
These are serious questions, from someone who admittedly knows very little about it.
There are currently schemes to try and store hyrdrogen in a stable state so that it won’t explosively combust when ignited. Storing it inside a metal “matrix” for example or as methanol.
But one big plus of hydrogen in terms of safety is that it’s lighter than air so any flames would go up and dissapate instead of hanging around. You would get a big whoosh of a fireball but likely, very little burning.
Research the past few years suggests rather conclusively that the horrifying fire when the Hindenburg went down was started and fed by the dirigible’s skin (rubberized cloth–you’ll recall that Rutan’s private spaceship uses rubber as its fuel while the Shuttle uses it as a binder in its solid boosters) and paint (nitrocellulose dope, aka: guncotton) and powdered aluminum (flash powder in fireworks and the fuel in the Shuttle’s solid boosters). The hydrogen was wrapped in what amounts to a bomb mixed with rocket fuel and the Hindenburg is likely to have gone down in much the same way had it been filled with helium. The safety advantage hydrogen has over gasoline, and the reason non-flammable helium would not have put out the Hindenburg’s fire, is that both gases are very much lighter than air and would not hang around the fire while gasoline just sits there and burns.
RE the generatlon of hydrogen - what about windmill farms which collect it into batteries/cells? Is this really feasible & what risks could there possibly be?