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Widespread Use of Hydrogen May Hurt Ozone Layer
Saeger writes "The AP has a story about a CalTech study which has found that the Hydrogen Economy may deplete the ozone layer by 'as much as 8 percent' on the assumption that '10 percent to 20 percent of the hydrogen would leak from pipelines, storage facilities, processing plants and fuel cells in cars and at power plants.'" CalTech's press release has more information.
The Cal Tech study seems to be a little extreme:
Don't know if it's better or worse... You get to choose: global warming or skin cancer. Actually, if you use methanol-based fuel-cells, you might actually get both (CH3OH->H2 creates CO2 and likely leaks some H2).
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Hydrogen has to be produced. Currently, most of it comes from fossil fuels in a process that releases CO2. Some if it comes from electrolosis, which requires energy which comes from sources like burning fossil fuels.
The only thing hydrogen would do in our current situation would be to move pollution from your car to a power plant.
From http://www.e-sources.com/hydrogen/safety.html:
The simple reaction of many people, when confronting the issue of hydrogen as a fuel for the first time, is to say "But won't it explode?" The truth of the matter is that hydrogen is highly explosive in confined spaces, because of a high flame speed. The shape of the space in which the hydrogen is confined plays an important part, as does the mode of ignition. However, it also has a very high dispersion coefficient and this means that it is almost impossible to cause a hydrogen explosion in an open area. For the same reason, a hydrogen fire will burn out much more quickly than a gasoline or methane fire. It is also true to say that hydrogen is not intrinsically explosive - it must be mixed with air or oxygen before detonation can occur.
Hydrogen is also flammable and explosive over a much wider range of mixtures than any conventional fuel, but its lower limits of 4% and 13% respectively in air are better than gasoline (1% and 1.1%) and similar to natural gas (5.3% and 6.3%).
I don't see why he was modded as a troll, most of what he stated is true except for...
Ozone in the high atmosphere is created by UV. UV can also photodissociate ozone.
Ozone is not created in the absence of UV.
The same "Global winds" that "prevent human emissions from settling over antartica" also "prevent human emissions from settling over North America." The atmosphere is well mixed over a period of a few years, so it is not a supprise that the effects of freons are observed world wide.
What caused the Ozone hole, is ice forming in the high atmosphere. In case you hadn't noticed, ice forms where it is coldest. It is coldest over the antartic, so that is where ice forms. When ice forms, it catalyzes certain reactions. Ozone is an unstable molecule. In fact ozone is so unstable that it is a high explosive and is extrmely dangerous to handle and can detonate even as a gas. It is not a great supprise that ice can catalyze the decomposition of ozone. Most things do.
Second, it's *extremely* explosive. The cost of leaking even a small part of the amount you're moving is death in a fiery inferno.
Actually, this statement is a little off. It is a common perception however. Gasoline is a far worse substance to handle or deal with than Hydrogen. Gasoline can stick to you, spill, and it can explode as well.
Ironically, the destruction of the Hindenburg, which is the famous example of the dangers of Hydrogen was not as bad as people imagine, the majority of the problem was that the skin of the ship was rocket fuel. The gas, while it was burning ferociously, can be seen to be floating up and away from the ship itself. The most interesting thing about the Hindenburg disaster is that only 35 of the 97 passengers died. If Hydrogen was a heavier than air gas, this would not have been the case.
Since Hydrogen rises very fast, if you have a leak, it immediately seeks to escape out into the air. Not so with gasoline, which will form a dangerous pool on the ground. Movies such as "Chain Reaction" (ARRRGHHH!!!) perpetuate the "risk" that hydrogen poses. Given the choice, being involved in a gasoline leak (pools on ground) or Hydrogen (rapidly floats up into sky, or celing in an enclosed environment) I would choose being around Hydrogen as I could hit the deck, and have the gas float up and away from me.
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Actually todays energy usage in the US could be supplied by 1,000sq miles of modern multilayer high yield photovoltaic cells in Nevada, excluding transmission losses. That's only 100 miles X 10 miles, hardly the whole desert! Of course the amount of materials and nasty chemicals needed to make all those cells would be pretty darn high but hey there is no such thing as polution free energy. The closest thing would be microwaved solar from space but even that has some problems with ionization of the atmosphere along the transmission path.
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The article briefly mentioned it, but Chrysler (and others?) are working on using NaBH4 to carry the hydrogen. The NaBH4 can be induced to yield its hydrogen, leaving borax, a common element in laundry soap. The borax can be recycled to produce more NaBH4 (or Tide, I guess), essentially acting as transportation vehicle for the hydrogen. I imagine NaBH4 has a lower energy density than fossil fuels, particularly gasoline, but it may be safer and easier to produce and ship around. IANACE (I Am Not a Chemical Engineer), of course.
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The only thing hydrogen would do in our current situation would be to move pollution from your car to a power plant.
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Close, but there is another benefit to hydrogen that many people don't remember. There's lots of ways of producing the hydrogen needed for the cycle. Consider that a secondary problem, though. Fossil fuels are far from unlimited. The hydrogen fuel, though, excluding small leakages out of the atmosphere, is nearly limitless. Supply worries are nearly eliminated, once a stable production system can be put into place.
Granted, the proper production system is not in place yet. But as some other technologies (solar cells, wind turbines) that are less polluting improve, we would be able to move to those technologies for hydrogen production WITHOUT giving up the things that run off the hydrogen. Instead of replacing the whole system, you now only have to rework one part of it.
It's a very powerful idea when you stop and think about it. Right now, your statement is probably right. But, think about the consequences a little further down the road. THAT'S why hydrogen power is so attractive.
-Jellisky
Actually the byproduct of hydrogen combustion is H2O - which in the wrong places acts as a greenhouse gas....
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One of my grandfathers used to sell ozone makers back in the 1970s, for use in pollution reduction. (Bubble ozone through whatever, it'll oxidize a lot of things.) The problem, of course, is twofold: it takes a lot of energy to make ozone, when you could just pipe chlorine through the water (or air) and do pretty much the same thing, and having all that ozone around at ground level requires people working in the area to wear protective gear (or suffer burns). If you want to boost the thickness of the ozone layer (and consequently increase the SPF of the atmosphere), the thing to do is to generate ozone way up at the top of the atmosphere, not down at the bottom.
Corrections and additions from actual chemists and environmental scientists are absolutely welcome, as I'm just working from a layman's knowledge here.
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The reason this article might not reflect what actually happens is that hydrogen production might be done on a decentralized local scale.
This might make leakage worse. When Mao decided to decentralize steel production the quality was very low and the environmental effects were miserable. It really could go one way or the other - this is probably more of a social design issue than a technical one. In any case you'll need economic incentives to keep leaks low (both the economic loss of the fuel and possible fines on leakers).
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This study by NASA explains why volcanic plumes, which contain tremendous amounts of chlorine, don't leave much chlorine in the strtatosphere.
Really good question. You don't hear about CFC's "destroying" the ozone layer any more because the evidence that this happens isn't anywhere near to being conclusive See Ozone, Skin Cancer, and the SST for more information.
The IPCC has purposely engineered a massive scientific fraud.
There are a lot of different hydrogen storage projects being worked on- it's one of the few non-defense scientific areas where government funding has been increasing substantially. National labs and universities as well as corporate entities are working on this. There are a number of difficulties to get the ideal hydrogen storage cell. They'd like it to:
1. Store a lot of hydrogen per volume
2. Store a lot of hydrogen per mass (10%-15% of the mass is the target)
3. Release and reabsorb hydrogen at moderate temperature and pressure
4. Be able to do this a large number of times
5. Depending on how good it is at 4, be easily recycled
6. Be cheap
7. Not be dangerous (toxic, explosive, etc.)
This is not easy, and there are specific goals attached to specific dates (If I recall correctly, 10% hydrogen by mass by 2010, 15% by 2015.)
NaBH4 was mentioned as one of the early candidates, as were variants like NaAlH4 and LiBH4. The mass percentage of hydrogen isn't as high for these as they'd like.
The World's population will not rise over 11 or 12 Billion people.