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The Physics of the Hydrogen Economy
Spy der Mann writes "A Physics Today article entitled The Hydrogen Economy explores the possibility of using hydrogen as an energy source. The article explores the current methods, limitations, and the need for more research. For those wanting to point out the Hindenburg incident, the article doesn't talk about gaseous hydrogen only, but also about hydrogen fuel cells. My favorite quote: 'The natural world began forming its own hydrogen economy 3 billion years ago, when it developed photosynthesis to convert CO2, water, and sunlight into hydrogen and oxygen'. Interesting read for eco-fans."
This looks like something I read in January's Popular Science last week!
Not to mention that it was designed to be used with helium, not hydrogen. However, the only source of helium was in the United States which had restricted exports to Germany in response to the rise of the Nazis.
Hydrogen is energy storage and transfer medium, not a power source. At least not in what is generally called "hydrogen economy". It takes a lot of energy to make Hydrogen (H2) in large amounts, and only quita s small portion of that "original" power is regained when the Hydrogen is later used as fuel.
Of course fusion power would use Hydrogen as power source, but that's a totally different issue, and it happening is probably much farther in the future than "Hydrogen Economy"...
I should know, I never could get work as a physicist:-( There are other analyses that say a hydrogen economy is a daydream. you still have to GET the energy from some where If that is to be done without further burning of fossil fuels, we have to commandeer a huge amount of land for solar and wind farms and those are political and financial undertakings that are NOT an easy sell. Especially when the biggest fossil burning country reneges on Kyoto accords and is run by former president and vice president of oil or oil services companies.
SLASHDOT: news for people who can't concentrate on work or have no life at all and got tired of yelling back at the TV.
The article makes no mention of the potential environmental effects of large-scale hydrogen production. To make hydrogen, you could use a nuclear reactor as suggested but that produces nuclear waste. You could invent some kind of biochemical method but that will probably require living cells and large quantities of clean water - which is also needed by growing human populations. The solar method is clean when working but the photochemical cells would probably be quite toxic.
I do not think the "hydrogen economy" will provide limitless clean energy without any environmental costs or risks.
[Sir Garlon] is the marvellest knight that is now living, for he destroyeth many good knights, for he goeth invisible.
The article isn't about how wonderful the hydrogen economy will be etc. etc. Nor is it about the Hindenburg. It's about the immense basic science challenges that will likely prevent any commercial viability for decades...
Given that the article was directed at research physicists (readers of Physics Today), the intent was probably to motivate people to look into these challenges as basic science research areas for their labs.
The main reason they think there's any point at all is because of the energy conversion efficiency of fuel cells, and the natural link between fuel cell use and hydrogen. But as the original post implies, one of the best ways to store hydrogen is in the form of hydrocarbons:
Energy: time to change the picture.
How does this alleviate global warming? Does biodiesel not release carbon dioxide when it burns?
Of course it does, but its creation consumes as much.
OK Since I'm the one who submitted the article, please allow me to clarify some logical errors in your statements.
,insert the electrodes, add some acid as catalyst, and plug the wires into a battery. Voila! Oxygen in one, hydrogen in the other. Now Try making oil from wood with your chemistry kit.
So, in order to have a large-scale hydrogen "economy", you need an alternate power source to make all that hydrogen in the first place.
News for you. Hydrogen is not "made". It's extracted. OK, putting the word jokes aside, I understand that what you mean is that *PURE* hydrogen is not found *NATURALLY* on Earth.
So we need an ALTERNATIVE power source to obtain it. So what? Electricity is not energy either! It's a bunch of electrons and possitive ions waiting for us to mix them together. We use turbines in dams to produce it. (kynetic energy -> electrical energy). We need engines (kynetic->chemical) to take out the oil from the deposits below Earth.
Didn't you study physics in high school? Just climbing some stairs transforms the kinetic energy you use to move, into "potential energy". And by falling you turn it into kinetic energy, too. And guess what, we're made of protons,electrons and neutrons, and all of these are made of quantums, which are discrete packets of *energy*.
EVERYTHING's energy, dude! So what's the mystery if hydrogen needs some alternate energy to be extracted from water or other compounds? Don't forget your thermodynamics lessons from college. All engines do is transforming one form of energy into another. And since no engine is 100% efficient, then we have what is known as "entropy", which constantly is increased across the universe.
So, what power source can we have to extract pure H2 from other materials? Well, we can have, for example, solar power.
Hydrogen can be built *instantly* with some electrolysis (either chemically or solar powered). I did it myself at home when i was a kid. You put these water-filled tubes in a bucket (upside down)
The H2-generating process is sub-optimal right now (as was the vacuum tube in the 70's to act as a current switch), but technology always improves with time. And don't forget that big companies like Shell are investing millions of dollars into research.
The point with using hydrogen, is that:
a) It's combustible and can produce energy when reacting chemically with other elements/compounds.
b) Unlike fossil fuels, it doesn't require millions of years to be produced/extracted/whatever.
c) It's clean, it doesn't produce CO2 when burned.
Did you RTFA by the way? How do you think fossil fuels are made? Plants transformed H2O + CO2 + SOLAR POWER + nutrients into wood (and O2 as a byproduct). And these with time were transformed into hydrocarbons. Which consist of long hydrogen and carbon chains (not to be confused with carbohydrates - sugars -, which have oxygen in them).
The real energy in hydrocarbons is stored in the chemical bonds between the carbon and hydrogen atoms. By burning them, the combustion process releases these bonds. O2 + (long chains of C + H) ---> H2O + CO2. See? There's the hydrogen, and the C. What we're wanting to do, is get the carbon out of the equation. O2 + 2H2 ---> 2 H2O.
So, is hydrogen economy all that far-fetched? No, it isn't! We've been using hydrogen in our cars for a lot of time. The problem is that we're also using carbon.
Frankly, I'm amazed why your post was moderated as "insightful" (someone MOD it as overrated, please!). More mysterious than the universe is the human ignorance.
P.S. If this post is modded up, please do so as "informative".
My dad worked in two nuclear power plants and on several naval vessels (some nuclear) as a welder. He says the same thing about looking for steam leaks (with a broomhandle instead of a 2x4), but it's not because the steam will ignite the wood -- it's because those leaks may be thousands of PSI. What you're looking for, is for the end of the broom to suddenly fall off as the steam pressure carves it right in two.
-- Old Man Kensey