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."

Comments

2 remarks:

[Roland Piquepaille]

1- Re the Hindenburg incident: there is now fair evidence that the whole thing happened not because the hydrogen is flamable (it was in airtight balloons, and any hydrogen leaking out was highly vented), but because of the envelope fabric, that had cellulose acetate butyrate coating, which is highly flamable and prone to cause static electricity. If the blimp had been filled with helium, a ravaging fire would have engulfed its skin anyway, but with less violence. The hydrogen gas here was a facilitant more than a cause of the disaster.

2- Hydrogen is only a vector. It is not an energy source, it's only a way to carry energy created elsewhere. There is no "hydrogen economy", just the existing energy economy with an additional vector that can be compared to batteries.

Re:What bullshit

[Urkki]

• 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. Basically, even though hydrogen may be extra-clean, you're just moving the pollution ardound anyways.

It's not just moving pollution around, it's more about changing the *type* of pollution. You can produce Hydrogen with nuclear power or renewable energy source, which both (debatable of course) are far safer that burning fossil fuels (which cause acid rain, CO2 emissions, Middle East wars...) to get equal amount of energy.

why not a diesel economy?

[avandesande]

diesel requires no new infrastructure, and we can gracefully move to biodiesel as the oil reserves are tapped out.
Why is this only obvious to me? Why can't I buy a honda civic with a diesel?

Re:What bullshit

[athakur999]

"Moving the pollution around" isn't necessarily a bad thing. If you move the source of pollution from millions of loosely regulated and privately owned vehicles and transfer it to relatively small number of well regulated hydrogen processing plants, the net effect will still be positive.

Reducing emissions as new technology comes about will entail upgrading those processing plants rather than trying to get millions of drivers to upgrade their vehicle.

Lousy writing... but did you read it?

[delibes]

I have two complaints; one about the article, and the second about other posts.

First, I hate that the article contains the submitter's favourite: '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'. What crap. Photosynthesis generates saccharides - chains of sugars, which are used by plants in to generate energy from respiration, just as animals do. There may be a brief moment where water molecules are split into H. and OH. radicals, but no hydrogen gas is produced or used as an energy store. Bury the plants deep undergound for a few million years and you have fossil fuels, not hydrogen gas pockets.

Now, for those of you pointing out how crap hydrogen's energy density is - you're right! It sucks. It's so hard to deal with the stuff. I mean, the only way they make it work for the Space Shuttle is to deep freeze it so that it liquifies, and it takes yet more energy to cool it down which makes it suck more...

If you read the article, it admits that using hydrogen in vehicles is very challenging. A tank full of H2 is unlikely to ever happen on this planet. Instead, the suggested vehicle storage solutions include nanostructure materials, surface absorbption/adsorption, or ionic compounds. However, cars and planes are not everything in the world. H2 gas could be used in homes and businesses instead of natural gas. Various methods of generating H2 gas from a much denser hydrogen store - such as water - are suggested: heating it up to 3000C (~5400F) using solar collectors or nuclear power, bacterial processes, and catalysts (see figure 2 in the article - looks fancy doesn't it?).

So, OK, some of the style of the article feels bad to me, but there is some useful physics in there.