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Wednesday, August 31, 2011

Hydrogen Breakthrough?

Sunny
Image from TripAdvisor
Visitors to this site will find me to be a general bummer when it comes to energy news, but I did find this latest bit somewhat encouraging. I will, of course, caveat the shit out of it, because that is my nature.

Scientists: Alloy will Revolutionize Energy by Generating Hydrogen on the Cheap

State-of-the-art hydrogen extraction from water ("water splitting"), as I understand it, involves significant (electrical) energy inputs and CO2 generation, rendering its production prohibitive as a sustainable energy source.

If these barriers could be overcome, it could be a game-changer. From the article:
Research funded by the U.S. Department of Energy has demonstrated how to "tweak" an inexpensive semiconductor material to generate hydrogen from water by using sunlight, a finding that could revolutionize the energy sector...

Currently a large amount of electricity is needed to generate hydrogen by water splitting and the process entails a large amount of carbon dioxide emissions...

The finding shows that an alloy formed by a 2 percent substitution of antimony (Sb) in gallium nitride (GaN) has the right electrical properties to enable solar energy to split water molecules into hydrogen and oxygen. "When the alloy is immersed in water and exposed to sunlight, the chemical bond between the hydrogen and oxygen molecules in water is broken. The hydrogen can then be collected," reported the Science Daily...

The researchers are working on the production of the alloy and would test its ability to convert solar energy to hydrogen, the report says.
The Alloy
The components of the alloy, gallium nitride and antimony, are widely used in the electronics industry. While gallium nitride is used to make bright-light LEDs, antimony has been used as metalloid element in the microelectronics industry.
I poked around the web a bit, and it seems that this alloy is manufacturable at reasonably high quantities. It would be ugly if it were an energy source, but from what I understand from the article above and the nature of the alloy is that it seems to be a relatively inert catalyst for extracting the hydrogen from the water (and, to remind, when hydrogen is used in energy production, it simply goes back to water.)

This means that once manufactured, panels made from this alloy would not be "used up" in the process of extracting the hydrogen, creating a relatively low-maintenance power plant. This is pretty important, because it looks like there is some significant energy input in the extraction of the elements involved (gallium and antimony), and in their synthesis.

Gallium does not exist in a free form, but it is relatively ubiquitous. Antimony is about as abundant as silver, and it should be noted that China appears to have the most abundant supply of it - currently providing 84% of the world supply - and the rest is coming from places that are not North America (just as an economic aside.)

Solar Panels

This development is really simply another form of solar panel - harvesting and storing solar energy just as the heat-gathering and electricity-generating panels that already are available do.

The numbers are not in on how efficient these fancy new panels will be vis. the currently available ones, but it appears that they do have an edge on the storage of this energy. Heat (usually stored as hot water) dissipates, and storing electricity is relatively high-tech and involves a lot of toxic materials. Pressurized metal tanks storing hydrogen fuel is much more elegant.

Caveat 1

This still would reduce our supply of energy from what we have become accustomed to. The fossil-fuel driven energy boom was a matter of mining up loads of "ancient sunlight" from eras past. This method, just like any solar energy method, would restrict our per-annum energy supply to what energy the sun offers us every year.

While water is very abundant, and when used as an energy supply in this fashion, simply returns to water (admittedly awesome when compared with the release of carbon into the atmoshphere), it is the use of the sun that actually "creates" the energy.

As I have noted before, Earth already has some significant need for the solar output outside of what might be diverted towards heating, air-conditioning, manufacture and transportation. Climate patterns and the needs of life are dependant upon it. We will need to come to terms with just how much of this energy can be harvested for other purposes.

This brings us to...

Caveat 2

Single use vehicles are dead, dead, dead. We will also have to come to terms with the loss of the free-wheeling entitlements like long-distance vacations, etc. Mass transit will also come up against the exigencies of diverting solar energy from its primary purposes.

Caveat 3

Food production at our current population levels is dependant upon the "burning of the battery" as well, so we still face a an uncomfortable population reduction in our near future.

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So - all in all, this may be a significant and sustainable technology as we move forward in history. But, the abundancy party's still over, and we need to keep our heads about that.

2 comments:

  1. Great blog post, Petro.

    I was having dinner with some guy from Wikimedia at a conference, and he poo-poo'd my concern with peak oil by saying hydrogen would save us from having to change anything in our current practices. I tried to explain that hydrogen was an energy transport medium rather than a source, and to talk about limitations of scale, but I don't think I was as articulate as you've been here. In any event, he didn't get it.

    Having an easy industrial way to convert solar to hydrogen would be *big*. But it wouldn't get around your caveats.

    Thanks.

    ReplyDelete
  2. I appreciate your comment, . josé .

    Thanks for reading!

    ReplyDelete

I welcome all reactions and points of view, so comments here are not moderated. Cheerfully "colorful" language is great. I'll even tolerate some ad hominem directed against me... each other, not so much. Racist or excessively abusive comments (or spam) will be deleted at my discretion.