Organism Uses Solar Energy to Produce Hydrogen

Stan Freeman writes "CNET is reporting that Stanford University researchers have discovered a soil microorganism that splits water into hydrogen and oxygen. They are trying to adapt this naturally occurring anaerobic organism into one that can survive in a more normal environment. There is some more information on biological water splitting here on the National Renewable Energy Laboratory's (NREL) web site."

Comments

Re:Cost measurements?

[MindStalker]

Definatly not free energy. Remember you can get energy out of combining oxygen and hydrogen, thefor it must take atleast that much energy to seperate them. The bateria non withstanding require that energy. As stated in the link they get their energy from the sun. So essentially this is a form of solar energy. So the cost calculations need to be in the form of percentage conversions minus what the bateria itself needs to survive, and cost of building a large enough container to collect sunlight. (And your other factors of course).

If it can beat out existing solar energy I'm all for it, but I doubt it.

Do Hydrogen Cars Generate More CO2 Per Mile?

[Doug Dante]

Most Hydrogen generated today is made using Steam reforming of natural gas

This process produces "7.05 kg CO2 ... per [1.0] kilogram hydrogen".

Now new cars are getting near 140.9 [grams] C02 [per kilometer] (This is a target, double it if you want)

So, how many KGs of Hydrogen does a Hydrogen powered car need per mile? Multiply x7.05kg to get emissions based on current production technologies.

Are these hydrogen cars poisoning the planet? With a 500 km (310 miles) range, a gas powered car at the target level could sequester and store about 70 kgs (154 pounds) of CO2.

If gas stations were required to accept and sequester this CO2, we could effectively eliminate CO2 emissions from most new automobiles without criss crossing the world with Hydrogen delivery lines or developing a totally new CO2 free hydrogen creation system.

Just capture 50% of CO2 emissions and you'll be doing quite fine as far as cutting emissions goes.

This solves the biodiesel dead end?

[museumpeace]

We have read that ethanol is an energy dead-end using more energy than it delivers when all costs are included. Due to the fact that current biodiesel production processes need a vegtable oil feedstock, it too is a lousy energy source when all costs are considered.
But, U.Wisconsin chem researchers have a chemical [heat and catalysts, not bio-reactors] process that make biodiesel out of cellulose, which is 3/4 of dried plant material by weight . This means most of what farms [and cities too, if you count leaves and grass clippings] burn, bury or compost could be feedstock. Study the diagram...the UW process needs an H2 in-feed [it hydrogenates carbon chains to make the diesel, the H2 shown leaving the reactor is a fraction of what goes in]. So their process would be an energy winner if only a source of H2 that does not consume fossil fuel were available .

NREL, Stanford, meet U. Wisconsin. U. Wisconsin, meet Stanford and NREL. if you guys play nice together and don't play politics, maybe my grandchildren won't be bicycling to the library to read about an age when combustible hydrocarbon liquids were used to run selfpropelled vehicles.
I'd love to know exactly how credible the UW claims are. To whet the appetite of chemically knowledgible /.ers who might otherwise not have seen this article, their energy bottom line:

About 67 percent of the energy required to make ethanol is consumed in fermenting and distilling corn. As a result, ethanol production creates 1.1 units of energy for every unit of energy consumed. In the UW-Madison process, the desired alkanes spontaneously separate from water. No additional heating or distillation is required. The result is the creation of 2.2 units of energy for every unit of energy consumed in energy production.

I was so tempted to try posting the UW result when it came out but /. can't get forty comments on biology topics in 2 hours. [and they get over 900 on ethanol...go figure!] The eds like stories that get hundreds, not tens of responses. Is there a /. equivilent for sustainablity nerds?

Salt Water?

[Ironsides]

Can this bug survive in salt water? If so, it makes it easier since we wont have to supply it with de-salinized water. On the other hand, could it help in making a cheaper de-salinizing water process?

Re:Cost measurements?

[linzeal]

It does not need to cost less than current forms of H energy either. All it needs to do is find a nitrate souce from a waste process that makes more money than the current use. Believe you me, there are so many different types of waste sources and uses that this is interesting just for that.

Re:Oxygen contamination?

[xanthines-R-yummy]

Yes, I did RTFA's. However, neither you nor TFA's had any indication of how easy or cost-effective their proposals were. I didn't read every paper the lab had ever published, but nothing in the links indicated where they decided that $30/kg was attainable. Also, the articles seem to indicate (although I admit I could be wrong) that O2 is produced in the anaerobic phase, although in smaller amounts than during the photosynthetic phase. It's on page 7 of the first PDF listed. O2 seems to present in the sulfur tank. I don't know how much is present, but it's there.

So again, does anyone know how easy and cheap it is to separate O2 from H2? Is it necessary to separate them for actual use in something like H2-fueled cars, as opposed to inhibiting the algae? I know something about molecular biology, but I'll be the first to admit I don't know anything about engineering...are you always this condescending?

Re:Oxygen contamination?

[museumpeace]

"....O2 seems to present in the sulfur tank. I don't know how much is present...."
You have a point here...we are pretty much just going on pictures here and the arrows seem to indicate that O2 is both emitted and consumed in roughly equal amounts. Its not clear that oxygen is a byproduct in the sulfate stage. Numbers would be helpful.
I'm not always that condescending and I regret the tone of my reply.

I'm not a chem. engineer but what little I know about fuel cells leads me to expect that it IS necessary to separate the hydrogen from the oxygen...the electron exchange in presence of of catalysts must take place across a membrane or barrier in order for a current/voltage to arise. What is less clear to me is whether the UW process can tolerate oxygen as a contaminent in the H2 fed into the reaction vessel.
and no, I have no clue how you'd separate the mixed gases. I do know that H2 and O2 have very distinct absorbtion frequencies...perhaps that would make it possible to draw the mixed gasses through a maser cavity under very low pressure causing one of the gasses to dissociate to atomic or even ionzied state and then use MHD to separate the charged from uncharged gas. This would be somewhat like a mass spectrometer [which would provide separation but at enormous cost]. I won't go any farther out on this limb: seems it would be a total energy loser even if it did work.