Umm... so the process produces 11kg of CO2 for every 2kg of H2, right? As far as I can work out, that's at least factor of 2 better than a gas engine in terms of CO2 per unit of engine, but hardly carbon neutral.

Fossil fuel CO2 comes from plants too, just older ones.

Stan--

True enough, but burning biomass can be carbon neutral.

CO2 in concentrated form gets you carbonated beverages, dry ice, and is useful to feed algae farms if they can ever get the costs down on the bioreactors. The better question is, Is the process described above suitable only for large scale hydrogen creation, or could it be useful for home production? How affordable is it likely to be compared to oil and coal?

I question its ability to digest cellulose, also the great thing about biomass is making it into industrial organic chemicals, hydrogen has no use other then fuel and fertilizer. Then again: remember "Back to the Future" were Doc shows Marty how the 2015 revamped DeLorean runs off garbage?, well this is exactly that: just chuck your compost into the car out comes hydrogen fuel!

This guy rocks: Mr Y.-H. Percival Zhang. Here is a link for more info on his research. http://filebox.vt.edu/users/ypzhang/research.htm. There is still a long way to go many years before this research result in a sugar fuel cell electric car. As I now get it is that biomass will be converted at a central factory using enzymes same process that is needed for cellulose ethanol. Then you simply load sugar and water on the car plus some enzymes. A reactor uses this to generate hydrogen for a standard hydrogen full cell. The whole process from sugar conversion to hydrogen to electricity to torque has a record efficiency conversion rate of 55%! Beating all other known processes. Show stoppers are currently the speed of the sugar hydrogen generator. When you drive the car you need energy fast and the enzymatic process seems to take hours (from what I understand) when it should take minutes. Another show stopper is making cheap enzymes. If all this is indeed solved and others succeed in making a 70 kW hydrogen fuel cell for the target price of $4000 then fuel cell cars is a relay good alternative to BEVs because they have a far more energy dense system. In addition the processes that convert lignocellulose to sugars is useful also for creating cheap sugar for humans and animal feed out of wood and grass. Wow! Even if the speed of the process can’t be solved there would still be much to gain from having a cheap but slow way to make hydrogen. All the best wishes to this guy and his team. The world needs people like him to combat GW.

Wow! Things getting more and more exiting with every day passing by.

Glucose is main energy source/carrier for every living creature. Human body gets glucose mainly from sugars and starches (carbohydrates), proteins, and fats, and burns glucose in all organs. BTW, efficiency of conversion of food stock into mechanical work by muscles is only about 10%.

I can imagine biorefinery which converts glucose to ethanol (exactly what it is done by yeast in liquor and corn ethanol plants), to methane (in bogs, cow’s guts, or sewage/manure anaerobic digesters), to butanol, to organic acids (vinegar fermentation), or now – into hydrogen, or flexible combination of all.

The main problem remains to get glucose not from food stuff, but from cellulose. Cellulose is, actually, polymer consisting from long chains of glucose blocks. Hydrolysis of cellulose by some bacteria or refined from bacteria cultures enzymes cuts these long polymers into small blocks, which could be consumed further by other microorganisms. This is exactly the process which is usually described as first, most troublesome step of cellulosic ethanol production. But now it could be also first step of cellulosic hydrogen production.

Tom: You might want to clerify your point about energy in carbon unless you're thinking of some kind of exotic nuclear reaction.

When oxygen is present, microorganisms oxidize carbon and hydrogen in organic stock to get energy and materials for living, and release CO2 and H2O. Composting is the example. When there is no oxygen, another microorganisms thrive, and they derive they energy by oxidizing carbon with present in organic material oxygen, and by breaking down complex organic molecules to simpler ones with less energy potential. Thre is no enough oxygen in organic materials to oxydize all carbon and hydrogen "fuel" down to CO2 and H2O. As a result, substantial amounts of “waste” products are produced: vinegar (acetic acid), alcohol, methane, butanol, hydrogen, acetone, hydrogen sulfide, ammonia, and many others. The most complete energy utilization, preferred in nature, is methanogenes, where all mentioned chemicals are finally reduced by different microorganisms to ultimate waste: biogas (methane and CO2, about 50/50 by mass). If specific conditions are created, like in grain distillery, some microorganisms become predominant, and produce desired "waste", such as alcohol, or in our case hydrogen.

Aerobic processes, as composting, reduce organic nitrogen to nitrogen gas and wastes valuable fertilizer. Anaerobic digestion of any sort converts organic nitrogen to ammonia, which could be recycled back to fields as fertilizer. No waste whatsoever, and the process could be truly closed-cycle, with energy input of solar radiation, atmospheric CO2 as raw material, and output of desired chemicals.

Unfortunately, lignin, constituting about 30% of woody tissue, could not be digested. Usually it is returned back to field as soil conditioner, but it also could be gasified, thought this process is not energy and economically efficient so far because of hurdles to get it sufficiently dry from suspension in water.

DS there is a lot of potential in this sugar fuel cell electric car both because of an incredible energy dense system and because of potentially cheap fuel. Note that it only takes 12 gallons of sugar/starch warter to fill the tank. That is 48 kg. It produces 4 kg of hydrogen enough to do about 110 kWh of electricity in a standard hydrogen fuel cell. The potential is that a 50 kg tank plus a 50 kg hydrogen reactor plus a 50 kg fuel cell or a total system wiight of 150 kg could deliver 110kWh enough for at least 300 miles of range in a heavy SUV like the Sequel. The weight of 110kWh of A123 batteries is 1000 kg and then we have not included packaging and cooling that could add 200 kg. Now add another 300 kg because the car needs to be stronger to carry the weight of this 1200 kg system and there you see 1500 kg for the lithium system versus 150 for the sugar fuel cell system. The sugar fuel cell car would also be a lot faster because of the reduced weight. Still rather hypothetical I admit but not entirely unrealistic.

Let’s look at the economics. 110 kWh would only need to cost 5c/kWh during off peak hours. That is $5,5 to fill the battery. The sugar fuel cell car would need 27 kg of sugar. That costs 9 c per lb =0,453 kg for raw sugar. That is, to fill the sugar tank costs (27/0,453)*9c = $5,36. Now we don’t have the price for enzymes and we don’t know whether they are catalysts instead of reactants (could be a combination of both since several enzymes are involved), but still. It appears it will be far cheaper than filling the tank with gasoline at today’s prices. The price of sugar could even drop significantly if Mr Zhang cellulose conversion technique succeeds (he is not the only guy working on that issue. POET will have a 110 mgy factory for this ready by 2009). For comparison the gasoline version of this heavy SUV would need about 20 gallons at $3,3 = $66. I am excited about this. And the fact that mother nature has spend several 100 million of years to optimize energy systems that essentially use sugar for everything makes me confident that this will also be the energy carrier of choice for human transportation. Completely non-toxic and non-flammable and can be handled and produced even in remote third world countries. We just need to master the enzymatic processes. So DS with all respect for Rube Goldberg this development is seriously more profound.

Forgot to consider the potential cost of producing an energy system based on a sugar fuel cell versus a battery system. The 110 kWh A123 system would cost $1500 per kWh for the battery only at today’s prices. That is $165000 for the 110 kWh system and this is not including packing and cooling. Say they can get it down to $200 /kWh in the future 10 years from now including the packing and cooling. This is very optimistic. That would still be 110*200 = $22000 for the energy system and we need a car also. The sugar fuel cell car needs a 70kWh hydrogen fuel cell which they think they can do for $4000 in a few years say 10 from now. It also need a sugar tank which $100 or so. Finally it needs a sugar hydrogen reactor and that will be cheap because these enzymatic processes happen below 50 degree Celsius at atmospheric pressure. No need for strong expensive materials that can resist chemical corrosion. Still the enzymes may cost. A wild guess is that this reactor can be produced for less than $1000. Now that is $5100 for the total sugar fuel cell system versus the minimum $20000 for the comparable battery system. You can buy a lot of sugar for the $16900 difference. You can also use it for shipping and aviation. Let’s hope it will be 2018 for a sugar fuel cell car at the car dealer and that it will be 2011 for adequate proof that enzymatic sugar from cellulose is commercially viable (the 110mgy POET project that go online in 2009). The more I consider this news about sugar fuel cells the more I think that this is the most awesome and significant news I have ever read on green car congress. Let’s hope they will be able to execute on it as well.

The potential problem with freezing should not be a big technical issue. If the tank freezes it could be heated by excess heat from the fuel cell or the plug-in battery. The invasive micro-organisms issue could be solved by adding some chemicals (or even some enzymes) to the sugar water that kills the most micro-organisms but that does not interfere with the process of the hydrogen reactor. But that probably need to be tested extensively before a good solution can be settled. I still see the most important show stoppers as reaction speed and enzyme costs.