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To: Jim Willie CB who wrote (5332)	8/28/2002 5:57:45 PM
From: yard_man	Respond to of 89467

but electrolysis takes energy -- I've heard this before, but haven't read anything feasible. Got any good links or sources that add to the plausibility of this. In a way the far-fetched (?) electolysis route is funny -- you are simply storing energy in a battery of sorts, separating the hydrogen from the oxygen and then recombining it. Methane is mostly H -- CH4. Even supposing the plausibility of using the sun's energy to power the electrolysis -- you have to collect and distribute H -- still a big hurdle.

To: Jim Willie CB who wrote (5332)	8/28/2002 6:33:05 PM
From: yard_man	Read Replies (1) \| Respond to of 89467

thought this was interesting -- powerball.net using renewables to convert NaOH into NaH -- but I am not a chemist. Supposedly NaH woould be easy to split -- but then what do you have left. Hopefully not elemental Na ... Apparently just for the distribution part of the problem. Here's something for the production sciencedaily.com It seems all I am reading has one thing in common -- everything is not even at the proof-of-principle stage. The above article alludes to electrolysis being inefficient. If you look at the total process -- hydrogen production and then the fuel cell -- well ... I think folks are fooling themselves by talking about efficiency of one step, namely the production of electricity from the combining the hydrogen with oxygen. Another one that alludes to the seabed hydrates pacific.bizjournals.com Would love to see something that tells how dense this stuff is on the sea floor and how it might be extracted. in this same article -- there is what I consider to be a REAL niche for fuel cells -- look at the justification -- insufficient traditional "infrastructure" >>The state Legislature this year appropriated $200,000 for hydrogen research. The bill was signed into law last week by Lt. Gov. Mazie Hirono. That money is separate from the defense research being undertaken by the university and IFC, a Connecticut-based subsidiary of United Technologies Inc. and one of the world's leaders in fuel cell development and research. Also, the National Tropical Botanical Garden on Maui is expected to award a contract within the next month to build a visitor center that will be powered by fuel cells. Fuel cells are more cost-effective to meet power demands for the Hana facility, since it would cost between $200,000 and $400,000 to extend the existing power grid to the area, says Michael Veith, former botanical gardens president who now owns H2 Energy Systems LLC. Veith says the system to be installed in Hana should cost less than $150,000. It will be able to produce five kilowatts of electricity during peak hours and, if there is excess power made during the day, it can be stored for times when there is above average demand, or on days when there is no sun to produce more hydrogen. "The power that will be produced is comparable to a residential-sized home's power needs," Veith says. << Maybe it is a problem for the biotech field?? sbcsc.k12.in.us

To: Jim Willie CB who wrote (5332)	8/28/2002 6:50:22 PM
From: yard_man	Read Replies (2) \| Respond to of 89467

this is what I was trying to get to in talking about hydrolysis -- seems to me you need the same energy input to separate the H from the O that you would get from the recombination -- so it comes down to nothing more than a glorified enery storage device. >> Question - How much energy does it take to overcome the "barrier" to seperate hydrogen and oxygen and are there catalists that can make the process more efficient? ---------------------------- Eugene, When gaseous hydrogen is burned in gaseous oxygen to make gaseous water: H2 + 1/2O2 ===> H20 242 kJ energy is released for every released mole (18 grams) of water produced. The same amount of energy must be input to drive the reaction backwards to produce hydrogen and oxygen from water in the gaseous state. Scientists are working to discover a means by which the process can be accomplished more efficiently and economically. Nevertheless, whether accomplished with catalysts or via some biological method, the energy input required remains the same. Science is constrained by the laws of thermodynamics. Regards, ProfHoff ========================================================= This question is not quite specific enough. It has two possible meanings: 1. The separation of a gaseous mixture of H2 and O2 gas: Because of the difference in the size and diffusion properties, no doubt a membrane permeable to H2 but not to O2 could be engineered, and the only energy necessary would be to keep the pressure on the gaseous mixture. 2. The formation of H2 and O2 from liquid H2O: I suspect that this is the context of the question. If it is the work (free energy) required to decompose 1 mol of liquid water (about 18 cm^3) into gaseous H2 and O2 at 1 atm pressure and 25 C. is 56.7k-cal/mol H2O). There are catalysts that promote this reaction, e.g. Pt powder, but that does not change the energy requirements, which are substantial. Vince Calder <<

To: Jim Willie CB who wrote (5332)	8/28/2002 6:54:30 PM
From: yard_man	Respond to of 89467

nice summary of known production methods objecttechcem.com I think we need to keep in mind that we would not only need 1) Fuel cells of the right size for each app -- (even if it is just transportation) 2) A totally new type of distribution infrastructure -- including both transport and local delivery We would also need: 3) A new production infrastructure based on separate energy technologies that are currently not used to produce large quantities of energy in the national mix that is consumed -- i.e. renewables. This stuff is really blue-sky until petroleum becomes prohibitively expensive, unless 1) Fuel cells become considerably cheaper 2) there is some way to reuse an existing delivery infrastructure and 3) production becomes cheaper than fossil fuel extraction From an energy standpoint -- taking a real energy source (not simply a conversion device like a fuel cell) -- hopefully a renewable -- using that energy to split H from the O and then using a fuel cell to recombine the two to extract the energy stored from the renewable production -- just isn't likely to ever be efficient when the whole process is considered, IMO. Why not instead just use the output of the renewable energy at the pt of production and what are the costs associated with charging a conventional battery as opposed to a charging a fuel cell with H??