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Re: E-M:/ Where to find alternative fuel stations in Michigan ...



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Enviro-Mich message from Rane Curl <ranecurl@engin.umich.edu>
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On Thu, 29 Jun 2006, Lowell Prag wrote:

...snip...
In the long term, only a hydrogen based fuel economy will solve those
problems, as hydrogen can easily be obtained from water, not fossil fuels
or other hydrocarbons, and the only by product of using hydrogen in fuel
cells, is pure water and heat.

Two problems with hydrogen though, producing it from water in a manner
that does not also produce CO2, and over coming the oil lobby in
Washington, in order to build a nationwide hydrogen delivery
infrastructure.

"The term 'H2 economy' is a misnomer. Our present economy is based on fossil fuels with a small contribution from nuclear energy. H2 is an inefficient energy carrier, not an energy source. For the next foreseeable 20-30 years, we will still depend on fossil fuels, so what use would H2 achieve? Conversion of fossil fuels to H2 inherently involves a large irreversible energy loss. The best lower heating value (LHV) efficiency of a H2 plant from natural gas is 65%, and of a coal plant is 55%. There is no available energy conversion device based on H2 that has a sufficiently large advantage to compensate for this loss, and conversion of nuclear or solar electricity to H2 makes no sense. The electricity alone to produce one million BTU would be about $50, while its market value as hydrogen would be only $16."


from "Demystifying the Hydrogen Myth" by Prof. Reuel Shinnar (2004).
http://csauth.ccny.cuny.edu/ci/cleanfuels/upload/Hydrogen-Myth.pdf

As I have pointed out before, the current fuel crisis is because the world is running out of oil ("peak oil"), but the world ran out of hydrogen billenia ago. It would have to be manufactured, and that is inefficient compared to using the electricity necessary for electrolysis directly. All hydrogen can be is a less efficient way than electricity to distribute energy from a nuclear or solar generating station.

Prof. Shinnar does not address the best option for a future transportation fuel, which would be cellulosic alcohol(s) (currently being discussed primarily in terms of ethanol, but not restricted to that). This is an alternate way of capturing solar energy, but only useful if it is self supporting - the efficiency being made high enough so that no fossil fuel is necessary in its cultivation and processing. No adequate research program for accomplishing this is yet on the table.

--Rane L Curl


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