Please read the thread you were replying to before reprinting official drivel. This is what I posted yesterday:
....I am repeatedly surprised by the fascination many environmentalists have with the wonderful future world of hydrogen. Let's see, we build power plants to generate electricity to extract hydrogren, then ship, by pipe or other means the hydrogen to someplace else to make electricity? And so we end up with less energy than we started with. Why is this good?....
Because the *solar* energy "we started with" is mostly unusable until it is stored as hydrogen. Wind farms in North Dakota. Solar farms in Arizona-New Mexico. Enough for all our transportation uses and much more. Plus huge numbers of jobs from construction of the farms, reconfiguration of the vehicle fleet, revitalization of depressed areas, etc., etc.
Shane Mage
"Thunderbolt steers all things."
Herakleitos of Ephesos, fr. 64
Hydrogen is most definitely not a pure energy source for earth-bound inhabitants. and that is beacause most all of hydrogen is locked up with oxygen in water, for example. to be available as hydrogen, one needs to seperate the water molecule into components, and that takes -- drum roll -- ENERGY. In another scheme, hydrogen is created from mixing steam and methane. And steam comes from ....
Hydrogen IS an energy source for inhabitants of stars, because they are lucky enough to have hydrogen in its elemental form, and also lucky enough to have it in a form dense and hot enough to support nuclear reactions.
We earthlings are not so lucky.
As described in Joan Ogden's "Hydrogen: The Fuel of the Future?" in the same issue (page 69), the centerpiece of the present US Department of Energy plan to improve vehicle technology apparently involves a fuel-cell-powered vehicle, the "Freedom Car." That vehicle, which would use stored hydrogen as fuel, could ultimately reduce petroleum consumption, greenhouse gas generation, and air pollution. However, a practical, economical hydrogen source that does not generate carbon dioxide will be required to obtain those benefits. The development of such a hydrogen source is a major challenge, as are the needs for practical hydrogen distribution and storage and for fuel-cell technology. It is uncertain just when such a hydrogen-powered vehicle could have a significant effect on the total fuel consumption of the US vehicle fleet; at best, that time is several decades away.
http://www.aip.org/web2/aiphome/pt/vol-55/iss-11/p12.html
Similar basic issues surround the Hydrogen Fuel Initiative, says Malcolm Weiss, a transportation specialist at the Massachusetts Institute of Technology. Separating hydrogen from sources such as natural gas produces nearly as much greenhouse gas as petroleum fuels, he says, and hydrogen gas cannot be moved through conventional pipelines. That means that it may be necessary to produce hydrogen at the pump, perhaps through electrolysis of water. But the technologies to do this cheaply do not yet exist.
http://www.nature.com/cgi-taf/DynaPage.taf?file=/nature/journal/v422/n6928/full/422104a_fs.html
cf. http://www.nature.com/nsu/030609/030609-14.html http://www.nature.com/nsu/000330/000330-3.html
Future fuel cells may be able to convert about 80% of the Gibb's free energy released by combining hydrogen with oxygen to make water into electrical energy (at present, this factor is around 50%). Also included in this should be the losses in both electricity conversion and electric-motor efficiency, around 20%, to 'shaft energy' to move the car. Thus the overall efficiency is 64%, much better than can be obtained from gasoline or diesel engines. So, we would need to generate around 230,000 tonnes of hydrogen daily -- enough in liquid form to fill 2,200 space-shuttle booster rockets or, as a gas, to lift a total of 13,000 Hindenburg airships. Hopefully the thirst for this enormous quantity could be quenched by a factor of two or three by employing more efficient aerodynamic and drive-train designs in future hydrogen vehicles. But then folks would probably drive that much more.
Hydrogen is not a 'primal' energy source. Unlike fossil fuels or uranium, more energy is used to extract hydrogen from its source than is recovered in its end use. For simplicity, and to bypass issues of carbon and carbon dioxide sequestration, let us assume that the hydrogen is obtained by 'splitting' water with electricity -- electrolysis. Although this isn't the cheapest industrial approach to 'make' hydrogen, it illustrates the enormous production scale involved -- about 400 gigawatts of continuously available electric power generation have to be added to the grid, nearly doubling the present US national average power capacity. The number of new power plants that would need to be built -- based on presently available technologies -- to meet this demand is roughly 800 natural-gas-fired combined-cycle units generating 500-megawatts, or 500 800-megawatt coal-fired units, 200 Hoover Dams (two gigawatts each), or 100 French-type nuclear clusters (four reactors, about one gigawatt each).
http://www.nature.com/cgi-taf/DynaPage.taf?file=/nature/journal/v424/n6945/full/424129a_fs.html
les schaffer
