augeri@regina.DEC (03/27/85)
Jeff Hull recently said in net.physics: >While I tend to agree with Lauren that there is a lot of garbage being >passed around as truth, I have to wonder why our cars aren't powered >by liquid hydrogen (a non-polluting fuel) rather than gasoline. And a >host of other similar questions. There is all too much evidence that >people tend to follow their own, very limited, self-interest, rather >than look for ways to benefit themselves while providing for the >common good. With regard to hydrogen fueled vehicles, let me make an observation. The local PBS station (WGBH, Boston MA) recently re-ran the 1979 series "Diamonds in the Sky", which was about commercial aviation. In the last epsisode of the 7-part series they looked at the future of commercial aviation and considered alternative fuel sources. There was an interview with an executive of Boeing, where the executive said they (Boeing) had done feasibility studies that showed they could build hydrogen-fueled jet aircraft in order to alleviate future demand for our dwindling supply of fossil fuels. I have not made any attempt to verify the veracity of his statement, but the gist of what he said is the following: The problem is one of logistics (economics aside) since their calculations indicated it would take the power output from two (2) nuclear power plants of current capacity to provide the energy required to produce enough hydrogen to fuel just the aircraft that fly out of O'Hare Field in Chicago! Now, you may dispute the numbers (quite frankly, I do), but before you say that this is a load of bull, you should be willing to provide alternative statistics. For example, does anyone have some numbers on how much hydrogen would be necessary to replace today's gasoline-powered automobiles with an equivalent number of hydrogen-fueled automobiles (just the USA of course)? How much energy would it require to produce that amount of hydrogen? How much energy does it take to produce the amount of gasoline that would be replaced? The problem clearly is not technical (we *can* do it), but is it economical? Without a doubt, when we no longer have fossil fuels, it *will be* economical, but not now, nor in the immediate future. Mike Augeri (DEC-Maynard)
graner@ut-ngp.UUCP (Nicolas Graner) (03/28/85)
Mike Augeri recently said in net.physics: > With regard to hydrogen fueled vehicles, let me make an observation. > > [...] their calculations indicated it > would take the power output from two (2) nuclear power plants of current > capacity to provide the energy required to produce enough hydrogen to fuel > just the aircraft that fly out of O'Hare Field in Chicago! > [...] > Now, you may dispute the numbers (quite frankly, I do) > [...] > does anyone have some numbers on how much > hydrogen would be necessary to replace today's gasoline-powered automobiles > with an equivalent number of hydrogen-fueled automobiles (just the USA of > course)? How much energy would it require to produce that amount of > hydrogen? I don't think it makes much sense to compare directly hydrogen to gasoline. We use gasoline as a source of energy: energy coming from the Sun millions of years ago was stored in the ground and we can now retrieve it and use it for (almost) free (except for minor economical considerations :-) . Since there is no hydrogen stored on earth, we have to produce it by decomposing water. And when it is used in an engine, it re-creates water, releasing the energy that was consumed to produce it. Therefore hydrogen should only be considered as a *storage*, not a *source* of energy - very much like a battery. I have no idea how efficient this process is compared to a conventional battery, either in terms of released energy/stored energy or of stored energy/mass, but the above statistics suggest that it is pretty low. Nic. {ihnp4,seismo,...}!ut-ngp!graner *If Murphy's law can go wrong, it won't*