History, energy, automobiles
gjkscruggs at comcast.net
Sat Mar 16 08:17:06 EST 2002
Bob, et al...
The two numbers 75% for a gasoline engine vs. 68% for a hydrogen engine are
not all that far apart. Other assumed efficiency factors for the various
steps would, of course, give different numbers. The actual numbers would
certainly give differing calculation results from what I have here. It is
noteworthy, however, that introducing additional steps in any process often
results in an overall decrease in the efficiency of whatever is being
done. My point is that the use of hydrogen as an auto fuel does little, if
anything, to preserve the environment when compared to using either
gasoline or diesel. It sounds nice but the overall effect isn't much
benefit to the environment.
Good points regarding the 'hidden charges' in what otherwise appears to be an attractive alternative. Your snapshot of today's state of the art for making hydrogen is on target but these processes and efficiencies are not stationary. I think that these intermediate processes will become more efficient thus making the overall energy conversion numbers more attractive. Since we're not talking next week or anytime soon, how about if our electrical production is also done in fuel cells with hydrogen as the fuel... thus reducing the fossil fuel pollution component of the process.
But let me switch to a larger picture. A couple years ago I held a small conference in Montery (on an unrelated topic) where one of my speakers was from Department of Energy, Policy Division. He laid out a vision of our energy future that was quite compelling. I'll make this short... essentially we are entering the final days of petroleum-based energy production. Within 40-60 years we will have converted to a natural gas-based energy production. Natural gas is plentiful and doesn't have to be refined to use. (By the way 80% of all known natural gas reserves are off shore and Russian owned... so make sure your kids have lots of "Gazprom" and "Schlumberger" stock.) The natural gas period will last only about 60 years but will introduce a lot of the infrastructure for the next period... hydrogen. The reason to use hydrogen is that, in addition to being clean burning, it is everywhere, it doesn't have to be mined or refined only 'extracted' from water.
As hydrogen becomes more readily available we will transition more easily to fuel cells for electricity production but on a distributed vice concentrated basis. Everyone will have their own home-sized fuel cell... they're already available but expensive... that will power your home and be hooked to the grid to share peak loads as they fluxuate with time-of-day peak usage.
But for automobiles the current challenge is storage and btu content. A contemporary engine that produces 300hp on gasoline only makes 50hp on hydrogen and current storage technology allows similar range reductions. Although carbon nanotube ("Buckytube") storage cylinders show great promise toward increasing the amount of hydrogen storage in the same volume they are yet to be produced.
Problems and challenges certainly but count on hydrogen powering our stuff in the future.
Regards, Gross Scruggs
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