russ_watters said:
In other words, burn more fossil fuels to make hydrogen? How does that help anything? Certainly not - I'm just not sure what hydrogen has to do with anything in this context. I think you probably understand the issue, but to the general public, they hear the politicians talking about a hydrogen economy and picture the hydogen materializing at the gas pump. Politicians (the people driving the issue) for the most part completely ignore the issue of manufacturing the hydrogen. And that's a dealbreaker for the whole idea. Its like talking about landing a man on the moon without first discussing how to get one in orbit around earth.
Realistically if Bush or Kerry (both have picked up the issue) succeed in getting a million hydrogen powered cars on the road in 10 years and a hundred thousand hydrogen fueling stations, where is that hydrogen going to come from? Realistically. My bet is it'll come from hydrogen manufacturing plants that either take their coal-fired electricity straight from an already overloaded grid or make their own power using oil-fired gas turbine generators. Net result: more pollution, more dependancy on domestic coal and foreign oil, and a bigger energy crisis.
Russ, has hit a raw nerve on this subject. Hydrogen is already manufactured from Hydrogen ores by industries that supply those who need hydrogen in industry. These people are not economic idiots, so it is a sure bet that they are producing that hydrogen in the most economically efficient processes currently known. the history of the chemical industry is replete with examples of new processes being developed and old suppliers being supplanted by more efficient ones.
So if ANY of the solar powered renewable bio-hydrogen processes were even remotely viable economically they would be in use already. Economic viability in a competitive market usually means energy efficient, since the cost of energy to process things is a big factor in the economics of it. So the likelihood of any new hydrogen process replacing the present methods which probably get it by processing natural gas; is slim to none.
And yes sea water is about as low on the stored chemical energy food chain as it is possible to get.
If extracting hydrogen from water was economically viable at all, then by inference it should be just as practical to extract another fuel; namely carbon, from the abundant supplies of it in the atmosphere, or the oceans, Doing that would make the whole CO2 problem moot. Not likely to happen, nor is any major shift to hydrogen.
Hydrogen vehicles such as inner city buses may make a lot of sense from a local air pollution point of view but for the mass of transportation needs it is a pipe dream; but one that Bush threw out there so the environmentallists could not say he was anti-environment. Now it is up to THEM to try and make a hydrogen economy real.
The practicality of increasing electricity generation capacity to the point where either hydrogen fuel cell or pure electric cars could totally replace the internal combustion engine, is just too silly to contemplate. We have enough problems now with regulations just getting enough electricity for electricity needs. The Nuclear opponents aren't going to sanction any massive swing to nuclear specially when it becomes apparent that breeder reactors will be necessary to make that long term viable. Fat chance in today's terrorist strewn world.
There is one other nasty problem with that lovely hydrogen picture. It also requires lots of additional energy just to get it into a storable form. The energy cost of gas compression, or the materials cost of metal hydrides, makes hydrogen a lot less pretty. Then there is all that 'clean' water vapor that will be emitted; well I suppose you could condense the water and save it in an onboard 'ungas' tank. But then water vapor is also a green house gas, and in fact is the major green house gas with by far the most influence on the environment and climate. Renewable (solar) energy sources sound like a great idea, until you realize how poorly concentrated they are. Surely they have to be used in niche situations where they make sense, as does every other energy source we have, but so far there are few real alternatives to hydrocarbons.
Arguably it would make much more sense to use the hydrocarbon fuels as we do now, and recycle the carbon. but even that only makes sense if you believe that CO2 is a significant problem to the environment. I for one do not believe it plays much role at all. With CO2 being 0.037% of the atmosphere, and water vapor as much as 4% at times, I think the problem of thermal flux balance of the Earth is not dependent on CO2 to any great extent compared to water.
