In theory you can get Hydrogen from water: the H2 in H2O (hey can you do subscripts on this board?). You would extract the Hydrogen for use as fuel, and release the Oxygen into the atmosphere. Later, when the Hydrogen fuel is burnt, it is reunited with Oxygen, and the only by-product is water, exactly what you started out with. It sounds like the perfect system: pure energy, nothing wasted, no pollution. The only problem is that it takes a lot of energy to get the Hydrogen from the water -- I guess that's where nuclear and other sources come in. If you use nuclear or fossil fuels to extract the Hydrogen, then you're not really any further ahead.

Perhaps somebody more enlightened than me can tell me if that's anywhere near the mark, and if so, what sort of attempts have been made to resolve the problem. Any takers?

[ 29 September 2004: Message edited by: Albireo ]

This can be accomplished, at least on an experimental level, by running an electrical current of alternating positive and negative charges through distilled water.

The separated oxygen and hydrogen atoms are then fused together via a high-energy spark creating a huge amount of energy. The only by-product of this is steam, which, of course, can be used again indefinitely.

Extracting hydrogen from petroleum or coal compounds still relies heavily on fossil fuels, and nuclear power is simply too powerful and unstable to control.

The question is how well can power cells or engines that use hydrogen directly extracted from water really be made to work.

I'm not convinced that best way is hydrogen.

Compressed air, flywheels, or simply better batteries are also possibilities. Hydrogen may have quicker "recharge" (fill-up) and longer range. But it is probably less energy-efficient, and requires more infrastructure, and is more centralized.
Meanwhile, range on one "charge" for flywheels and compressed air is largely limited by material strength--flywheel power storage depends on how fast they spin, which is basically limited by what speed makes them fly apart. Compressed air storage is limited by pump strength and how strong you can make fairly light storage tanks. Given current advanced materials, they could well challenge hydrogen on range--hydrogen itself doesn't have the range of gasoline as I understand it.

Edited to note: this is all in the context of cars. Other uses, other storage, including low-tech ones like pumping water back uphill.

[ 01 October 2004: Message edited by: Rufus Polson ]

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Eric Sonnichsen, who founded Test Devices in 1972, points out that a wheel created from carbon fibers is safer than a steel wheel, because even if a few fibers break, the wheel won't come apart. On the other hand, if a flywheel does disintegrate, says Sonnichsen, "it's more like potentially lethal lumps of coal coming at you, traveling at kilometers per second."

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