The Oil Drum

238 comments on DrumBeat: August 12, 2006

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totoneila on August 12, 2006 - 9:47am

Hello DIYer,

I am imagining more of a multiple series of small ribbed metal logs across the sluicepath and connected to gearboxes to spin the correct RPM for the dynamos, not a turbine.

Because water is less dense than steelies: that is why you need the big drop to spin the turbine. The steelies could roll much slower because of their tremendous energy density. The arch design of the sluicepath would determine the rolling speed and how many millions of tons of rolling pressure would push the steelies relentlessly forward.

Bob Shaw in Phx,Az Are Humans Smarter than Yeast?

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DIYer on August 12, 2006 - 10:11am

I understand your fascination with steelies, they're fun to play with. But along with the other objections listed below, I doubt you could get more efficiency out of them than falling water. You're still allowing something to fall and trying to recover energy from it. (note: filling that lake with mercury would allow you to use a magnetohydrodynamic generator with no moving parts other than the mercury stream)

But as others have mentioned, there is a tremendous amount of embedded energy in the steel itself. We use water for this application because (maybe not in the Sonoran desert, but some places) it is readily available, environmentally innocuous (give or take a breaking dam) and nature does some of the lifting for us.

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wkwillis on August 12, 2006 - 6:08pm

NaK is cheaper than mercury, a much, much better conductor, and fluid at any place they need electricity for summer airconditioning peaking.
Go with flow cells for cheap energy storage for any place that doesn't have hydroelectricity to use instead.