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Wednesday

Here's a brief science quiz for ya. If you pump water up a hill so that it can run back down the hill and power an electrical generator, how much electricity will you net benefit?

The state of Utah was apparently not interested in the scientific question. That's just engineering details to be worked out later. No, the most important question is how much environmental damage will their perpetual motion machine cause?

OK, the project actually seeks to time-shift energy usage by doing the pumping in off-peak hours and using to generate power during peak hours. But it's still a net loss of electricity, despite the claim in the article that:
Symbiotics LLC, in arguing for the project, pointed to hydroelectricity's renewable energy potential and claimed the project could meet about 85 percent of Utah's current peak energy demands if used in concert with conservation efforts.


They still need a power plant somewhere to supply 100% of Utah's current power demands, plus whatever additional this Roosevelt-esque make-work project. That would be, for the math challenged among you, greater than 100%. It's theoretically possibly they'd have to build a new power plant to meet the extra demand. I guess they plan to make it up in volume.

These people better not laugh too hard at the penis thievery panic in the Congo.

Comments

The proposed scheme is not a perpetual motion machine. It is based on operational efficiency at producing power being variable and dependent on the amount of power being produced.

If operation at the optimum efficiency point produces more power than is needed at the "low demand" point then the excess power can be used to pump water to a higher reservoir. During periods when the demand is greater than the optimum operation point the reservoir can be used to supplement the production of power.

As you point out, there are losses in pumping the water into the reservoir and losses in generating power from the reservoir. However, if those losses are smaller than the losses incurred from operating the fossil fuel plant at a point other than optimum efficiency then there is still a _net_ gain in efficiency, i.e., a lesser amount of fossil fuel used to produce the required power over the period of the day.

Kind of like the idea used in a hybrid car.

Of course, none of that means it is in fact a good idea; only that it is theoretically _possible_ that it is a good idea. Kind of like the hybrid car.

Posted by Bob r at Monday, May 26, 2008 10:49 PM

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