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To: Sioux-san

I live near the Mojave Desert, which is becoming full of these windmills. Ruins the view, among the other ills. Where’s the view police? And they blink their red lights on top all night (interestingly they are all synchronized to blink at the same time). Doesn’t this waste some of the precious electricity?

About the hydroelectric dams. Talking with a long time controller for one of the dams on the Columbia; about 20 years ago he managed the water to get the most electricity from it. Now he has to waste it then the wind power is at a surplus. Makes me sick. Hard to puke when I’m already puked out from everything else.

Solution — Use the surplus wind power to run the dams’ turbines backwards to pump the water back upstream to store it behind the dams. Simple and straight forward.

Oops, don’t let a ‘greenie’ read this — they will try to do it.


10 posted on 11/23/2012 11:23:18 AM PST by Scrambler Bob (If you could read my mind ... just count up the felonies!)
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To: Scrambler Bob
Solution — Use the surplus wind power to run the dams’ turbines backwards to pump the water back upstream to store it behind the dams.

You think you're joking. This is done in California now and has been for years.

San Luis Reservoir

They pump water uphill all winter, and use the water to produce power all summer. It would be interesting to see this done on the Columbia.

11 posted on 11/23/2012 12:05:22 PM PST by tpmintx (Problem: People who work for a living are almost outnumbered by those who VOTE for a living (47%).)
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To: Scrambler Bob
Use the surplus wind power to run the dams’ turbines backwards to pump the water back upstream to store it behind the dams. Simple and straight forward.

Oops, don’t let a ‘greenie’ read this — they will try to do it.

Too late, it's already being done. Well, not exactly like what you describe, but close to it. It works best with "low head turbines" coupled to motor/generators. A dam is built across the mouth of a bay, impounding a large storage volume. During times of low power demand, excess is used to drive the turbines as pumps, raising the volume of water behind the dam. As demand for power increases water is released back through the turbines, driving the generators and making more power available to the grid.

One advantage a "low head" system has is that if tidal forces coincide with the power demand cycle (high tide/low demand and vice versa) they may be used to add to the amount of water moved into and out of storage.

There have been "high head" systems tried as well but the greater the height of the storage reservoir above the source the lower the overall efficiency of the process.

That is, converting electric power (current x voltage) to mechanical power (torque x speed) involves losses due to electrical resistance, magnetic hysteresis, windage, and bearing drag. Converting mechanical power to hydrodynamic power (pressure differential x flow rate) involves losses due to pump slip and bearing drag. Delivering the hydrodynamic power to the storage reservoir involves wall friction which causes pressure drop. Each of these loss factors has a coefficient of performance, the overall efficiency is the product of all of the COP's of the various stages, divided by 2 since you lose power pumping water uphill and again when you let it flow back down.

A lot of processes are reversible but there are no free lunches. If you lose 25% of the input energy going from "A" to "B", you will lose another 25% coming back to "A". The only time something like this makes sense is when your electric grid is largely powered by large, central generating stations with steam powered turbines. It doesn't matter how the steam is generated, atomic energy, geothermal, coal, oil, or bio-mass. All large central stations run most efficiently at a constant load, unfortunately consumer demand varies on a 24 hour cycle.

In the final analysis, gas turbine driven generators are simple, efficient, quick to start and can be quickly "throttled" up and down to mach a varying load. It would seem to me at the ideal grid would have 75% of it full power requirement supplied by nuclear plants with the remaining 25% by gas turbines to handle "peaking" loads. Forget about wind, solar, and tidal as they cost more then thermal based generation and none of them is available 24/7. They can only compete when the Government shovels in tons of taxpayer money.

Regards,
GtG

14 posted on 11/23/2012 1:07:51 PM PST by Gandalf_The_Gray (I live in my own little world, I like it 'cuz they know me here.)
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