Utility District believes in perpetual motion

"Andy Asberry" wrote: (clip) Am I missing something here? ^^^^^^^^^^^^^^^^^^^^ Probably. We have a dam in California (maybe more than one, where they have a large fore-bay. At night they use surplus electricity to pump water up into the fore-bay. When demand is high, in the afternoon and evening, they release the stored water to increase their generation capacity.

Yes. I'ts called "pumped hydro". The impeller is in the pipe, but, as another poster said, they use excess capacity to suck the water up, then use the gravity of that water to run the system as a generator. The gain in the system comes from not having to have a separate "demand" power plant that uses fossil fuels in the peak times. There's one in Scotland, I think, that can generate several gigawatts for about 3 hours at a time. They use it right after national socker games when EVERYONE (apparently) puts on an electric tea pot. We have several similar systems here in the US, too.

Sure wish I had a 405 foot head of water out behind me! I'd pump the water up using a woodgas powered engine. Like having a HUGE battery that never goes dead.

Pete Stanaitis

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Andy Asberry wrote:

They must have discovered some new principle, 32 feet is all I've ever heard of anyone sucking water up - and that's under ideal conditions.

Engineman

Yes. =EF=BF=BDI'ts called "pumped hydro". =EF=BF=BDThe impeller is in the= pipe, but, as

veral gigawatts

"engineman" wrote: They must have discovered some new principle, 32 feet is all I've ever heard of anyone sucking water up - and that's under ideal conditions. ^^^^^^^^^^^^^^^^^^^^ Spaco misspoke. It wouldn't make sense to put the pump/turbine at the upper level, for the reason you state, and also because the water would be sucking on the turbine on the way down.

I skipped the meeting, but the Memos showed that Andy Asberry wrote on Mon, 12 Jan 2009 18:27:50 -0600 in rec.crafts.metalworking :

Yes.

Unless you believe that they believe they can recoup all the costs of pumping the water up 405 feet.

-- pyotr filipivich We will drink no whiskey before its nine. It's eight fifty eight. Close enough!

Standard practice in the Snowy Mountains Hydro scheme (NSW Australia) is to use cheap off-peak power to pump low water up high for use later on (peak period) for power generation.

The water is simply stored energy.

Yes - they *do* do it.

-- Jeff R.

What they are doing, is keeping power plants running at night when demand is lower, to pump the water. During the day when they get peak demands, they release water through turbines to generate electricty. There are losses, but by using untapped capacity at night, they gain capacity during high demand, for a lower overall cost than building another power plant.

Jon

On Mon, 12 Jan 2009 18:27:50 -0600, the infamous Andy Asberry scrawled the following:

Maybe trying to recoup some of their pumping losses?!?

-- Acceptance is such an important commodity, some have called it "the first law of personal growth." -- Peter McWilliams, Life 101

Ah, "cost" - they charge extra for the electricity delivered by the pumped water. But does the amount of electricity produced equal or exceed the amount consumed in the pumping?

-- pyotr filipivich We will drink no whiskey before its nine. It's eight fifty eight. Close enough!

Pumped storage in well-engineered, utility-scale applications typically recovers over 70% of the energy consumed. So, economically, it's at least as good as other large-scale load-balancing approaches, which, in most cases in the US, is otherwise done with gas turbines.

Those big steam-turbine generators absorb pretty big losses in startup and shutdown, so the utility companies gain, also, by keeping them running at high capacity all night long.

-- Ed Huntress

"pyotr filipivich" wrote: Ah, "cost" - they charge extra for the electricity delivered by

^^^^^^^^^^^^^^^^^^^^^^^^^ The water keeps coming down the river whether you can use it or not. During peak load periods there may not be enough water to meet their generation needs. During the wee hours of the morning there is more water than they can use. Pumping water uphill into a pond is like charging a storage battery--you get to use it later.

I skipped the meeting, but the Memos showed that "Ed Huntress" wrote on Tue, 13 Jan 2009 12:05:11 -0500 in rec.crafts.metalworking :

So compared to "completely" wasting the power, they only "lose"

30%, and can charge more for the 70%. Sound like a friend who used to go to the horse races and bet everything. Lost a lot, but on the whole, would come home with about 2/3rds of what he went with - all legal winnings.

Yeah, there is that too.

pyotr

-- pyotr filipivich We will drink no whiskey before its nine. It's eight fifty eight. Close enough!

If you can find a cost-effective way to double the efficiency, I'm sure you could be rich beyond your wildest dreams...

They charge less than they would otherwise, because they'd either be charging you for wasted base capacity, or they'd be charging you amortization plus fuel on gas-fired turbines for peak capacity.

Utilities have been doing this around the world for close to 100 years. It's a money saver. In the US, it also saves gas and makes better use of coal or nuclear -- sometimes, hydro.

No, it's not much like that.

It's the best way to go for load-balancing, where it's physically and geographically possible.

-- Ed Huntress

This is a water district; not a power company.

Maybe I didn't explain this well. There is NO storage. They are pumping it in one end of a pipe and putting the generator on the other end. Power used and power generated is at the same time. Stop the pump/stops the generator.

Seems to me placing a restriction in the pipe only increases the power required to pump the water.

Maybe they figure the pipe is a transmission line. Possibly it is cheaper than hanging wires.

Maybe cheaper than acquiring a new right-of-way for a power line. jw

Seems like ordinary, garden-variety, load balancing to me. Overbuild for anticipated loads. During the times your load is minimal use some of your capacity, while the generators are lightly loaded, to pump the water to the source.

Next day, when the load is highest drop the water back through the penstocks to ramp up the other generators.

Power is cheap in the wee hours, especially if you're your own customer, and loads are light. Then you use the "banked" water to pick up the load during the day when demand is high and you can charge more.

You have to keep a crew on duty all night anyway. Why not let them do something useful and cost effective?

If pipeline's high point is higher than the second lake (for example, the lake is in a deep bowl), the difference between the potential energy of the water at the high point and at 405 feet is available at the discharge.

Maybe some other entity is paying for the "push" at the other end ;)