Any comments on this large energy storage device? 7

[MartinLe]

Look at this:

http://www.heindl-energy.com/

Essentially they plan to cut a large plug from bedrock, raise it by pumping water underneath to store energy:

The thing looks insane. They address a few design issues on their site. I'm unsure about the feasiblity, what do you think?

 

[GroovyGuy]

All,
I would think that if this is a viable energy-storage alternative, we should have seen a scaled-down version (ie proof of concept) by now. N'est pas?
I don't see this thing taking off; too much risk.
GG

http://www.theglobeandmail.com/repo...ge-system-off-toronto-island/article27306527/

The pessimist sees difficulty in every opportunity. The optimist sees the opportunity in every difficulty.
Winston Churchill

 

[IRstuff]

In some sense, the concept isn't really scaleable. The trench digger that cuts the cylindrical portion of the plunger cannot be arbitrarily shrunk, so there's a limitation on the kerf width around the cylinder, and therefore, a limitation on the cylinder width as well.

TTFN (ta ta for now)
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[verymadmac]

If one put a large car park building on the top of the plug for a residential area one could get "free" energy. Cars leave during the day (reducing mass) when it is charging and return adding mass just before the start of peak power consumption.

Is it likely to act like a giant compass? (OK that would be dependent on the rock and its only going to move very slowly but its not a trivial mass to stop rotating).

 

[BUGGAR]

If it could act like a giant compass and it rotated in it's hole, would the world wobble?

 

[IRstuff]

No, but if it did it a lot, or there were a lot of them doing it, it would slow down the Earth's rotation.

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[HamburgerHelper]

I wouldn't mind each day being a little longer.

 

[JNieman]

Days longer, year remains the same... assuming salaried paid, I'm coming out ahead!

 

[MortenA]

I think a flow battery will be the future of large scale storage of energy:

https://en.wikipedia.org/wiki/Flow_battery

 

[cranky108]

If you build a better mouse trap. But I have not seen efficiency numbers on any of the proposed schemes. Are any of them better than 50%?

At least with power plants there are numbers of Dollars per megawatt, which is a cost to construct. And there are heat rate numbers to help define the efficiency.

 

[HamburgerHelper]

 

[moltenmetal]

Conflating the storage of low grade heat with the storage of mechanical or electrical energy is not helpful...but it's a hamburgerhelpful graph.

 

[KENAT]

btrue, if I recall correctly some of the early hydraulic accumulators did just use a mass on top of the column of water. Quick look on Wikipedia didn't contradict it as I recall but I can't remember if it 100% confirmed it either.

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[HamburgerHelper]

Moltenmetal,

Hamburgerhelpful graph? I don't know what that means exactly but I like graphs so I'll roll with it.

These numbers line up with stuff I have seen elsewhere with the exception of thermal storage for electricity. Numbers I have seen elsewhere place it around 70-80%. None of these methods that I have seen use low grade thermal storage. All of them that I have run across on the web that are for grid energy storage use molten salts.

 

[MartinLe]

Heindl claims their dvice could be as efficient as pumped hydro, which makes sense.

Storage efficiency ~90% for heat can't mean electrical power as output. No heat engine that efficient.
Storing heat as heat OTOH makes a lot of sense.

 

[CheckerHater]

Considering size and pressure requirement for the pumps, wouldn't it be easier just to "reverse" hydro-electric station and pump water uphill, back into reservoir?

Pumped storage seems to be viable solution for years.

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[MartinLe]

The idea is to have a smaller footprint than a valley (which is the usual footprint of pumped hydro). But let's do a dirty quick & calc if it actually holds up:

Let's say 100mx100m piston (DxH), density of 2600kg/m³, moving height 50m - Approx: 280MWh stored (potential energy of plug, ignoring water we pump down to move the plug up)

For the same potential energy you need at 50m pumped height 2 mill. m³ water.

How much water level fluctuation do you permit in the upper reservoir of your pumped hydro storage?
Let's say 1 m (my nearest plant has 70cm in the lower reservoir) so we arrive at 2 mill m² surface - 2km x 1km or so. A small valley.

The idea behind the plug is that we run out of good sites for pumped hydro sooner or later. Looking at what others in this thread have written, I now doubt there's a good site to build the plug.

 

[cranky108]

Actually you don't need a lower lake for pumped hydro. If you have a river where the water level is normally high enough, it can be used as your lower source.

Another method may not require any generation on the back end, in that water systems all over use a upper storage so they don't have to run pumps all the time. But if those upper storage were to expand, and the pumps only timed with the excess generation, then it would appear as a form of energy storage.

 

[moltenmetal]

Just thinking aloud here- I have read a little about this but have never designed or operated a hydro station- but I understand that in some cases there would be no real need for pumping at all- you'd just modulate the flow of water to the turbines and allow the upper reservoir level to rise while you're not running them. Some reservoirs can handle the variable level, and the downstream body of water can also handle the varying outflow, so some hydro facilities are used for "peaking" in this way. But most can't be used that way- their output can be modulated based on demand, but the excess water soon has to be spilled and its potential energy wasted when the full output isn't required.

The real problem with storage of any kind is that electricity is just too cheap to bother storing in most locales. Why would you want to build a facility capable of operating in this fashion unless there was a payback for the extra capital required? You'd need to build turbines capable of, say, 3x the average flow, and then operate them only 1/3 of the time.

 

[cranky108]

Actually we do operate some of the hydro plants at some fraction of their rated output most of the time. The reason is limited water flow, demand, maintaining water level, etc.
The fact is that people don't demand peak electricity or water all the time. Some people like a lake that does not have a daily high and low tide.

And some of our high lakes are frozen for part of the year, so the hydros are not operated during those months.

 

[SnTMan]

The real problem with storage of any kind is that electricity is just too cheap to bother storing in most locales.

Well, the politicians and greens are working on the problem

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand