Any comments on this large energy storage device?
Any comments on this large energy storage device?
(OP)
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:
[img link http://www.heindl-energy.com/fileadmin/user_upload...]
The thing looks insane. They address a few design issues on their site. I'm unsure about the feasiblity, what do you think?
Essentially they plan to cut a large plug from bedrock, raise it by pumping water underneath to store energy:
[img link http://www.heindl-energy.com/fileadmin/user_upload...]
The thing looks insane. They address a few design issues on their site. I'm unsure about the feasiblity, what do you think?





RE: Any comments on this large energy storage device?
"For every expert there is an equal and opposite expert"
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RE: Any comments on this large energy storage device?
RE: Any comments on this large energy storage device?
RE: Any comments on this large energy storage device?
RE: Any comments on this large energy storage device?
To me it looks like they put a lot of thought into this and I don't see the huge flaw that makes it unbuildable. Still don't trust the idea.
RE: Any comments on this large energy storage device?
Then after cutting the rock from the hole, you would need to seal it enough to keep the water from escaping around it.
Another thought is the rock would not need to be round, except that we like nice shapes. If big enough, one could place the solar panels or wind machines on the rock. Or one could even add to the rock after it has been excavated.
But in general, the problem looks to be the seals. But you would not need to use water, as high pressure air could also work (maybe not as well).
RE: Any comments on this large energy storage device?
Massively scaled up version of the old style Gas Holders (Gasometer) of Oval cricket ground fame.
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Any comments on this large energy storage device?
RE: Any comments on this large energy storage device?
RE: Any comments on this large energy storage device?
Just think of how much damage the potato gun of this caliber can do.
"For every expert there is an equal and opposite expert"
Arthur C. Clarke Profiles of the future
RE: Any comments on this large energy storage device?
TTFN (ta ta for now)
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RE: Any comments on this large energy storage device?
I'd not worry tremendously about the static seals along the walls and floor of the cylinder, but the rolling diaphragm piston seal...working at several tens to a hundred bars...across a meter or three of radial span? That's a pretty tricky job, given the seal will be formed in-situ, so no real chance of using cured elastomers. Not saying it's impossible, but we use rolling diaphragms in our products, and design for 100-200 psi is non-trivial in a long-stroke rolling diaphragm.
I'm also curious as to how uniform in density the piston rock will be. They show a system of rollers to guide the piston along the upper edge, but if the rock is heavier on one side, how many megatons do those rollers have to be designed for, and will the seal still get pinched if the piston tilts?
RE: Any comments on this large energy storage device?
http://www.bloomberg.com/news/articles/2016-09-15/...
RE: Any comments on this large energy storage device?
It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.
RE: Any comments on this large energy storage device?
Assuming granite.
Pressure needed to lift it is roughly
290 MPa (42,000 psi).4 MPa (550 psi) [Thank you Btrueblood for checking my math]I guess that's high enough to contain useful amounts of energy.
Should be an interesting turbine.
Designing the seal for the rock cylinder may be non-trivial.
I guess just coating the pit will flex seal will keep the water in.
RE: Any comments on this large energy storage device?
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers
RE: Any comments on this large energy storage device?
Good luck sealing.
RE: Any comments on this large energy storage device?
By cutting a plug from bedrock, they have a volume = surface area of plug x 3m to move, to manufacture a plug they would need to handle the whole volume. The theory is that their way, the costs scale with R², not R³.
@btrueblood
I think you raise good points.
To me (but I never designed one!) the rolling seal looked like a good idea. At the large size, you have little curvature so that certainly helps.
But you'd have to assemble the membrane in place, which doesnt help at all ...
Another point raised by btrueblood:
How well can we know the inner workings of such a large plug?
RE: Any comments on this large energy storage device?
I still think that Li-ion isn't going to be the right tool for grid storage. Something with less energy density but with similar efficiency at significantly less $/kWh is going to be developed. Right now everyone is still racing after the highest energy density rather than digging through the old work to find a chemistry which can generate cheap cells with outstanding cycle life but with lousy energy density.
My bet is ultimately on flow batteries- they're significantly worse in efficiency but you can't beat their storage cost- tanks for holding liquid at room temperature and atmospheric pressure are very cheap indeed.
RE: Any comments on this large energy storage device?
They could build a shell and fill it with rubble from the dig.
RE: Any comments on this large energy storage device?
Mint, double checking, for 150 o.d. x 150 ht. piston, volume is about 2.65 x 10^6 m^3, mass (assume 2750 kg/m^3) is 7.3 x 10^9 kg, yielding about 4.04 MPa lift pressure required neglecting any buoyancy correction, or about 586 psi.
At 290 MPa, you'd be worried about the granite being crushed (compressive strength of typical granite is around/north of 200 MPa).
Here's a fun idea: build condos atop the piston, and advertise as view property.
RE: Any comments on this large energy storage device?
RE: Any comments on this large energy storage device?
But to trueblood's estimates, his values might be realistic at a depth below surface of 300-500 metres but close to surface, no way. Without getting into technicalities, its all "rotten rock" down to 100 metres or so. This is due to geological forces / erosion over the eons. And if it were attempted, its not crushing of the rock that I'd be worried about, its hydrofracturing where the hydraulic pressures involved start to open up the microfractures in the rock and all of a sudden you've got no lift pressure because its all being bled away into the surrounding rock. And please don't suggest grouting. Bin there done that , know its limitations.
RE: Any comments on this large energy storage device?
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers
RE: Any comments on this large energy storage device?
By my estimates, I assume you are referring to the crush strength of the rock. Agree, the 200 MPa value is probably for slabs/chunks used in buildings, not for raw rock with fissures and seams as you say. I was just trying to figure out if my numbers for the lift pressure were way off...290 MPa is pushing things even for mild steel...I'm pretty sure the actual pressure in the lift cylinder will be on the order of hundreds to a thousand psi (dep. on height of piston and number of condos atop it), but not 42000 psi.
IRStuff...hunh? Pressure to lift a granite cylinder is what I calculated, not sure why you think the pump outlet area factors in?
RE: Any comments on this large energy storage device?
RE: Any comments on this large energy storage device?
how much energy do you get back out ?
What you want is an anti-gravity device to temporarily take the weight of the pump, fill hole with water, restore weight to pump to pressurise the water.
another day in paradise, or is paradise one day closer ?
RE: Any comments on this large energy storage device?
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Any comments on this large energy storage device?
Yeah, but with gravity rather than a spring or pneumatic energy storage. To be true 19th century, it would be a steam lift, not water, and have a lot more brasswork and decorative cast iron :)
The first time I ever heard about gasometers was when reading Simon Winchester's book about Krakatoa - apparently the blast wave was recorded on gasometer level recorders across the world (ok, mostly in Europe), including several reverberations.
RE: Any comments on this large energy storage device?
From the site:
"The Gravity Storage is cut out of surrounding rocks. Because rocks nearly always have crevasses and fine cracks through which water can flow, it is necessary to completely seal the piston and the surrounding piston cylinder against the surrounding area.
For this purpose, all freely exposed surfaces are sealed with a geomembrane and concrete."
Plausible/workable?
RE: Any comments on this large energy storage device?
RE: Any comments on this large energy storage device?
I'm not at all certain, and I think miningman's gripe may also be: there is no way to guarantee the integrity of the piston rock, and failure of that rock along a seam (i.e. shear or tensile stresses) means a big chunk could come loose, with some fairly dramatic consequences. Ain't no geomembrane gonna hold up 150 tons of rock.
RE: Any comments on this large energy storage device?
The whole thing has the ring of someone who is a little too enamored with his own concept.
RE: Any comments on this large energy storage device?
https://www.scientificamerican.com/article/energy-...
Seperately, how come no one talks about thermal storage?
RE: Any comments on this large energy storage device?
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers
RE: Any comments on this large energy storage device?
RE: Any comments on this large energy storage device?
Just a thought, but don't crystals generate a voltage when compressed? Or is it when the compression changes?
Or maybe just the difference in pressure between the upper lake and the cavity.
RE: Any comments on this large energy storage device?
Either start at the top, or start at the bottom.
Starting at the top:
Cut out the cylindrical kerf.
Line both surfaces with geotextile and concrete].
somehowsupport the giant cylinder of rock while excavating the disc below it.
Seal bottom of pit and cylinder.
Starting at the bottom:
Excavate a disc from the bottom and seal bottom of cylinder and bottom of pit.
somehow support the giant cylinder of rock while excavating the kerf around it.
Seal both cylindrical surfaces.
Not impossible I guess, although supporting a couple billion pounds of rock while working under or around it might not be so easy.
But is sure ain't gonna be cheap.
Doesn't seem economically viable.
RE: Any comments on this large energy storage device?
If you drill vertically and use a simple hoist arrangement, it's a lot of drilling - probably more rock displaced than the piston concept at some scale.
But I like the idea of the railcars or mine hoists, because if one fails, you have a few dozen cars to scrape out of the pit at the bottom, while the next line over continues doing its thing. Not sure how you make the rock hydraulic accumulator piston idea redundant. But then, I still don't know how you'd make a 500 psi, 1m wide rolling diaphragm either.
RE: Any comments on this large energy storage device?
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/report-on-business/...
The pessimist sees difficulty in every opportunity. The optimist sees the opportunity in every difficulty.
Winston Churchill
RE: Any comments on this large energy storage device?
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers
RE: Any comments on this large energy storage device?
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).
RE: Any comments on this large energy storage device?
RE: Any comments on this large energy storage device?
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers
RE: Any comments on this large energy storage device?
RE: Any comments on this large energy storage device?
RE: Any comments on this large energy storage device?
https://en.wikipedia.org/wiki/Flow_battery
RE: Any comments on this large energy storage device?
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.
RE: Any comments on this large energy storage device?
RE: Any comments on this large energy storage device?
RE: Any comments on this large energy storage device?
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Any comments on this large energy storage device?
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.
RE: Any comments on this large energy storage device?
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.
RE: Any comments on this large energy storage device?
Pumped storage seems to be viable solution for years.
"For every expert there is an equal and opposite expert"
Arthur C. Clarke Profiles of the future
RE: Any comments on this large energy storage device?
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.
RE: Any comments on this large energy storage device?
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.
RE: Any comments on this large energy storage device?
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.
RE: Any comments on this large energy storage device?
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.
RE: Any comments on this large energy storage device?
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
RE: Any comments on this large energy storage device?
so "at best" this'd make available 70% of the energy it took in ? so this is more about allowing the main line power stations run at constant, or at worse a slowly varying, load and so allow these to be more efficient. The point of this is to harness the potential energy of the plug. what sort of water pressure are we talking about ?
another day in paradise, or is paradise one day closer ?
RE: Any comments on this large energy storage device?
Not a bad idea. When a house connects to the water utility, they have to provide their own energy plug in their back yard. They could put a platform on it and give the kids a ride while storing and retrieving energy. The resources are all in place: pressure, quantity of media (except maybe during drought), distribution.
RE: Any comments on this large energy storage device?
A.
RE: Any comments on this large energy storage device?
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Any comments on this large energy storage device?
.
Me wrong? I'm just fine-tuning my sarcasm!
RE: Any comments on this large energy storage device?
Round the back, they have a cafe with a working model. Various relatives enjoyed being pumped up and down to play the part of the deadweight.
A
RE: Any comments on this large energy storage device?
Realistic? Equally no.
There's no way you can excavate a solid plug like that. You would never be able to cut the horizontal section unless you mined it out and then propped it up while you sealed the base of the"cylinder"
The cost of the concrete shell,the seal, the hundreds of rollers compared to the storage capacity must be uneconomic.
The pressure even of an un feasible 100m high plug is only 26 bar.
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RE: Any comments on this large energy storage device?
RE: Any comments on this large energy storage device?
Giant o-rings or rolling bellows working against cut rock faces do not sound viable.
Mike Halloran
Pembroke Pines, FL, USA
RE: Any comments on this large energy storage device?
If you want a narrow kerf, sink a shaft alongside the plug.
Dig horizontally to the edge of the future plug.
Dig a circular tunnel under the desired cut line.
Drill two small passages from the surface to the tunnel and feed cutting cable down one side, around a pulley in the tunnel, and then back up to the cutting rig through the other hole. The original holes can be filled with epoxy/cement and are cut to finished width with an overcut.
Move the cutting rig along the top and move a turning pulley along the bottom to make the cut.
When the plug side is finished, move the cable drive or turning pulleys to the bottom of the side shaft and place pulleys at either side of the opening, with the cable looped around the plug base.
As the cable cuts, backfill to support the plug and prevent cable pinching. Access to backfill the cut will be available immediately behind the cable as it advances.
Cable cutting does wonders on limestone and ships; no reason to believe that it can't work here, just a matter of cost/time.