The main point is, not efficiency, but how much energy it can potentially store. Unfortunately, hopelessly little. If a commerically sized storage plant can store 20 MWh, then 160.000 of such plants are needed to cover energy needs of the US for one single day. That's if every click on this video magically generated two such plants! And it is not the case, that, as the technology gets better, it will get much more effective. They can optimize the software as they want, but there is no way around the fact, that huge amount of mass would needed, probably trillions of tons, for this technology to make any impact at scale. That's why the only real option is water dams, and this startup will not change that. This solution is doomed to stay a niche market (maybe even successful at that), but there is absolutely no basis for the hype in this video.
@@balazskecskemeti do you think this might be useful for small villages? certainly this may not work on a national level but I can imagine this somehow in small areas
Definitely, I think it could be useful on a small scale under special conditions. I hope they'll make it work, so that similar solutions become a viable option at least in some situations. The only thing I take issue with, it the "this will save the world" nonsense.
Mad Hatman you'd use a rail electric system - when you're moving the sleds up, you draw current and when sliding down, you generate and conduct it to the same rails...
So data is missing in this video: - 30+ year life with zero degradation & 80% - 90% round trip efficiency (same round trip has Lithium(90%) ). - 20-35-80 MWh storage capacity; 4-8 MW of continuous power for 8-16 hrs. - How most zero OPEX. - Between 40 - 60€/MWh LCOS. - 100% automated operation . - Repurposes recycled waste materials for composite brick production. - Ideally suited to long duration storage with very fast response times, The system may also be used to deliver short and medium-term ancillary services. Thanks
Put it on cliffs, use the natural terrain. The further you can lift any single block, the better the overall efficiency (within the limit of the weight of the lifting cable itself). A system that just lifts or drops, with all the other (sideways) handling being managed on a simple rail-based system. Loads guided up the cliff face on rails or guide wires, into loading/unloading stations. Tran-shipping stations halfway up, with minimal storage, to split work into shorter stages. Lots of things to do with this idea.
Use grey water. Perfectly viable. And use a water tower. Still gonna be cheaper, easier, and more efficient than any sort of crane that has all sorts of wasted laterial motion.
It would be useful to compare the costs of the two methods. Not sure how it would turn out. Concrete is much heavier than water, so tank size would be a limiting factor.
Pretty good idea instead of using lithium batteries. If you can store solar/wind energy, you can use the stored energy during downtime. The best part it doesn't decay like rechargeable batteries.
i dont have data on this but i think that the battaries dont loose that much energy that they get less efficient than the crane, they are cheaper and aesier to maintain then the crane and you dont need to charge battaries for some years.
Pretty cool system. According to their tests so far, it seems to be about 85% efficient. Pretty good return for storing extra energy. My biggest concern is how to prevent the stacks from falling from environmental influence (high winds, earthquakes, etc)
you can build an extensive plant which lifts the blocks for a few meters very slowly. of course that would take ad hoc equipment and not standard cranes that are used in construction.
It's the classical approach, but if something equivalent could be done in a smaller area, it would be more feasible in terms of environmental licensing, and would be possible to apply in more scenarios, maybe closer to where wind and solar power plants are, that wouldn't necessarily be suitable for water pump storage. The problem is that this design here is probably tremendously flawed. There are criticisms regarding the wind and precision dropping w/ cables, inefficiencies in stacking versus perhaps always lifting and dropping from a fixed platform/place, and maybe even the potential energy stored. There's apparently a more functional analog in operation with train tracks that lift weights up to a hill, solving some of these problems, but requiring a larger area.
they could also be built underground to avoid impacting the scenery. lifting them over a canyon would be a punch to the eye, and also you can lift many drums over a low height instead of one drum for 100 meters of height, and very slowly, you just need more lifting cables.
Heard of water? You can store energy in that too, and water is free! You just pump the water up into a well when there's a surplus and release it when the energy is needed.
i was thinking of a disc that spins up on a long spiral (when its powered by sun/wind) and when night/no wind blows, falls spiraling down (thus producing energy again by the rotation of this disc). if you reach the top of the spiral and the wind is still blowing, it automatically switches to lifting the next disc on spiral waiting in line. the good thing is that you can block the downward fall if nobody needs energy. And you can place this long spiral underground. It would be great to have such a mechanical battery at home (not just for the city) and to connect it to your fitness room, so that when you work out you participate in lifting the battery disc, instead of pointlessly lifting weights/running on fitness bicycles/etc .
Here's a good question: If this invention is meant for places where water is scarce, then how do you intend to mix the concrete? Furthermore: A) How do you make the hook both self attach and self detach in a rapid and safe manner? B) Unless you had four or five cranes working simultaneously and coordinating with each others, the power supplied will be awfully spotty. C) These cranes can only work so fast, and work can slow all the way to inactivity in bad weather.
Concrete requires a small amount of water and it requires it only once. A. As far as I could tell, there was no hook. It looked as if the top of each block was metal. The crane used an electromagnet to lift the blocks. B. In that case, have four or five cranes working together or use a flywheel to maintain a stable supply. C. Perhaps a building could be put up around the crane to protect it.
So this is the same idea as building a holding tank above dams. Pumping water in it as energy is in excess and releasing it onto a water turbine when you need energy. Concrete blocks and a crane doesn't seem like it will be adopted all that much.
Pity, the clip did not make a claim about total efficiency of the conversion cycle using this prototype. As for some suggestions regarding water towers: Some five years back I did a calculation using one particular hydroplant with a hill-top reservoir (Dlouhé stráně, the Czech Republic) as an energy accumulator and a common water tower of the type used for drinking water distribution. There needs to be built roughly 10^4 (low tens of thousands) of such water towers to be built to be equivalent to a single such hydro-gravitational accumulator. While I am in favor of inventive solutions, we need to keep in mind that LAND is just as a precious resource as anything.
While the figures in the video look a bit off (about a factor of 5 to 10 to high), it seems reasonable. For ppl who complain that it won't work: it does, storing potential energy is done for ages, for example in clocktowers or grandfather clocks: a weight on a rope you wind up once a day
The issues lie more in the fact that they are costly, susceptible to harsh weather and damage and the fact that they are in a lot of ways vastly inferior to just using water.
This isn't about producing energy; it's a pretty clever idea for storing what would have otherwise been wasted energy. It's not about putting power into the system, but making the system more efficient.
Yes, the greatest problem with renewables is energy storage for when wind isn't blowing or sun isn't shining. Energy storage is the only way to cut out fossil fuels.
Interesting. Iron ore has a density ~2x that of concrete and a not too dissimilar price per ton. That would make it a better candidate (i.e. double the energy storage in the same space or same energy in half the space).
@@davidwilliston1209 maybe, maybe not. There's a lot of factors involved. Just let them finish their work, and then we can modify it to better suit the variables. Instead of telling them what to do in every single step..
Why not use say... water? And just pump it when there is energy surplus? You don't need to maintain blocks that will rode. Oh wait its less futuristic to do hydro pump storage isnt it?
Wouldn’t it lose a considerable amount of power operating the crane during its power distribution phase? Nice idea but I feel there are more efficient ways of doing the same thing
At Niagara falls the hydro comes via gravity without having to pump it, and those power plants run at a fraction of their capacity at night and in the winter leaving a vast untapped source of renewable energy that this could harness. It seems like it would benefit everyone involved
If we say these larger versions are able to lift a 35 ton block a full 120 meters, a single block will be storing some 11.5kWh, which is about enough electricity a house needs in a day (avg UK household), including the crane's inefficiencies but ignoring transmission inefficiencies. I'd be interested to see how dense they can pack it in, and how much a unit would cost.
If they set this on the edge of a cliff or built a large platform they could store all the blocks on a level instead of having the diminishing returns of a tower of blocks.
Any spring will degrade in time, some with permanent deformation. Having big springs can cause catastrophic failure when suddenly released. Also, they don't provide linear power output.
the only semi-practical versions of this I've seen is basically a cog train with concrete filled boxes that stores energy by climbing up a mountain side. to release, the train just descends the mountain. I've also seen it done with an artificial lake at the top of a mountain. water pumped up to store kinetic energy, released through turbines to generate.
I honestly think your onto something, perhaps the thermal expansion of the home from day to night can also be used to store a bit of passive mass energy in jacks or moving platforms underneath
Build the system in a disused mineshaft, maybe have 'fast' and 'slow' channels of energy release using shafts with a near perfect seal to the weight. Offset slow periods of energy availability with solar.
Seems like lots of people are missing on of the main values of this... yes, dams work more efficiently and work off a similar concept, but dams are being removed all around the world for their environmental damage. Additionally, 5-10% efficiency is not going to matter much as our energy production is converted to renewables. Cities will likely operate with significant surpluses of energy at most times of the year due to the difficulty in predicting demand at any given point in time. The much larger issue will be price, and that is why this looks like a fairly good option where hydroelectric power is not available.
As intersting as it is, this serves a very difference purpose from a water-based power plant. The power plant is extracting the potential energy from the water that is brought there by the sun (sun heats water, water forms cloud, cloud rains and forms river). This is simply a means of STORING energy that still needs to be extracted from somewhere else
@@SKyrim190 You misunderstood. You're comparing the "biggest battery on Earth" (Bath County Virginia pumped storage facility) to vaporware that doesn't even exist except in a crappy animation (in other words, a cartoon).
Rakusan2 this is just not a good design. It looks like it is way too fragile (look at how much the cable wobbles in this small scale proof of concept) to operate, too expensive to build and maintain (you’d have to constantly repair/replace damaged concrete blocks, spent electric motors, stretched cables, etc, that is if the whole thing doesn’t topple over in a light summer breeze), and WAY too inefficient (those electric motors on the crane don’t run on cosmic energy).
@@Rakusan2 you can also store pressurized water in deep pits, such as you would get from decommissioned oil wells, salt mines, etc. flat as saskatchewan is, i bet you guys have a lot of holes underground. another option is rails, which oddly enough uses gravity, but in a more logical way that would actually work.
How is this cutting edge? It's just clocktower weights. You could do this with a weight, a pully, a motor, and a solar panel to charge and store energy for night time easily.
I believe this is energy recovering (just like regenerative braking). In the end the net energy expended for lifting is slightly recovered during storing. But you still lose energy as a whole.
exactly, they need "excess energy" from a conventional grid. But that excess rarely is delivered for free. Usually is sold to the next regions for system efficiency.
How does it compare to battery charging/discharging efficiency though? I get that this may be a cheaper alternative, but what's the carbon footprint for that concrete as well? Could as easily fill those drums w/readily available sand. Could make sense for solar energy storage though. In any case, this is nothing new, we've been pumping water upstream to create head and letting gravity do its thing for a while.
I am trying to do the calculation using given numbers from Quartz, is it real? 35 metric tons blocks from concrete: concrete mass density is 2400 kg per cub. m, so such block would have to be 14.58 m3. With 2m diameter it would be 4,64 m tall blocks. OK, if it can handle the integrity of all the blocks above it (up to 25 with 120 m tall crane). Average height where the "storing" block in full 120 m long tower could be would be 60 m. Its potential energy would be 20580 kJ, what is 5,7 kWh, with 85 % efficiency it is 4,85 kWh. But that would mean putting it to an empty space, not on top of another brick. 35 MWh system would need 7216 of such blocks. With that 25 blocks towers it means 288 towers. That is circa 20 blocks (40 m) in diameter, 20 m radius, plus the inner empty area for the storing part. Than you need the area for the "used" blocks - more is better as you need to place them as low as possible. Big cranes can have up to about 150 m long jibs, so there is definitely some space.
i dont trust the 85%, can someone check this please and tell me if my wind-turbine knowledge is out of place? i think they took 65-70% of the kinetic energy so can this crane really save 85%, it seems a bit off for such an "simple" technology....
The challenge is what is the levelized cost of energy per kwh stored versus what other technologies can do, like batteries. It seems like this might have some additional maintenance. But if you could do this where there is already some elevation, like on the edge of a cliff, then the cost might go down.
"Energy Vault’s CEO estimates that after building 10 plants, the cost of energy storage for the system will be around US$150 (AU$205) per kWh. This makes the technology competitive with lithium-ion batteries, which currently cost around US$280 to US$350 per kWh. However, Quartz reported that the cost of lithium ion batteries could fall to US$100 per kWh, making them stronger competition in the long term." www.createdigital.org.au/concrete-block-battery-alternative-pumped-hydro
How do they keep the power consistent between switching blocks thou, stop start wont work for power - and what about the power needed to move the crane when between blocks, I assume they have something for this, its just not mentioned. .
The problem with this machine is that it violates the first law of thermodynamics, the law of conservation of energy. You would need to put more energy into the system than it would produce. Basically the energy produced by lowering the bricks would be lost to the energy needed to lift them. This device is in an open system meaning that some of the energy is lost to its surroundings. Plus more energy is lost when converting mechanical energy to electrical energy. Eventually this machine would lose its efficiency and would require additional energy to keep it going. That's the main reason why perpetual motion machines are impossible.
It's not a power plant, it's a merely an energy storage solution. Nobody said it has a net output. Let's say you have a small community powered by a wind turbine. During windy days, instead of wasting a lot of the electricity output, you store it. Then when there is no wind, you at least have SOME energy to use for emergency purposes.
Just asking for your opinion on a different concept of my own that is quite basic. The build can at least be of 2 ultra strong permanent magnets, one above another where the top magnet stays stationary on a plastic* container maybe filled with water while the other is inside that container. Between the top magnet and the container needs to be a very narrow gap for which a light sheet of lead* can easily slide between the magnets just enough to cause the bottom magnet to fall as if it were a delicate power switch that the rise and fall will help* generate more electrical power than it would take to move the lead* sheet in and out of that gap in least frictionless way, maybe levitated by other magnets. The water is basic to prevent damaging and even far too much noise. . In summary... it would be as if the permanent magnets can be switch on and off like electro-magnets. . I tend to come up with a whole lot of various ideas that worked out awesomely, but... not often able to test my ideas out.
I wouldn't put them on cranes, suspended in the air. I would lay them down against those hills in the background and have them run on a track at the angle of the hill. That way they would be less vulnerable to seismic events and also able to be stopped and worked on at any point along the length of the weight's run simply by chocking the weight in place wherever it is and not having to lower the thing all the way to the bottom before you can work on it. You can also make the weights of enormous size if they're on a track rather than in a suspended configuration. They could be made the size of apartment buildings and be made primarily of a box filled with earth and rock. Very cheap and gigantic. Depending on the height and size of the hill, it could store several days worth of energy even from a very large solar and wind array.
Sea swell can easily lift a massive ship up and down.. so perhaps some sort of development of this idea with perhaps a chain and ratchet system combined with a big enough float could lift massive concrete blocks up to a height to be released and run a generator on the way back down.
If these barrels are filled with concrete, they probably weigh around 400kg. So the entire demo video contraption stores less than one kWh of energy. In fact it's about 170 Wh of energy right there in that stack if it's 12m high (I don't think it is, but call it that). That wouldn't drive an EV one mile.
There's something you have to realise A 20ft container sized concrete block only store 0.2 kwh of energy per meter you need 10 of them at 25 meter to have the same energy storage as a tesla model 3 battery.
How you will lift them up? Will you use electro power for that? But than you have to generate that power again? I think it has a potential if it will use a wind or ocean energy
I think the biggest question should be _why_ you would want to store energy. When was the last time anyone experienced a powergrid not being able to handle its load?
Happens constantly. Wind generators and similar get turned off if the demand is lower than the production. Instead we could keep the generators running, it is "free" energy at that point so no harm, to store some of the energy. So it's less about the grid more about turning off generators when we shouldn't.
I had an idea once where, you would have some sort of machine set up that was able to lift your entire house, or a really heavy object during the night when electricity prices are lower, and then generate electricity during the day by allowing the house/object to slowly fall down.
Fill shipping containers with gravel and roll them up a steep hill on tracks. Repeat daily. Or use a ski lift with bags of gravel in place of the skiers. Crane is impractical except for a test.
Gosh that looks like a stretch. It just seems way to complex and like it will fall. I like the idea of just rolling a train down long decline. They have it England. It goes down the hill fast enough on it's own and to turn an electric motor backwards so it stores electricity and then it uses it to take people back the other way. If you did this though you should go smaller and do it in a vacuum. Things fall at 9.81meters/s^2 until they hit terminal velocity. For the human body that is 122 mph. But in a vacuum we would continue to accelerate until approaching the speed of light (You would hit the speed of sound in a 6 second drop which I think is the biggest drop you could get but what a ton of power).
They should lift a self propelled heavy train (thousands of tons carrying heavy loads of dense metals like tungsten) uphill using electricity. Then let it roll down very slowly like the weights of a grandfather‘s clock ( same as concrete blocks here). This is better than Hydro power where you lose 50% of the energy as the water escapes the turbines. Here the energy conversion is near 90%. Only the wheels friction is the loss.
I find it hard to see how a combination of pulleys and weights to store excess energy can be *practical* for continuous energy supply. For one, you cannot convert the stored gravitational potential energy into a 100% *continuous* electrical energy in a straight-forward manner, because energy conversion is zero once a weight touches the ground. So, to get something close to continuous electricity, weightS would need to be transferred down in succession as frequent as possible. Even then, electrical energy storage devices like capacitors or big-ass fast-recharging batteries and some control system would still be required to store the converted energy and to make sure the energy converted gets outputted as a smooth electrical power, something akin to electrical systems you find in wind turbines.
In order to provide stability to the main grid.. in a frequency deviation by example, where in matter of seconds a great energy generation is needed, this could be hlepful. Its basically to improve voltage and frequency quality. This is a instanenous power, not a energy, application...
How efficient is this ? That's the point. Instead of using the grid , use the solar and wind power to rise massive objects, because the most difficult part is to store this irregular energy
Interesting concept! Minimal upfront capex vs massive capex for hydro, much easier planning consent, more site locations, 2.4x energy density vs water, increased efficiency from crane power generation vs lossy water turbine. All in all, a competitive alternative to hydro for long term storage? Pretty promising tech to supplement solar/wind.
Why do people always say "hurr dur enrgy conversion" like no, you're just TURNING A GENERATOR. One way or another, it's still turning a generator! Nuclear reactors, coal reactors, hydroelectric dams, blah blah it's all the same thing! Turning a generator! Either with steam or water, just don't complicate things!
I'm skeptic. This concept seems to use quite a lot of land per energy stored (although I didn't see official figures). I'm personally still hoping for synthetic diesel production to solve the intermittency issue. The produced fuel would have an extremely high energy density, enough to store winter supplies without too much space. Using it to power turbines to feed electricity back into the grid is only 66% efficient (Samavati, Martin, Santarelli, and Nemanova, 2018), but more scalable than the stacking method and pumped hydro. Incidentally, we could also power the transportation sector with zero CO2 emissions, and carbon capture technology would become cheaper to (maybe hopefully, given the right political and economic circumstances) account for the remaining use of fossil fuels in heavy industry.
This article is the perfect use case for Bret Victor's Tangle (or Mike Bostock's Observable, or any other smart notebook). Don't just give me paragraphs of text with figures - plug the formulas into the article itself and let me drag a scale slider to find sweetspots. Or one level of abstraction higher, paint me chart of where the sweetspots are.
its a great idea and something i've been thinking about for some time, what would be truly awesome, would be a scalable version for domestic and rural applications,
Likely a more efficient in operation than hydroelectric systems (no fluid turbulence losses, viscosity losses, ...). But the resources in material (sand, limestone, ...) and space space needed for erecting really large scale systems concern me. Also concrete produces loads of CO2 in mining for the resources and the hardening process.
They intend to use old concrete from construction debris, that would otherwise go to landfills. Some old concrete gets recycled, but usually for low-stress uses like fill to level a construction site. But if your use requires strength, like a highway overpass, you want to use new materials and controlled curing. The US generates 500 million tons a year of demolition waste, much of which is old concrete, so there is plenty of it to use.
@@SeedFactoryProject -- I really want to see this succeed. But even with the sensible choice of recycling (as they do mention on their site -- I just checked) I guess there's a need for a few percent virgin filler concrete as "glue" for the old crumbles (wikipedia has no numbers on how much virgin is usually needed yet). I'd really like to see a rough calculation of the minimal CO2 emissions per some unit system size that would currently be to expect, before I'm willing to recommend this with good consciousness. **Regarding recycling:** Most of today's demolition hammer equipped vehicles I know of use gasoline (and that in a not particular efficient and clean way). Grinding old big concrete rubble to finer grades in "cone type gyrator crushers" (I guess this is the way it's done?) seems energy intensive, but could in principle be done with renewable energy. That is, if electricity suppliers give the option to direct the payments only to those CO2 neutral producers (at some premium).
A facility for lacquering the barrels against rust (once every few years) could (and should) be integrated right into the system I guess. Add a few colors (barrels as pixels) and you could sell advertising space or (better but less likely) employ artists to minimize the uglification of our landscapes.
Some types of concrete creation uses up CO2, hard to understand why that is not being used, conservative builders and idiotic politicians can probably be blamed.
HAHAH so simple effective and efficient, and it is not that popular i ever read something about this concept. I think it is a very good energy storage! Cheap efficient simple and you can build it everywhere... The energy recompensation is still beeing used for long time but never as energy storage... It could also be build like 10 or 100 cranes in parallel and in a sequence so that you always can run a certain amout of them without stop...
You misunderstand commenters this isn't for generating energy it's for STORING it as gravitational potential rather than chemical in batteries
thanks man very helpful
The main point is, not efficiency, but how much energy it can potentially store. Unfortunately, hopelessly little. If a commerically sized storage plant can store 20 MWh, then 160.000 of such plants are needed to cover energy needs of the US for one single day. That's if every click on this video magically generated two such plants!
And it is not the case, that, as the technology gets better, it will get much more effective. They can optimize the software as they want, but there is no way around the fact, that huge amount of mass would needed, probably trillions of tons, for this technology to make any impact at scale. That's why the only real option is water dams, and this startup will not change that.
This solution is doomed to stay a niche market (maybe even successful at that), but there is absolutely no basis for the hype in this video.
@@balazskecskemeti do you think this might be useful for small villages? certainly this may not work on a national level but I can imagine this somehow in small areas
Definitely, I think it could be useful on a small scale under special conditions. I hope they'll make it work, so that similar solutions become a viable option at least in some situations. The only thing I take issue with, it the "this will save the world" nonsense.
The language is ambiguous, it may be they expect 20MWh from each of the 35 metric ton blocks, not each plant.
It's probably relatively effcient but i think you'll need an extremly large amount of concrete blocks to store relatively little energy.
Depends on the size and height of the blocks.
It’s not efficient
*Nice idea.* It would be also possible to lift the blocks up the mountain, and let them drive down in a sled. That would be fun to watch.
Cool so you would put energy in but not get any out?
This system is for locations without hills or mountains.
Mad Hatman you'd use a rail electric system - when you're moving the sleds up, you draw current and when sliding down, you generate and conduct it to the same rails...
probably more energy loss due to friction though than a straight up and down
alex no shit
Who else is thinking about a giant Jenga tower?
So data is missing in this video:
- 30+ year life with zero degradation & 80% - 90% round trip efficiency (same round trip has Lithium(90%) ).
- 20-35-80 MWh storage capacity; 4-8 MW of continuous power for 8-16 hrs.
- How most zero OPEX.
- Between 40 - 60€/MWh LCOS.
- 100% automated operation .
- Repurposes recycled waste materials for composite brick production.
- Ideally suited to long duration storage with very fast response times, The system may also be used to deliver short and medium-term ancillary services.
Thanks
So, basically an expensive, hard to maintain, less effective water dam, that doesn't use water?
@@Pax.Britannica basically
Put it on cliffs, use the natural terrain. The further you can lift any single block, the better the overall efficiency (within the limit of the weight of the lifting cable itself). A system that just lifts or drops, with all the other (sideways) handling being managed on a simple rail-based system. Loads guided up the cliff face on rails or guide wires, into loading/unloading stations. Tran-shipping stations halfway up, with minimal storage, to split work into shorter stages. Lots of things to do with this idea.
It would work on slopes, with the ballast on rails, hauled by cable. BIG ballast.
That is exactly what I thought yeah
Seems like it would be a lot cheaper/easier to just use a water tower, pumps, and go with a hydroelectric set up.
it is, but the system is meant for places without a natural watersource since you cant use clean drinkingwater (where woud you pump it?)
Use grey water. Perfectly viable. And use a water tower. Still gonna be cheaper, easier, and more efficient than any sort of crane that has all sorts of wasted laterial motion.
David Hall and do it closed loop so none is lost - you have what approximates a permanent charge of the medium, minus some leaks and evap...
your idea looks great
It would be useful to compare the costs of the two methods. Not sure how it would turn out. Concrete is much heavier than water, so tank size would be a limiting factor.
Pretty good idea instead of using lithium batteries. If you can store solar/wind energy, you can use the stored energy during downtime. The best part it doesn't decay like rechargeable batteries.
That's correct. More details here: qz.com/1355672
i dont have data on this but i think that the battaries dont loose that much energy that they get less efficient than the crane, they are cheaper and aesier to maintain then the crane and you dont need to charge battaries for some years.
Xylius Schaaij friction/efficiency losses in the crane & motor for starters
@@lolfraggles Your the ignorant one. You don't know what your talking about.
Ilsunny Lo gas is stored solar energy. So is oil. And wood, and coal.
Pretty cool system. According to their tests so far, it seems to be about 85% efficient. Pretty good return for storing extra energy. My biggest concern is how to prevent the stacks from falling from environmental influence (high winds, earthquakes, etc)
Rejor111 shape the blocks to interlock and they will be more stable. #lego
you can build an extensive plant which lifts the blocks for a few meters very slowly. of course that would take ad hoc equipment and not standard cranes that are used in construction.
85% efficienty seems a bit too much i think and i dont know if the crane+repairments+etc. have a realistic break even mass....
@@timbraasch1514 so they should lower their efficiency?
no i meant that i dont believe the 85% efficiency mark
Why not just pump water from a lower lake to a higher one? Let's call it: **pump storage hydroelectricity.**
It's the classical approach, but if something equivalent could be done in a smaller area, it would be more feasible in terms of environmental licensing, and would be possible to apply in more scenarios, maybe closer to where wind and solar power plants are, that wouldn't necessarily be suitable for water pump storage. The problem is that this design here is probably tremendously flawed. There are criticisms regarding the wind and precision dropping w/ cables, inefficiencies in stacking versus perhaps always lifting and dropping from a fixed platform/place, and maybe even the potential energy stored. There's apparently a more functional analog in operation with train tracks that lift weights up to a hill, solving some of these problems, but requiring a larger area.
Her I thought that this was my idea and now I see that someone is way ahead of me. I have variations in mind but these guys are on the right track.
The Bottom Drum stores no energy!
its already on the ground.
Rather than stack them on one another, wouldn't it be better to have a shelf?
they could also be built underground to avoid impacting the scenery. lifting them over a canyon would be a punch to the eye, and also you can lift many drums over a low height instead of one drum for 100 meters of height, and very slowly, you just need more lifting cables.
Or you can push train loads of these things up hills/mountains, etc. Though you need to lay tracks of course.
The commercial unit is intended to use blocks that are 35 tonne. How big is your shelf going to be?
The bottom block IS the shelf.
Lmao a shelf.
I've often thought of this
Heard of water? You can store energy in that too, and water is free! You just pump the water up into a well when there's a surplus and release it when the energy is needed.
Free and available everywhere? I guess I haven't heard of that.
i was thinking of a disc that spins up on a long spiral (when its powered by sun/wind) and when night/no wind blows, falls spiraling down (thus producing energy again by the rotation of this disc). if you reach the top of the spiral and the wind is still blowing, it automatically switches to lifting the next disc on spiral waiting in line. the good thing is that you can block the downward fall if nobody needs energy. And you can place this long spiral underground. It would be great to have such a mechanical battery at home (not just for the city) and to connect it to your fitness room, so that when you work out you participate in lifting the battery disc, instead of pointlessly lifting weights/running on fitness bicycles/etc .
That's an amazing idea! Well done! 👍
Here's a good question:
If this invention is meant for places where water is scarce, then how do you intend to mix the concrete?
Furthermore:
A) How do you make the hook both self attach and self detach in a rapid and safe manner?
B) Unless you had four or five cranes working simultaneously and coordinating with each others, the power supplied will be awfully spotty.
C) These cranes can only work so fast, and work can slow all the way to inactivity in bad weather.
Concrete requires a small amount of water and it requires it only once.
A. As far as I could tell, there was no hook. It looked as if the top of each block was metal. The crane used an electromagnet to lift the blocks.
B. In that case, have four or five cranes working together or use a flywheel to maintain a stable supply.
C. Perhaps a building could be put up around the crane to protect it.
So this is the same idea as building a holding tank above dams. Pumping water in it as energy is in excess and releasing it onto a water turbine when you need energy. Concrete blocks and a crane doesn't seem like it will be adopted all that much.
Pity, the clip did not make a claim about total efficiency of the conversion cycle using this prototype. As for some suggestions regarding water towers: Some five years back I did a calculation using one particular hydroplant with a hill-top reservoir (Dlouhé stráně, the Czech Republic) as an energy accumulator and a common water tower of the type used for drinking water distribution. There needs to be built roughly 10^4 (low tens of thousands) of such water towers to be built to be equivalent to a single such hydro-gravitational accumulator. While I am in favor of inventive solutions, we need to keep in mind that LAND is just as a precious resource as anything.
They should team up with an artist and instead of stacking boring blocks, make an enormous statue that is set up and pulled down like a zen tower.
But how about the price
A chamber especially designed for such a system is necessary as external agents can destabilize the blocks causing energy leakage
While the figures in the video look a bit off (about a factor of 5 to 10 to high), it seems reasonable. For ppl who complain that it won't work: it does, storing potential energy is done for ages, for example in clocktowers or grandfather clocks: a weight on a rope you wind up once a day
The issues lie more in the fact that they are costly, susceptible to harsh weather and damage and the fact that they are in a lot of ways vastly inferior to just using water.
This isn't about producing energy; it's a pretty clever idea for storing what would have otherwise been wasted energy. It's not about putting power into the system, but making the system more efficient.
Yes, the greatest problem with renewables is energy storage for when wind isn't blowing or sun isn't shining. Energy storage is the only way to cut out fossil fuels.
Interesting. Iron ore has a density ~2x that of concrete and a not too dissimilar price per ton. That would make it a better candidate (i.e. double the energy storage in the same space or same energy in half the space).
The company plans to use waste material to help cut down costs of concrete, and also be more environmentally friendly.
Scrap metal is easily recycled to make new products and may be better suited to that stream
doesn't work if you think of a worldwide application. waste construction material which is a problem nowadays is their thinking.
@@davidwilliston1209 maybe, maybe not. There's a lot of factors involved. Just let them finish their work, and then we can modify it to better suit the variables. Instead of telling them what to do in every single step..
Came here to say this. Selection of concrete rather than iron is ridiculous.
fill with water a 200 meter deep shaft , that way the concrete Pontoon block will float all the way to the top. wish i had money, so many ideas :)
I had the same idea. If the weight floats, there is no need to spend money bringing it back to the top.
Why not use say... water? And just pump it when there is energy surplus? You don't need to maintain blocks that will rode. Oh wait its less futuristic to do hydro pump storage isnt it?
Wouldn’t it lose a considerable amount of power operating the crane during its power distribution phase? Nice idea but I feel there are more efficient ways of doing the same thing
It's 85% efficient. That's not bad.
It's amazing a company got this far with its tunnel vision without someone saying "Umm we got better alternatives already its called water".
I am concerned about weather events impacting a tall, thin structure.
People laughed at me when I had this idea but I googled and and low and behold.. somebody's already doing it!
At Niagara falls the hydro comes via gravity without having to pump it, and those power plants run at a fraction of their capacity at night and in the winter leaving a vast untapped source of renewable energy that this could harness. It seems like it would benefit everyone involved
If we say these larger versions are able to lift a 35 ton block a full 120 meters, a single block will be storing some 11.5kWh, which is about enough electricity a house needs in a day (avg UK household), including the crane's inefficiencies but ignoring transmission inefficiencies. I'd be interested to see how dense they can pack it in, and how much a unit would cost.
If they set this on the edge of a cliff or built a large platform they could store all the blocks on a level instead of having the diminishing returns of a tower of blocks.
One barrel full of concrete stores whooping 200kJ at 50m height. In other words, you need only 20 barrels to store 1kWh, LOL
I absolutely love this
related: springs as batteries
Any spring will degrade in time, some with permanent deformation. Having big springs can cause catastrophic failure when suddenly released. Also, they don't provide linear power output.
the only semi-practical versions of this I've seen is basically a cog train with concrete filled boxes that stores energy by climbing up a mountain side. to release, the train just descends the mountain. I've also seen it done with an artificial lake at the top of a mountain. water pumped up to store kinetic energy, released through turbines to generate.
Instead of a Tesla powerwall, could you build a home on rails such that the weight of the home could be used the same way?
So you could do your commute down the mountain without leaving home, saving gas?
A home that stores energy by raising and lowering? That's a crazy good idea.
I honestly think your onto something, perhaps the thermal expansion of the home from day to night can also be used to store a bit of passive mass energy in jacks or moving platforms underneath
We could all Live in helium filled blimp houses tethered by motors/generatos on the ground
Yeah a version for the garden...
Build the system in a disused mineshaft, maybe have 'fast' and 'slow' channels of energy release using shafts with a near perfect seal to the weight. Offset slow periods of energy availability with solar.
A company called Gravitricity are working on this: www.gravitricity.com/
The idea is to locate the crane where the power is generated. Next to a wind park or a solar farm.
Seems like lots of people are missing on of the main values of this... yes, dams work more efficiently and work off a similar concept, but dams are being removed all around the world for their environmental damage. Additionally, 5-10% efficiency is not going to matter much as our energy production is converted to renewables. Cities will likely operate with significant surpluses of energy at most times of the year due to the difficulty in predicting demand at any given point in time. The much larger issue will be price, and that is why this looks like a fairly good option where hydroelectric power is not available.
As intersting as it is, this serves a very difference purpose from a water-based power plant. The power plant is extracting the potential energy from the water that is brought there by the sun (sun heats water, water forms cloud, cloud rains and forms river). This is simply a means of STORING energy that still needs to be extracted from somewhere else
Look up "pumped storage hydropower." This "problem" doesn't even exist because it was solved in the early 20th Century!
@@colormedubious4747 It's nice to have different approaches for the same problem. One solution can outperform the other depending on the situation
@@SKyrim190 There's a slight problem with that assertion. You're comparing a proven solution that actually EXISTS with a cartoon that never will.
@@colormedubious4747 why stacking and unstacking concrete blocks is "cartoon" logic?
@@SKyrim190 You misunderstood. You're comparing the "biggest battery on Earth" (Bath County Virginia pumped storage facility) to vaporware that doesn't even exist except in a crappy animation (in other words, a cartoon).
They should look up crane failures before they scale this system up.
wow 20 seconds of power from each block
HAHAHAHAHAHA! Gravity powered "batteries" already exist. They're called HYDROELECTRIC DAMS.
Problem is there are places like Saskatchewan, Canada which are flatter than an ice ring
Cool story. Those must be available like, everywhere.
hahaha and you must say thunderfoot sent you...hahaha
Rakusan2 this is just not a good design. It looks like it is way too fragile (look at how much the cable wobbles in this small scale proof of concept) to operate, too expensive to build and maintain (you’d have to constantly repair/replace damaged concrete blocks, spent electric motors, stretched cables, etc, that is if the whole thing doesn’t topple over in a light summer breeze), and WAY too inefficient (those electric motors on the crane don’t run on cosmic energy).
@@Rakusan2 you can also store pressurized water in deep pits, such as you would get from decommissioned oil wells, salt mines, etc.
flat as saskatchewan is, i bet you guys have a lot of holes underground.
another option is rails, which oddly enough uses gravity, but in a more logical way that would actually work.
people have never been so eager to find a neutron star piece.
How is this cutting edge? It's just clocktower weights. You could do this with a weight, a pully, a motor, and a solar panel to charge and store energy for night time easily.
I believe this is energy recovering (just like regenerative braking). In the end the net energy expended for lifting is slightly recovered during storing. But you still lose energy as a whole.
exactly, they need "excess energy" from a conventional grid. But that excess rarely is delivered for free. Usually is sold to the next regions for system efficiency.
How does it compare to battery charging/discharging efficiency though? I get that this may be a cheaper alternative, but what's the carbon footprint for that concrete as well? Could as easily fill those drums w/readily available sand. Could make sense for solar energy storage though. In any case, this is nothing new, we've been pumping water upstream to create head and letting gravity do its thing for a while.
I am trying to do the calculation using given numbers from Quartz, is it real?
35 metric tons blocks from concrete: concrete mass density is 2400 kg per cub. m, so such block would have to be 14.58 m3. With 2m diameter it would be 4,64 m tall blocks. OK, if it can handle the integrity of all the blocks above it (up to 25 with 120 m tall crane).
Average height where the "storing" block in full 120 m long tower could be would be 60 m.
Its potential energy would be 20580 kJ, what is 5,7 kWh, with 85 % efficiency it is 4,85 kWh. But that would mean putting it to an empty space, not on top of another brick.
35 MWh system would need 7216 of such blocks.
With that 25 blocks towers it means 288 towers. That is circa 20 blocks (40 m) in diameter, 20 m radius, plus the inner empty area for the storing part.
Than you need the area for the "used" blocks - more is better as you need to place them as low as possible. Big cranes can have up to about 150 m long jibs, so there is definitely some space.
i dont trust the 85%, can someone check this please and tell me if my wind-turbine knowledge is out of place? i think they took 65-70% of the kinetic energy so can this crane really save 85%, it seems a bit off for such an "simple" technology....
That wasted my time, nothing new here, been done with water.
The challenge is what is the levelized cost of energy per kwh stored versus what other technologies can do, like batteries. It seems like this might have some additional maintenance. But if you could do this where there is already some elevation, like on the edge of a cliff, then the cost might go down.
"Energy Vault’s CEO estimates that after building 10 plants, the cost of energy storage for the system will be around US$150 (AU$205) per kWh. This makes the technology competitive with lithium-ion batteries, which currently cost around US$280 to US$350 per kWh. However, Quartz reported that the cost of lithium ion batteries could fall to US$100 per kWh, making them stronger competition in the long term."
www.createdigital.org.au/concrete-block-battery-alternative-pumped-hydro
How about the company and the media read up on how much co2 one ton of concrete produces.
How do they keep the power consistent between switching blocks thou, stop start wont work for power - and what about the power needed to move the crane when between blocks, I assume they have something for this, its just not mentioned. .
The problem with this machine is that it violates the first law of thermodynamics, the law of conservation of energy. You would need to put more energy into the system than it would produce. Basically the energy produced by lowering the bricks would be lost to the energy needed to lift them. This device is in an open system meaning that some of the energy is lost to its surroundings. Plus more energy is lost when converting mechanical energy to electrical energy. Eventually this machine would lose its efficiency and would require additional energy to keep it going. That's the main reason why perpetual motion machines are impossible.
It's not a power plant, it's a merely an energy storage solution. Nobody said it has a net output. Let's say you have a small community powered by a wind turbine. During windy days, instead of wasting a lot of the electricity output, you store it. Then when there is no wind, you at least have SOME energy to use for emergency purposes.
Just asking for your opinion on a different concept of my own that is quite basic. The build can at least be of 2 ultra strong permanent magnets, one above another where the top magnet stays stationary on a plastic* container maybe filled with water while the other is inside that container. Between the top magnet and the container needs to be a very narrow gap for which a light sheet of lead* can easily slide between the magnets just enough to cause the bottom magnet to fall as if it were a delicate power switch that the rise and fall will help* generate more electrical power than it would take to move the lead* sheet in and out of that gap in least frictionless way, maybe levitated by other magnets. The water is basic to prevent damaging and even far too much noise.
.
In summary... it would be as if the permanent magnets can be switch on and off like electro-magnets.
.
I tend to come up with a whole lot of various ideas that worked out awesomely, but... not often able to test my ideas out.
I wouldn't put them on cranes, suspended in the air. I would lay them down against those hills in the background and have them run on a track at the angle of the hill. That way they would be less vulnerable to seismic events and also able to be stopped and worked on at any point along the length of the weight's run simply by chocking the weight in place wherever it is and not having to lower the thing all the way to the bottom before you can work on it. You can also make the weights of enormous size if they're on a track rather than in a suspended configuration. They could be made the size of apartment buildings and be made primarily of a box filled with earth and rock. Very cheap and gigantic. Depending on the height and size of the hill, it could store several days worth of energy even from a very large solar and wind array.
Sea swell can easily lift a massive ship up and down.. so perhaps some sort of development of this idea with perhaps a chain and ratchet system combined with a big enough float could lift massive concrete blocks up to a height to be released and run a generator on the way back down.
I've thought of buying land on a mountain for this purpose. The problem is that you need a huge mass and lots of elevation to store required energy.
let's be real, you've never seriously considered "buying land on a mountain for this purpose"
Other than the added density of concrete rather than water I can't see how this in any way would be better than pumped-storage hydroelectric.
Similar concept to Gravatricities' mine shaft idea. Suspend a large weight in a shaft and lower it to generate electricity
I think they used something like this with shipping container cranes but store the energy in ultracapacitors.
but having to move the crane towards the next block does take energy as well so you lose out quite a bit there...
no numbers, in and out kwh, cost, space/size, efficiency etc... similar concepts have been lack luster in performance. facts not xylophones.
If these barrels are filled with concrete, they probably weigh around 400kg. So the entire demo video contraption stores less than one kWh of energy.
In fact it's about 170 Wh of energy right there in that stack if it's 12m high (I don't think it is, but call it that). That wouldn't drive an EV one mile.
Hopefully, we will be seeing those numbers if this thing ever gets into production.
Pump on demand water systems solved this supposed issue centuries ago.
Another solar roadway, water from air fraud.
There's something you have to realise
A 20ft container sized concrete block only store 0.2 kwh of energy per meter you need 10 of them at 25 meter to have the same energy storage as a tesla model 3 battery.
How you will lift them up? Will you use electro power for that? But than you have to generate that power again? I think it has a potential if it will use a wind or ocean energy
I think the biggest question should be _why_ you would want to store energy. When was the last time anyone experienced a powergrid not being able to handle its load?
Happens constantly. Wind generators and similar get turned off if the demand is lower than the production. Instead we could keep the generators running, it is "free" energy at that point so no harm, to store some of the energy. So it's less about the grid more about turning off generators when we shouldn't.
Going to be a lot bigger issue as solar and wind expand. Germany and California already face this issue with some frequency.
I had an idea once where, you would have some sort of machine set up that was able to lift your entire house, or a really heavy object during the night when electricity prices are lower, and then generate electricity during the day by allowing the house/object to slowly fall down.
You will probably want something that's less expensive than your house to move around.
Good Idea.
You Can use a disused mine to increase the altitude difference.
I love it! Have wanted to see this for a long time.
Would be a good use for all that depleted uranium.
it seems that lifting and lowering water work better?
Or sand
Fill shipping containers with gravel and roll them up a steep hill on tracks. Repeat daily. Or use a ski lift with bags of gravel in place of the skiers. Crane is impractical except for a test.
I wonder if it would be better for a smaller setup at indivudual homes. With heavier materials
Gosh that looks like a stretch. It just seems way to complex and like it will fall. I like the idea of just rolling a train down long decline. They have it England. It goes down the hill fast enough on it's own and to turn an electric motor backwards so it stores electricity and then it uses it to take people back the other way. If you did this though you should go smaller and do it in a vacuum. Things fall at 9.81meters/s^2 until they hit terminal velocity. For the human body that is 122 mph. But in a vacuum we would continue to accelerate until approaching the speed of light (You would hit the speed of sound in a 6 second drop which I think is the biggest drop you could get but what a ton of power).
Key words: Swiss homes
great idea for a home build
hang on..... thats how my grandfather clock works lol
They should lift a self propelled heavy train (thousands of tons carrying heavy loads of dense metals like tungsten) uphill using electricity. Then let it roll down very slowly like the weights of a grandfather‘s clock ( same as concrete blocks here). This is better than Hydro power where you lose 50% of the energy as the water escapes the turbines. Here the energy conversion is near 90%. Only the wheels friction is the loss.
every heard of pumped-storage hydroelectricity?
I find it hard to see how a combination of pulleys and weights to store excess energy can be *practical* for continuous energy supply.
For one, you cannot convert the stored gravitational potential energy into a 100% *continuous* electrical energy in a straight-forward manner, because energy conversion is zero once a weight touches the ground. So, to get something close to continuous electricity, weightS would need to be transferred down in succession as frequent as possible. Even then, electrical energy storage devices like capacitors or big-ass fast-recharging batteries and some control system would still be required to store the converted energy and to make sure the energy converted gets outputted as a smooth electrical power, something akin to electrical systems you find in wind turbines.
In order to provide stability to the main grid.. in a frequency deviation by example, where in matter of seconds a great energy generation is needed, this could be hlepful. Its basically to improve voltage and frequency quality. This is a instanenous power, not a energy, application...
you could, you know, have more than one device lifiting and dropping the weights...
Yes I am sure they would have multiple cranes and stagger them to provide constant output.
How efficient is this ? That's the point.
Instead of using the grid , use the solar and wind power to rise massive objects, because the most difficult part is to store this irregular energy
Interesting concept! Minimal upfront capex vs massive capex for hydro, much easier planning consent, more site locations, 2.4x energy density vs water, increased efficiency from crane power generation vs lossy water turbine. All in all, a competitive alternative to hydro for long term storage? Pretty promising tech to supplement solar/wind.
what happens during an earthquake? does the jenga tower fall down and we lose all the potential energy?
what about all the c02 emissions produced when manufacturing the concrete blocks?
JAJJAJAJA Y YO PENSABA QUE ESTABA LOCO. PERO AHORA QUEDE MAS LOCO.
Why do people always say "hurr dur enrgy conversion" like no, you're just TURNING A GENERATOR. One way or another, it's still turning a generator! Nuclear reactors, coal reactors, hydroelectric dams, blah blah it's all the same thing! Turning a generator! Either with steam or water, just don't complicate things!
The problem with this idea is how many huge blogs we would need to lift in order to store enough energy. But the idea is interesting.
So if I want to use this in a flashlight I have to buy a crane and concrete blocks.........
I'm skeptic. This concept seems to use quite a lot of land per energy stored (although I didn't see official figures). I'm personally still hoping for synthetic diesel production to solve the intermittency issue. The produced fuel would have an extremely high energy density, enough to store winter supplies without too much space. Using it to power turbines to feed electricity back into the grid is only 66% efficient (Samavati, Martin, Santarelli, and Nemanova, 2018), but more scalable than the stacking method and pumped hydro. Incidentally, we could also power the transportation sector with zero CO2 emissions, and carbon capture technology would become cheaper to (maybe hopefully, given the right political and economic circumstances) account for the remaining use of fossil fuels in heavy industry.
Didn't the safety and hazard deem the concept too dangerous for energy storage for generalized application anyways?
Haven't we learnt our lesson yet?
Basically this concept is a carousel of marbles
Wouldn't just a group of very heavy flywheels just be simpler ?
A combination would be nice
This article is the perfect use case for Bret Victor's Tangle (or Mike Bostock's Observable, or any other smart notebook). Don't just give me paragraphs of text with figures - plug the formulas into the article itself and let me drag a scale slider to find sweetspots. Or one level of abstraction higher, paint me chart of where the sweetspots are.
ok would have to see the numbers on that never seen or heard of that before although im not in the power game sooo
its a great idea and something i've been thinking about for some time, what would be truly awesome, would be a scalable version for domestic and rural applications,
Looks like a pretty good way to scam some startup money...
Is it as efficient as Ammonia or Aluminum storage?
Likely a more efficient in operation than hydroelectric systems (no fluid turbulence losses, viscosity losses, ...). But the resources in material (sand, limestone, ...) and space space needed for erecting really large scale systems concern me. Also concrete produces loads of CO2 in mining for the resources and the hardening process.
They intend to use old concrete from construction debris, that would otherwise go to landfills. Some old concrete gets recycled, but usually for low-stress uses like fill to level a construction site. But if your use requires strength, like a highway overpass, you want to use new materials and controlled curing. The US generates 500 million tons a year of demolition waste, much of which is old concrete, so there is plenty of it to use.
@@SeedFactoryProject -- I really want to see this succeed. But even with the sensible choice of recycling (as they do mention on their site -- I just checked) I guess there's a need for a few percent virgin filler concrete as "glue" for the old crumbles (wikipedia has no numbers on how much virgin is usually needed yet). I'd really like to see a rough calculation of the minimal CO2 emissions per some unit system size that would currently be to expect, before I'm willing to recommend this with good consciousness. **Regarding recycling:** Most of today's demolition hammer equipped vehicles I know of use gasoline (and that in a not particular efficient and clean way). Grinding old big concrete rubble to finer grades in "cone type gyrator crushers" (I guess this is the way it's done?) seems energy intensive, but could in principle be done with renewable energy. That is, if electricity suppliers give the option to direct the payments only to those CO2 neutral producers (at some premium).
A facility for lacquering the barrels against rust (once every few years) could (and should) be integrated right into the system I guess. Add a few colors (barrels as pixels) and you could sell advertising space or (better but less likely) employ artists to minimize the uglification of our landscapes.
Some types of concrete creation uses up CO2, hard to understand why that is not being used, conservative builders and idiotic politicians can probably be blamed.
Gravity Batteries increasingly look like a good idea, but why concrete? Why not just use rock from various mines? or any other heavy material?
I think the intention was to utilise waste from building construction - the kind of material that companies usually pay to dispose of
Why not just use depleted uranium
HAHAH so simple effective and efficient, and it is not that popular i ever read something about this concept. I think it is a very good energy storage! Cheap efficient simple and you can build it everywhere... The energy recompensation is still beeing used for long time but never as energy storage... It could also be build like 10 or 100 cranes in parallel and in a sequence so that you always can run a certain amout of them without stop...
They should drill a large 1km hole in the ground and have a massive weight. Its alot safer.
Very smart, see just a basic idea will work.
The best would be to raise and drop batteries!