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Energy Vault – Gravitational Batteries

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Re: Energy Vault – Gravitational Batteries

#51

Post by thechao »

lordnacho wrote: post #31
kumarvvr wrote: post #11

1 Ton of mass, at 100 m height, holds 0.2778 kWh of energy. 100 tons (3 bricks as per their design) - 27.778 kWH 100 x 100 Tons (300 bricks ) - 27.78 MWH. However, as per their design, not all bricks store the same amount of energy. The lower section of bricks would not be economical. Every Ton of Concrete, on average produces 0.9 Tons of CO2 during its manufacturing process. 1 MWH of electricity generation, on avera…

Couldn't you instead of making solid concrete blocks fill them with junk, using just a little concrete to make the shape right?

They are, already. They use a type of rock "glue" to fuse together rubble — in some cases old broken up concrete. The GP comment is a pretty basic HN middle-brow response.

Re: Energy Vault – Gravitational Batteries

#52

Post by nullsmack »

dmos62 wrote: post #36
kumarvvr wrote: post #12

I really wish humanity comes up with a good way to store large quantities of electricity (not counting Hydro Batteries). Compressed air in mines is a good alternative, with heat of compression also stored. I am actually looking for ways to make this small scale. As in, creating a storage system for domestic use. In developing countries, average energy usage per house hold, would be not more than 10 kWh per day. Compr…

I've read about using a lot of small cheap containers, like plastic bottles, as compressed air batteries, but can't find the article right now. Apparenly a lot of small containers is a significant improvement over few (or single) large compressed air containers. Many small containers offer better space efficiency, they're cheaper, because you require less pressure (regular plastic bottles v. steel tanks), and their p…

There's this article about using small containers: https://solar.lowtechmagazine.com/2018/05/ditch-the-batterie...

But it's not talking about using cheap things like plastic bottles. I'd be interested in reading the article you're talking about. It's hard to find much about CAES online because it's easy to run into the crazy people that think they're going to get free energy out of it or something.

Re: Energy Vault – Gravitational Batteries

#53

Post by Retric »

algo_trader wrote: post #46
kumarvvr wrote: post #44

Earlier quoted context omitted.

One of my long term thoughts on this was to think and mentally design a system suitable for one 250 Watt solar panel. Assuming an average of 6 hours of sunlight, a 250 W solar panel can collect about 1.2 kWh of energy, or about 5 x 10^6 Joules. In terms of potential energy that is 5000 kg x 9.8 x 100 meters. Pretty huge for one solar panel. I have been thinking about storing energy in underground storage tanks, with…

An "obvious" improvement is to push blocks up, and insert new blocks below (yes, u need gearing, and maybe lean them on a slope). But you get quadratic energy per tonne. Its amazing how much energy a 250W panel outputs. Imagine storing energy from a 1MW wind mill (free pole? ;).

It’s the same total energy per bock. Their design starts out with 2 rings of stone. To simplify assume both piles are equivalent. The first layer of stones is raised by the width of a single stone. The next layer is raised twice the height of a single stone. The n+1 set is raised 2n+1 layers.

Starting with more piles means a lower initial height. But, the only things that matters when stacking is initial and final heights, and transmission losses.

Re: Energy Vault – Gravitational Batteries

#54

Post by Retric »

leonletto wrote: post #47
Retric wrote: post #22

Earlier quoted context omitted.

Cycling stress like that is going to dramatically reduce the lifespan due to tress fractures. I think they would be lucky to get 10-20 years from the blocks. Stress fracture are already a significant issue for concrete dams when you frequently vary the water levels, and this is much worse as different stacking is going to stress each block slightly differently every time. In theory they might be perfectly flat surfac…

Wouldn’t you just grind them up and recycle them?

They can’t recycle it into blocks of the same material properties. It’s not worthless by any stretch, just a poor fit for such demanding applications.

Re: Energy Vault – Gravitational Batteries

#55

Post by Tade0 »

newyankee wrote: post #50
Tade0 wrote: post #45

Earlier quoted context omitted.

I studied the topic and it appears that none of the manufacturers/retailers is willing to sell at this price to consumers - they already sell all their stock to car manufacturers and the like.

Is it because demand greatly outstrips supply at this point and will remain so for a few more years at least till new production capacity catches up ? Or is there any other reason that makes it trickier ? Would appreciate any links if you have some.

My best source was a first-hand account from a business owner who tried to switch from one-off EV projects to an a full-blown assembly line. He called up a few manufacturers and they basically told him to come back when he's at the scale of hundreds of MWh - sort of a chicken-and-egg scenario.

Retailers didn't want to talk about special pricing, regardless of scale.

Re: Energy Vault – Gravitational Batteries

#56

Post by ncmncm »

walrus01 wrote: post #10
imtringued wrote: post #2

Building cranes is most the boring part of this project. It's far more interesting to know how they are going to make the 35 ton weights. I don't know anything about the construction industry but some googling showed that 1 m^3 of concrete weighs 2.4 tons. You will need 15 m^3 weights. 1 m^3 costs $200 so each weight costs $3000. 35000kg×9.81m/s^2×100m is 34335000 Joules or 9.5kWH. $3000 / 9.5kWH is $315 per kWH. I'm…

I wonder how they've calculated the costs of building this giant crane and concrete block system, vs building small scale pumped storage hydroelectricity. Not by the usual method of impounding a reservoir at the top of a hill, but putting a giant array of load-balancing medium sized water tanks at the top of a hill, running a pipe to the bottom where there's the pump/generator, and a similarly sized array of tanks.

A big tank is overwhelmingly cheaper than a collection of small tanks.

Ground water makes a remarkably capacious reservoir, which may be deeper than your hill is high, doubling the energy storage capacity, for a possible upper limit on instantaneous wattage.

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