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Gravity batteries try to beat chemical ones with winches, weights, mine shafts

sciencemag.org

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Re: Gravity batteries try to beat chemical ones with winches, weights, mine shafts

#51

Post by kragen »

ardit33 wrote: post #31
guerby wrote: post #21

"But Schmidt’s calculation of the lifetime cost per megawatt-hour for lithium-ion batteries, $367, is more than twice as much" This is ridiculous. I'm charging right now my EV from a 14 kWh 16S LFP pack which costed me $1400 tax paid and delivered. LFP properly managed will do minimum 3000 cycles, so that's 42 MWh for $1400 which gives $34 per MWh out of the battery. Note: 5kW 48V inverter cost $500.

It is over 25 years, I don't think your battery will last 25 year. You probably have to replace it 3-4 times over that period of time. A mechanical system can last that much, even more, with minimal maintenance.

You may have accidentally responded to the wrong comment. The comment to which your response has been attached already takes into account the limited cycle life of batteries.

Re: Gravity batteries try to beat chemical ones with winches, weights, mine shafts

#52

Post by eraserj »

tshaddox wrote: post #36
function_seven wrote: post #29

Earlier quoted context omitted.

> It's a perpetual energy source right in front of us It's not. Once something has fallen down, it can't fall down again. To draw energy from the gravitational attraction of 2 bodies, you must first separate them. That consumes energy. On second thought, I suppose tidal energy fills the bill. Extracting that energy is really exploiting the Moon's motion, using gravity as the "conduit". Not strictly perpetual, but ess…

Isn’t tidal energy just harnessing some of the existing gravitational potential energy of the Moon-Earth system, which is roughly similar to any system that harnesses energy from a massive object falling due to gravity?

But again, slowing tidal currents must be drawing energy from somewhere until there is none left.

Re: Gravity batteries try to beat chemical ones with winches, weights, mine shafts

#53

Post by t0mas88 »

jb775 wrote: post #37
function_seven wrote: post #29

Earlier quoted context omitted.

> It's a perpetual energy source right in front of us It's not. Once something has fallen down, it can't fall down again. To draw energy from the gravitational attraction of 2 bodies, you must first separate them. That consumes energy. On second thought, I suppose tidal energy fills the bill. Extracting that energy is really exploiting the Moon's motion, using gravity as the "conduit". Not strictly perpetual, but ess…

But that "something" keeps being pulled down until it is stopped/blocked by something (e.g. the ground). Gravity is perpetual relative to the source of the gravity. It's just that our surroundings change and give the illusion of gravity changing...i.e. we don't "run low" on gravity I don't think Maxwell's Demon is 100% solved. Tidal energy could play into it, some underwater tides deep in the ocean are insanely stron…

You're confusing force with work. Gravity is a perpetual force, but a force doesn't generate energy.

To generate power you need gravity to move something downwards, releasing the potential energy. And when that thing hits the bottom of the shaft you've used up all the potential every that was stored in it.

Re: Gravity batteries try to beat chemical ones with winches, weights, mine shafts

#54

Post by binbag »

amanzi wrote: post #4

This is a clever system. I remember reading about a similar system in Australia that used excess solar power to lift giant concrete bricks, and then these bricks were lowered to the ground in the evenings to drive generators. Not sure if this is the same one I read about, but it's the same concept: https://energyvault.com/

It's talked about in the article. But it doesn't talk about the impracticalities.

Re: Gravity batteries try to beat chemical ones with winches, weights, mine shafts

#55

Post by flal_ »

inasio wrote: post #45

Gravity and electromagnetic forces are somewhat similar, they both have infinite range, decay as 1/r, one key difference is that the electromagnetic force is 10^36 stronger than gravity [0]. Just for that reason I'm always immediately skeptical of projects of this type. [0] https://en.wikipedia.org/wiki/Fundamental_interaction

Yet, gravity is strong enough to initiate nuclear fusion at the core of stars, or create black holes... That 10^36 argument is non sensical to me.

Re: Gravity batteries try to beat chemical ones with winches, weights, mine shafts

#57

Post by sscarduzio »

inasio wrote: post #45

Gravity and electromagnetic forces are somewhat similar, they both have infinite range, decay as 1/r, one key difference is that the electromagnetic force is 10^36 stronger than gravity [0]. Just for that reason I'm always immediately skeptical of projects of this type. [0] https://en.wikipedia.org/wiki/Fundamental_interaction

Would you say a magnetostatic (rather than gravitational) potential energy storage offer better performance?

Re: Gravity batteries try to beat chemical ones with winches, weights, mine shafts

#58

Post by tryonenow »

flal_ wrote: post #55
inasio wrote: post #45

Gravity and electromagnetic forces are somewhat similar, they both have infinite range, decay as 1/r, one key difference is that the electromagnetic force is 10^36 stronger than gravity [0]. Just for that reason I'm always immediately skeptical of projects of this type. [0] https://en.wikipedia.org/wiki/Fundamental_interaction

Yet, gravity is strong enough to initiate nuclear fusion at the core of stars, or create black holes... That 10^36 argument is non sensical to me.

It's about energy density. Generally you can fit many orders of magnitude more energy in the same physical space when storing energy electromagnetically. The comparison implies some assumptions but the point stands. It's space inefficient.

Re: Gravity batteries try to beat chemical ones with winches, weights, mine shafts

#59

Post by drran »

_rpd wrote: post #19
sollewitt wrote: post #16

We already have pumped hydroelectric storage, it's used as a load balancer on some national grids.

pumped hydro is great, but requires uninhabited geography of a type that is in short supply in many nations.

We can use underwater bubbles to pump air into, or displace water in lakes/sea with something with large volume and very lightweight.

Re: Gravity batteries try to beat chemical ones with winches, weights, mine shafts

#60

Post by PurpleFoxy »

Gauge_Irrahphe wrote: post #56

The technology isn't incredibly immature. On the contrary, it's understood to the tiniest detail. If it doesn't work, it won't work.

Isn’t pumped hydro a realistic solution? There should be a massive amount of energy in moving all that water up a mountain.
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