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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

#101

Post by meepmorp »

thirdlamp wrote: post #94
masklinn wrote: post #89

Earlier quoted context omitted.

> Here's an idea: what if -- instead of digging a deep hole into the ground -- we use the tower of a wind turbine as the vertical space in which the weight is raised/lowered? First, there's not really any room in there, wind towers are built for the job, we don't add twice the amount of steel and an elevator shaft for funsies. Second, even if there were some room it would be inconsequential, you need a lot of crap ve…

What if we used load bearing batteries as part of the tower structure?

Turbine fires would turn into something really special.

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

#102

Post by tarsinge »

throwaway189262 wrote: post #100
rakoo wrote: post #48

As usual everyone is fixated on price when the real hurdle will be scale. If we're going to replace our existing fossil fuel plants we need at least as much capacity. A quick grep in the article tells me these guys have a plan for a 4MW plant that involves a 1km shaft. That's the same order of magnitude as a single wind turbine, which is already one of the worst ratio of power output per quantity of resource and land…

> as a single wind turbine, which is already one of the worst ratio of power output per quantity of resource and land use. This is just false. Every wind turbine I've ever seen uses 50 square feet on a farm or cattle ranch. Not once have I seen a wind farm where the land underneath isn't still used for it's previous purpose. And at least in US we have enough farmland to power entire US with wind. And that's not count…

Resources are also construction material, that’s where wind get its bad ratio.

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

#103

Post by masklinn »

thirdlamp wrote: post #94
masklinn wrote: post #89

Earlier quoted context omitted.

> Here's an idea: what if -- instead of digging a deep hole into the ground -- we use the tower of a wind turbine as the vertical space in which the weight is raised/lowered? First, there's not really any room in there, wind towers are built for the job, we don't add twice the amount of steel and an elevator shaft for funsies. Second, even if there were some room it would be inconsequential, you need a lot of crap ve…

What if we used load bearing batteries as part of the tower structure?

You risk damaging the batteries and you make maintenance a pain in the ass. If you've got that amount of batteries, just put them on the ground the normal way.

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

#104

Post by audunw »

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.

Battery does not just degrade with power cycles. It also degrades with time. Not sure about the numbers for LFP, but it's something you need to take into account. For some areas time may be a more important factor than cycles. If it does a full cycle every 3 days or so, it'd take roughly 25 years to reach the cycle limit.

It's also important to remember that capacity will be reduced gradually. After 25 years both the energy storage capacity and power output of batteries will be seriously reduced, while the gravity-based system will most likely still be at full capacity.

I still think the estimate may be too high. Especially taking into account that these systems will compete in the future at a time where battery costs will be lower. But it might still make sense to build gravity based systems for a while to make sure all the lithium we mine goes to batteries for transportation.

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

#105

Post by throwaway189262 »

This is an obvious scam if you do the math.

Assuming the full scale version delivers peak power for 11 seconds like the prototype, 2MW peak power would be 6 kilowatt hours of energy.

That's terrible. We're taking about dropping hundreds, maybe thousands of tons down a mine shaft to get the same amount of power as $700 of lithium batteries you could carry in a backpack. For instantaneous loads you're way better off using flywheels, which we've already had for decades.

Gravity is weak, literally. The only realistic use case for gravity generation is hydro power. And MAYBE reverse hydro power where we put giant gas bags underwater and they make energy floating up

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

#106

Post by throwaway189262 »

tarsinge wrote: post #102
throwaway189262 wrote: post #100

Earlier quoted context omitted.

> as a single wind turbine, which is already one of the worst ratio of power output per quantity of resource and land use. This is just false. Every wind turbine I've ever seen uses 50 square feet on a farm or cattle ranch. Not once have I seen a wind farm where the land underneath isn't still used for it's previous purpose. And at least in US we have enough farmland to power entire US with wind. And that's not count…

Resources are also construction material, that’s where wind get its bad ratio.

Construction material is a meaningless metric. If you compare coal or gas plants you need to consider the materials they consume and infrastructure needed for fuel transport. This is a big number, many times the material used for the plant itself.

The only meaningful comparison is material used vs solar. Once these things are built they use near zero resources. For everything else you have to keep mining shitloads of material forever.

How much coal do we have to mine for coal plants? How many gas wells and pipelines for gas plants? What about transport? How much does it take to mine and process all the uranium into fissile isotopes for nuclear?

With wind and solar you plop the thing in a field and get years, maybe decades of energy with no input.

I'm convinced that all these land use and building materials costs studies are just FUD funded by the fossil fuel industry.

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

#108

Post by thehappypm »

runeks wrote: post #76

Here's an idea: what if -- instead of digging a deep hole into the ground -- we use the tower of a wind turbine as the vertical space in which the weight is raised/lowered? A wind turbine is already equipped with a generator, so it'd be a matter of building some sort of "switch" which would make it either: (a) generate electricity using the turbine, as per usual; (b) raise the weight using the turbine, thus not produ…

I’ve always been surprised that there is no product wind turbine with a guaranteed power output, that is, a turbine with an embedded battery. Sure it would cost much more, but in some applications steady power is worth it.

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

#109

Post by kleiba »

throwaway189262 wrote: post #100
rakoo wrote: post #48

As usual everyone is fixated on price when the real hurdle will be scale. If we're going to replace our existing fossil fuel plants we need at least as much capacity. A quick grep in the article tells me these guys have a plan for a 4MW plant that involves a 1km shaft. That's the same order of magnitude as a single wind turbine, which is already one of the worst ratio of power output per quantity of resource and land…

> as a single wind turbine, which is already one of the worst ratio of power output per quantity of resource and land use. This is just false. Every wind turbine I've ever seen uses 50 square feet on a farm or cattle ranch. Not once have I seen a wind farm where the land underneath isn't still used for it's previous purpose. And at least in US we have enough farmland to power entire US with wind. And that's not count…

In places with cold winters, it is often forbidden to approach wind turbines because of the risk of falling ice.

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

#110

Post by fighterpilot »

jillesvangurp wrote: post #77
rakoo wrote: post #48

As usual everyone is fixated on price when the real hurdle will be scale. If we're going to replace our existing fossil fuel plants we need at least as much capacity. A quick grep in the article tells me these guys have a plan for a 4MW plant that involves a 1km shaft. That's the same order of magnitude as a single wind turbine, which is already one of the worst ratio of power output per quantity of resource and land…

Your assumption that we need that much storage is simply wrong. This pops up in just about any article on HN mentioning batteries. Somebody will jump to the wrong conclusion that we need to provide massive amounts of battery storage and that therefore we need coal/nuclear/etc. (i.e. really expensive ways to generate energy) because buying so many batteries is obviously stupendously expensive. It's a popular argument…

> Somebody will jump to the wrong conclusion that we need to provide massive amounts of battery storage

+1 for the post, but I don't see this that much.

Whenever I see the debate come up, it's when someone is directly comparing the cost of solar to nuclear/natgas without factoring in the additional cost of batteries and DC lines, which obviously leads to an invalid (or at least incomplete) comparison.

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