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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

#241

Post by goldenkey »

frankus wrote: post #217
goldenkey wrote: post #2

And these systems are way larger, more dangerous (wind) and not as efficient as magnetic bearing flywheels. https://en.wikipedia.org/wiki/Flywheel_energy_storage

One of the downsides (or maybe double-edged swords) of kinetic energy storage is that it's relatively easy to accidentally get all of the energy out at once. A stick of butter and an 2-tonne truck at 216 km/h both "contain" about 1 kilowatt-hour of energy. The butter could maybe burn your house down but the truck could easily kill a couple of dozen unprotected humans in a fraction of a second.

Flywheels made for energy storage are vacuum chambered and surrounded by very very dense material, made to withstand any accidents. So it isn't an issue.

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

#242

Post by jasonwatkinspdx »

waynecochran wrote: post #166
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…

The problem with wind is storing the energy. I live in the Pacific NW and when you drive through the Columbia Gorge you see hundreds of these windmills. I have have visited the Wild Horse Wind facilities and they store energy using batteries -- terrible. The dams below can back up water, but wind blows whenever is may. The dams also provide safety from flood, a waterway, recreation, ... windmills just pollute the sky…

You misunderstand the impact of the dams on the ecosystem. Salmon are hanging by a thread in the Columbia, and only a very aggressive hatchery program has kept them from collapse.

Essentially all buildable sites have already been built, and there's a growing awareness some existing damns need to come down. The Gorge is not some great untapped resource for pumped storage that people were too distracted by wind power to discover.

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

#243

Post by yongjik »

jacobolus wrote: post #211
masklinn wrote: post #194

Earlier quoted context omitted.

> I was thinking what if we used buildings built on jacks as our source of mass. Then you've got no height. Plus buildings are not dense so it's a pain in the ass, and when (not if) the jacks fail you're out a building.

It’s amusing to think of whole houses getting jacked 100 ft into the air on giant stilts during the middle of the day when solar panels are operating, then slowly dropping to release the stored energy in the evening/morning.

I don't know how much a typical house weighs, but assuming 100t, raising it by 30m will give you potential energy of ... 8.2 kWh, or about $1.6 in today's electricity rate.

Gravity is weak.

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

#244

Post by BenjiWiebe »

audunw wrote: post #104
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…

In 25 years, a mechanical structure with tons of force on moving parts is going to be needing some maintenance, too.

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

#245

Post by geosimcos »

A long time ago I was interested in alternative ways to store energy, one good method but quite expensive is to convert it to Rotational energy of a flywheel, NASA had pretty good results with magnetic bearings and vacuum.

https://en.m.wikipedia.org/wiki/Flywheel_energy_storage

It isn't practical and much more complicated than the other alternatives mentioned

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

#246

Post by waynecochran »

jasonwatkinspdx wrote: post #242
waynecochran wrote: post #166

Earlier quoted context omitted.

The problem with wind is storing the energy. I live in the Pacific NW and when you drive through the Columbia Gorge you see hundreds of these windmills. I have have visited the Wild Horse Wind facilities and they store energy using batteries -- terrible. The dams below can back up water, but wind blows whenever is may. The dams also provide safety from flood, a waterway, recreation, ... windmills just pollute the sky…

You misunderstand the impact of the dams on the ecosystem. Salmon are hanging by a thread in the Columbia, and only a very aggressive hatchery program has kept them from collapse. Essentially all buildable sites have already been built, and there's a growing awareness some existing damns need to come down. The Gorge is not some great untapped resource for pumped storage that people were too distracted by wind power t…

Salmon are good -- I fish there. Salmon are even spawning well above the dams. I don't know where folks get that misinformation.

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

#247

Post by jacobolus »

yongjik wrote: post #243
jacobolus wrote: post #211

Earlier quoted context omitted.

It’s amusing to think of whole houses getting jacked 100 ft into the air on giant stilts during the middle of the day when solar panels are operating, then slowly dropping to release the stored energy in the evening/morning.

I don't know how much a typical house weighs, but assuming 100t, raising it by 30m will give you potential energy of ... 8.2 kWh, or about $1.6 in today's electricity rate. Gravity is weak.

I was estimating based on a 200-ton house, 30 kWh/day electricity use, and a need to store up to half of daily energy at any one time.

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

#248

Post by FooHentai »

arbitrage wrote: post #117
FooHentai wrote: post #73

Earlier quoted context omitted.

I did a bit of scratch math with the notion this might be more suited for individual, home power storage rather than grid supply - You need something in the order of a 5m tall tower bearing 73 tonnes to store 1 kilowatt hour (even then, ignoring conversion losses). So that's the weight of ~ten class-4 fully laden heavy trucks. Once you can get it up in the air then the higher you can go you're doubling your storage i…

I think you are drastically underestimating the density of bulk metal. Trucks, while impressive as an illustration, are not quite dense enough to be practical or applicable in an energy-storage scenario.

Absolutely, useful just to illustrate the scale we're talking about for a given amount of energy stored as a real-world analog easy to recall.

Assuming you used cast iron as weights that has a density of ~7800kg/m³ at regular temperatures, so you're looking at about 10 cubic meters for that 1kWh of potential energy storage using an abundantly available, non-toxic material that will endure.

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

#249

Post by FooHentai »

tekstar wrote: post #134
FooHentai wrote: post #73

Earlier quoted context omitted.

I did a bit of scratch math with the notion this might be more suited for individual, home power storage rather than grid supply - You need something in the order of a 5m tall tower bearing 73 tonnes to store 1 kilowatt hour (even then, ignoring conversion losses). So that's the weight of ~ten class-4 fully laden heavy trucks. Once you can get it up in the air then the higher you can go you're doubling your storage i…

This exists at least in one place, with trains on a hill in Nevada. https://aresnorthamerica.com "ADVANCED RAIL ENERGY STORAGE"

That's awesome, thanks for the link

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

#250

Post by nickik »

015a wrote: post #225
throwaway189262 wrote: post #105

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 us…

I think an important thing to note about gravity batteries is how environmentally friendly they are, even relative to lithium ion batteries. Lithium mining is an insanely tight bottleneck in LI battery production, mostly outsourced to countries where we don't think much about it (Australia is a big one right now, but in terms of untapped reserves, Chile Argentina and China are all huge). They require complicated manu…

> Lithium mining is an insanely tight bottleneck in LI battery production

If anything lithium refining and production into high quality is far closer to the bottleneck.

> mostly outsourced to countries where we don't think much about it (Australia is a big one right now, but in terms of untapped reserves, Chile Argentina and China are all huge)

This is also very questionable. Lithium exists basically everywhere. Basically one of the most common elements. Pretty much in every desert you have tons. There is tons in water brines all over the world. There are huge hard rock reserves all over the world (US, Wales, Canada, Australia, Czech Republic and so on). There are even larger clay reserves, Nevada alone has lithium enough for all US needs. Mexico has huge amounts of brine as well.

South American brine is losing market share quickly and they will never get it back.

> They require complicated manufacturing processes that are centralized into maybe four or five advanced manufacturing companies around the planet.

This is true but many more companies are currently working on it all over the world. It is difficult but not its not some totally crazy technology.

Other technology have a place, but I don't know if gravity battery is one of those. Liquid air batteries, liquid metal batteries and others might be better solutions.

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