6 ms·

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

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

xyzzyz 6y ago
Yeah, if you do the math, it turns out that you need impractically large weights lifted to unreasonable height. Like, suppose you’re lifting 100 ton weight 100 meters high. That’s a rather large and heavyweight system. How much energy you can store this way? Less than $5 worth of electricity, as it turn out. This is basically the same as pumped water storage, but instead of immense amount of water you can pump between very large reservoirs, you’re limited to one solid weight that’s too light to store nontrivial amount of energy, but heavy enough to be significant problem from engineering perspective. It just doesn’t make practical sense.
- ecpottinger 6y ago
  Great, now calculate how much a flywheel system that stores that much energy will cost vs cheap concrete blocks. Magnetic bearings and large vacuum chambers do not come cheap.
- Mulpze15 6y ago
  Yes, the math does not look good. I remember dreaming about a house that could go up and down like this. Then I went to buy a AAA battery... same. That said, if they can manage to find that 1km shaft in an old mine like they hope, and put some crazy amount of weight and make it work, that would be impressive and cool.
- tchvil 6y ago
  How about to retrofit wind turbines? They are tall, strong, and empty inside.
  - masklinn 6y ago
    > How about to retrofit wind turbines? They are tall, strong, and empty inside. It's still basically piss-stakes: the largest wind turbine right now (14MWe Haliade-X) has 765t sitting on top of a 150m tower, so let's say you keep the 150m tower, rejigger it so it can move a 765t weight up and down the shaft without crumpling, and add your weight (a lead weight 4m in diameter and 5.4m tall), how much energy does that store? 250kWh, 2.5 teslas, or a medium-large electric bus battery. And it's not like you can add that to a working turbine: the tower was set up for 765t not 1500, and you need space for the crane.
- ObscureScience 6y ago
  Too me, pumping water seems like a pretty good solutiuon. If you are located on the coast, and can move let's say a million tons something like 100-200m up, that's not trivial and doesn't seem that impractical.
  - deleted 6y ago
    [deleted]
- labawi 6y ago
  That's why you should use trains, which can safely go a few km high in good terrain.
travisjungroth 6y ago
Now I want one. Home powered by solar and a flywheel is so retro-future. How does your house get electricity? Oh, power from the sun gets this flywheel spinning super fast and then it slows down and powers the house all night.
- goldenkey 6y ago
  The heavier the flywheel, the less rpm you'll need for your storage requirements. Not sure how efficiency factors in. But yeah, would be awesome!
frankus 6y ago
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.
- goldenkey 6y ago
  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.

xyzzyz 6y ago

Yeah, if you do the math, it turns out that you need impractically large weights lifted to unreasonable height. Like, suppose you’re lifting 100 ton weight 100 meters high. That’s a rather large and heavyweight system. How much energy you can store this way? Less than $5 worth of electricity, as it turn out. This is basically the same as pumped water storage, but instead of immense amount of water you can pump between very large reservoirs, you’re limited to one solid weight that’s too light to store nontrivial amount of energy, but heavy enough to be significant problem from engineering perspective. It just doesn’t make practical sense.

ecpottinger 6y ago
Great, now calculate how much a flywheel system that stores that much energy will cost vs cheap concrete blocks. Magnetic bearings and large vacuum chambers do not come cheap.
Mulpze15 6y ago
Yes, the math does not look good. I remember dreaming about a house that could go up and down like this. Then I went to buy a AAA battery... same. That said, if they can manage to find that 1km shaft in an old mine like they hope, and put some crazy amount of weight and make it work, that would be impressive and cool.
tchvil 6y ago
How about to retrofit wind turbines? They are tall, strong, and empty inside.
- masklinn 6y ago
  > How about to retrofit wind turbines? They are tall, strong, and empty inside. It's still basically piss-stakes: the largest wind turbine right now (14MWe Haliade-X) has 765t sitting on top of a 150m tower, so let's say you keep the 150m tower, rejigger it so it can move a 765t weight up and down the shaft without crumpling, and add your weight (a lead weight 4m in diameter and 5.4m tall), how much energy does that store? 250kWh, 2.5 teslas, or a medium-large electric bus battery. And it's not like you can add that to a working turbine: the tower was set up for 765t not 1500, and you need space for the crane.
ObscureScience 6y ago
Too me, pumping water seems like a pretty good solutiuon. If you are located on the coast, and can move let's say a million tons something like 100-200m up, that's not trivial and doesn't seem that impractical.
- deleted 6y ago
  [deleted]
labawi 6y ago
That's why you should use trains, which can safely go a few km high in good terrain.

travisjungroth 6y ago

Now I want one. Home powered by solar and a flywheel is so retro-future. How does your house get electricity? Oh, power from the sun gets this flywheel spinning super fast and then it slows down and powers the house all night.

goldenkey 6y ago
The heavier the flywheel, the less rpm you'll need for your storage requirements. Not sure how efficiency factors in. But yeah, would be awesome!

frankus 6y ago

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.

goldenkey 6y ago
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.