this post was submitted on 17 Sep 2025
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Technology
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How come we can't design energy storage that lifts something heavy when there's excess power, and lets it fall to generate electricity when needed?
1 Watt is the equivalent of moving 1Kg 1 metre in 1 second.
If you want a kilowatt - you need to move 1,000Kg 1 metre in 1 second. Or, I guess, 1Kg a Km.
Plug the numbers together and you'll see that you need a massive physical load and a huge distance in order to store a useful amount of energy.
This seems like a way different conclusion than the car * 7.3m / day guy
The secret ingredient is gravity!
Hmm
You got your units confused.
1 Watt = 1 J/s = 1 N m/s = 1 kg m^2 / s^3
Just moving things horizontally changes does not take energy (except for friction). But when we move something upwards, we move it against the surface acceleration of earth of g = 9.81 m/s^2. So we can say:
1 W ≈ 0,1 kg m/s
This means to store 1 kW, we would need to raise e.g. 1 ton with 0.1 m/s. So 1 minute of medium power cooking (1 kW), corresponds to lifting 1 ton approximately 6 meters.