I visited a pumped storage facility a while back that stored electricity by pumping water uphill to store it and then draining it past a turbine to reclaim it. Ever since I’ve been intrigued by using gravity instead of batteries.

For home use, it seems like you could rig up some heavy stones on pulleys to do the same thing could be fun because you’d get to physically see your batteries filling up. Back of the envelope calculations suggest that an array of ten 10-ton concrete blocks lifted 10m in the air could power a house for a day (ignoring generator inefficiencies)

An AA battery contains approximately the same as 1 ton raised 1m. (About 3Wh)

A Tesla Powerwall contains about 13.5kwH (about 4,000 times as much)

So you can either raise 100 tons 10m above your house, or you can have 1/13 of a Tesla Powerwall.

Every time I see again the idea of moving big concrete blocks for storing energy, I remember the time I made the calculations, and estimated around USD100K of infrastructure to store the same amount of energy as a nissan leaf.

Hoisting 100 tons of stuff high into the air, and then efficiently converting that into the high RPM needed to drive a generator seems like it would take a truly staggering construction effort. Suspending that amount of weight high above your house also has some... interesting potential failure modes.

Gravity based with weights is generally considered not cost effective; others already did the math that your 100 ton proposal can still only store a fraction of what a consumer grade battery pack can do, but on top of inefficiency there's space and maintenance requirements. It works in situations where e.g. trains go uphill empty and full downhill, but generally it doesn't work.

Water based systems work better because water is easy to move, plentiful, and there's natural basins to pump into / flow out of that can contain billions of liters.

You need a lot of weight. IMO for home use the risks heavily outweigh the benefits for anything outside of a hobbyist project... that's just a lot of potential energy in a system that can go wrong. Weights falling quickly, pullies and cables under tension.

The same is true for batteries of course, but at the very least there are protections and checks for failures in most consumer accessible home solutions (and decades of engineering at this point). Worst case you at least have smoke detectors... not sure if there's a "cable is wearing thin and might snap and decapitate you" warning system.

Pumping water up is a super old idea, but as far as I know you'll need some natural terrain to build it efficiently.

Someone has already been thinking along the same lines: https://www.swissinfo.ch/eng/business/energy-vault_revolutio...

This type of plant is generally used for emergency power to balance the grid, whilst other plant come online.

Relevant video on a pumping water on the roof + turbine system : https://youtu.be/CMR9z9Xr8GM It's quite far from powering your whole house tho !

EnergyVault are building these GESS (Gravity Energy Storage System) arrays right now.

https://www.energyvault.com/projects/cn-rudong

Some guy on Youtube tried this. I think the conclusion was, not worth it.

https://www.youtube.com/watch?v=l19AMYd0oks

Stones are typically not very dense. Iron or lead or 2-4x denser than typical stones, and so will net you better energy density.

> an array of ten 10-ton concrete blocks lifted 10m in the air could power a house for a day

No, that's only 2.7 kWh. Most homes use 10-20 kWh/day. A battery of that size is easily under $1k. Good luck building your ridiculous concrete block system for that.

Batteries are really good. Gravity, not so much. It only works when you can lift & store a tremendous amount of stuff "for free" because nature has done most of the work, e.g. in valleys, mountains, aquifers, caves, etc. If you have to build the whole thing it will never be viable.

Gravity is weakest force of nature. Any strong force battery idea ?

You already have some decent amount of weight in the house itself, so I'd look into raising it all or parts of it

Of course it's probably not the simplest engineering effort...

There are some videos on Youtube discussing the hypotheticals of this. They're never really very positive about the feasibility. Neither on a small scale nor on a country-wide scale.

If you'd want to store 1kWh at 10m height, assuming no loss at all from heat, friction, etc, you'd need about 4 of those blocks block weighing 10 tons (according to ChatGPT). So you'd need a lot of those blocks to power a house for a day, unless you're very efficient.