On: How cheap does solar power need to get before it t...

[rm445]

The potential energy of a mass m at height h is mgh.

Play with this and you'll immediately see it doesn't seem useful. e.g. storing a 50-tonne weight at 10m gives you less than 1.5 kWh of energy.

[Gustomaximus → rm445]

So probably needs in excess of 750 ton. And more likely twice as a house would more likely have a 5m 'chimney'. Clearly not viable. Thanks.