Gravity storage

Lifting heavy weights and lowering them to make power.

Storage · Mechanical · No. 79

• Storage
• Duration: Hours

Lowering a 35-tonne concrete block 100 m yields only about 9.5 kWh, so gravity stores must be huge or deep.

Chart: Illustration: Gravity storage

Where it comes from

Chart: Map of where it comes from

Spare electricity winches heavy masses upward, and lowering them turns the motors into generators; energy is mass times gravity times height.

Three things to know

1. Doubling the depth of a mine shaft quadruples the energy a weight can store.
2. Blocks can be made from construction debris and coal ash, turning waste into a store of energy.
3. A 1,000 MW, 10-hour gravity plant would cost about USD 130/MWh, above pumped hydro's USD 110 (2021 estimates).

The journey

1. 1 Spare powerWind or solar output not needed
2. 2 LiftMotors raise blocks, weights or rail cars
3. 3 HoldStored as height, no chemical fade
4. 4 LowerMotors turn into generators as masses fall
5. 5 GridFour-hour shifting or fast regulation

Go deeper pick a tab to open it in full