Lifting heavy masses to store gravitational potential energy
Gravity storage systems lift heavy masses (concrete blocks, water, rock) using surplus electricity and release them to generate power when needed. Various designs exist: tower-based, shaft-based, and underwater systems.
Gravity storage works on the simple principle of potential energy: E = mgh (mass Γ gravity Γ height). When charging, electric motors lift heavy masses, converting electrical energy to gravitational potential energy. When discharging, the masses are lowered, driving generators through winches or hydraulic systems. Energy Vault uses composite blocks and a crane system in a tall tower structure. Gravitricity uses heavy weights in deep shafts. RheEnergise uses a high-density fluid in underground hillside tanks.
Mass blocks/material: 25-35% | Structure (tower/shaft): 20-30% | Hoisting machinery: 15-25% | Motor/generator: 10-15% | Power conversion & controls: 5-10% | Balance of plant: 5-10%
Gravity storage is emerging as a viable alternative to pumped hydro without geographic constraints. Multiple companies are developing different architectures, with Energy Vault leading commercial deployments. The technology is particularly attractive for mine repurposing.