A gravitational energy storage device is described where the kinetic energy to recover while braking a vertically moving mass is compensated by an auxiliary storage device based on supercapacitors. The characteristic power surge occurring by a fast decrease of the mass's velocity is absorbed by the added complementary device.

The system structure is described, together with the associated control strategy. The paper includes also the design of the supercapacitor bank for this specific high-power component.

The paper includes the simulation of the system where an energy discharge of the storage device is followed by a zero-power mode and a further an energy recharge.