Abstract: A reliable, eco-friendly, and reactive device for storing large amounts of recoverable energy with high overall energy efficiency enables the electrical energy on a grid to be collected when there is an abundant amount of available electrical energy on the grid, and redistributes the electrical energy to the grid when the electrical energy is running out. The device mainly includes a compact, dense ballast, the ballast having a matching hydrodynamic and aerodynamic shape, and a flow cavity suitable for holding energy corresponding to the maximum energy of the ballast in the cavity, the ballast being capable of moving along the main axis of flow in the cavity, the device further including an energy collection and recovery element and a control element. A braking coefficient and a safety factor are defined and adjusted on the basis of the nature of the movement of the ballast in the flow cavity.