A system for storing energy includes a body and a shaft having walls defining an internal volume for containing a fluid, a seal member disposed between the body and the walls of the shaft, and a fluid passage in fluid communication with the shaft. The body is disposed within the internal volume of the shaft for movement with gravity from a first elevation position to a second elevation position within the internal volume of the shaft. The seal member divides the internal volume into a first portion located below the body and a second portion located above the body. The fluid passage communicates fluid with the first portion of the interior volume of the shaft. The system further includes a pump/turbine operatively coupled with the fluid passage to drive a motor/generator to generate electricity upon movement of the body from the first elevation position to the second elevation position.