Dynamic modeling and design considerations for gravity energy storage

Pumped hydro energy storage (PHES) has made significant contribution to the electric industry. Towards the improvement of this energy storage technology, a novel concept, known as gravity energy storage, is under development. This paper addresses the dynamic modeling of this storage system. A mathematical model is needed for descripting the hydraulic components of gravity storage as they include various time variant parameters. The objective of this paper is to build a robust model that simulates the dynamics of gravity storage system. This work concentrates on the hydraulic dynamics of the system rather than investigating the dynamics of the mechanical equipment such as turbine, and synchronous machine. The proposed model has been implemented in Matlab/Simulink, and demonstrated by a case study. The dynamic simulation is carried out to gain insight into the performance of the system. The model can predict the volume and the pressure of both chambers, as well as the piston motion throughout the charging and the discharging of the storage system. (C) 2017 Elsevier Ltd. All rights reserved.