Experimental Validation of Gravity Energy Storage Hydraulic Modeling

Energy storage is widely believed as a solution to the high integration of renewable energy technologies. As more renewable energy systems are deployed, there will be an increasing need for more energy storage. So far, pumped hydro storage (PHS) is considered the most significantly used storage technology. Investors are looking for systems able to overcome PHS drawbacks. As an alternative to PHS, gravity energy storage is a system that is currently under development. This technology is based on PHS working principle. The modeling and simulation of this system is the subject of this paper. This work focuses on the hydraulic dynamics of the system. Since gravity energy storage requires complex fluid and structural systems, a mathematical model has been developed using Simulink to investigate the system performance. The proposed model has been validated experimentally. The results obtained from the performed simulation allow for the identification of important parameters such as duty cycle time, piston position, chambers pressure and volume, as well as quantification of the system power and capacity. It is demonstrated that the simulated model can successfully mimic the operation of a real model with relatively small errors.