Hybrid solid gravity energy storage system (HGES) technology is being advanced as a solution for securing a real-time balance between electric power supply and demand in distribution and transmission grids.

A combination of gravity energy storage and power-based storage systems, such as batteries and supercapacitors, in a single system, eliminates losses and fluctuations in output power typical of gravity-based storage caused by repeated starting and stopping of the motor. In this architecture, the gravity energy storage unit absorbs excess power from the grid or releases power when demand exceeds production. The power-based module provides rated power in order to compensate for the fluctuating active power during gravity system operation.

The basic structure and operational flows of the HGES. Source: J. Energy Storage (2023)

The feasibility and efficiency of the proposed HGES were confirmed in a series of simulations. No power fluctuation problems undermine storage scheme performance, which is characterized by a response speed improvement of one to two orders of magnitude compared to a single gravity energy storage system.

The technology described in the Journal of Energy Storage is predicted to achieve an efficiency of over 80%, especially if applied in distribution and transmission grids.

Researchers from North China Electric Power University (China), State Grid Smart Grid Research Institute Co. (China), Xi'an Jiaotong University (China) and International Institute of Applied Systems Analysis (Austria) participated in this study.