FGI Medium Voltage Drive Helps the World's Largest Salt Cavern Compressed Air Energy Storage Station Achieve Full Operation
Long-Duration Energy Storage is Key to Solving Renewable Energy Fluctuation Challenges
Under the "dual carbon" goals, the new power system is developing rapidly. Salt cavern compressed air energy storage has advantages such as large capacity, long life, low cost, safety and environmental friendliness, making it an important technical solution in the field of long-duration energy storage. However, non-compensated compressed air energy storage systems face a major challenge: precise control of the molten salt thermal storage subsystem. Traditional valve throttling causes low efficiency, high mechanical stress, poor control accuracy, safety risks, and heavy maintenance workloads.
FGI Medium voltage Drive Solution Successfully Applied to the World's Largest Compressed Air Energy Storage Station
The Jiangsu Guoxin Su Salt Huai’an 2×300MW salt cavern compressed air energy storage demonstration project has been fully commissioned and is now the world's largest compressed air energy storage station, with a total storage capacity of 2,400 MWh and an annual power output of 792 million kWh. FGI leveraged its 30+ years of power electronics expertise to provide a complete high-voltage VFD solution for the station’s molten salt thermal storage subsystem. This solution enables intelligent control of cold and hot salt pumps under all operating conditions, solving the challenge of precise flow control in high-temperature molten salt circulation systems.
Core Technical Advantages
Precise Flow Control Under All Conditions: No throttle valve is needed, eliminating throttling losses, and automatically achieving closed-loop control with stable flow, stable temperature, and stable system pressure.
Soft Start and Smooth Transition: Soft start and controlled deceleration avoid mechanical and grid shock, preventing pipeline vibration and the risk of molten salt leakage.
Intelligent Protection Under Special Conditions: Under low loads, the system automatically maintains a low stable speed. Before shutdown, it runs a low-speed circulation temperature equalization program to prevent molten salt solidification and pipeline blockage.
High Automation and Intelligence: Seamless integration with the station's DCS system enables full remote automated control, greatly reducing maintenance workload.
High-Reliability Design: Modular design with automatic unit bypass allows a single unit fault to not shut down the system, with comprehensive multiple protection functions.
Customer Feedback: Stable and reliable operation improves energy efficiency, lifespan, safety, and cost.
Since the project was put into operation, FGI’s Medium voltage Drive has operated reliably and stably. All performance indicators have met or exceeded design requirements. Compared to traditional control methods, the system saves significant energy, reduces auxiliary power consumption, and increases overall station efficiency. Soft start and smooth speed control eliminate mechanical and electrical stress, greatly extending equipment life. Motor starting current drops from 6–7 times to within rated current, removing grid stress. Full automation reduces labor intensity, lowers equipment failure rates, and cuts annual maintenance costs. Intelligent protection effectively prevents major safety incidents such as molten salt solidification and pipe blockage, ensuring 24/7 stable operation.
FGI Continues to Support Energy Structure Transformation and the Achievement of "Dual Carbon" Goals
By successfully serving the world’s largest salt cavern compressed air energy storage station, FGI has fully demonstrated the reliability and advanced performance of its high-voltage VFD technology in complex energy storage operating conditions.
In the future, FGI will continue to focus on the needs of the new power system construction, increase R&D investment in energy storage, renewable energy, industrial energy efficiency, and other fields, and provide more efficient, intelligent, and reliable power electronics solutions to support China's energy structure transformation and the achievement of "dual carbon" goals.
