Novel Hybrid Thermal Energy Storage System Enhances Flexibility of Ultra-Supercritical Coal-Fired Power Plants

Strategic Insights -

Investigations into enhancing the flexibility of ultra-supercritical coal-fired power plants have led to the development of a novel hybrid thermal energy storage system. This system integrates molten salt and phase change salt to improve the efficiency and capacity of power plants. The research, conducted by a team at Southeast University, has shown promising results, with a peak shaving depth of 21% rated power load in the minimum dry-state load and a peaking capacity of 9.67% rated power load in the discharging process.

Key Takeaways:

  • The novel hybrid thermal energy storage system integrates molten salt and phase change salt to enhance the flexibility of ultra-supercritical coal-fired power plants.
  • Comprehensive performance evaluations were conducted through entransy analysis from a heat transfer perspective and exergy analysis from a thermodynamic viewpoint.
  • A systematic investigation was performed on the effects of key parameters, including steam split ratios, hot tank temperature, and pinch point temperature, on system performance.
  • A multi-objective optimization framework was developed to address the complex trade-off between peaking capacity and system efficiency.
  • The system efficiency in the charging process increased by 3.15% with only a reduction of 11.4 MW in peaking depth after multi-objective optimization.
  • The research was funded by the National Natural Science Foundation of China (NSFC), Jiangsu Provincial Department of Science and Technology of China, Youth Elite Scientists Sponsorship Program of Jiangsu Province, and National Key Research & Development Program of China.

Statistics:

  • Peak shaving depth: 21% rated power load in the minimum dry-state load
  • Peaking capacity: 9.67% rated power load in the discharging process
  • Cycle efficiency: 53.8%
  • System efficiency increase: 3.15% in the charging process
  • Reduction in peaking depth: 11.4 MW after multi-objective optimization

Sources:

  • "Multi-objective Optimization Design of Hybrid Molten Salt-phase Change Salt Thermal Energy Storage System: an Enhanced Peak Shaving Scheme of Ultra-supercritical Coal-fired Power Plant" (Journal of Energy Storage, 2025;127)
  • NewsRx. New Energy Storage Study Findings Have Been Reported by Researchers at Southeast University (Multi-objective Optimization Design of Hybrid Molten Salt-phase Change Salt Thermal Energy Storage System: an Enhanced Peak Shaving Scheme of ...). Energy Weekly News. August 22, 2025; p 228.