Abstract: Flexibility retrofitting of thermal power units coupled with electrically heated molten salt thermal energy storage systems for peak and frequency regulation has become an important approach to improving unit performance and economic benefits. Through multi-dimensional comparative analysis, this paper recommends high-voltage electrode heaters for peak regulation and electric tubular heaters for frequency regulation. A power calculation method for frequency-regulating electric heaters is proposed based on existing AGC frequency regulation revenue policies. Several applicable wiring schemes for coupled electrically heated molten salt systems are presented with reference to typical cases, and techno-economic comparisons are carried out. The research results provide guidance for the electrical design of thermal power units integrated with molten salt thermal energy storage systems.