Calculating Power System Marginal Cost and Electricity Price Based on Aggregation of Multi-Unit Supply Curves

This paper proposes and validates a systematic approach for constructing system marginal cost curves based on the aggregation of multiple generator supply curves. The core of this methodology lies in integrating individual generator supply curves to construct a strictly monotonically increasing system-level marginal cost curve, thereby accurately characterizing the cost variation characteristics of power supply under different total system output levels. Building upon this system marginal cost curve, the study further derives a calculation mechanism for zonal electricity prices and develops an efficient and accurate electricity pricing system on the Excel platform, providing a practical technical support tool for power market trading decisions. Through validation with typical cases, it has been demonstrated that in scenarios with a limited number of generators and relatively simple operational constraints, this method can effectively leverage Excel's computational capabilities to achieve rapid verification and efficient calculation.