Abstract: With the construction and operation of new transmission lines under different investment or financing modes, transaction modes are becoming more and more complicated. The currently employed electricity quantity based single-part pricing mechanism cannot meet the requirement of the new investment and market environment, and is not consistent with the essential characteristics of transmission investment recovery. The two-part pricing mechanism is more appropriate for transmission pricing. Given this background, this paper quantitatively analyzes the one-part electricity quantity based pricing and two-part transmission pricing. Firstly, we introduce the characteristics and calculating principles of the one-part electricity quantity based pricing and two-part transmission pricing. Then, we carry out the quantitative comparison of annual income and its fluctuation for a given transmission company under two transmission pricing mechanisms, and present two indexes including the unbalance rate and the average fluctuation rate of transmission income. Further we analyze the annual income changes of the transmission company concerned with respect to the capacity income rate in the two-part pricing mechanism. Finally, we adopt an actual transmission line in China Southern Power Gird for demonstration. The research results show that the electricity quantity based single-part pricing mechanism can speed the investment cost recovery in the case with redundant rain in the planning years, while the two-part pricing mechanism is able to mitigate the insufficient income risk in the case with deficient rain in the planning years.

Key words: two-part transmission pricing, transmission company, annual income, fluctuation risk