Research On The Design Of Flexible Market Mechanisms For High Proportion Renewable Energy Power System

Decarbonization of power system is a key link to achieve the goal of "double carbon" in China.In the future,a high proportion of renewable energy sources will be connected to the power system as an inevitable trend.The power output of wind power,photovoltaic and other renewable energy sources is intermittent,volatile and random,while the spot market is still under construction in China,resulting in the traditional power generation plan dispatching mode is undergoing a double challenge.Under this circumstance,in order to ensure the safe and stable supply of electricity at all times,the demand for flexibility of power system will be greatly increased.In order to meet the demand for power system flexibility under the new situation,in addition to changing the power generation and consumption patterns and developing new technologies,modifying and improving the power market mechanism to fully release the flexibility potential of existing resources is also an effective solution to enhance system flexibility.This paper firstly analyzes the revenue composition of the participants in the flexibilityrelated power market,and secondly compares the mechanisms and processes of the current flexibility-related power market,clarifies the trading methods and trading processes of the market participants in different markets,and what services they provide and what revenues they obtain respectively.Secondly,we analyze the characteristics of the high percentage renewable energy power system,the basic characteristics of the high percentage renewable energy power system,the flexibility resources in the power system,and the impact of the high percentage renewable energy access on the electricity spot market price.After that,a flexibility product is proposed based on the shorter time scale flexibility demand generated by the high proportion of renewable energy sources connected to the power system,and a supporting flexibility product market mechanism is designed.The flexibility product and its market mechanism proposed in this paper can effectively measure the flexibility value of the market participants in balancing the fluctuation of system electricity supply and demand,and also can form a good connection with the existing electricity market mechanism.In this paper,thermal power units and energy storage plants are selected as the main providers of flexibility products,and an economic dispatch model of the power system considering the cost of flexibility products and environmental costs is established based on the full consumption of wind power and photovoltaic renewable energy power,with the objective of minimizing the comprehensive system cost.Short-term intra-day time series simulations are conducted for the renewable energy output reduction under different scenarios,so as to test the provision of this flexibility product and its market mechanism for upward flexibility adjustment capability and its cost benefit.The research results show that the flexibility products and related market mechanisms proposed in this paper can meet the effective provision of flexibility demand for the power system in both the early and mature stages of flexibility product market development.With the increase of renewable energy penetration in the power system,the flexibility retrofit coal and gas units with higher capability of flexibility ramping in thermal power units can better adapt to the future flexibility demand of the power system with high proportion of renewable energy,so the flexibility transformation of coal units can effectively improve the system flexibility regulation capability.The effectiveness of energy storage plants in providing flexibility products depends on the cost of energy storage and the coordination of the charge/discharge multiplier with the rate of load fluctuation.The proposed flexibility product and its market mechanism can help coal-based thermal power units position themselves to shift to flexible regulation and capacity guarantee resources,and also help energy storage participate in the power market by providing new auxiliary services and creating new business models.