Purchase Strategy of Electricity Retailer Considering Electric Vehicles with Renewable Portfolio System

Under the renewable portfolio standards (RPS), electricity retailers are obliged to absorb renewable energy. In addition to the purchase of conventional electricity, electricity retailer also needs to purchase corresponding power products in the green electricity contract market and green certificate market to fulfill the consumption responsibility. In order to enhance the inertia of the power system, electric vehicle (EV) can be used as a flexible and low-cost energy storage device through vehicle-grid (V2G) interaction technology. In the face of several power products with different price fluctuations, electricity retailers should comprehensively evaluate the cost and risk of power purchase, and optimize the power purchase ratio to maximize the overall benefit. In this paper, the conditional value-at-risk (CVaR) is used to quantify the risk, and the dual-objective optimization model with the lowest risk and the lowest purchase cost is constructed, which is transformed into a single objective problem of the minimum expected electricity purchase cost under the constraint of CVaR, and is solved by using the CPLEX solver. Through the case study, the application effect of the model in different market development periods and different quota targets is verified, which is of great significance for electricity retailer to optimize the electricity purchase strategy and achieve long-term development, and provides a reference for the improvement of the electricity market mechanism, the promotion of V2G interaction, and the optimization of renewable energy policies.