Abstract: As a complementary way of completing renewable energy certificates, excessive consumption has a new impact on the power procurement and sale strategies of electricity retailer. In response to this problem, the excessive consumption that can be sold at the end of the month was calculated, and a strategy model for electricity purchase and sales was established that considers the transaction of excessive consumption. The model used Latin hypercube sampling combined with simultaneous backward reduction to generate multiple scenarios of renewable energy and loaded to describe its uncertainty. The model predicted the price of two renewable energy certificates of excessive consumption and green certificate, and introduced the consumption responsibility penalty and incentive mechanism. The objective function of the electricity retailer’s optimal power procurement and sale strategies was the maximum profit from power procurement and sale strategies and the minimum conditional value-at-risk (CVaR). Calculation examples comparatively analyze the influence of factors such as the transaction mechanism of renewable energy certificates, the minimum renewable portfolio standard (RPS) weight, the renewable energy uncertainty. The results show that the introduction of the excessive consumption transaction mechanism and the setting of appropriate fines and bonuses promote the implementation of the consumption responsibility of electricity retailer.