The tradable flexibility certificate market policy for flexible investment incentive

With the rapid growth of renewable energy, the shortage of flexibility has become the primary challenge to the safe operation of renewable-dominated power systems. This paper proposes a market policy named tradable flexibility certificate (TFC) to overcome the challenge in a financial way. The TFC policy mandates that renewable energy generations purchase TFCs provided by flexible resources; otherwise, they cannot participate in the energy market. The proposed mechanism provides over-payment from renewable generations to flexible resources, then keeping the capacity of flexible resources growing in tandem with that of renewable generations. The clearing model of the TFC market based on the adaptive robust optimization method is proposed to avoid physical violation due to flexible services. In addition, the long-term influence of the proposed policy on the energy transition is measured with the system dynamic model. Conclusions are drawn from a numerical case study. The results show that the TFC policy can increase the revenue of flexible resources, reduce the curtailment of renewable energy, and encourage the improvement of the accuracy of renewable output forecasting in the long term.