A method of evaluating the performance robustness of energy supply systems under uncertain energy demands is proposed based on the maximum regret criterion. The regret in the performance of a system with its design specified is evaluated with the performance of the system with its design optimized as a reference. The regret is maximized with respect to uncertain energy demands, and this optimization problem is formulated as a multilevel mixed-integer linear programming one. At the first step, uncertain energy demands are discretized, the energy demands which maximize the regret are selected among their discretized values, which means that the maximum regret is underestimated, or the robustness is overestimated. In addition, a mixed-integer linear programming method utilizing the hierarchical relationship between design and operation variables proposed previously is adopted to solve the optimization problem efficiently. A case study on a gas turbine cogeneration system for district energy supply is conducted, and the maximum regret in the annual total cost of a system is evaluated. Through the study, the validity and effectiveness of the evaluation method and features of the economic robustness of the system are clarified.
