Low-carbon economic operation of multi-energy microgrid based on multi-level robust optimisation

The economic and low-carbon operation strategy of multi-energy microgrids (MEM) has become an important research topic in smart grids. The operation of MEM is affected by uncertain factors from renewable energy and internal load. To handle uncertainties from both source and load sides, the authors propose a novel worst-case-and-probability uncertainty sets and a novel worst-expectation min-max-max-min two-stage four-level robust optimisation (RO) model considering stepped carbon trading for MEM. This four-level RO model is a more generalised model compared with the traditional two-stage RO and distributionally robust optimisation based models. First, the unsolvable original four-level model is decoupled into a master problem and a sub-problem (SP). Second, Karush–Kuhn–Tucker condition is applied to convert SP into a solvable problem. Third, column and constraint generation (C&CG) algorithm is employed to solve the reformulated four-level RO. Finally, the effectiveness of the proposed model and solution method is verified by case studies. The results indicate that the convergence behaviour of this solution method is excellent. The MEM operator can select appropriate robustness factors and comprehensive norms to control its conservatism level. Besides, MEM could reduce carbon emissions by participating in carbon trading and installing carbon capture devices.