A bi-level program for the planning of an islanded microgrid including CAES

Compressed air energy storage (CAES) can mitigate the fluctuations of renewable energy output due to its large scale storage capacities, high ramp rate, and quick start-up time. It has become a novel choice for the energy storage in microgrids. An islanded microgrid which consists of the wind turbine, photovoltaic array, diesel generators, and CAES is investigated in this paper. The constant-pressure CAES is modelled considering the trade-off between reflections of its main characteristics and flexibility in microgrid operation analysis. A bi-level program is proposed for the microgrid planning problem. The model entails one problem embedded within another: the sizing problem is formulated on the upper level, while the unit commitment problem with spinning reserve requirement for the microgrid is described on the lower level. The effectiveness of the approach is validated by case studies where the proposed methodology is compared with other similar ones.