A Bi-Level Program for the Planning of an Islanded Microgrid Including CAES

Compressed air energy storage (CAES) can mitigate 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 energy storage in microgrids. An islanded microgrid, which consists of wind turbines (WTs), photovoltaic (PV) array, diesel generators, and CAES, is investigated in this paper. The constant-pressure CAES is modeled in terms of its power capacity and energy capacity. A bi-level program (BLP) is proposed for the microgrid planning problem. It considers optimization of operation at the design stage of microgrids. The sizing problem is formulated on the upper level (UL), while the unit commitment (UC) problem with spinning-reserve requirement for the microgrid is described on the lower level (LL). The effectiveness of the approach is validated by case studies where the proposed methodology is compared to other similar ones.