A novel approach for sizing thermal and electrical energy storage systems for energy management of islanded residential microgrid

Abstract

This paper proposes an energy management scheme (EMS) for islanded operation of a residential Microgrid (MG) using a Lithium-Ion battery (LIB) energy storage system (LIBESS) and distributed generators (DGs). The LIBESS handles primary frequency control and energy management during peak-load period while the dispatchable DGs supply the base load. During peak-load periods, the thermostatically controlled loads (TCLs) like air conditioners (ACs) make up a significant part of MG demand. A Thermal energy storages (TES) is quite similar to a TCL except that it can also store thermal energy for later use. Here, instead of using the ACs, it is proposed to use a TESS to provide the required thermal energy for keeping the inside temperatures of residences within the desired range. Instead of using the ACs, a pre-charged TES can be used to provide the needed cooling thermal energy during islanded operation that power generation capacity is insufficient. By not using the ACs, the total energy consumption of MG and the required LIB capacity for energy management decreases considerably. Various daily scenarios from available recorded data and randomly generated data are used to consider the uncertainties of the variations of the MG load profile, the ambient temperature and the renewable power generations. Also, the outage of the DG with the largest generation capacity is considered as the worst contingency that could ever happen during the islanded operation of MG. The LIBESS sizing results with and without the outage of the DG show that with the ACs being totally replaced with a TES, the overall cost of the TES and the LIBESS is decreased by 33% and 63% respectively than the case that the TES is not utilized.