Economic Modeling of the Application of Battery and Pumped Thermal Energy Storage to Self-contained Microgrid on the Southwest Research Institute Campus

Results from Southwest Research Institute”s internally funded study of a self-contained microgrid for our San Antonio campus are presented. This study incorporates new modeling tools that combine behind the meter photovoltaic (PV) generation with multiple storage modalities including battery storage and pumped thermal energy storage (PTES). The study evaluates impact on electricity cost., including both energy and demand charges., of increasing levels of PV generation with and without storage. Key results show that adding behind the meter PV decreases total electricity cost until the amount of PV is large enough to cause significant curtailment. Once curtailed energy is available., adding storage becomes essential to minimizing electricity costs and greenhouse gas emissions. Conclusions are drawn on the optimal types and capacities of storage to meet economic targets for the campus electricity supply. The modeling tools developed for this study are general and easily applied to other evaluations of behind the meter renewable plus storage applications.