Economic Power Dispatch for Energy Cost Reduction of a Hybrid Energy System Considering Maximum Demand Charges and Time-based Pricing in a Healthcare Institution

This paper presents a model of a hybrid energy system connected to a healthcare institution. The hybrid system proposed for the case study consists of a dual axis PV tracking system and electrical energy storage device supplying power to a critical load in conjunction with an existing grid connection. The healthcare entity is subjected to time-based pricing and maximum demand charges. A medical facility in the city of Bloemfontein in South Africa is chosen as a case study, where solar irradiance is in abundance. The developed model and presented algorithm aim to economically dispatch power between the hybrid energy systems and energy storage scheme in order to minimize the energy usage from the grid and associated costs. The energy usage is subjected to Time-of-Use tariffs and maximum demand charges. The results from simulating the operation of the developed economic dispatch model revealed significant potential energy and associated cost savings. Employing the proposed economic dispatch strategy may potentially reduce the entity's monthly operation cost by approximately 55%, while maximizing the localized renewable energy production and use of the energy storage scheme.