Modelling and simulation of hybrid renewable energy system to achieve a net-zero and flexible-interconnected service area for highways

The increasing prevalence of distributed photovoltaics (PV) and electric vehicle charging stations within low-voltage distribution networks has led to issues such as the overloading of transformers in service areas. Expanding transformer capacity is typically quite challenging. To address these problems, a hybrid renewable energy system with high penetration of solar photovoltaic, batteries, and chargers is proposed, aiming to achieve a net-zero and flexible interconnected service area. A case study is conducted in Shaanxi province, where a mathematical model for photovoltaic (PV), battery, and other components is developed to simulate energy flow throughout an entire year. Energy sharing is facilitated through the use of an energy router. In the event of a power shortage in one region, the energy router enables the dispatch of surplus electricity from another region to compensate for the deficiency. The modelling and simulation are conducted by MATLAB platform to investigate the daily energy flow and the techno-economic performance of the hybrid renewable energy system. The results indicate that the northern region experiences a maximum electrical load deficit of 50 kW, which requires compensation from the southern region by the energy router during the evening. Considering the typical load for vehicle charging, the self-consumption rate can reach up to 87.5%, compared to 49.7% without the vehicle charging load. This demonstrates significant PV self-consumption enhancement by the application of charging stations in the service area. The self-sufficient rate can reach 67% with vehicle charging, compared to 36% without that. This difference is due to the fixed output of the PV system, which results in a lower self-sufficiency rate when the load is higher.