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

Abstract

The increasing prevalence of distributed photovoltaics (PV) and electric vehicle charging stations within low-voltage distribution networks has led to challenges, such as transformer overloading in service areas and typically expanding transformer capacity is costly. To address these problems, a hybrid renewable energy system with high penetration of solar PV, battery storage, EV charger, and energy router is proposed, which aims to achieve a net-zero and flexible interconnected service area in Shannxi province. In this work, the mathematical model of PV, battery, and other components is developed to simulate energy flow throughout an entire year. The influence of the PV and battery capacity on the performance of the system is discussed to find the optimal system configuration, and the system performance is compared under different climate conditions. The results indicate that the northern region experiences a peak electrical load deficit of 50 kW, thus necessitating compensation from the southern region during the evening. The self-consumption rate (SCR) is 88.2 % and 53.9 % respectively, when the charging station load is considered or not. With battery capacity ranging from 100 to 300 kWh, the SCR increases from 86.6 % to 89.6 %, and the self-sufficiency rate (SSR) rises from 36 % to 37.3 %. When the PV capacity varies from 500 kW to 900 kW, the SSR increases from 29 % to 41.6 %, while the SCR decreases from 97 % to 77 %. The performance of the system in Shanghai is also simulated, and the results demonstrate that the SSR is 28.2 % and 61.6 % in Shanghai, respectively, which is lower than that in Shannxi province due to the higher solar irradiance, and the LCOE is 0.19 ￥/kWh higher than in Shannxi (0.13￥/kWh). The carbon reduction is 1294 t per year through the employment of the system, showing great benefit to the environment.