Techno-economic optimization of renewable-integrated electric vehicle charging infrastructure in campus microgrids considering heterogeneous charging behaviors

The rapid electrification of transportation has intensified the need for charging infrastructure that is both economically viable and environmentally sustainable. University campuses, characterized by predictable load patterns and concentrated mobility demand, represent promising environments for renewable-integrated electric vehicle charging systems. However, existing studies rarely integrate heterogeneous EV charging behaviors, real campus load data, and detailed electricity tariff structures within a unified techno-economic optimization framework. This study proposes a techno-economic optimization framework for campus-scale hybrid renewable energy systems integrated with electric vehicle charging infrastructure, explicitly accounting for heterogeneous charging behaviors, actual 8760-hour load and meteorological data, time-of-use tariffs with demand charges, and country-specific emission factors. Nine hybrid microgrid configurations and five distinct EV charging profiles—including fast, residential, office, public, and fleet charging—are systematically evaluated using the HOMER Grid optimization platform. Comparative results indicate that photovoltaic–battery-supported architectures consistently deliver superior performance across economic, operational, and environmental dimensions. The optimal configuration achieves a levelized cost of energy (LCOE) of 0.045 $/kWh, an internal rate of return exceeding 84%, and a simple payback period of approximately 1.2 years. Seasonal analyses confirm stable operation under diverse climatic conditions, with battery storage effectively mitigating renewable intermittency and peak demand stress. Environmental assessment indicates an annual reduction in carbon dioxide emissions of approximately 552 t/year, accompanied by notable decreases in sulfur dioxide and nitrogen oxide emissions. Sensitivity analyses demonstrate that system performance remains robust under variations in charging station capacity and EV charging tariffs, confirming the scalability and adaptability of the proposed framework. Overall, the findings provide a data-driven and policy-relevant roadmap for deploying cost-effective, low-carbon EV charging infrastructure within renewable-integrated campus microgrids.