Optimal design and techno-economic analysis of a campus microgrid integrating electric vehicles

This thesis evaluates the techno-economic feasibility and operational performance of a grid-connected hybrid microgrid at the campus scale of Eskişehir Osmangazi University (ESOGU), integrating a photovoltaic (PV) generation system, a battery energy storage system, and electric vehicle charging. Using the HOMER Grid model for hybrid renewable optimization, a total of twenty-four scenarios were simulated, in which PV capacity ranged from 300–800 kW, the battery energy storage system was fixed at 200 kWh, electric vehicle connection durations varied between 3–6 hours, and both instantaneous demand-based and deferred or smart charging strategies were compared under single-time and time-of-use grid tariffs. Performance was assessed in terms of net present cost, cost of energy, renewable fraction, and service reliability. Across scenario groups, higher PV capacities and deferreable charging strategies systematically increased the renewable share while reducing grid dependency and costs; however, diminishing marginal benefits were observed beyond 700–800 kW. Under a 3-hour electric vehicle connection duration, the optimal configuration (Scenario 6) consisted of an 800 kW PV system, a 200 kWh battery energy storage system, and a 613 kW bidirectional converter under the single-time tariff. Scenario 6 achieved cost of energy of 0.04765 dollars per kilowatt-hour and a net present cost of −13,060.58 dollars, with a renewable fraction of 73.40%, grid purchases of 25.50%, and grid sales of 40.30%. The quality of electric vehicle service was preserved at 10,022 annual charging sessions, 534,066 kilowatt-hours of annual energy delivery, and an average of 2.50 missed sessions per day. Sensitivity analyses examined PV degradation rates of 0.8/0.9/1.0 percent per year, tariff escalation rates of 29.80/32.78/55.55 percent per year, electric vehicle charging price increases of 20/25/30 percent per year, and campus load growth of 0.5/1.0 percent per year. In the long term, rising PV degradation and tariff increases raised costs and reduced the renewable share to 65.90%. Nevertheless, the preservation of service reliability underscores the importance of tariff-responsive operation, demand management, and phased capacity expansion for sustainability.