Design and Evaluation of Hybrid Energy Systems in a Campus-Scale Application

This study presents a scenario-based techno-economic evaluation framework for grid-connected institutional hybrid energy systems aiming to reduce grid dependency through renewable energy integration. The framework is demonstrated through a campus-scale application at Doğuş University Dudullu Campus, where electricity demand is currently met entirely by the national grid, resulting in high energy costs and carbon emissions associated with fossil fuel-based generation. In the study, four different scenarios were modelled using HOMER Pro software: (1) grid-supported photovoltaic (PV) and converter systems; (2) systems where renewable energy contribution is increased with battery integration; (3) systems consisting of PV, wind, and batteries based entirely on renewable energy sources; and (4) Policy-Aware Carbon-Integrated Transition (PACIT), which evaluates the optimal configuration under regulatory frameworks including monthly net metering and a 40 dollars/tCO₂ carbon tax threshold. Across all evaluated scenarios, the grid-connected hybrid system with battery integration (Scenario 2) consistently emerged as the most techno-economically favorable option. In this scenario, the initial investment cost was calculated as 991,426 dollars, the levelized cost of energy (COE) was 0.0817 dollars/kWh, and the annual operating cost was 149,810 dollars. In addition, the renewable energy rate reached 50.3%, and carbon emissions were reduced by 45.96%. Scenario 3, which is based entirely on renewable energy, provides zero carbon emissions but is not economically viable due to the 12.1 million dollars investment cost and high energy costs. The results indicate that grid-connected hybrid energy systems offer the best balance in terms of cost and sustainability. By offering a transferable evaluation model, this study provides actionable insights for institutional energy planning and policy development in comparable grid-connected facilities.