Synergizing solar, wind, and biogas with battery storage: A techno-economic and environmental assessment of a grid-interactive hybrid microgrid for an Ethiopian university

Abstract

Reliable and sustainable electricity supply is essential for university campuses in developing regions facing grid instability, high energy costs, and environmental concerns. This study develops and evaluates a grid-connected hybrid renewable energy system for Raya University, Maichew, Ethiopia, integrating solar photovoltaic (PV), wind turbine (WT), biogas generation, battery energy storage system (BESS), and grid support. Hybrid optimization of multiple energy resources Pro was used to optimize alternative configurations over a 25 yr project lifetime and assess their techno-economic and environmental performance. The university has an average electricity demand of 481.8 kWh/day and a peak load of 146.5 kW. Of 2899 simulated configurations, 2288 were technically feasible. Case I, comprising PV–WT–biogas generator–BESS–grid, was identified as the best configuration, achieving a net present cost of $112 998 and cost of energy of $0.021 85/kWh, compared with $184 885 and $0.071 07/kWh for the base case. Case I achieved a renewable fraction of 90.16% and reduced annual CO2 emissions from ∼3078 to 575 kg/yr, while limiting excess electricity to about 8499 kWh/yr. The system achieved a 6.18 yr payback period, 12.4% return on investment, and 15.8% internal rate of return. Sensitivity analysis identified wind speed as the most influential meteorological parameter, reducing operating costs by up to 97.6%, followed by solar irradiation, whereas temperature had a comparatively minor adverse effect. These results demonstrate that coordinated renewable generation, battery storage, and grid interaction can provide a cost-effective, low-emission, and sustainable energy solution for university campuses in resource-constrained regions.