Driving sustainable aquaculture with photovoltaics through energy and cost optimization in Tilapia recirculating systems

This study evaluated the technical and economic performance of integrating photovoltaic (PV) systems into a recirculating aquaculture system (RAS) for Nile Tilapia culture, with emphasis on energy management and cost reduction. The experimental setup consisted of 36 circular tanks (3,000 L each) operated across two culture cycles, with stocking densities of 1,400 and 1,800 fish per tank. Tilapia fingerlings (3.0 g) were reared to an average harvest weight of 21.7 g within 65–71 days. Energy consumption averaged 7.35-8.44 kWh per kilogram of fish produced, which was used to guide PV system sizing. Two PV configurations were compared: (i) an off-grid system with 21 kWp of installed capacity and 81 kWh of battery storage, and (ii) an on-grid system with 4 kWp capacity designed to cover daytime loads without storage. Economic analysis indicated that the off-grid system achieved full energy coverage and higher annual savings (USD 4,130) with a payback period of approximately 7.5 years, whereas the on-grid system provided partial coverage with annual savings of USD 770 but required lower investment and yielded a shorter payback period (3.2 years). Beyond cost savings, the findings highlight that PV-powered RAS can enhance energy self-sufficiency, reduce greenhouse gas emissions, and serve as a practical guideline for stakeholders to preliminarily assess the feasibility and economic viability of PV integration in aquaculture.