Evaluation of Water and Solar Energy Use in Hydroponic Systems to Assess Sustainability in Crop Production

Abstract

Sustainable agricultural production is increasingly challenged by water scarcity, high energy demands, and climate variability, especially in regions with limited resources such as the Middle East and North Africa (MENA) region. This study evaluates the sustainability of integrating hydroponic systems with solar energy for crop production under controlled conditions in Lebanon. The research occurred in a 72 m2 pilot-scale glasshouse at the American University of Beirut (AUB), incorporating different hydroponic systems such as the vertical rotating towers, A-shaped nutrient film technique (NFT), and gutters system, powered by a hybrid solar and grid energy setup. Different parameters were assessed including water consumption, energy usage, crop performance, chlorophyll content, and basic nutritional composition. Results showed that while system level water use did not significantly differ between the hydroponic systems, water consumption per plant was significantly lower in the vertical towers compared to the NFT-gutters and soil cultivation. Energy consumption was initially higher but later decreased following operational optimizations, although reliance on grid electricity remained necessary. Crop growth and yield were satisfactory across systems, with chlorophyll levels indicating consistent plant development, and comparable nutritional quality observed between hydroponic and soil-grown crops. Economic evaluation indicated that while hydroponics requires technical expertise and investment, it offers advantages in resource efficiency and productivity. The findings suggest that solar-powered hydroponic systems can enhance water use efficiency and support sustainable crop production, however, their overall sustainability is strongly conditioned by the environmental cost associated with energy demand, partial reliance on grid electricity, and operational inputs, which must be carefully balanced to minimize the system’s resource intensity.