Assessment, Optimization, and Utilization Mapping of Clean and Renewable Energy Technologies for Powering Unmanned Aerial Vehicles

Unmanned aerial vehicles (UAVs) serve various civil and military purposes, typically powered by batteries for short missions or fossil fuel combustion engines for longer flights. Previous studies have not adequately compared clean power technologies for UAVs of similar size and conditions. Thus, this study examines and optimizes clean energy systems, including fuel cells (FCs), batteries, and solar photovoltaic (PV) cells, to enhance the endurance and efficiency of fixed-wing UAVs. The study assesses all these powering systems as separated and integrated (i.e., FCs, PV, PV/battery, and FCs/battery/PV). It has been noticed that UAVs of different sizes require different power systems for optimal performance. For example, an FCs-UAV of 5 kg could have a flight endurance of more than 22 h with an energy consumption of 0.93 kWh. PV-UAVs are feasible for small UAVs (over 3 kg) during some sunny hours, and they need a battery for 24-h endurance and longer wings to secure sufficient area for solar cells. Integrated FCs/battery/PV systems are best for larger UAVs if there are no limitations on the wingspan up to 80 m, with a total flight endurance of up to 58 h for 500 kg UAVs without refueling the H₂ tank. The optimization and mapping assessment recommend batteries primarily for mini (< 0.1 kg) and secondarily for very small UAVs (up to 3 kg), FCs primarily for very small and small UAVs (> 0.1–100 kg) and secondarily for sizes > 100 kg, and FCs/battery/PV for larger UAVs over 100 kg.