Review of Mechanical and Electromechanical Transmission Efficiency in Land-Based Airborne Wind Energy System

Land-based airborne wind energy systems (LB-AWESs) offer a promising approach to harvesting high-altitude wind resources while significantly reducing costs. However, overall performance is heavily constrained by energy dissipation along the power chain, spanning from aerial traction to ground electromechanical conversion. While existing research and reviews predominantly focus on aircraft configurations or control strategies, comprehensive analyses of the energy transmission efficiency remain scarce. To fill this gap, this paper provides a holistic review of four critical stages: wind energy capture, tether transmission, ground mechanics, and electromechanical coupling. Distinct from traditional reviews centered on individual components, this study adopts a holistic perspective of the transmission chain to prioritize the analysis of loss mechanisms across different stages. In particular, it highlights that internal friction losses within multi-strand braided tethers under large-scale, cyclic loading conditions constitute a significant yet long-overlooked factor affecting energy transmission efficiency. Additionally, the stability and performance factors of umbrella-ladder configurations are qualitatively evaluated. By integrating existing theoretical studies, experimental findings and engineering practices, this paper identifies the key design factors affecting transmission efficiency, comprehensively elucidates the energy dissipation mechanisms of various subsystems, and proposes core efficiency enhancement methodologies, providing a foundational reference for the optimal design of next-generation LB-AWESs.