A Comprehensive Framework of Technological Strategies to Improve Self-Starting in Darrieus-Type VAWT

The self-starting capability of straight-bladed Darrieus vertical axis wind turbines (VAWTs) remain a major constraint for their widespread deployment, particularly in urban environments with highly variable wind conditions. This article presents an in-depth review of technological strategies aimed at enhancing the self-starting performance of Darrieus VAWTs, classified into five key categories: (1) aerodynamic blade profile design, (2) rotor structural configuration, (3) passive flow control, (4) active flow control, and (5) incident flow augmentation. Multiple approaches are analyzed, highlighting design parameters, operating conditions, and performance metrics, with a focus on torque coefficient and power coefficient during the startup phase. Findings suggest that hybrid strategies can substantially enhance initial torque generation, such as combining optimized profiles with control mechanisms. Nevertheless, critical challenges remain, including limited experimental validation, insufficient use of 3D simulations coupled with structural models, and a lack of comprehensive assessments regarding technical and economic feasibility. A future research agenda is proposed, emphasizing the integration of artificial intelligence, additive manufacturing, and real-world testing for the development of more autonomous, efficient, and urban-adaptable wind turbines.