the present work, development and aerodynamic performance prediction of a unique contra-rotating vertical axis wind turbine (VAWT) have been studied. The purpose of this paper is to investigate the effectiveness of employing the contra-rotating concept to a VAWT system while enhancing its conversion efficiency. The performance evaluations of the current model were established in terms of key aerodynamic performance parameters such as power, torque, power coefficient and torque coefficient. The systematic analysis of these quantities showed the effectiveness of the contra-rotating technique on VAWT system and the ability to extract additional almost threefold power over the entire operating wind speed ranges covered. The system has also improved the inherent difficulties of the Darrieus rotor to self-start. Moreover, the results of the new concept also demonstrated a significant increase in terms of conversion efficiency for both power and torque compared to a single-rotor system of a similar type. It is anticipated that this current approach will revolutionize wind energy harvesting strategies and will find application in a wide range of wind turbine sites that are characterized by relatively low and moderate wind speed regimes and particularly be useful in the urban environment where turbulence intensity is high. (C) 2017 Elsevier Ltd. All rights reserved.