Abstract This paper aims to investigate the innovative design of a ducted horizontal-axis wind turbine and to compare its energy production with a traditional free turbine for energy harvesting, both at laboratory and on relevant environment scales. The ducted wind turbine was designed considering a convergent-divergent duct, with the turbine in the throat section, where the velocity is maximum. The first part of the present paper describes the test rig and the experimental activities at the University of Genoa (Italy) wind tunnel, aimed comparing between the ducted and the traditional wind turbine at laboratory scale, considering the same rotor and comparing the power production. The second part describes the pre-commercial prototype of the ducted turbine (1 m rotor diameter), installed in the harbor of Genoa and tested under real conditions. The two experimental campaigns have shown a power increase up to 2.5 from the same rotor, compared to the free turbine configuration. In both experimental campaigns, the influence of the angle between the wind direction and the duct was investigated to determine the maximum power output of the turbine, corresponding to a yaw angle of 20°. As a final step, a possible application of this kind of ducted wind turbines is presented, investigating the case study of highway tunnel illumination: in this case, the presence of a yaw angle allows for reducing the number of turbines for the same energy production.