As a requirement of the modern society, renewable and clean energy systems are being developed. Following this trend, urban energy systems are being studied and installed. The following study has for aim to check the possibility of install two wind turbines on the top of the roof of the Läkerol Arena situated in the city of Gävle, Sweden. For this, several data have to be measured in order to calculate the maximum output possible to get, the optimal point of the roof and the kind of turbine used. The measurement of all these data has been processed in the wind tunnel of the University of Gävle. It permitted to pick up thirteen different positions on the roof of the Läkerol Arena model at the scale 1:200. These measurements gave the velocity of the points and the turbulences. The extrapolation of the wind data over Valbo provides site-specific estimates of wind speed and direction characteristics that has been used to predict the annual energy output for a proposed wind turbine. Different turbines have been tested to enable Gavle Energi Company to make a comparison.