A numerical method, called WEST (Wind Energy Study of Territory), has been used to study and evaluate the wind energy potential of 5 windfarms in Apulia Region (Italy). This model, based on historical meteorological and geophysical data, allows characterizing anemometric fields of a territory and, therefore, calculating its wind power potential. In this work, to evaluate turbulence effects of mutual interferences between wind turbines within the windfarms, a wake loss model based on the assumption "relative wind speed evolution equal to pollutant evolution" has been applied by means of WEST. In the cases under investigation, the results confirm the new proposed methodology as acceptable way for windfarm analysis and show that the wind-shadow effect, being confined within the first 500 m downstream of wind turbines, can be considered negligible with respect to other factors, as morphology of land and turbine rotor diameter. (C) 2019 Elsevier Ltd. All rights reserved.