An aero-structure code has been developed to predict the performance of a horizontal axis wind turbine (HAWT) with adaptive blades. The code is a combination of an aerodynamic code, an adaptive mesh generator and a finite element code, all developed especially for this purpose. It has been shown that for a high elastic coupling, a coupled aero-structure simulation approach is necessary to have acceptable results while a single step simulation approach can only be used to estimate the blade loading and wind turbine power. (c) 2005 Elsevier Ltd. All rights reserved.