This two-part paper introduces a novel aeroelastic approach to the design of large-scale wind turbine blades. By suitably tailoring the blade's elastic response to aerodynamic pressure, the turbine's Annual Energy Production is shown to increase, while simultaneously alleviating extreme loading conditions due to gusts. In Part I, we use a current blade as the baseline for an aerodynamic analysis aimed at maximising the turbine's yielded power. These results are then used to identify ideal aeroelastic behaviour. In Part II, we exploit material and structural bend-twist couplings in the main spar to induce appropriate differential blade twist, section by section, while bending flap-wise. (C) 2014 Elsevier Ltd. All rights reserved.