Previous research on the vertical axis turbines efficiency has used blades with a typical static camber to improve the turbines efficiency. Typically, the static camber increases the drag force, which affects negatively the optimal harvesting of energy. The present study proposes deformable blades that change their shape relative to their angular position. The new blade shape is achieved by deforming the airfoil camber line via a sinusoidal rounded arc. The computed results show that the present type of deformation involves two typical flow control mechanisms. Firstly, a leading edge control that alters the flow angle of attacks and therefore the leading edge vortex (LEV) time of growth. Secondly, this type of deformation comprises a trailing edge control that affects the physical size and strength of the LEV. The lift force can be effectively increased. As a main result, the turbine power coefficient appears to be higher by about 20% for the optimal operating conditions.