A blade for a wind turbine can include an elongated and curved sheet having a root, a tip positioned opposite the root, a leading edge spanning between the root and the tip along a length of the blade, and a trailing edge spanning between the root and the tip opposite the leading edge. The blade can include a generally concave surface formed by curvature of the blade about a longitudinal axis. The blade can further include one or more air dams, which can be in the form of strip elements oriented transverse to the longitudinal axis and extending away from the concave surface. The air dams improve torque and efficiency of the blade. In some embodiments, an edge of the root can include a plurality of curved projections distributed thereon. A wind turbine system can include a generator and a wind turbine having a mounting element to support turbine blades.