Wind turbines convert kinetic energy from wind into electrical power. They are designed using aerodynamic modeling to determine the optimal tower height, control systems, number of blades, and blade shape for the location. Conventional horizontal axis turbines have three main components: the rotor, generator, and structural support tower. Most use three blades for balance and slower rotation to reduce costs and increase efficiency. The airfoil shaped blades create lift and drag forces, with lift being maximized for efficiency. Small wind turbines can provide energy in off-grid areas, while wind power is becoming increasingly competitive with other sources and can power irrigation and desalination.