Wind turbines are being used more and more to generate electricity. In fields of hundreds of turbines, the turbines spin as wind pushes them, and the spinning motion is converted into electrical energy that can be sent to homes and businesses. However, not all of the kinetic energy of a spinning turbine gets converted into electrical energy. What best explains why the turbines are not one hundred percent efficient? The turbines are spinning outdoors, and solar energy from the Sun interferes with how machines work, causing kinetic energy to be lost to the air. Some of the energy of the wind’s motion is converted into a force by the machine, so some energy is lost to force. Since electrical energy is more useful than the kinetic energy of wind, the wind turbines are more than one hundred percent efficient. As the turbines spin, friction occurs between different parts of the machine, so some of the energy is converted into heat instead of electrical energy.