Someone please help me understand this concept that has always confused me: Is the movement of the turbine itself a loss of efficiency since that is energy that is not being converted into other (e.g., electrical) energy? For example, if a wind turbine is not hooked up to anything, it will spin freely, but none of the air's kinetic energy is converted into electrical or other forms of energy. If the turbine is hooked up to a weak magnet, some of the kinetic energy is converted, and the resistance of the magnet causes the turbine to slow a little. If the turbine is hooked up to a strong magnet, even more of the energy is converted and the turbine slows a lot. So is a stronger magnet that hardly allows the turbine to move at all the most efficient design? Or is there a sweet spot where the resistance of the magnet is "just right"? Since I see lots of windmills spin fairly fast, I assume I am thinking about this all wrong.