If people could harvest all the energy in the Earth’s wind through the use of windmills, for instance, it would generate about 3.6 million kilowatts of power, enough to supply the energy needs of 3.6 billion Americans. Since Americans use much more energy than most people on the planet, it is safe to say that the energy needs of the nearly seven billion people on Earth could be met by wind power alone. Unfortunately, it would be impossible to extract all of this energy. Wind turbines have become economically feasible, but we could never place them over every land and sea surface on the planet.