Electricity, from wind

Wind power requires building the wind turbines, and maintaining them. An average lifespan of a wind turbine is about 20 years. However, during this time it experiences periods of slower (or faster) winds, and thus the real output of energy is significantly smaller than the nominal one (that is, the capacity factor is less than 100%, usually in a range of 20-40%). For this example, we will assume that a 600kW turbine in roughness class 1 terrain will only produce about 30 GWh during its lifetime.
The turbines are composed of four main parts: the generator, the blades, the tower, and the foundation. The foundations are usually either steel or steel/concrete mixture; the tower is usually steel, the blades are plastic (glass fiber with polyester or epoxy), and the generator uses mainly copper, aluminum and steel. The maintenance of wind turbines is rather simple, and uses mostly oil for the gearboxes.

As reported in here it takes about 60 acres of land to build enough turbines to produce 1 MW of electricity.