But newer wind turbines are far more productive than earlier models. Meanwhile, installed costs have fallen as dramatically as productivity has risen. At good sites, wind turbines pay for the energy in their materials within the first three to four months. Even at poor sites, energy payback occurs in less than one year. The Achilles' heel of renewables, especially wind energy, has always been the charge that they are too land-intensive, even for such land rich continents as North America.
Wind turbines do occupy more land than other energy technologies.
As a rule, open arrays like those in northern Europe, where wind turbines are spaced 5 rotor diameters apart across the wind and 8 diameters apart downwind, occupy 50 square meters of land for every square meter swept by the wind turbine's rotor. Fortunately, modern wind plants use no more land than that consumed in the fuel cycle of coal. In some European wind plants, farmers till the soil to the base of the towers. At others sheep graze the entire site, including the service roads. And wind turbines generate this electricity without the emissions associated with fossil fuels.