While a relatively benign technology, wind energy is not free of environmental impacts. Wind turbines are audible to those nearby, and wind turbines in California's Altamont Pass and in southern Spain have killed some birds. Fortunately, wind energy's impact on birds is site specific. Noise can be reduced by the greater use of sound insolation and isolation within the nacelle, and the use of new quieter airfoils. Careful siting can reduce impacts on both people and birds.
Wind turbines are also visible for great distances on certain landscapes.
Though the turbines may be visible, they are not necessarily intrusive, and careful consideration of a wind turbine's or a wind power plant's appearance can ameliorate aesthetic concerns. Thus, it is no longer a question of whether or not wind energy will be used, but where, and at what rate its role will grow. There are ample wind resources on most continents to make a sizable contribution toward a sustainable energy supply. There are even greater wind resources in Canada. But price and public policy will determine the rate at which these resources are developed.