In the past several years renewable sources of energy have won the support of governments in several countries, which has taken the form of various legal frameworks with stable and lasting premiums. Wind energy, together with hydroelectricity, solar energy and biomass, is one of the most promising renewable energy sources. During operation, wind power plants are friendly to surrounding environments, releasing no direct emissions, harmful pollutants or CO2. Newer technologies have made the utilitization of wind energy much more efficient and cost-effective. Wind is arguably the most convenient method to generate electricity in remote locations. Wind turbines use less space than an average coal-fired power station. With these advantages, wind power is playing an increasingly important role in the global electricity market. In 2009, global cumulative installed capacity reached 158,505 MW (MW 1⁄4 106 W), eleven times of that in 1996. Recent developments in wind energy have been particularly rapid with the annual growth rate of global installations reaching 29% and 32% in 2008 and 2009 respectively.