Improved turbine designs and plant utilization have contributed to a decline in large-scale wind energy generation costs from 35 cents per kWh in 1980 to less than 5 cents per kWh in 1997 in favorable locations . At this price, wind energy has become one of the least-cost power sources. Major factors that have accelerated the wind-power technology development are as follows:

1. high-strength fiber composites for constructing large low-cost blades.
2. falling prices of the power electronics.
3. variable-speed operation of electrical generators to capture maxi mum energy.
4. improved plant operation, pushing the availability up to 95 percent.
5. economy of scale, as the turbines and plants are getting larger in size.
6. accumulated field experience (the learning curve effect) improvingthe capacity factor.

picture below show the construction of Modern wind turbine for utility scale power generation