See the links for technical details. Besides reliability problems, early models suffered becuase the electricity they produced was too expensive compared to other sources. This has changed as the turbines have grow larger, manufacturing costs have declined, and reliability has lead to lower maintenance costs. In places like Denmark and Germany, electricity from wind is competitive with most other sources, especially when environmental costs are added in. Advances in aerodynamics have improved blade designs, experience has improved brake and tower designs, and powerful electronic control systems have improved system management and reduced operations costs.
Wind turbines are now utility-grade power generation systems rather than experimental devices.
Worldwide production of electricity from wind is growing at big rates, up to 6,000 MW in 1996. Germany alone installed 450 MW last year. Wind power generation surpassed nuclear generation for new installations in 1995. Another technological factor to consider is the complimentary relationship between wind and hydro resources. Wind is typically at peak production in the winter when water levels are low, and vice versa.