Cost
Wind energy itself is effectively free, but the cost to manufacture and install wind farms isn't cheap and the upfront costs can be prohibitive. Once a wind farm is developed, most modern turbines are estimated to have a 20-year lifespan without much maintenance required. Once the farms are developed, electricity from this source can be a very economical alternative to traditional power generators.
Comparison with Other Power Sources
The amount of electricity a modern wind turbine produces is dependent on wind speed. According to the American Wind Energy Association (AWEA), "A wind turbine at a typical location in the Midwestern United States should run about 65 percent to 90 percent of the time". During this time, a turbine will not be operating at full capacity all the time and will generate about 30 percent of the theoretical maximum output. This is known as the load factor. The load factor of conventional power stations is on average 50 percent, although according to AWEA, it can vary between 40 percent and 80 percent, depending on fuel type and other factors.