Under a power-purchase agreement, a supplier bears the cost and risks associated with installing the wind equipment in return for guaranteed purchase of power during a specified period. The wind farm may meet a Federal agency's power needs in the vicinity, or the power can be sold to someone else. Also, wind turbines operate in harmony with other land uses such as farming and ranching. A hybrid system using photovoltaics and wind turbines may meet overall power needs better than either system could alone. A power converter transforms the variable frequency to constant frequency compatible with the utility grid.
Power increases proportionally with the cube of wind speed.
An environmental impact statement is required for any construction or refurbishment involving power generation systems. Wind-energy costs have improved dramatically during the past decade. Costs for all applications are continuing to decline as technology advances.