What Is Wind Power?
This aerial view of a wind turbine plant shows how a group of wind turbines can make electricity for the utility grid. The electricity is sent through transmission and distribution lines to homes, businesses, schools, and so on. View the wind turbine animation to see how a wind turbine works or take a look inside.
Wind power or wind energy describes the process by which the wind is used to generate mechanical power or electricity. Wind turbines convert the kinetic energy in the wind into mechanical power. This mechanical power can be used for specific tasks (such as grinding grain or pumping water), or can be converted into electricity by a generator.
You can learn how wind turbines make electricity and see an illustration of the components inside a wind turbine, or view a wind power animation that shows how moving air rotates a wind turbine's blades and how the internal components work to produce electricity.
Wind Turbine Sizes and Applications
Wind turbines can provide energy for onsite use as well as for export for sale. The energy needs will determine the size of the turbine.
Wind turbine economics are maximized when the project size is designed to match the energy needs of the load while also monetizing economies of scale and equipment track record. Residential onsite energy use requires a small turbine (typically less than 10 kilowatts (kW)) that can generate the amount of power that the home requires for daily operation. Midsize machines can produce enough energy to match larger commercial onsite loads. Utility-scale machines that maximize generation for the site infrastructure footprint and cost are best suited for utility-scale projects.
Regardless of project size, projects connected to the electrical grid will require utility approvals and may require grid impact studies before construction can begin.
Residential-Scale Onsite Energy Use (<10 kW)
Residential, small turbines produce about as much energy as a home requires. Because these turbines are generally installed on shorter towers, you need to get a site evaluation in order to determine where to site the project to ensure it will perform as designed. These wind turbines are purchased with cash, so while return on investment can be important to consider, it is not always the deciding factor of whether a project goes forward. Many states provide incentives for this class of machine. Residential-scale wind turbines typically do not warrant a detailed onsite resource assessment.
Small Commercial-Scale Onsite Energy Use (10-50 kW)
This class of wind turbine produces more power than the average house consumes but can be well suited for small businesses; farms; ranches; facilities such as schools, office buildings, or part of a campus; or a public load such as a hospital. This turbine class typically incorporates a higher level of machine sophistication, resulting in greater efficiency and power production but also requiring increased maintenance. These turbines, however, typically require less maintenance than larger machines. This class of machine can cost as much as a house and is the smallest project size that might be financed, which would require a lender review. Projects of this size may also trigger the need for onsite resource assessment, but often projects can move forward by using nearby measurements and experienced siting and project modeling.
Commercial Onsite Energy Use (50-250 kW)
This wind turbine class produces commercial quantities of power and can be well matched with campuses, larger facilities, communities, and larger municipal public loads. This wind turbine class shares many technical and operational attributes of utility-scale machines and is often installed on towers that require special permits and coordination with other regulatory organizations or agencies. These turbines often represent a substantial capital investment and thus require corporate or institutional approvals. It is not unusual for facility managers to partner with financial players while developing projects of this size. These projects require experienced and detailed project modeling using onsite or nearby wind resource data.
Large Commercial or Industrial Energy Use (500 kW-1.5 MW)
This wind turbine class is at the top end of the midsize machines and is well suited for communities and very large onsite industrial loads and can even form the basis of small wind farms in certain situations. This machine class is typically indistinguishable from utility-scale turbines on a technology basis. The towers often exceed 200 feet, which need to be fitted with obstruction lighting. Projects of this size warrant community involvement and endorsement or approval at all levels. This class, except in very unusual situations, is typically financed through commercial lenders with their own due-diligence requirements and therefore require feasibility studies and onsite resource assessment campaigns.
Utility-Scale Energy Use (1.5-7.5 MW)
This class of wind turbine, while also occasionally installed at the point of use, is generally installed in large groups producing energy for sale. These are highly efficient, state-of-the-art wind turbines that operate with exceptionally high availability rates and generate cost-competitive electricity at power plant scales. These large turbines have rotors measuring more than 250 feet in diameter and are installed on tall towers that require aviation obstruction notification and lighting. Because of their size and the scale of the installations, utility-scale wind turbines require environmental, utility, and public coordination at the highest levels. Utility-scale wind farms require exacting resource assessments, legal and financial due diligence, utility integration, and financing typical of very large capital investments installations, such as airports.