Intro to Wind Power
Wind turbines produce electricity by harnessing the kinetic energy in wind. When wind blows, it flows over the turbine blades creating a lift effect that makes the blades to turn. A gearbox connects the shaft from the blades (rotor) to a generator, which converts the captured kinetic energy into electrical energy. There are economic and environmental advantages of using wind as the main “fuel” to produce electricity. Wind is a free and renewable resource as opposed to other fossil fuel sources used for electricity production (e.g., coal, natural gas). In addition, wind-based electricity can significantly reduce greenhouse gas (GHG) emissions if it replaces fossil-based electricity. While electricity produced from wind is growing it still makes up less than 10% of the mix with about 75% of electricity generated in the upper Midwest coming from coal and natural gas. There are challenges related to integrating wind energy into the grid. As wind does not blow all the time, it is generally not used to cover baseload electricity demand. Farmers play an important role in the development of wind power, installing small-scale wind turbines for their own consumption and/or leasing land for larger wind turbines on ‘wind farms’ that are connected to the national electric transmission system (the grid).
Farm Scale Wind Power
Farm-scale and utility-scale turbines have similar technical aspects with some differences. Agriculture farm scale wind turbines have less capacity (maximum power output) than large commercial wind turbines ranging from 0.3 – 100 kW of capacity. Generally, these smaller turbines are installed for on-site electricity consumption with the aid of an inverter that converts direct current (DC) to alternating current (AC) that can power electric devices and is compatible with the grid. As a result, it is common to see a single small-scale wind turbine on a farm as opposed to commercial wind farms which may have an array of 10 to more than 100 turbines. Placement is important for smaller turbines as they are generally supported by shorter towers than large turbines. As a result, it is important that small turbines are placed away from trees or other objects that could block the wind flow. Renewable electricity generated on-site reduces the farm’s reliance on fossil-based grid electricity and at the same time reduces the demand on the distribution and transmission systems when the wind is blowing. The farm is responsible for investment, operation and maintenance costs and typically still needs a connection to the grid when wind power is not sufficient to meet the needs of the farm.
Utility Scale Wind Power
Utility-scale wind turbines are larger than farm owned turbines and are installed in large multi-turbine groups (wind farms) that are connected to the transmission grid. Wind provides nearly 8% of the nation’s electricity supply and new installations are growing steadily second only to natural gas. Utility-scale wind turbines are mostly land-based and continue to grow in size to maximize economies of scale with an average rated capacity of 2.5 MW in 2019. Off-shore wind projects have been gaining increased attention as wind blows more consistently offshore with a potential of reaching 2,000 GW of installed capacity in coastal areas of the U.S. Off-shore wind turbines are more expensive to build and to maintain than land-based turbines and have other challenges related to grid connection and potential environmental impacts as they interact with both aquatic and avian species.
Visit our Energy Generation page to know more about MREC related wind projects and resources to other great informational pages.
Resources on Wind Energy
- Wind – International Energy Agency (IEA)
- Wind Explained – U.S. Energy Information Administration (EIA)
- Small wind turbine research – National Renewable Energy Laboratory (NREL)
- Distributed wind research – National Renewable Energy Laboratory (NREL)
- Wind – Environmental and Energy Study Institute (EESI)
- Wind Research and Development – Office of Energy Efficiency and Renewable Energy
- Wind turbines and farm stray voltage – Midwest Rural Energy Council