To solve this problem, there are constant speed turbines as well as variable-speed turbines. Variable-speed turbines have power controls in the generator to avoid overloads or other issues.
Some smaller wind turbines can be used for providing power off the grid. 250-watt turbines can be used for charging batteries on a sailboat, and even smaller 50-kilowatt turbines can power grain and dairy farms, as well as small, remote villages.
The largest wind turbines are used by utility companies to provide electricity to a power grid. These turbines range from 250 kilowatts all the way up to 3.5 to 5 MW machines used offshore. In 2009, the average land-based wind turbine could create 1.75 MW. Utility-scale turbines are placed in groups or rows called wind farms. These farms often consist of hundreds of turbines, creating electricity to power thousands of homes.
Wind Farms
The largest wind turbines generate enough electricity to supply 600 US homes with electricity for a year. Wind farms with hundreds of these turbines can power thousands of homes. Smaller, single turbines placed in a backyard can create enough power for a single home.
But, they must first catch the wind to create power.
Foto: © PNE AG
So for wind turbines, placement is everything. To build an efficient wind farm, utility companies need to know how much wind passes through an area, how fast or slow the winds are, and how long those speeds last.
Kinetic energy in wind rises exponentially in proportion to its speed, meaning a small bump up in wind speed creates a large increase in power potential. Scientists have determined that a doubling of wind speed creates an eight-fold increase in power potential.
Wind farms are the most cost-efficient use of wind-energy. Most utility-scale wind turbines have power volumes between 700 KW and 1.8 MW, and they’re placed for maximum capture of available wind resources. The turbines are spaced far apart in rural areas with high wind speeds; agriculture development around wind farms remains largely unaffected due to the small footprint of the turbine towers.
Now that we know wind is a viable solution, we must figure out how much it will help us.