Wind Power Basics http://www.kidwind.org/lessons/BBwindpowerbasics.html

Wind Power Basics

Dutch Windmill
source: scruss.com

A wind turbine is the modern advancement of the windmill. Instead of using the wind to lift water or move heavy rocks to grind seeds wind is used to turn an electrical generator to make electricity. Sometimes, students mistake our model wind turbines for a fan. While a fan uses electricity to produce wind, a wind turbine uses the wind to produce electricity!



How Wind Turbines Work

To put it simply, the wind turns the blades, which spin a shaft, which connects to a generator to make electricity. The electricity is sent through transmission lines to a substation, then on to homes, business and schools.


Parts of a Wind Turbine
source: Vestas

Wind turbine blades spin because of lift, the same force that allows airplanes to fly. If the blades are all oriented in the same direction they will start to spin, just as the wind spins a pinwheel. The blades are attached to a hub, which spins as the blades turn. Most modern wind turbines have three blades. The blades and the hub together are called the rotor. As the rotor turns, it spins a drive shaft which is connected to a generator inside the housing at the top of the tower. This housing is called the nacelle. The spinning generator produces electricity. The generator inside of a wind turbine converts the mechanical energy of moving wind into electrical energy that we can use in our houses. Depending on the size of the wind turbine there may be a gearbox between the spinning rotor and the generator. This is to help the generator spin fast enough to make electricity for the grid. Generators on the large grid connected turbines spin at 1600 RPM. For more detailed information on wind turbine technology, click here.






Minnesota Wind Farm
source: NREL

The amount of electricity that a turbine is able to produce depends on the diameter of the rotor and the speed of the wind that propels the rotor. The wind turbines that are manufactured today range greatly in their output capacity from as little as 100 watts to as much as 5 Megawatts—enough to power a small town! Wind Turbines are often grouped together in wind farms to produce large amounts of electricity. Some wind farms have only a coupe turbines, but the largest wind farms are made up of hundreds and hundreds of wind turbines.





Wind Energy Growth

Wind energy is the fastest growing energy source in the world. In 2007, 19,696 MW of new wind energy capacity were installed, reaching a global installed capacity of 93,849 MW by the end of 2007. This represents a 26.6% growth rate in that year alone! Global installed capacity exceeded 100,000 MW in early 2008. In the United States, the installed capacity if wind energy grew by an incredible 45% in 2007 and another 50% in 2008. The United States installed 8,358 MW of new wind energy in 2008. Wind energy is growing at this rate because the cost of electricity produced by wind energy is competitive with electricity produced by natural gas, oil, coal, or nuclear power. Also, wind energy is a clean, renewable technology that does not contribute to global warming. This makes it a healthier, more sustainable choice than other forms of electricity generation.