Renewable Energy: Wind
The Science — Why Does the Wind Blow?
Wind is actually a form of solar energy. The sun radiates both heat and light energy, some of which makes its way to the surface of the Earth. The ground and other surfaces absorb the solar energy and heat the surrounding air, causing differences in temperature and pressure in different places and at different times.
As the air is warmed, it rises and cooler air descends to fill the void. These differences in temperature and the resulting rise and fall of air result in what is known as local winds. Prevailing winds are caused by the rotation of the Earth and temperature differences between the polar caps and the equator.
For other good explanations of how wind works, see the British Wind Energy Association website or the Canadian Wind Energy Association website.
The Technology — How Do Wind Turbines Work?
The wind itself carries kinetic energy (energy of motion). The challenge is how to translate that energy into more useful mechanical or electrical energy.
The blades on a wind turbine use lift the same way airplanes do. The wind passes over the blades and the lift created causes them to move. The moving blades turn a shaft, which in turn rotates a series of large electromagnets called the “rotor” inside a tightly wound copper wire coil called the “stator” within the generator.
The moving magnetic field between the coil and the magnets creates an electric current, which is drawn off and transmitted as electricity. Turbines come in a variety of sizes and capacities from 300 W ‘mini’ turbines that homeowners can install themselves, to utility-scale turbines in the 3 to 5 megawatt (MW) range that can be over 120 metres tall.
For more information on wind turbine technology and specifications, see the CanWEA Fact Sheets web page.
The Application — What Can Wind Power Do?
Did You Know?
Since the 1990s, wind power growth has exploded globally. According to the Global Wind Energy Council, at the end of 2006 there was 74,223 MW of installed wind power capacity worldwide. Although Canada is not yet one of the top 10 wind energy producers, we ranked seventh for new installed capacity, nearly doubling our wind capacity in 2006. According to CanWEA, as of July 2007, the total installed capacity of wind farms in Canada was 1,588 MW, or enough to power 480,000 homes. Ontario’s capacity is just over 415 MW, which in Canada, is second only to Alberta.
Wind has been used for thousands of years. One of the earliest known and most important uses was for sailing. Even the ancient Egyptians used the wind to sail the Nile River.
Windmills have also been used, as their name would suggest, to grind (mill) grains, pump water, and most recently, to generate electricity.
We have been using the wind to generate electricity for longer that most people likely expect. From the 1800s to the 1930s, much of rural North America was powered by wind. It wasn’t until after rural communities began to be connected to the main electricity grid that the demand for wind power declined.
There are two basic applications for modern turbines: small-scale personal use and large-scale generation. Small-scale turbines provide power generally for personal or home use, and are situated where the power will be used.
In Ontario, most small-scale wind turbine owners are likely to use most of the energy generated themselves, with maybe only a little left over to sell back to the electricity grid under the province’s net metering program. Larger-scale wind turbines, however, provide more power than can be used by a single home or group of homes. Instead, large-scale (also known as utility scale) turbines sell their electricity to the Ontario power grid, similar to other traditional generators.
For more information on wind power in Canada, wind technology, or statistics on wind power capacity in Canada, see CanWEA's website.
Other good resources on wind power include the American Wind Energy Association, the Canadian Renewable Energy Network, the European Wind Energy Association, especially their publication "Wind Energy: The Facts", the Global Wind Energy Council and the World Wind Energy Association.
Benefits of Wind Power
Wind power is the fastest growing generation technology in the world, and there is a huge potential for wind development in Canada.
Many of the windiest areas on the planet are along shorelines and in prairie regions.
There are many economic, environmental and social benefits associated with wind power. The wind industry is experiencing high levels of growth globally including in Canada. In Ontario, wind capacity grew from a mere 15 MW in 2003 to over 415 MW as of July 2007.
According to the Global Wind Energy Council, wind power has become an economic power, employing more than 120,000 people world-wide, with an annual turnover of more than US $14 billion, and an annual growth rate of more than 28% over the last 10 years. Enough power is being produced by wind to power more than 25 million households.
Did You Know?
In conventional energy systems, like that of Ontario, at least 75 cents of each energy dollar leaves the local economy. One American study found that locally owned wind generation creates about 10 times more economic activity in the local community than large developments owned by companies from outside of the community and state.
Wind power displaces traditional, polluting energy sources such as coal and gas and nuclear power, thereby helping to reduce greenhouse gas and other emissions that contribute to pollution and climate change.
Furthermore, community ownership of wind power can have a significant impact on local society and economies. Community renewable energy projects can generate local jobs, favourable investment opportunities, benefits for local businesses, opportunities for education and greater capacity at the community level to bring about change. One study in the United States showed that locally owned generation can produce from 25 to 150 more jobs and between $700,000 to $4.3 million more in total value added than centralized, large-scale developments.
Click here for more information on wind projects underway by OSEA members.
