Electricity generation with no direct greenhouse gas emissions
For centuries, people have been harnessing the power of the wind to work for them. Now the wind can be used to generate electricity cleanly, reliably and economically.
Electricity is created by converting one form of energy, such as motion, heat or pressure, into another. Most commercially produced electricity is generated when a turbine captures that energy and converts it into a spinning motion which drives the generator. A generator is basically a large magnet (a dynamo) which spins near a wire. Every time the magnet spins past the wire, it causes a pulse of energy to flow along the wire — electricity.
The energy that turns the turbine can be many different things, but the most common sources are water, steam (generated by burning of fossil fuels such as coal, oil and natural gas or by nuclear energy), combustion exhaust or wind.
Wind turbines have large blades that rotate as the air flows past them. This rotation drives the generator, which produces electricity. It works just like the toy wind mill that you blow on to make it spin. The illustration on the left shows the parts of a wind turbine.
It takes an average wind of 20 km/h to run a wind turbine and it needs to be as continuous as possible to be efficient. There are many places in Canada where that is not a problem. According to the Canadian Wind Energy Association, Northern Quebec (Nunavik) alone has enough wind resource to produce 40% of Canada’s electricity needs. However, it is not feasible to have wind energy produce more than about 20% of our electricity.
Wind power installations can be as simple as one small turbine to supply electricity to a single home or farm, or as large as several thousand turbines, supplying energy to a small city. A group of wind turbines in one power generation development is often referred to as a wind farm.
A 1 MW (megawatt) turbine operating in an area with an “average” wind resource produces about 2,600 MWh (megawatt hours) per year — that is enough to supply power to about 320 homes. A turbine has an average life expectancy of 20-25 years. As with any machinery, some parts may wear out and need replacement during that time, but a modern wind turbine is 98% reliable.
There will always be times when there is no wind or not enough to run a wind turbine. That means that wind power cannot be the only source of electricity generation. However, combining the power output from wind farms in different places and from different sources of renewable energy can help even out the variations. Wind and hydro are especially complimentary, since the seasonal variation of wind energy is highest through the winter, when hydro tends to be low due to decreased water levels in reservoirs and rivers.