Wind energy has been used for centuries, for grinding grain, pumping water and
generating electricity. Small wind turbines were an important source of
electricity for rural families in North America in the 1920's and 1930's. Wind
energy faded into the background with the rural electrification efforts of the
1940's and the development of reliable small engine generators.
Modern small wind turbines are technically advanced and reliable; incorporating
permanent magnet alternators, sophisticated electronics, and innovative blade
Wind and Solar
In many Canadian locations a wind turbine is an excellent supplement to a solar
electric system. Small wind systems are often combined with photovoltaics
because seasonal variations in wind and solar resources are complementary. Most
places in Canada do not have adequate wind to use as a primary power source.
Locations such as the prairies that have constant prevailing winds are most
suited to wind power. Contrary to popular beliefs, coastal areas are not always
the best sources of power as the winds are not constant and predictable such as
Wind is a variable resource. The winds may be calm for a week or more, but when
it does become windy it often blows very hard - most notably in the winter. For
this reason wind energy systems usually require a larger battery to take
advantage of the energy when it is available and store it for extended calm
periods. In wind only systems the battery storage should be designed for 10
days of autonomy or more.
Wind flowing over the surface of the earth is slowed by the friction of the
ground. Objects such as trees and houses create turbulence. This reduces the
energy a turbine can extract from the wind and stresses on the turbine
components. The higher a turbine is placed the more power is generated. A wind
turbine should be at least 33 feet (10 meters) above any object within a 330
foot (100 meter) radius. Local geography also needs to be considered.
The power of the wind is easy to feel and the sight of a wind turbine rotating
in the wind provokes a lot of interest. Proper location is critical to the
success of a wind turbine installation. The determining factor of a good
location is the amount of wind that is available. If there is an average wind
speed of 8 mph (13 km/h) or higher, wind power may be a viable source of
electricity. The power available in the wind increases with the cube of the
wind speed if the wind speed doubles the power available increases by eight!
Unlike photovoltaic modules, wind turbines have moving parts. Periodic
maintenance of bearings, brushes and shafts is required. It is important when
installing a wind generator to consider how easy it will be to access the
generator and remove it.
Towers are a critical component of wind power systems. Proper location and
height of tower are necessary to get maximum energy from a wind turbine.
Improper tower design or installation may result in personal injury, property
damage or a damaged generator and will very likely result in less than
satisfactory performance from your wind turbine.