Hydroelectric generation is the predominant form
of electric generation in Canada (nearly two-thirds of power generated
each year uses this process). A major part of the economic history
of Canada throughout the 20th century consisted of the development
of sites with large hydroelectric potential. This sequence started
with sites found close to population (such as Niagara and Shawinigan)
around the year 1900, and largely ended with the development of
huge sites in the northern parts of several provinces in the 1960s
and 1970s. There have been relatively few large hydro sites developed
since that time as the environmental and human effects to be avoided
or mitigated in such large projects make them increasingly difficult
and costly to plan and build.
Figure 1 gives details about the nature and process of hydroelectric
power generation. Hydroelectric energy is produced by the force
of falling water. The capacity to produce this energy is dependent
on both the available flow and the height from which it falls. Building
up behind a high dam, water accumulates potential energy. This is
transformed into mechanical energy when the water rushes down the
sluice and strikes the blades of turbines. The turbine's rotation
spins electromagnets which generate current in stationary coils
of wire. Finally, the current is put through a transformer where
the voltage is increased for long distance transmission over power
lines.
[D] Click for larger version, 68 KB Figure 1. Process of Hydroelectric Power Generation
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