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The Greening of IT
260 How Companies Can Make a Difference for the Environment

Comparison with Other Methods of Power Generation

Hydroelectricity eliminates the flue gas emissions from fossil fuel
combustion, including pollutants such as sulfur dioxide, nitric oxide,
carbon monoxide, dust, and mercury in the coal. Hydroelectricity also
avoids the hazards of coal mining and the indirect health effects of coal
emissions. Compared to nuclear power, hydroelectricity generates no
nuclear waste and has none of the dangers associated with uranium min-
ing, or nuclear leaks. Unlike uranium, hydroelectricity is also a renew-
able energy source.
Compared to wind farms, hydroelectricity power plants have a more
predictable load factor. If the project has a storage reservoir, it can be
dispatched to generate power when needed. Hydroelectric plants can be
easily regulated to follow variations in power demand.
Unlike fossil-fueled combustion turbines, construction of a hydro-
electric plant requires a long lead-time for site studies, hydrological
studies, and environmental impact assessment. Hydrological data up to
50 years or more is usually required to determine the best sites and oper-
ating regimes for a large hydroelectric plant. Unlike plants operated by ptg
fuel, such as fossil or nuclear energy, the number of sites that can be eco-
nomically developed for hydroelectric production is limited; in many
areas, the most cost-effective sites have already been exploited. New
hydro sites tend to be far from population centers and require extensive
transmission lines. Hydroelectric generation depends on rainfall in the
watershed and might be significantly reduced in years of low rainfall or
snowmelt. Long-term energy yield might be affected by climate change.
Utilities that primarily use hydroelectric power might spend additional
capital to build extra capacity to ensure sufficient power is available in
low water years.
In parts of Canada (the provinces of British Columbia, Manitoba,
Ontario, Quebec, Newfoundland, and Labrador), hydroelectricity is used
so extensively that the word hydro is often used to refer to any electric-
ity delivered by a power utility. The government-run power utilities in
these provinces are BC Hydro, Manitoba Hydro, Hydro One (formerly
“Ontario Hydro”), Hydro-Québec, and Newfoundland and Labrador
Hydro, respectively. Hydro-Québec is the world’s largest hydro-
electric-generating company, with a total installed capacity (2005) of
31,512 MW.