Environmental Engineering Reference
In-Depth Information
First, most conventional power plants operate at the same capacity around the clock (this
is especially true of nuclear power), even though demand for electricity varies greatly
between day and night. Pumped storage therefore provides a way to take advantage of
the surplus power produced at night. This energy can then be released and sold at a
higher price during the day. Second, pumped storage works well alongside other renewable
technologies. Wind and solar power are, by their nature, highly intermittent; solar power
only works during the day, while wind is quite unpredictable. By combining wind and solar
plants with pumped water storage, it is possible to ensure a steady flow of electricity into
the grid.
Benefits and Costs of Hydropower
Hydropower is a predictable energy source that serves the two extremes of the power
market: large-scale production to meet peak demand and small-scale production to serve
isolated communities. At the crossroads of two major issues for sustainable development
- energy and water - hydroelectric reservoirs often provide other services in addition to
electricity supply, such as a secure water supply for drinking, irrigation and flood control.
Hydropower is also technically mature, and it has one of the best conversion efficiencies
(about 90 per cent) of all energy sources. While they require high initial investment,
hydroelectric plants have a long life span with relatively low operation and maintenance
costs.
Many parameters, including the high costs of structures such as dams and canals, affect
the cost of hydropower. However, the market price of electrical power is not the sole
determinant of the economic value of hydropower projects. Hydropower plants designed
to meet peak electricity demands may have relatively high costs, but the cost per unit of
power during periods of peak demand is also higher. Moreover, hydropower projects may
provide multiple services in addition to the supply of electric power.
The cost per kilowatt-hour of hydroelectricity is 5-40 U.S. cents for off-grid micro
applications (< 1 megawatt), 5-12 U.S. cents from small hydro (< 10 megawatts), and 3-5
U.S. cents (2005) per kilowatt-hour for large hydro (> 10 megawatts). In the case of large
projects, the technology is therefore already competitive with fossil fuels (Kumar et al.
The Potential of Hydropower
While large-scale hydropower was pioneered in Europe and North America, with
groundbreaking projects such as the Hoover Dam in Nevada, the current emphasis in these
