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2. Hydroelectricity is the term referring to electricity generated
by hydropower; the production of electrical power through
the use of the gravitational force of falling or flowing water. It
is the most widely used form of renewable energy,
accounting for 16 percent of global electricity consumption,
and 3,427 terawatt-hours of electricity production in 2010,
which continues the rapid rate of increase experienced
between 2003 and 2009.[1]

3. Hydropower is produced in 150
countries, with the Asia-Pacific
region generating 32 percent of
global hydropower in 2010. China
is the largest hydroelectricity
producer, with 721 terawatt-hours
of production in 2010,
representing around 17 percent of
domestic electricity use. There are
now three hydroelectricity plants
larger than 10 GW: the Three
Gorges Dam in China, Itaipu
Dam in Brazil, and Guri Dam in
Venezuela

5. The cost of hydroelectricity is relatively low, making it a
competitive source of renewable electricity. The average
cost of electricity from a hydro plant larger than 10
megawatts is 3 to 5 U.S. cents per kilowatt-
hour.[1] Hydro is also a flexible source of electricity since
plants can be ramped up and down very quickly to
adapt to changing energy demands. However, damming
interrupts the flow of rivers and can harm local
ecosystems, and building large dams and reservoirs
often involves displacing people and wildlife.[1] Once a
hydroelectric complex is constructed, the project
produces no direct waste, and has a considerably lower
output level of the greenhouse gas carbon
dioxide (CO2) than fossil fuel powered energy plants.[2]

7. Hydropower has been used since ancient times to grind
flour and perform other tasks. In the mid-1770s, French
engineer Bernard Forest de
Bélidor published Architecture Hydraulique which
described vertical- and horizontal-axis hydraulic
machines. By the late 19th century, the electrical
generator was developed and could now be coupled with
hydraulics.[3] The growing demand for the Industrial
Revolution would drive development as well.[4] In 1878 the
world's first hydroelectric power scheme was developed
at Cragside in Northumberland, England by William
George Armstrong. It was used to power a single arc
lamp in his art gallery.[5] The old Schoelkopf Power
Station No. 1 near Niagara Falls in the U.S. side began to
produce electricity in 1881. The first Edison hydroelectric
power plant, the Vulcan Street Plant, began operating
September 30, 1882, in Appleton, Wisconsin, with an
output of about 12.5 kilowatts.[6] By 1886 there were 45
hydroelectric power plants in the U.S. and Canada. By
1889 there were 200 in the U.S. alone.[3]

8. Hydropower or water power is power derived from the energy of falling water,
which may be harnessed for useful purposes. Since ancient times, hydropower has
been used for irrigation and the operation of various mechanical devices, such
as watermills, sawmills, textile mills, dock cranes, and domestic lifts.
Since the early 20th century, the term is used almost exclusively in conjunction with
the modern development of hydro-electric power, which allowed use of distant
energy sources. Another method used to transmit energy used a trompe, which
produces compressed air from falling water. Compressed air could then be piped to
power other machinery at a distance from the waterfall.
Water's power is manifested in hydrology, by the forces of water on the riverbed and
banks of a river. When a river is in flood, it is at its most powerful, and moves the
greatest amount of sediment. This higher force results in the removal of sediment
and other material from the riverbed and banks of the river, locally causing erosion,
transport and, with lower flow, sedimentation downstream.

10. Generating methods
Conventional (dams)
Most hydroelectric power comes from the potential energy of dammed water driving
a water turbine and generator. The power extracted from the water depends on the
volume and on the difference in height between the source and the water's outflow. This
height difference is called the head. The amount of potential energy in water is
proportional to the head. A large pipe (the "penstock") delivers water to the turbine.
Pumped-storage
Main article: Pumped-storage hydroelectricity
This method produces electricity to supply high peak demands by moving water
between reservoirs at different elevations. At times of low electrical demand, excess
generation capacity is used to pump water into the higher reservoir. When there is higher
demand, water is released back into the lower reservoir through a turbine. Pumped-storage
schemes currently provide the most commercially important means of large-scale grid
energy storage and improve the daily capacity factor of the generation system

12. .
Run-of-the-river
Run-of-the-river hydroelectric stations are those with small or no reservoir capacity, so that
the water coming from upstream must be used for generation at that moment, or must be
allowed to bypass the dam.
Tide
A tidal power plant makes use of the daily rise and fall of ocean water due to tides; such
sources are highly predictable, and if conditions permit construction of reservoirs, can also
be dispatchable to generate power during high demand periods. Less common types of
hydro schemes use water's kinetic energy or undammed sources such as
undershotwaterwheels.
Underground
An underground power station makes use of a large natural height difference between two
waterways, such as a waterfall or mountain lake. An underground tunnel is constructed to
take water from the high reservoir to the generating hall built in an underground cavern
near the lowest point of the water tunnel and a horizontal tailrace taking water away to the

14. Hydropower types
Hydropower is used primarily to generate electricity. Broad categories include:
A conventional dammed-hydro facility (hydroelectric dam) is the most common type of
hydroelectric power generation.
•Conventional hydroelectric, referring to hydroelectric dams.
•Run-of-the-river hydroelectricity, which captures the kinetic energy in rivers or
streams, without the use of dams.
•Small hydro projects are 10 megawatts or less and often have no artificial
reservoirs.
•Micro hydro projects provide a few kilowatts to a few hundred kilowatts to isolated
homes, villages, or small industries.
•Pumped-storage hydroelectricity stores water pumped during periods of low
demand to be released for generation when demand is high.

15. Used as a source of generating power for
hundreds of years, Hydropower is the
harnessing of the force of moving water and
producing energy to be used in multiple
applications.
Dating back to ancient times, hydropower
was used for the operation of various
machines, such as watermills, sawmills, dock
cranes and also for irrigation purposes. Back
in Roman times, water was the source of
energy that powered mills to extract flour
from grains and to cut timber and stone in
the construction of the city and its
dwellings.
Along with the impact on ecosystems, a
lesser-known result from the construction of
hydroelectric plants is the dispersing of the
local population. It is not often thought
about, but it has been estimated that
between 40 and 80 million people
worldwide have been relocated due to the
construction of dams and other hydropower
plants.

17. The first known hydropower plant built in
the U.S. occurred in 1880, in Grand Rapids,
Michigan. The so-called “boom” in larger
scale plants did not take place until the 1930s
and into the 1940s as part of President
Roosevelt's "New Deal" program.
In the modern world, the use of hydropower
is the catalyst in producing hydroelectricity.
In its practice, hydroelectricity allows an end
user the use of the energy produced by the
water source in a lower, more cost effective
manner.
Hydroelectricity is produced from
hydropower, which is the generation of
energy through the use of gravitational forces
from flowing or falling water, usually from
dams or rivers. Throughout the world,
hydroelectric power supplies nearly 19% of
electricity, or 715,000 MWe (megawatt
electrical). It also represents more than 63%
of the electricity used from renewable
sources

18. .
The greatest benefit from the use of hydropower is that it produces no carbon dioxide
emissions or other harmful discharges, such as sulfur dioxide, carbon monoxide, and
nitric acid, unlike the use of fossil fuels. Hydropower also generates no waste by-
products and has no affect on today’s growing concerns with global warming.
One of the most widely used devises for the production of hydropower is the dam.
Currently there are more than 75,000 dams in the U.S. blocking more than 600,000
miles of our nation’s rivers, or 17% of the free flowing water.

19. With the use of dammed water, the
potential energy source is used to drive
water turbines and generators. The key
element to the production of hydropower is
dependent on the volume of the water, and
the height difference between the original
source of the water, the dammed water, and
the position of the outflow. This difference
in the height is paramount to produce the
optimal amount of energy from the flowing
water.
Within the United States, the Grand Coulee Dam, on the Columbia River in
Washington State, currently holds the title as the country’s largest electric power
producing facility, and is the fifth largest producer in the world. The dam also holds
the distinction of being the largest concrete structure in North America as well,
surpassing the Hoover Dam when constructed in 1942.
Rounding out the top five dams in the world, the Grand Coulee is surpassed by only the
Three Gorges Dam in China, the Guri Dam in Venezuela, the Itaipu Dam on the border
of Paraguay and Brazil, and the Sayano-Shushenskaya Dam in Russia.
In addition to the more common practices of waterpower, several other forms are in use
or in developmental stages as well. Included are damless hydropower, which harnesses
the kinetic energy of rivers, streams and oceans, and wave power, which captures the
energy produced by waves.

20. One of the up-and-coming developments is from the use of tidal stream power. Still in its
infancy, this technology draws energy from the currents of high volume river and streams.
Requiring much more research, early models have shown some promise.
Despite the numerous advantages that hydropower possesses, there certainly are concerns
that are raised by the construction and usage of hydroelectric plants. The most common,
negative perception of these plants is the affects surrounding environmental damage,
namely the disruption of the local ecosystems.

21. Hydropower's effect on the environment
Hydropower is a clean source of energy. There are no problems with air pollution, chemical
runoff, toxic waste or the like.
Hydropower plants also create recreation areas and animal habitat. Because of the change in
water location, wide areas after the dam become great for water edge species of
animals. And the large reservoir is good for many types of large fish. Boating areas are
created in the reservoir too, as well as bird watching sites downstream of the dam.
Some problems may still occur though., but through careful planning these can be
eliminated almost completely.
Temporary disruption in the ecology to build the dam, but afterwards this cleared land
can be used to make animal habitat.
downstream of the dam, water flow may be significantly reduced, but careful
monitoring of the land downstream of the dam can give operators enough information
to allow more water to pass through the dam.
Catadramous fish (fish that live in salt water and spawn in fresh water) migration may
be interupted- but fish ladders and fish elevators may be installed to eliminate this
problem. Anadromous (fish that live in fresh water and spawn in salt water) fish do not
have this problem, because they can go right through the turbines which only spin at
81.8 rpms.
Flooding of land upstream of the dam can be a problem, but careful monitoring of the
land upstream of the dam can give operators enough information to allow more water
to run through the dam to compensate for this problem.

23. Advantages of hydropower
It is a clean and safe source of energy
They are self sustaining
They create habitat for more types of
fish
They can act as a flood controller
They are the most efficient energy
source running from 90-95% efficiency
Other forms of Hydropower
Tidal power: electricity generated by
turbines moved by the tides. This is still in
experimental stages.
Ocean thermal power: power generated by
the thermal expansion of the ocean. This can
only be used in a location like the Gulf
stream.
Geothermal power: natural steam is used
underground to turn turbines. This is
limited to location which have these
phenomenon.