2. •Hydroelectricity is a form of hydropower.
•It is form of renewable energy.
•It produces no waste and carbon dioxide
(CO2), which contributes to greenhouse gases.
•Hydroelectricity now supplies about 715,000
MW or 19% of world electricity, accounting for
over 63% of the total electricity from renewable
in 2005.

3. Hows ?
 Water in a high reservoir has potential energy.
 The water is allowed to fall under gravity.
 The water gains kinetic energy.
 The kinetic energy drives the turbines.
 The turbines drives the generators.
 The kinetic energy of the shafts of the
generators is converted into electrical energy.

4. Gravitational Mechanical Electrical

6.  The two basic types of hydroelectric systems
are those based on falling water and natural
river current.
 First system , water accumulates in reservoirs
created by the use of dams.
 Second system, called a run-of-the-river system
 Another kind of hydroelectric power generation is
the pumped storage hydroelectric system.

7. This system, called a run-of-the-river system.
The force of the river current (rather than falling water)
applies pressure to the turbine blades to produce electricity.
Since run-of-the-river systems do not usually have reservoirs
and cannot store substantial quantities of water.
 Power production from this type of system depends on
segeonal changes and stream flow.
 These conventional hydroelectric generating units range in
size from less than 1 megawatt to 700 megawatts. Because
of their ability to start quickly and make rapid changes in
power output.

8. Another kind is pumped storage
hydroelectric system.
Pumped storage hydroelectric plants
use the same principle for generation
of power as the conventional.
Hydroelectric operations based on
falling water and river current.
However, in a pumped storage
operation, low-cost off-peak energy is
used to pump water to an upper
reservoir.
Where it is stored as potential energy.
The water is then released to flow
back down through the turbine
generator to produce electricity .

9.  The La Grande Complex in Quebec, Canada, is the
world's largest hydroelectric generating system.
 The eight generating stations of the complex have a
total generating capacity of 16,021 MW.
 The Robert Bourassa station alone has a capacity of
5,616 MW.
 A ninth station (Eastmain-1) is currently under
construction and will add 480 MW to the total.
 Construction on an additional project on the Rupert
River was started on January 11, 2007. It will add
two stations with a combined capacity of 888 MW.

11. 1. Cragside, Rothbury, England completed 1870.
2. Appleton, Wisconsin, USA completed 1882, A waterwheel
on the Fox river supplied the first commercial
hydroelectric power for lighting to two paper mills and a
house, two years after Thomas Edison demonstrated
incandescent lighting to the public.
3. Duck Reach, Launceston, Tasmania. Completed 1895. The
first publicly owned hydro-electric plant in the Southern
Hemisphere. Supplied power to the city of Launceston for
street lighting.

13.  Can convert as much as
90% of the available
energy into electricity.
 Best fossil fuel plant is
only about 50% efficient.
 The use of hydropower
prevents the burning of
22 billion gallons of oil or
120 million tons of coal
each year.
 The carbon emissions
avoided is equivalent to
67 million cars on the
road.

14. 1) They use up valuable and
limited natural
resources.
2) They can produce a lot of
pollution.
3) Companies have to dig
up the earth or drill
wells to get coal, oil, or
gas.
4) For nuclear power plants,
there are waste disposal
problems.

15.  No pollution and no consumption of resources. Hydrogen is
produced from water and oxidized back into water. There are no
byproducts, toxic or otherwise, produced by the process.
 Safety. Hydrogen systems have an enviable safety record; in
many cases, hydrogen is safer than the fossil fuel it replaces. In
addition to dissipating quickly into the upper atmosphere if it
leaks, hydrogen is completely non-toxic, unlike fossil fuels.
 High Efficiency. Fuel cells convert chemical energy directly into
electricity with greater efficiency than any other current power
system.
 Long life and minimal maintenance. Though fuel cells have not
been in use long enough to give a definite lifespan, fuel cells may
have significantly longer lifetimes than the machines they replace.

16.  You have to flood a
valley to build a big
dam
 there is a big impact
on the environment
 possible loss of
habitat for some
species
 initial costs are high