The ability or capacity to do work
While energy surrounds us in all aspects of life, the ability to
harness it and use it for constructive ends as economically as
possible is the challenge before mankind
Refers to energy sources which are not based on burning of
fossil fuels or the splitting of atoms.
The renewed interest in this field of study comes from the
undesirable effects of pollution both from burning fossil fuels
and from nuclear waste byproducts.
There are many reasons why the world is looking
toward alternative energy sources in an effort to
reduce pollutants and greenhouse gases.
Alternative, or renewable energy sources show
significant promise in helping to reduce the
amount of toxins that are byproducts of energy use
and help preserve many of the natural resources
that we currently use as sources of energy.
Solar energy is used commonly for heating,
cooking, the production of electricity, and
even in the desalination of seawater.
Solar power works by trapping the sun’s rays
into solar cells where this sunlight is then
converted into electricity.
Additionally, solar power uses sunlight that
hits solar thermal panels to convert sunlight
to heat water or air.
Other methods include using sunlight that
hits parabolic mirrors to heat water or simply
opening a room blinds or window shades to
allow entering sunlight to passively heat a
Solar power is a renewable resource. As long
as the sun exists, its energy will reach Earth.
Solar power generation releases no water or
air pollution, because there is no chemical
reaction from the combustion of fuels.
Solar energy can be used very efficiently for
practical uses such as heating and lighting.
The benefits of solar power are
seen frequently to heat pools,
spas, and water tanks all over.
Solar power does not produce energy if the
sun is not shining. Nighttime and cloudy days
seriously limit the amount of energy
Solar power stations can be very expensive
Wind energy harnesses the power of the wind
to propel the blades of wind turbines.
The rotation of turbine blades is converted
into electrical current by means of an
In the older wind mills, wind energy was used to
turn mechanical machinery to do physical work,
like crushing grain or pumping water.
Wind towers are usually built together on wind
Now, electrical currents are harnessed by
large scale wind farms that are used by
national electrical grids as well as small
individual turbines used for providing
electricity to isolated locations or individual
Wind power produces no pollution that can
contaminate the environment since no
chemical processes take place, as in the
burning of fossil fuels. There are no harmful
byproducts left over.
Since wind generation is a renewable source
of energy, we will never run out of it.
Wind power is intermittent. Consistent wind
is needed for continuous power generation.
If wind speed decreases, the turbine lingers
as less electricity is generated.
Large wind farms can have a negative effect
on the scenery.
Literally means “earth heat”
It harnesses the heat energy present
underneath the earth.
Hot rocks under the ground heat water to
produce steam. When holes are drilled in the
region, the steam that shoots up is purified
and is used to drive turbines, which power
If done correctly, geothermal energy
produces no harmful byproducts.
Once a geothermal plant is built, it is
generally self-sufficient energy.
Geothermal power plants are usually small
and have little effect on the natural
If done incorrectly, geothermal energy can
Improper drilling into the earth can release
hazardous minerals and gases.
Geothermal sites are prone to running out of
Comes from the potential energy of dammed water
driving a water turbine or generator.
Another variation is to make use of water’s
kinetic energy or undammed sources such as
Hydropower works by harnessing the
gravitational descent of a river that is
compressed from a long run to a single
location with a dam or a flume.
This creates a location where concentrated
pressure and flow of water can be used to
turn turbines or water wheels to drive an
Electric generators powered by hydro power
can be run backwards as a motor to pump
water back up for later use.
Water can be accumulated above the dam
and released to coincide with peaks in
demand. So, unlike other types of power
stations, hydroelectric power stations can
promptly increase to full capacity.
Electricity can be generated constantly,
because there are no outside forces, unlike
other forms of alternative energy, which
affect the availability of water.
Hydroelectric power produces no
pollution or waste since there is no
chemical reaction to produce power.
Water used for hydro power can be
Dams can be very expensive to build.
There needs to be a sufficient and
powerful enough supply of water in the
area to produce energy.
Produced through the use of tidal energy generators
Produced by the surge of ocean waters during the rise
and fall of tides
Converts the energy of tides into useful forms of
power mainly electricity.
These large underwater turbines are placed
in areas with high tidal movements, and are
designed to capture the kinetic motion of the
ebbing and surging of ocean tides in order to
Tidal power has great potential for future
power and electricity generation because of
the massive size of the oceans. However, the
amount of water produced so far has been
There are currently two commercial-sized
tidal power plats operating in the world. One
is located in La Rance, France; the other is in
Annapolis Royal, Nova Scotia, Canada. There
is a third experimental plant operating in
Kislaya Giba, Russia.
Tidal Energy generators
There are currently three different
ways to get tidal energy: tidal
streams, barrages and tidal lagoons.
For most tidal energy generators,
turbines are placed in tidal streams.
A tidal stream is a fast-flowing
body of water created by tides. A
turbine is a machine that takes
energy from a flow of fluid. That
fluid can be air (wind or
Because water is much more dense
than air, tidal energy is more
powerful than wind energy.
Unlike win, tides are predictable
and stable. Where tidal generators
are used, they produce a steady,
reliable stream of electricity.
Placing turbines in tidal streams is
complex because the machines are
large and disrupt the tide they are
trying to harness.
A low dam
Can be constructed across tidal rivers,
bays, and estuaries.
With a barrage, water can spill over
the top or through turbines in the
dam because the dam is low.
Turbines inside the barrage harness the
power of tides the same way a river
dam harnesses the power of a river.
The barrage gates are open as the tide
rises. At high tide, the barrage gates
close, creating a pool, or tide lagoon.
The water is then released through the
barrage’s turbines, creating energy at
a rate that can be controlled by
A body of ocean water that is partly
enclosed by a natural or manmade barrier
Might also be estuaries and have
freshwater emptying into them.
A tidal energy generator using tidal
lagoons would function much like a
barrage. However, these can be
constructed along the natural
A tidal lagoon power plant could also
generate continuous power. The
turbines work as the lagoon is filling
Energy output from generators using
tidal lagoons is likely to be low.
There are no functioning examples