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A nonrenewable resource is not replaced as it is used.
Because it takes so long for these resources to form, someday we will not have enough fossil fuels to produce the electricity we need.
The three major fossil fuels are coal, oil, and natural gas.
Video clip on fossil fuels
Electricity from renewable resources (often called alternative energy sources)
A renewable resource can be replaced naturally in a relatively short period of time.
The Sun and wind are renewable resources that can be used as energy sources.
Electricity from renewable resources
It is also possible to use:
moving water (hydroelectric)
hot spots near Earth’s surface (geothermal)
tides to produce electricity.
Let’s look at some of these!
Hydroelectric - Using water to make power.
Buford Dam at Lake Lanier
Buford Dam at Lake Lanier
Video clip on Hydroelectric power
Once the dam is built, the energy is
virtually free. No waste or pollution produced. Much more reliable than wind, solar or
wave power. Water can be stored above the dam ready
to cope with peaks in demand. Hydro-electric power stations can increase
to full power very quickly, unlike other
Electricity can be generated constantly.
The dams are very expensive to build. However, many dams are also used for flood control
or irrigation, so building costs can be shared. Building a large dam will flood
a very large area upstream, causing problems
for animals that used to live there. Finding a suitable site can be difficult –
the impact on residents and the
environment may be unacceptable. Water quality and quantity downstream
can be affected, which can have an
impact on plant life.
Wind power Windmills are built together in a “wind farm.”
Video clip about Wind power
Wind is free, wind farms need no fuel. Produces no waste or greenhouse gases.
The land beneath can usually still be used for farming.
Wind farms can be tourist attractions. A good method of supplying energy to remote areas.
The wind is not always predictable –
some days have no wind.
Suitable areas for wind farms are often near
the coast, where land is expensive.
*Some people feel that covering the landscape
with these towers is unsightly.
Can kill birds - migrating flocks tend to
like strong winds. Splat!
Can affect television reception if you live nearby. Noisy. A wind generator makes a constant,
low, "swooshing" noise day and night,
which can drive you nuts. An entire wind farm makes quite a racket!
Solar power Several ways to use the sun for power!
Solar cells to make electricity like your solar calculator does.
Info on picture Solar power plants that can produce large amounts of electricity instead of for one house.
Places where solar power plants would work!
We even use solar power in orbit! Why would that be a good way to power satellites? Video clip on solar power
Solar energy is free - it needs no
fuel and produces
no waste or pollution.
In sunny countries, solar power
can be used
where there is no easy way to get
electricity to a remote place.
*Doesn't work at night. * Very expensive to build solar power stations. Solar cells cost a great deal compared to the amount of electricity they'll produce in their lifetime. *Can be unreliable unless you're in a very sunny climate. Disadvantages
Video clip on tidal power Turbines are placed underwater like with a dam. Tidal turbines have to spin 180 degrees because the tide switches directions 4 times a day!
Once you've built the dam, tidal power is free.
It produces no greenhouse gases or other waste.
It needs no fuel.
It produces electricity reliably.
Not expensive to maintain.
Tides are totally predictable.
Very expensive to build.
Affects a very wide area - the environment is changed for many miles upstream and downstream. *Many birds rely on the tide uncovering the mud flats so that they can feed. * Only provides power for around 10 hours each day, when the tide is actually moving in or out. *There are very few suitable sites for tidal power stations.
This is steam, not polluted air!
Video clip on nuclear power
Nuclear power costs about the same as coal,
so it's not expensive to make.
Does not produce smoke or carbon dioxide,
so it does not contribute to the greenhouse effect.
Produces huge amounts of energy from
small amounts of fuel. Produces small amounts of waste. Nuclear power is reliable.
Although not much waste is produced,
it is very, very dangerous. It must be sealed up and buried for many
years to allow the radioactivity to die away. Nuclear power is reliable, but a lot of money
has to be spent on safety –
if it does go wrong, a nuclear accident
can be a major disaster.
Geothermal energy The earth has lots of heat inside!
Sometimes it is very close to the surface.
Video clip on geothermal energy
What do you think would be the advantages and disadvantages of geothermal energy?