Natural Resources

• A natural resource is a feature of Earth that benefits people.

• Earth’s natural material resources are things like air, fresh water, and soil.

16.2 Electricity from fossil fuels• 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!

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 power stations.

•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 downstreamcan be affected, which can have an impact on plant life.

Windmills are built together in a “wind farm.”

Video clip about Wind power

                                                                     

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!

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 producesno waste or pollution.

•In sunny countries, solar power can be used where there is no easy way to getelectricity 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.

La Racine France

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!

Advantages

•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 fromsmall 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.

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?

Biomass is the second most common form of renewable energy.