Transcript Document

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.
• A nonrenewable resource is not replaced as
it16.2
is used.
Electricity from fossil fuels
• 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!
http://www.window.state.tx.us/specialrpt/e
nergy/renewable/hydro.php
Buford Dam at Lake Lanier
Sir Adam Beck Hydroelectric
plant, Niagara Falls
Tom Miller
Dam in Austin,
Texas in 1940
And today
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 downstream
can be affected, which can have an
impact on plant life.
Heat from the center of the
Earth
The earth has lots of heat inside!
Sometimes it is very close to the surface.
Heat from the Earth’s Center
• Earth's core maintains temperatures in excess of 5000°C
– Heat comes from gradual radioactive decay of elements
• Heat energy continuously flows from hot core
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Conductive heat flow
Convective flows of molten mantle beneath the crust.
Dissipates to the atmosphere and space.
Tends to be strongest along tectonic plate boundaries
• Volcanic activity transports hot material to near the surface
– Only a small fraction of molten rock actually reaches surface.
– Most is left at depths of 5-20 km beneath the surface,
http://www.worldbank.org/html/fpd/energy/geothermal/technology.htm
Geothermal Site Schematic
Boyle, Renewable Energy, 2nd edition, 2004
Steam Power Plants
• Steam extracted from natural reservoir, used to
drive a turbo-generator, and condensed and
pumped back into the ground
• Hot Springs: hot water only
• Geysers: hot water and steam
• Fumarole: steam only
Boyle, Renewable Energy, 2nd edition, 2004
Dry Steam Schematic
Boyle, Renewable Energy, 2nd edition, 2004
Hot Springs
Hot Springs in Steamboat Springs area.
http://www.eia.doe.gov/cneaf/solar.renewables/page/geothermal/geothermal.html
Geysers
Clepsydra Geyser in Yellowstone
http://en.wikipedia.org/wiki/Geyser
Fumaroles
Clay Diablo Fumarole (CA)
http://lvo.wr.usgs.gov/cdf_main.htm
White Island Fumarole
New Zealand
http://volcano.und.edu/vwdocs/volc_images/img_white_island_fumerole.html
Global Geothermal Sites
http://www.deutsches-museum.de/ausstell/dauer/umwelt/img/geothe.jpg
Geothermal Prospects
• Environmentally very attractive
• Attractive energy source in right locations
• Likely to remain an adjunct to other larger
energy sources
– Part of a portfolio of energy technologies
• Exploration risks and up-front capital costs
remain a barrier
Windmills are built
together in a “wind farm.”
http://video.pbs.org/vid
eo/2289327437/
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.
Solar power plants that can produce
large amounts of electricity instead of for
one house.
Info on picture
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.
La Racine France
Turbines are
placed
underwater like
with a dam.
Tidal turbines
have to spin 180
degrees because
the tide switches
directions 4
times a day!
Video clip on tidal power
•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.
Biomass is the second most common form of
renewable energy.
NONRENEWABLE
RESOURCES
A nonrenewable resource is a natural resource that
cannot be re-made or re-grown at the same rate that
it is consumed or used.
(Can no be replaced during your lifetime)
NUCLEAR ENERGY
Nuclear fission uses
uranium to create
energy.
Nuclear energy is a
nonrenewable
resource because once
the uranium is used, it
is gone!
This is steam, not polluted air!
Control room in nuclear
power plant
•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.
COAL, PETROLEUM, AND Natural GAS
Coal, petroleum, and
natural gas are
considered
nonrenewable because
they can not be
replenished in a short
period of time. These
are called fossil fuels.
HOW IS COAL MADE ???
HOW ARE OIL AND GAS MADE
???
WHAT WAS THE DIFFERENCE BETWEEN COAL
AND OIL/GAS?
How are
coal and
oil/gas
similar?
Review
If nonrenewable
resources are resources
that cannot be re-made
at the same rate at
which it is consumed,
what are renewable
resources?
RENEWABLE RESOURCES
Renewable resources are
natural resources that can be
replenished in a short period
of time. (within your life
time)
● Solar ● Geothermal
● Wind ● Biomass
● Water