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!

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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 –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,

Geothermal Site Schematic Boyle, Renewable Energy, 2 nd 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, 2 nd edition, 2004

Dry Steam Schematic Boyle, Renewable Energy, 2 nd edition, 2004

A geyser is a type of hot spring that erupts periodically, ejecting a column of hot water and steam into the air. The name geyser comes from Geysir, the Icelandic verb gjósa, "to gush".hot springwatersteamGeysir Icelandic The formation of geysers requires a favorable hydrogeology which exists in only a few places on Earth, about 1000 exist worldwide, with about half of these in Yellowstone National Park, USA (Glennon, J.A. 2005). Geyser eruptive activity may change or cease due to ongoing mineral deposition within the geyser plumbing, exchange of functions with nearby hot springs, earthquake influences, and human intervention (Bryan, T.S. 1995). hydrogeologyYellowstone National ParkUSAGlennon, J.A.

Hot Springs Hot Springs in Steamboat Springs area.

Geysers Clepsydra Geyser in Yellowstone

Fumaroles Clay Diablo Fumarole (CA) White Island Fumarole New Zealand

Global Geothermal Sites

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.”

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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 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

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.

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?

If nonrenewable resources are resources that cannot be re-made at the same rate at which it is consumed, what are renewable resources? Review

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