Chapter 4. Resources and Energy

Transcription

1 Chapter 4 Resources and Energy

2 I. Resources are classified into two main types. A. Non renewable resources 1. Resources that have a limited supply. 2. They cannot be replaced in a human lifetime. 3. Are composed primarily of minerals 4. Many are metals such as: Gold (Au) or Silver (Ag).

3 Mineral Use of an Average U.S. Citizen in a Lifetime

4 B. Renewable resources 1. Resources that can be replaced as they are consumed, or within a human lifetime. 2. Examples include: Trees, water, livestock, air.

5 II. Fossil fuels A. Fuels with an organic origin such as coal, petroleum, and natural gas are called fossil fuels. B. Because they are composed primarily of hydrogen and carbon, they are called hydrocarbons C. The three most common fossil fuels are coal, petroleum, and

6 Fossil Fuel Deposits in the U.S.

7 C. natural gas. D. Coal comes in four different grades or types. 1. Peat The youngest coal a. Brownish-black in color b. Formed from partial decomposition of plant remains 2. Lignite coal a. Brown in color b. Formed from peat that

8 b. Has been subjected to pressure of overlying sediments longer than peat squeezing out more fluids and gases. 3. Bituminous coal (soft coal) a. The most abundant type of coal. b. Made from the further compression of lignite coal c. Second hardest coal.

9 4. Anthracite coal a. Hardest of all forms of coal b. Formed from bituminous coal that has been subjected to extreme temperature and pressure due to the folding of the earth s crust. c. 80% to 90% Carbon

10 Harvesting Peat In Scottish Lowlands

11 How a Coal Fired Power Plant Works

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13 E. Petroleum and natural gas 1. Formed largely from micro-organisms that lived in oceans or large lakes millions of years ago. a. Petroleum: hydrocarbon in liquid form. b. Natural gas: hydrocarbon in gaseous form.

14 2. as microorganisms died and settled on the ocean floor, they built up and compacted, creating heat and pressure. This caused chemical changes to take place which formed petroleum and natural gas.

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18 F. Tar Sands 1. Mixtures of clay, sand, water and black bitumen tar. 2. Produces heavy, low grade crude oil that is difficult and costly to recover. 3. Waste byproducts from refining present environmental problems. G. Oil Shale

19 1. Shale (rock) that contains kerogin (oil). 2. It is mined and heated to separate (vaporize) the kerogen. 3. Kerogen is refined into usable crude oil.

20 F. Incidental fossil fuel facts 1. Crude oil is unrefined petroleum 2. Petrochemicals are chemicals derived from crude oil 3. Worldwide, our coal reserves will last about another 200 years at current usage level. 4. Burning of high sulfur coal is the main cause of acid rain.

21 5. Burning of gasoline in automobiles and the use of natural gas damage the environment by releasing pollutants and CO 2 gas which causes the green house effect (global warming) 6. Deep trenches left from coal strip mines destroys watersheds.

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23 G. Ores can be defined as metals or non metals that can be mined profitably from the Earth 1. Some ores can be removed as uncombined metals or non metals. 2. Most ores are chemically combined and the usable elements or compounds must be separated by refining.

24 H. Ores can be formed in several different ways 1. Contact metamorphism occurs when hot magma comes in contact with existing rock. a. Heat and chemical fluids from the magma change the rock around it. b. The amount of contact

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26 b. metamorphism depends on the magma temperature, pressure, composition and permeability of the existing rock. 2. Veins are formed when hot mineral solutions move through many small cracks in a large mass of rock. These hydrothermal

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28 solutions form veins in the cracks of the rocks. 3. Ores are also deposited by moving water. a. Fragments of dense native metals like gold are carried along in streams until they reach calm water, then they settle out. These are called Placer Deposits

29 b. Placer deposits are usually: (1). Heavy/dense (2). Durable (3). Chemically nonreactive c. Following placers upstream may lead to the original source d. Water carries dissolved

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32 E. Mineral resources can be divided into two categories: metals and non metals. 1. Metallic minerals are: a. usually malleable, b. good conductors of electricity c. good heat conductors d. many have shiny luster

33 2. Metals can be used for: a. aircraft parts, b. electrical parts c. jewelry, dental appliances many other uses. 3. Non Metallic minerals are a. poor electrical conduct b. brittle, c. high melting points. d. usually dull in luster

34 4. Some common non metallic minerals and their uses are: a. Gemstones jewelry b. Gypsum building mat. c. Sulfur gunpowder and medicine d. Halite (salt) - food preparation e. Quartz (sand)- glass

35 F. Mineral conservation 1. With growing population, minerals are being depleted at a rapid rate. 2. We can save natural minerals by: a. Using alternatives like plastics. b. Recycling c. Cutback on use of non renewable minerals

36 III.Nuclear energy A. Nuclear fission is the reaction which allows us to produce electricity with nuclear fuel. 1. In fission reactions, a neutron is fired like a bullet into a nucleus of uranium-235 (U- 235). 2. The nucleus breaks apart, releasing energy, forming 2

37 2. atoms (or elements) and sending out more neutrons to collide with other nuclei, causing even more energy to be released. 3. The two new nuclei formed in the collision are Barium - 141(Ba-141) and Krypton- 92(Kr-92) 4. Check out diagram on next slide.

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39 Nuclear Fission Reaction

40 Nuclear Reactors in the United States

41 5. Electricity is generated by a giant steam driven turbine. 6. The energy released in the fission reaction is used to heat water and turn it into steam. 7. The steam rises, creating pressure that turns the turbine which generates the electricity. 8. Next, the steam condenses

42 8. back into water and is used to make steam over and over again. 9. To keep the reaction from going out of control, control rods are inserted between the fuel rods to absorb excess neutrons, keeping the energy release at the desired level.

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44 How a Nuclear Power Plant Works

45 B. Nuclear fusion is a nuclear reaction in which two small nuclei are fused together to make a larger one. 1. Nuclear fusion releases much more energy than fission. 2. Fusion reactors aren t practical. They need temperatures of over 15 million o C to work.

46 IV. Alternative energy sources will be the way of the future as our fossil fuels become depleted. A. Energy can be retrieved from sunlight using solar collectors B. Geothermal energy can be recovered from water that is flowing near hot magma and being converted into steam. C. Hydroelectric power, in which moving water is used to turn

47 C. turbines that generate electricity. This can be done with lakes, rivers, or tides. D. Windmills can harness energy from the wind to turn turbines to generate electricity.

48 IV. Alternative Energy Sources will be the way of the future as fossil fuels become depleted. A. Solar Energy 1. Uses radiation from the Sun to supply heat and energy. 2. Advantages of solar energy: a. It is free. b. It doesn t pollute.

49 c. It is versatile 3. Disadvantages of solar energy are: a. Equipment and installation are expensive. b. Extreme upper latitudes receive much less sunlight. c. The technology is very new.

50 Actual Solar Energy Plant

51 Solar Energy Plant Components

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53 B. Wind Energy 1. Wind turbines that are turned by large windmills can supply a large part of our electrical needs. 2. Advantages of wind energy: a. Wind is free. b. It can supply power to remote isolated areas. c. It doesn t pollute.

54 3. Disadvantages of wind energy are: a. It requires large tracts of expensive land. b. There are problems with noise.

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58 C. Hydroelectric Power 1. Involves using moving water to produce electricity. 2. Reservoirs of water are held behind dams allowing water to be released and channeled to turn large turbines that produce electricity.

59 Hydroelectric Power

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63 3. Advantages of hydroelectric power: a. It is a renewable resource. b. Reservoirs can also be used as a source of drinking water and recreation. c. It is a relatively pollution free source of energy.

64 4. Disadvantages of hydroelectric power: a. They consume large tracts of land. b. The life of a dam is finite (50 to 300 years). c. It only works in specific geographic areas.

65 D. Geothermal Energy 1. Uses natural underground sources of heat (steam and hot water) to turn water into steam that can turn electricity producing turbines. 2. Over 80% of the homes in Iceland are heated with geothermal energy.

66 Geothermal Energy Plant in New Zealand

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68 Geothermal Energy Plant

69 3. Geothermal energy is harvested in several different ways. a. From geyser fields such as The Geysers, near San Francisco, Ca. b. From rifts like the one in Iceland. c. Wells drilled in volcanically active areas.

70 4. Advantages of geothermal energy. a. It is a clean source of energy. b. Once located, the energy is relatively constant and easy to harness. 5. Disadvantages of geothermal energy. a. It isn t inexhaustable

71 Geothermal Heat Pumps

72 b. It can only be harvested in certain areas. E. Tidal power involves harnessing energy from the ocean s constantly changing tides.

73 Producing Electricity Using Tidal Changes

74 Tidal Dam on Rance River in France

75 Heat Exchange Electrical Generator

76 Hydrogen Fueled Auto Engine

77 Gas/Electric Hybrid Car