Chapter 9

1. Chapter 9 Energy Sources

2. Energy Sources

3. Outline • Energy Sources • Resources and Reserves • Fossil-Fuel Formation • Issues Related to the Use of Fossil Fuels • Renewable Sources of Energy • Energy Conservation • Are Fuel Cells and a Hydrogen Economy in the Future?

4. Energy Sources • Nonrenewable energy sources are those whose resources are being used faster than can be replenished. • Coal, oil, and natural gas • Renewable energy sources replenish themselves or are continuously present as a feature of the environment. • Solar, geothermal, tidal, etc. • Some forms are referred to as perpetual energy.

5. Energy Sources All energy sources

6. Resources and Reserves • A resource is a naturally occurring substance of use to humans that can potentially be extracted using current technology. • A reserve is a known deposit that can be economically extracted using current technology, under certain economic conditions. • Reserves are smaller than resources. • Reserve levels change as technology advances, new discoveries are made, and economic conditions vary.

7. Resources and Reserves

8. Fossil Fuel Formation • Coal • 300 million years ago, plant material began collecting underwater, initiating decay, forming a spongy mass of organic material. • Due to geological changes, some of these deposits were covered by seas, and covered with sediment. • Pressure and heat over time transformed the organic matter into coal.

9. Fossil Fuel Formation Recoverable coal reserves of the world 2004

10. Fossil Fuel Formation • Oil and natural gas probably originated from microscopic marine organisms that accumulated on the ocean floor and were covered by sediments. • Muddy rock gradually formed shale containing dispersed oil. • Natural gas often forms on top of oil.

11. Fossil Fuel Formation Crude oil and natural gas pool

12. Issues Related to the Use of Fossil Fuels • Fossil fuels supply 80% of world’s commercial energy. • Oil 35% • Coal 24% • Natural Gas 21%

13. Issues Related to the Use of Fossil Fuels • Coal is most abundant fossil fuel. • Primarily used for generating electricity. • There are three categories of coal: • Lignite • Is least desirable because of its high moisture content. • Bituminous • Most widely used because it is most abundant and easiest to mine. • Anthracite • Has the highest energy content and is cleanest burning, but is hard to obtain.

14. Issues Related to the Use of Fossil Fuels • There are two extraction methods: • Surface mining (strip mining), which is the process of removing material on top of a vein, is efficient but destructive. • Underground mining minimizes surface disturbance, but is costly and dangerous. • Many miners suffer from black lung disease, a respiratory condition that results from the accumulation of fine coal-dust particles in the miners’ lungs.

15. Issues Related to the Use of Fossil Fuels • Coal is bulky and causes some transport problems. • Mining creates dust pollution. • Burning coal releases pollutants (carbon and sulfur). • Millions of tons of material are released into atmosphere annually. • Sulfur leads to acid mine drainage and acid deposition. • Increased amounts of atmospheric carbon dioxide are implicated in global warming.

16. Issues Related to the Use of Fossil Fuels Underground mining

17. Issues Related to the Use of Fossil Fuels Surface-mine reclamation

18. Issues Related to the Use of Fossil Fuels Acid mine drainage

19. Issues Related to the Use of Fossil Fuels • Oil is more concentrated than coal, burns cleaner, and is easily transported through pipelines. • These qualities make it ideal for automobile use. • It is difficult to find. • It causes less environmental damage than coal mining.

20. Issues Related to the Use of Fossil Fuels • Present technology only removes 1/3 of an oil deposit. • Secondary recovery methods are used to recover more oil, such as forcing water or gas into wells to drive the oil out. • As oil prices increase, more expensive and aggressive secondary recovery methods will need to be used.

21. Issues Related to the Use of Fossil Fuels Offshore drilling

22. Issues Related to the Use of Fossil Fuels • Processing • As it comes from the ground, oil is not in a form suitable for use, and must be refined. • Multiple products can be produced from a single barrel of crude oil. • Oil Spills • Accidental spills only account for about 1/3 of oil pollution resulting from shipping. • 60% comes from routine shipping operations.

23. Issues Related to the Use of Fossil Fuels Processing crude oil

24. Issues Related to the Use of Fossil Fuels • The drilling operations to obtain natural gas are similar to those used for oil. • It is hard to transport and in many places is burned off at oil fields, but new transportation methods are being developed. • Liquefaction at -126o F (1/600 volume of gas) • It is the least environmentally damaging fossil fuel. • It causes almost no air pollution.

25. Renewable Sources of Energy • Currently, alternative energy sources supply almost 13.5% of the world’s total energy. • Some studies suggest these sources could provide half of the world’s energy needs by 2050. • Renewable sources will become much more important as fossil fuel supplies become more expensive. • Hydroelectric power • Tidal power • Geothermal power • Wind power • Solar energy • Biomass conversion

26. Renewable Sources of Energy Renewable energy as a share of total energy consumption (world 2003)

27. Renewable Sources of Energy • Hydroelectric power is created when flowing water is captured and turned into electricity. • Damming a river and storing water in a reservoir is the most common method. • Pumped storage plants use two reservoirs separated by a significant elevation difference. • The potential for developing hydroelectric power is best in mountainous regions and large river valleys. • The World Energy Council estimates that it would be technically possible to triple the electricity produced by hydropower with current technology.

28. Renewable Sources of Energy • Hydroelectric power currently supplies 16% of world’s electricity. • In South and Central America, 65% of electricity used comes from hydroelectric power. • Norway gets 99% of its electricity and 60% of all its energy from hydroelectric power. • Construction of “minihydro” (less than 10 megawatts) and “microhydro” (less than 1 megawatt) plants is increasing; these plants can be built in remote places and supply electricity to small areas.

29. Renewable Sources of Energy • Reservoir construction causes significant environmental and social damage. • Loss of farmland or forest land due to flooding. • Community relocation. • Prevention of fish migrations. • Trapping of silt fills in reservoir and stops flow of nutrients downstream. • Mercury accumulation.

30. Renewable Sources of Energy Hydroelectric power plant.

31. Renewable Sources of Energy • Tidal Power • Tides, the daily rise and fall of ocean levels relative to coastlines, are a result of gravitational forces and the revolution of the earth. • As water flows from a higher level to a lower level, it can be used to spin an electricity-generating turbine. • Since tidal changes of roughly 16 feet are needed to produce practical amounts of power, suitable sites are limited. • Little is understood about how altering the tides can affect complex aquatic and shoreline ecosystems.

32. Renewable Sources of Energy • Geothermal Power • Geothermal energy is linked to geologically active areas where heat from the Earth can reach the surface through thinner crust. • Wells are drilled to obtain steam trapped underground, and the steam powers electrical generators. • The U.S. has about half of the world’s geothermal electrical generating capacity. California produces 40% of world’s geothermal electricity. • It can cause unpleasant odors and high mineral content leads to high maintenance (corroded pipes and equipment).

33. Renewable Sources of Energy Geothermal power plant

34. Renewable Sources of Energy • Wind Power • As warm air becomes less dense and rises, cooler, denser, air flows in to take its place. This flow of air is wind. • U.S. Department of Energy has stated the Great Plains could supply the 48 contiguous states with 75% of their electricity. • Wind power is considered competitive with new coal and natural gas plants and cheaper than nuclear plants.

35. Renewable Sources of Energy • The European Wind Energy Association recently increased its target from 40,000 to 60,000 megawatts by 2010. • A push for energy deregulation and concerns about smog, acid rain, and global warming are driving policy makers to require utilities to sell electricity from renewable sources. • Eight states (Texas, Wisconsin, Massachusetts, Connecticut, New Jersey, Minnesota, Nevada, and Pennsylvania) require utilities to provide some “green” electricity.

36. Renewable Sources of Energy • There are some negative effects from wind generators: • The moving blades produce noise and some consider the windmills visual pollution. • Moving blades are hazardous to birds, although newer windmills have slower-moving rotors that many birds find easier to avoid. • Vibrations from generators can cause structural damage.

37. Renewable Sources of Energy • Daily energy from the sun is 600 times greater than energy produced each day by all other energy sources combined. • The major problems with solar energy are its intermittent and diffuse nature. • Solar energy is utilized in three ways: • In passive heating, the sun’s energy is converted directly to heat and used at collection site. • In an active heating system, the sun’s energy is converted into heat, but transported elsewhere to be used. • Solar energy is also transformed into electrical energy.

38. Renewable Sources of Energy Passive solar heating

39. Renewable Sources of Energy Solar heating designs.

40. Renewable Sources of Energy • In a passive solar system, light energy is transformed to heat energy when it is absorbed by a surface. • Buildings designed for passive solar heating in the Northern Hemisphere usually have large, south-facing windows. • Floors and walls, made of materials that absorb and store the sun’s heat during the day, slowly release heat at night when it is needed most. This feature is called direct gain.

41. Renewable Sources of Energy • An active solar system requires a solar collector, a pump, and a system of pipes to transfer the heat from the site of production to the area to be heated. • Water heating for domestic use is generally the most economical application of active solar systems. • A major consideration in the use of an active solar system is the initial cost of installation.

42. Renewable Sources of Energy • A photovoltaic cell (PV) is a solid-state semiconductor that converts sunlight directly into electricity. • The amount of PV power installed worldwide has increased from 100 megawatts in 1992 to 1,200 megawatts in 2002. • Thin-film technology has made it possible to build solar cells into roof shingles and tiles, building facades, and the glazing for skylights and atria.

43. Renewable Sources of Energy • Improving solar cell efficiency while holding down the cost per cell is an important goal of the growing PV industry, and significant progress has been made in this area. • Photovoltaics are probably the most benign method of power generation known. • They are silent, produce no emissions, and use no fuel other than sunlight.

44. Renewable Sources of Energy • Many of the developing countries of the world will introduce electricity to villages through the use of photovoltaics rather than the use of generators that require fuel and distribution lines.

45. Renewable Sources of Energy Photovoltaic shingles

46. Renewable Sources of Energy Solar generation of electricity

47. Renewable Sources of Energy • Biomass Conversion • All biomass is produced by green plants that convert sunlight into plant material through photosynthesis. • Biomass is still the predominant form of energy used by people in less-developed countries. • It accounts for 14% of world energy use.

48. Renewable Sources of Energy • There are four distinct sources of biomass energy: • Fuelwood • Municipal and industrial wastes • Agricultural crop residues and animal wastes • Energy plantations

49. Renewable Sources of Energy • In less-developed countries, fuelwood has been a major energy source for centuries. • Fuelwood is the primary energy source for nearly half the world’s population. • Due to intense population growth, an estimated 1.3 billion people cannot get enough fuelwood, or are using it faster than rate of regeneration. • It is a source of air pollution and particulate matter.

50. Renewable Sources of Energy • Solid waste is a major source of biomass and other burnable materials produced by society. • The burning of solid waste only makes economic sense when the cost of waste disposal is taken into account. • Using municipal waste as a source of energy: • Reduces landfill volume. • Requires large volume and dependable supply, and must be sorted. • Produces air pollution, including pollutants not found in other forms of biomass.