1. USING RENEWABLE SOLAR ENERGY TO PROVIDE HEAT AND ELECTRICITY A variety of renewable-energy resources are available but their use has been hindered by a lack of government support compared to nonrenewable fossil fuels and nuclear power. A variety of renewable-energy resources are available but their use has been hindered by a lack of government support compared to nonrenewable fossil fuels and nuclear power. Energy forms directly or indirectly related to solar Energy forms directly or indirectly related to solar Solar Solar Moving water Moving water Wind Wind Geothermal Geothermal Biomass Biomass

2. USING RENEWABLE SOLAR ENERGY TO PROVIDE HEAT AND ELECTRICITY The European Union aims to get 30% of its electricity from renewable energy by 2015. The European Union aims to get 30% of its electricity from renewable energy by 2015. Costa Rica gets 92% of its energy from renewable resources. Costa Rica gets 92% of its energy from renewable resources. China aims to get 10% of its total energy from renewable resources by 2020. China aims to get 10% of its total energy from renewable resources by 2020. In 2004, California got about 12% of its electricity from wind and plans to increase this to 50% by 2030. In 2004, California got about 12% of its electricity from wind and plans to increase this to 50% by 2030.

3. USING RENEWABLE SOLAR ENERGY TO PROVIDE HEAT AND ELECTRICITY Denmark now gets 20% of its electricity from wind and plans to increase this to 50% by 2030. Denmark now gets 20% of its electricity from wind and plans to increase this to 50% by 2030. Brazil gets 20% of its gasoline from sugarcane residue as a biofuel. Brazil gets 20% of its gasoline from sugarcane residue as a biofuel. In 2004, the world’s renewable-energy industries provided 1.7 million jobs. In 2004, the world’s renewable-energy industries provided 1.7 million jobs.

4. Heating Buildings and Water with Solar Energy We can heat buildings by orienting them toward the sun or by pumping a liquid such as water through rooftop collectors. We can heat buildings by orienting them toward the sun or by pumping a liquid such as water through rooftop collectors. Figure 17-12

5. Solar Tubes and Heating

6. Passive Solar Heating Passive solar heating system absorbs and stores heat from the sun directly within a structure without the need for pumps to distribute the heat. Passive solar heating system absorbs and stores heat from the sun directly within a structure without the need for pumps to distribute the heat. Figure 17-13

7. Fig. 17-13, p. 396 Direct Gain Summer sun Hot air Warm air Super- insulated windows Winter sun Cool air Earth tubes Ceiling and north wall heavily insulated

8. Fig. 17-13, p. 396 Greenhouse, Sunspace, or Attached Solarium Summer cooling vent Warm air Insulated windows Cool air

9. Fig. 17-13, p. 396 Earth Sheltered Reinforced concrete, carefully waterproofed walls and roof Triple-paned or superwindows Earth Flagstone floor for heat storage

10. Core Case Study: The Coming Energy-Efficiency and Renewable- Energy Revolution - Earthships The heating bill for this energy-efficient passive solar radiation office in Colorado is $50 a year. The heating bill for this energy-efficient passive solar radiation office in Colorado is $50 a year. Figure 17-1

11. Fig. 17-14, p. 396 Trade-Offs Passive or Active Solar Heating AdvantagesDisadvantages Energy is freeNeed access to sun 60% of time Net energy is moderate (active) to high (passive) Sun blocked by other structures Need heat storage system Quick installation No CO 2 emissions Very low air and water pollution High cost (active) Very low land disturbance (built into roof or window) Active system needs maintenance and repair Moderate cost (passive) Active collectors unattractive

12. Cooling Houses Naturally We can cool houses by: We can cool houses by: Superinsulating them. Superinsulating them. Taking advantages of breezes. Taking advantages of breezes. Shading them. Shading them. Having light colored or green roofs. Having light colored or green roofs. Using geothermal cooling. Using geothermal cooling.

13. Using Solar Energy to Generate High-Temperature Heat and Electricity Large arrays of solar collectors in sunny deserts can produce high- temperature heat to spin turbines for electricity, but costs are high. Large arrays of solar collectors in sunny deserts can produce high- temperature heat to spin turbines for electricity, but costs are high. Figure 17-15

14. Producing Heat with Solar Concentrated rays on the focal point to increase energy. Concentrated rays on the focal point to increase energy. Easy and cost efficient Easy and cost efficient Solar ovens Solar ovens Figure 17-16

15. How does solar work?

16. Producing Electricity with Solar Cells – Photoelectric effect Photovoltaic (PV) cells can provide electricity for a house of building using solar-cell roof shingles. Photovoltaic (PV) cells can provide electricity for a house of building using solar-cell roof shingles. Figure 17-17

17. Producing Electricity with Solar Cells Solar cells can be used in rural villages with ample sunlight who are not connected to an electrical grid. Solar cells can be used in rural villages with ample sunlight who are not connected to an electrical grid. Figure 17-18

19. Fig. 17-19, p. 399 Trade-Offs Solar Cells AdvantagesDisadvantages Fairly high net energyNeed access to sun Work on cloudy days Low efficiency Quick installation Need electricity storage system or backup Easily expanded or moved No CO 2 emissions High land use (solar-cell power plants) could disrupt desert areas Low environmental impact Last 20–40 years Low land use (if on roof or built into walls or windows) High costs (but should be competitive in 5–15 years) Reduces dependence on fossil fuels DC current must be converted to AC

21. Wind Power The wind’s energy results from an uneven heating of the earth. Hot air rises and cool air falls (hot air is less dense so it rises). On a very large scale the movement of hot and cold air causes wind. These are called convection currents. Convection is the heating of fluids (gas or a liquid). The wind’s energy results from an uneven heating of the earth. Hot air rises and cool air falls (hot air is less dense so it rises). On a very large scale the movement of hot and cold air causes wind. These are called convection currents. Convection is the heating of fluids (gas or a liquid). It’s an idea that has been used for centuries to grind grain and pump water. It’s an idea that has been used for centuries to grind grain and pump water.

22. History!!! Wind power has been used for nearly 7,000 years (ship propelling, pumping irrigation water, grinding grain) Wind power has been used for nearly 7,000 years (ship propelling, pumping irrigation water, grinding grain) Denmark was first to use it to produce commercial electricity in 1890 Denmark was first to use it to produce commercial electricity in 1890

23. PRODUCING ELECTRICITY FROM WIND Wind power is the world’s most promising energy resource because it is abundant, inexhaustible, widely distributed, cheap, clean, and emits no greenhouse gases. Wind power is the world’s most promising energy resource because it is abundant, inexhaustible, widely distributed, cheap, clean, and emits no greenhouse gases. Much of the world’s potential for wind power remains untapped. Much of the world’s potential for wind power remains untapped. Capturing only 20% of the wind energy at the world’s best energy sites could meet all the world’s energy demands. Capturing only 20% of the wind energy at the world’s best energy sites could meet all the world’s energy demands.

24. What?! Wind power is the world’s most promising energy resource because it is abundant, inexhaustible, widely distributed, cheap, clean, and emits no greenhouse gases Wind power is the world’s most promising energy resource because it is abundant, inexhaustible, widely distributed, cheap, clean, and emits no greenhouse gases

25. Wind turbines!

26. Wind turbines Capturing only 20% of the wind energy at the world’s best energy sites could meet all the world’s energy demands. Capturing only 20% of the wind energy at the world’s best energy sites could meet all the world’s energy demands. Capture the indirect form of solar energy and convert it to solar energy Capture the indirect form of solar energy and convert it to solar energy Can be up to 30 stories tall! Can be up to 30 stories tall!

27. Wind-power is making a dramatic comeback! Wind-power is making a dramatic comeback! Turbines are used to capture wind’s energy as efficiently as possible Turbines are used to capture wind’s energy as efficiently as possible Wind-farms can be controlled by a single laptop computer Wind-farms can be controlled by a single laptop computer Wind energy is the cheapest and most non polluting way to produce electricity Wind energy is the cheapest and most non polluting way to produce electricity Generating costs are expected to reach $0.025 per kw/h in a few years! Generating costs are expected to reach $0.025 per kw/h in a few years!

28. Located at sea

29. Birds dying 

30. WIND FARM

33. PRODUCING ELECTRICITY FROM WIND Wind turbines can be used individually to produce electricity. They are also used interconnected in arrays on wind farms. Wind turbines can be used individually to produce electricity. They are also used interconnected in arrays on wind farms. Figure 17-21

36. PRODUCING ELECTRICITY FROM WIND The United States once led the wind power industry, but Europe now leads this rapidly growing business. The United States once led the wind power industry, but Europe now leads this rapidly growing business. The U.S. government lacked subsidies, tax breaks and other financial incentives. The U.S. government lacked subsidies, tax breaks and other financial incentives. European companies manufacture 80% of the wind turbines sold in the global market European companies manufacture 80% of the wind turbines sold in the global market The success has been aided by strong government subsidies. The success has been aided by strong government subsidies.

37. Advantages High net energy High net energy High efficiency High efficiency Moderate capital cost Moderate capital cost Low electricity cost Low electricity cost Very low environmental impact Very low environmental impact No CO 2 emissions No CO 2 emissions Quick construction Quick construction Easily expanded Easily expanded Can be located at sea Can be located at sea Land below turbines can be used to grow crops or graze livestock Land below turbines can be used to grow crops or graze livestock Disadvantages Wind turbines kill as many as 40,000 birds a year  Wind turbines kill as many as 40,000 birds a year  A lot of land use A lot of land use Visual pollution Visual pollution NIMBY – Not In My Backyard NIMBY – Not In My Backyard Steady winds needed Steady winds needed Backup systems needed when winds are low Backup systems needed when winds are low Noise when located near populated areas Noise when located near populated areas

38. Fig. 17-22, p. 403 Trade-Offs Wind Power AdvantagesDisadvantages Moderate to high net energySteady winds needed Backup systems needed when winds are low High efficiency Moderate capital cost Low electricity cost (and falling) High land use for wind farm Very low environmental impact No CO 2 emissions Visual pollution Quick construction Noise when located near populated areas Easily expanded Can be located at sea Land below turbines can be used to grow crops or graze livestock May interfere in flights of migratory birds and kill birds of prey

39. PRODUCING ELECTRICITY FROM THE WATER CYCLE Water flowing in rivers and streams can be trapped in reservoirs behind dams and released as needed to spin turbines and produce electricity. Water flowing in rivers and streams can be trapped in reservoirs behind dams and released as needed to spin turbines and produce electricity. There is little room for expansion in the U.S. – Dams and reservoirs have been created on 98% of suitable rivers. There is little room for expansion in the U.S. – Dams and reservoirs have been created on 98% of suitable rivers.

40. PRODUCING ELECTRICITY FROM THE WATER CYCLE Ocean tides and waves and temperature differences between surface and bottom waters in tropical waters are not expected to provide much of the world’s electrical needs. Ocean tides and waves and temperature differences between surface and bottom waters in tropical waters are not expected to provide much of the world’s electrical needs. Only two large tidal energy dams are currently operating: one in La Rance, France and Nova Scotia’s bay of Fundy where the tidal amplitude can be as high as 16 meters (63 feet). Only two large tidal energy dams are currently operating: one in La Rance, France and Nova Scotia’s bay of Fundy where the tidal amplitude can be as high as 16 meters (63 feet).

44. Fig. 17-20, p. 400 Trade-Offs Large-Scale Hydropower AdvantagesDisadvantages Moderate to high net energyHigh construction costs Large untapped potential High environmental impact from flooding land to form a reservoir High efficiency (80%) High CO 2 emissions from biomass decay in shallow tropical reservoirs Low-cost electricity Long life span No CO 2 emissions during operation in temperate areas Floods natural areas behind dam May provide flood control below dam Converts land habitat to lake habitat Danger of collapse Provides water for year-round irrigation of cropland Uproots people Decreases fish harvest below dam Reservoir is useful for fishing and recreation Decreases flow of natural fertilizer (silt) to land below dam

45. Hydroelectric Power Pros Pros Water is free Water is free Non-polluting Non-polluting Tourist attractions Tourist attractions Very efficient Very efficient Cons Cons Expensive to build Effects biodiversity due to changes in geography, water flow, and nutrient distribution Limited locations

46. PRODUCING ENERGY FROM BIOMASS Plant materials and animal wastes can be burned to provide heat or electricity or converted into gaseous or liquid biofuels. Plant materials and animal wastes can be burned to provide heat or electricity or converted into gaseous or liquid biofuels. Figure 17-23

47. PRODUCING ENERGY FROM BIOMASS The scarcity of fuelwood causes people to make fuel briquettes from cow dung in India. This deprives soil of plant nutrients. The scarcity of fuelwood causes people to make fuel briquettes from cow dung in India. This deprives soil of plant nutrients. Figure 17-24

48. Fig. 17-25, p. 405 Trade-Offs Solid Biomass AdvantagesDisadvantages Large potential supply in some areas Nonrenewable if harvested unsustainably Moderate costs Moderate to high environmental impact No net CO 2 increase if harvested and burned sustainably CO 2 emissions if harvested and burned unsustainably Low photosynthetic efficiency Plantation can be located on semiarid land not needed for crops Soil erosion, water pollution, and loss of wildlife habitat Plantation can help restore degraded lands Plantations could compete with cropland Often burned in inefficient and polluting open fires and stoves Can make use of agricultural, timber, and urban wastes

49. Converting Plants and Plant Wastes to Liquid Biofuels: An Overview Motor vehicles can run on ethanol, biodiesel, and methanol produced from plants and plant wastes. Motor vehicles can run on ethanol, biodiesel, and methanol produced from plants and plant wastes. The major advantages of biofuels are: The major advantages of biofuels are: Crops used for production can be grown almost anywhere. Crops used for production can be grown almost anywhere. There is no net increase in CO 2 emissions. There is no net increase in CO 2 emissions. Widely available and easy to store and transport. Widely available and easy to store and transport.

50. Case Study: Producing Ethanol Crops such as sugarcane, corn, and switchgrass and agricultural, forestry and municipal wastes can be converted to ethanol. Crops such as sugarcane, corn, and switchgrass and agricultural, forestry and municipal wastes can be converted to ethanol. Switchgrass can remove CO 2 from the troposphere and store it in the soil. Switchgrass can remove CO 2 from the troposphere and store it in the soil. Figure 17-26

51. Case Study: Producing Ethanol 10-23% pure ethanol makes gasohol which can be run in conventional motors. 10-23% pure ethanol makes gasohol which can be run in conventional motors. 85% ethanol (E85) must be burned in flex- fuel cars. 85% ethanol (E85) must be burned in flex- fuel cars. Processing all corn grown in the U.S. into ethanol would cover only about 55 days of current driving. Processing all corn grown in the U.S. into ethanol would cover only about 55 days of current driving. Biodiesel is made by combining alcohol with vegetable oil made from a variety of different plants.. Biodiesel is made by combining alcohol with vegetable oil made from a variety of different plants..

52. Economics, Politics, Education, and Energy Resources Governments can use a combination of subsidies, tax breaks, rebates, taxes and public education to promote or discourage use of various energy alternatives: Governments can use a combination of subsidies, tax breaks, rebates, taxes and public education to promote or discourage use of various energy alternatives: Can keep prices artificially low to encourage selected energy resources. Can keep prices artificially low to encourage selected energy resources. Can keep prices artificially high to discourage other energy resources. Can keep prices artificially high to discourage other energy resources. Emphasize consumer education. Emphasize consumer education.

53. Fig. 17-27, p. 407 Trade-Offs Ethanol Fuel AdvantagesDisadvantages High octaneLarge fuel tank needed Some reduction in CO 2 emissions Lower driving range Low net energy (corn) High net energy (bagasse and switchgrass) Much higher cost Corn supply limited Reduced CO emissions May compete with growing food on cropland Can be sold as gasohol Higher NO emissions Corrosive Potentially renewable Hard to start in cold weather

54. Case Study: Producing Ethanol Biodiesel has the potential to supply about 10% of the country’s diesel fuel needs. Biodiesel has the potential to supply about 10% of the country’s diesel fuel needs. Figure 17-28

55. Fig. 17-29, p. 408 Trade-Offs Biodiesel AdvantagesDisadvantages Reduced CO emissionsSlightly increased emissions of nitrogen oxides Reduced CO 2 emissions (78%) Higher cost than regular diesel Reduced hydrocarbon emissions Low yield for soybean crops Better gas mileage (40%) May compete with growing food on cropland Loss and degradation of biodiversity from crop plantations High yield for oil palm crops Moderate yield for rapeseed crops Hard to start in cold weatherPotentially renewable

56. Case Study: Biodiesel and Methanol Growing crops for biodiesel could potentially promote deforestation. Growing crops for biodiesel could potentially promote deforestation. Methanol is made mostly from natural gas but can also be produced at a higher cost from CO 2 from the atmosphere which could help slow global warming. Methanol is made mostly from natural gas but can also be produced at a higher cost from CO 2 from the atmosphere which could help slow global warming. Can also be converted to other hydrocarbons to produce chemicals that are now made from petroleum and natural gas. Can also be converted to other hydrocarbons to produce chemicals that are now made from petroleum and natural gas.

57. Fig. 17-30, p. 408 Trade-Offs Methanol Fuel AdvantagesDisadvantages High octaneLarge fuel tank needed Some reduction in CO 2 emissions Half the driving range Lower total air pollution (30–40%) Corrodes metal, rubber, plastic Can be made from natural gas, agricultural wastes, sewage sludge, garbage, and CO 2 High CO 2 emissions if made from coal Expensive to produce Can be used to produce H 2 for fuel cells Hard to start in cold weather

58. GEOTHERMAL ENERGY Geothermal energy consists of heat stored in soil, underground rocks, and fluids in the earth’s mantle. Geothermal energy consists of heat stored in soil, underground rocks, and fluids in the earth’s mantle. We can use geothermal energy stored in the earth’s mantle to heat and cool buildings and to produce electricity. We can use geothermal energy stored in the earth’s mantle to heat and cool buildings and to produce electricity. A geothermal heat pump (GHP) can heat and cool a house by exploiting the difference between the earth’s surface and underground temperatures. A geothermal heat pump (GHP) can heat and cool a house by exploiting the difference between the earth’s surface and underground temperatures.

61. Geothermal Heat Pump The house is heated in the winter by transferring heat from the ground into the house. The house is heated in the winter by transferring heat from the ground into the house. The process is reversed in the summer to cool the house. The process is reversed in the summer to cool the house. Figure 17-31

62. GEOTHERMAL ENERGY Deeper more concentrated hydrothermal reservoirs can be used to heat homes and buildings and spin turbines: Deeper more concentrated hydrothermal reservoirs can be used to heat homes and buildings and spin turbines: Dry steam: water vapor with no water droplets. Dry steam: water vapor with no water droplets. Wet steam: a mixture of steam and water droplets. Wet steam: a mixture of steam and water droplets. Hot water: is trapped in fractured or porous rock. Hot water: is trapped in fractured or porous rock.

63. Fig. 17-32, p. 410 Trade-Offs Geothermal Energy Advantages Disadvantages Very high efficiency Scarcity of suitable sites Moderate net energy at accessible sites Depleted if used too rapidly Lower CO 2 emissions than fossil fuels Moderate to high local air pollution Low cost at favorable sites CO 2 emissions Noise and odor (H 2 S) Low land use Low land disturbance Cost too high except at the most concentrated and accessible sources Moderate environmental impact

64. A SUSTAINABLE ENERGY STRATEGY Shifts in the use of commercial energy resources in the U.S. since 1800, with projected changes to 2100. Shifts in the use of commercial energy resources in the U.S. since 1800, with projected changes to 2100. Figure 17-34

65. A SUSTAINABLE ENERGY STRATEGY A more sustainable energy policy would improve energy efficiency, rely more on renewable energy, and reduce the harmful effects of using fossil fuels and nuclear energy. A more sustainable energy policy would improve energy efficiency, rely more on renewable energy, and reduce the harmful effects of using fossil fuels and nuclear energy. There will be a gradual shift from large, centralized macropower systems to smaller, decentralized micropower systems. There will be a gradual shift from large, centralized macropower systems to smaller, decentralized micropower systems.

66. Fig. 17-35, p. 414 Small solar-cell power plants Bioenergy power plants Wind farm Rooftop solar cell arrays Fuel cells Solar-cell rooftop systems Transmission and distribution system Commercial Small wind turbine Residential Industrial Microturbines