Figure 16.2: This diagram shows how commercial energy flows through the U.S. economy. Only 16% of all commercial energy used in the United States ends up performing useful tasks; the rest of the energy is unavoidably wasted because of the second law of thermodynamics (41%) or is wasted unnecessarily (43%). Question: What are two examples of unnecessary energy waste? (Data from U.S. Department of Energ y)
Figure 16.4: These small, light-emitting diodes (LEDs) come in different colors (left) and contain no toxic elements. They are being used for industrial and household lighting, and also in Christmas tree lights, traffic lights (right), street lights, and hotel conference and dining room lighting. LEDs last so long (about 100,000 hours) that users can install them and forget about them. LED bulbs are expensive but prices are projected to drop because of newer designs and mass production. Shifting to energy-efficient fluorescent lighting in homes, office buildings, stores, and factories and to LEDs in all traffic lights would save enough energy to close more than 700 of the world’s coal-burning electric power plants.
Figure 16.5: This diagram shows changes in the average fuel economy of new vehicles sold in the United States, 1975–2008 (left) and the fuel economy standards in other countries, 2002–2008 (right). (Data from U.S. Environmental Protection Agency, National Highway Traffic Safety Administration, and International Council on Clean Transportation )
Figure 16.6: S olutions. A conventional gasoline–electric hybrid vehicle (left) has a small internal combustion engine and a battery. A plug-in hybrid vehicle (right) has a smaller internal combustion engine with a second and more powerful battery that can be plugged into a 110-volt or 220-volt outlet and recharged. This allows it to run farther on electricity alone.
Figure 16.7: The body on this concept car, made of carbon-fiber composite, is much safer and stronger than a traditional car body and the car gets better mileage because of its greatly reduced weight. Such car bodies are expensive but further research and mass production could bring their prices down.
Figure 16.8: City Hall in Chicago, Illinois (USA), has a green or living roof —an important part of the city’s efforts to become a more sustainable green city. Such a roof can save energy used to heat and cool the building. It absorbs heat from the summer sun, which would otherwise go into the building, and it helps to insulate the structure and retain heat in the winter. In addition, it absorbs precipitation, which would normally become part of the city’s storm water runoff and add to pollution of its waterways.
Figure 16.9: This thermogram , or infrared photo, shows heat losses (red, white, and orange) around the windows, doors, roofs, and foundations of houses and stores in Plymouth, Michigan (USA). Many homes and buildings in the United States and other countries are so full of leaks that their heat loss in cold weather and heat gain in hot weather are equivalent to what would be lost through a large, window-sized hole in a wall of the house. Question: How do you think the place where you live would compare to these buildings in terms of heat loss and the resulting waste of money spent on heating and cooling bills?
Figure 16.10: Individuals matter. You can save energy where you live. Question: Which of these things do you do?
Figure 16.12: This passive solar home (left) in Golden, Colorado (USA), collects and stores incoming solar energy which provides much of its heat in a climate with cold winters. Such homes also have the best available insulation in their walls and ceilings, and energy-efficient windows to slow the loss of stored solar energy. Notice the solar hot water heating panels in the yard. Some passive solar houses like this one (see photo on right) in Dublin, New Hampshire (USA), have attached sunrooms that collect incoming solar energy.
Figure 16.13: Rooftop solar hot water heaters, such as those shown here on apartment buildings in the Chinese city of Kunming in the province of Yunnan, are now required on all new buildings in China, and their use is growing rapidly in urban and rural areas.
Figure 16.15: Solar thermal power: In this desert solar power plant (left) near Kramer Junction, California (USA), curved (parabolic) solar collectors concentrate solar energy and use it to produce electricity. The concentrated solar energy heats a fluid-filled pipe that runs through the center of each trough. The concentrated heat in the fluid is used to produce steam that powers a turbine that generates electricity. Such plants also exist in desert areas of southern Spain, Australia, and Israel. In another approach (right), an array of computer-controlled mirrors tracks the sun and focuses reflected sunlight on a central receiver, sometimes called a power tower . This tower near Daggett, California (USA), can collect enough heat to boil water and produce steam for generating electricity. Excess heat in both systems can be released to the atmosphere by cooling towers. The heat can also be used to melt a certain kind of salt stored in a large insulated container. The heat stored in this molten salt system can then be released as needed to produce electricity at night. Such plants also exist in desert areas of southern Spain and North Africa. Because a power tower heats water to higher temperatures, it can have a higher net energy ratio than a parabolic trough system has.
Figure 16.17: S olutions. This woman in India is using a solar cooker to prepare a meal for her family.
Figure 16.19: S olutions. This system of solar cells provides electricity for a remote village in Niger, Africa. Question: Do you think your government should provide aid to help poor countries obtain solar-cell systems? Explain.
Figure 16.20: This solar-cell power plant in the U.S. state of Arizona near the city of Springerville has been in operation since 2000 and is the world’s largest solar-cell power plant. Analysis shows that the plant, which is connected to the area’s electrical grid, paid back the energy needed to build it in less than 3 years .
Figure 13.13: Trade-offs. Large dams and reservoirs have advantages (green) and disadvantages (orange) ( Concept 13-3 ). The world’s 45,000 large dams (15 meters (49 feet) or higher) capture and store about 14% of the world’s surface runoff, provide water for almost half of all irrigated cropland, and supply more than half the electricity used in 65 countries. The United States has more than 70,000 large and small dams, capable of capturing and storing half of the country’s entire river flow. Question: Which single advantage and which single disadvantage do you think are the most important?
Figure 16.23: S olutions. A single wind turbine (left) can produce electricity. Increasingly, they are interconnected in arrays of tens to hundreds of turbines. These wind farms or wind parks can be located on land (middle) or offshore (right). The land beneath these turbines can still be used to grow crops or to raise cattle. Questions: Would you object to having a wind farm located near where you live? Why or why not?
Figure 16.24: Maintenance workers get a long-distance view from atop a wind turbine, somewhere in North America, built by Suzlon Energy, a company established in India in 1995.
Figure 16.28: Bagasse is a sugarcane residue that can be used to make ethanol.
Figure 16.29: N atural capital. The cellulose in this rapidly growing switchgrass can be converted into ethanol, but further research is needed to develop affordable production methods. This perennial plant can also help to slow projected climate change by removing carbon dioxide from the atmosphere and storing it as organic compounds in the soil.
Figure 16.31: N atural capital. A geothermal heat pump system can heat or cool a house almost anywhere. It heats the house in winter by transferring heat from the ground into the house (shown here). In the summer, it cools the house by transferring heat from the house to the ground.
Figure 16.32: This geothermal power plant in Iceland produces electricity and heats a nearby spa called the Blue Lagoon.
Bio 105 Chapter 16
MILLER/SPOOLMAN LIVING IN THE ENVIRONMENT 17TH Chapter 16 Energy Efficiency and Renewable Energy
We Waste Huge Amounts of Energy (1)• Energy efficiency• Advantages of reducing energy waste: • Quick and clean • Usually the cheapest to provide more energy • Reduce pollution and degradation • Slow global warming • Increase economic and national security
We Waste Huge Amounts of Energy (2)• Four widely used devices that waste energy 1. Incandescent light bulb 2. Motor vehicle with internal combustion engine 3. Nuclear power plant 4. Coal-fired power plant
Flow of Commercial Energy through the U.S. Economy Fig. 16-2, p. 399
We Can Save Energy and Money in Industry and Utilities (1)• Cogeneration or combined heat and power (CHP) • Two forms of energy from same fuel source• Replace energy-wasting electric motors• Recycling materials• Switch from low-efficiency incandescent lighting to higher-efficiency fluorescent and LED lighting
We Can Save Energy and Money in Industry and Utilities (2)• Electrical grid system: outdated and wasteful• Utility companies switching from promote use of energy to promoting energy efficiency • Spurred by state utility commissions
We Can Save Energy and Money in Transportation• Corporate average fuel standards (CAFE) standards • Fuel economy standards lower in the U.S. countries • Fuel-efficient cars are on the market • 2016 - 39 miles per gallon for cars and 30 mpg for trucks• Hidden prices in gasoline: $12/gallon • Car manufacturers and oil companies lobby to prevent laws to raise fuel taxes
Average Fuel Economy of New Vehicles Sold in the U.S. and Other Countries Fig. 16-5, p. 402
More Energy-Efficient Vehicles Are on the Way• Superefficient and ultralight cars• Gasoline-electric hybrid car• Plug-in hybrid electric vehicle• Energy-efficient diesel car• Electric vehicle with a fuel cell
Solutions: A Hybrid-Gasoline-Electric Engine Car and a Plug-in Hybrid Car Fig. 16-6, p. 403
Light-Weight Carbon Composite Concept Car Fig. 16-7, p. 405
We Can Design Buildings That Save Energy and Money • Green architecture • Living or green roofs • Superinsulation • U.S. Green Building Council’s Leadership in Energy and Environmental Design (LEED)
A Green Roof in Chicago-City Hall Fig. 16-8, p. 405
We Can Save Money and Energy in Existing Buildings (1) • Conduct an energy survey • Insulate and plug leaks • Use energy-efficient windows • Stop other heating and cooling losses • Heat houses more efficiently
We Can Save Money and Energy in Existing Buildings (2) • Heat water more efficiently • Use energy-efficient appliances • Use energy-efficient lighting
A Thermogram Shows Heat Loss Fig. 16-9, p. 406
Individuals Matter: Ways in Which You Can Save Money Where You Live Fig. 16-10, p. 407
Why Are We Still Wasting So Much Energy?• Energy remains artificially cheap • Government subsidies • Tax breaks • Prices don’t include true cost• Few large and long-lasting incentives • Tax breaks • Rebates • Low-interest loans
We Can Use Renewable Energy to Provide Heat and Electricity • Renewable energy • Solar energy: direct or indirect • Geothermal energy • Benefits of shifting toward renewable energy • Renewable energy cheaper if we eliminate • Inequitable subsidies • Inaccurate prices • Artificially low pricing of nonrenewable energy
We Can Heat Buildings and Water with Solar Energy• Passive solar heating system• Active solar heating system
Passive Solar Home in Colorado Fig. 16-12, p. 410
Rooftop Solar Hot Water on Apartment Buildings in Kunming, China Fig. 16-13, p. 410
World Availability of Direct Solar Energy Figure 22, Supplement 8
U.S. Availability of Direct Solar Energy Figure 23, Supplement 8
We Can Cool Buildings Naturally• Technologies available • Open windows when cooler outside • Use fans • Superinsulation and high-efficiency windows • Overhangs or awnings on windows • Light-colored roof • Geothermal pumps
We Can Use Sunlight to Produce High- Temperature Heat and Electricity• Solar thermal systems • Central receiver system • Collect sunlight to boil water, generate electricity • 1% of world deserts could supply all the world’s electricity • Require large amounts of water – could limit • Wet cooling • Dry cooling• Low net energy yields
Solar Thermal Power in California Desert Fig. 16-15, p. 411
Solutions: Solar Cooker in India Fig. 16-17, p. 412
Solar Cell Array in Niger, West Africa Fig. 16-19, p. 413
Solar-Cell Power Plant in Arizona Fig. 16-20, p. 414
We Can Use Sunlight to Produce Electricity (2) • Key problems • High cost of producing electricity • Need to be located in sunny desert areas • Fossil fuels used in production • Solar cells contain toxic materials • Will the cost drop with • Mass production • New designs • Government subsidies and tax breaks
Global Production of Solar Electricity Figure 11, Supplement 9
We Can Produce Electricity from Falling and Flowing Water• Hydropower • Uses kinetic energy of moving water • Indirect form of solar energy • World’s leading renewable energy source used to produce electricity• Advantages and disadvantages• Micro-hydropower generators
Tradeoffs: Dams and Reservoirs Fig. 13-13, p. 328
Tides and Waves Can Be Used to Produce Electricity • Produce electricity from flowing water • Ocean tides and waves • So far, power systems are limited • Disadvantages • Few suitable sites • High costs • Equipment damaged by storms and corrosion
Using Wind to Produce Electricity Is an Important Step toward Sustainability (1)• Wind: indirect form of solar energy • Captured by turbines • Converted into electrical energy• Second fastest-growing source of energy• What is the global potential for wind energy?• Wind farms: on land and offshore
World Electricity from Wind Energy Figure 12, Supplement 9
Solutions: Wind Turbine and Wind Farms on Land and Offshore Fig. 16-23, p. 417
Using Wind to Produce Electricity Is an Important Step toward Sustainability (2)• Countries with the highest total installed wind power capacity • Germany • United States • Spain • India • Denmark• Installation is increasing in several other countries
Using Wind to Produce Electricity Is an Important Step toward Sustainability (3)• Advantages of wind energy• Drawbacks • Windy areas may be sparsely populated – need to develop grid system to transfer electricity • Winds die down; need back-up energy • Storage of wind energy • Kills migratory birds • “Not in my backyard”
Case Study: The Astounding Potential of Wind Power in the United States• “Saudi Arabia of wind power” • North Dakota • South Dakota • Kansas • Texas• How much electricity is possible with wind farms in those states? • Could create up to 500,000 jobs
United States Wind Power Potential Figure 24, Supplement 8
We Can Get Energy by Burning Solid Biomass• Biomass • Plant materials and animal waste we can burn or turn into biofuels• Production of solid mass fuel • Plant fast-growing trees • Biomass plantations • Collect crop residues and animal manure• Advantages and disadvantages
We Can Convert Plants and Plant Wastes to Liquid Biofuels (1)• Liquid biofuels • Biodiesel • Ethanol• Biggest producers of biofuel • The United States • Brazil • The European Union • China
We Can Convert Plants and Plant Wastes to Liquid Biofuels (2)• Major advantages over gasoline and diesel fuel produced from oil 1.Biofuel crops can be grown almost anywhere 2.No net increase in CO2 emissions if managed properly 3.Available now
We Can Convert Plants and Plant Wastes to Liquid Biofuels (3)• Studies warn of problems: • Decrease biodiversity • Increase soil degrading, erosion, and nutrient leaching • Push farmers off their land • Raise food prices • Reduce water supplies, especially for corn and soy
Bagasse is Sugarcane Residue-can be used to make ethanol Fig. 16-28, p. 421
Natural Capital: Rapidly GrowingSwitchgrass-can be converted to ethanol Fig. 16-29, p. 423
Case Study: Getting Gasoline and Diesel Fuel from Algae and Bacteria (1)• Algae remove CO2 and convert it to oil • Not compete for cropland = not affect food prices • Wastewater/sewage treatment plants • Could transfer CO2 from power plants• Algae challenges 1. Need to lower costs 2. Open ponds vs. bioreactors 3. Affordable ways of extracting oil 4. Scaling to large production
Getting Energy from the Earth’s Internal Heat (1)• Geothermal energy: heat stored in • Soil • Underground rocks • Fluids in the earth’s mantle• Geothermal heat pump system • Energy efficient and reliable • Environmentally clean • Cost effective to heat or cool a space
Natural Capital: A Geothermal Heat Pump System Can Heat or Cool a House Fig. 16-31, p. 425
Getting Energy from the Earth’s Internal Heat (2)• Hydrothermal reservoirs • U.S. is the world’s largest producer• Hot, dry rock• Geothermal energy problems • High cost of tapping hydrothermal reservoirs • Dry- or wet-steam geothermal reservoirs could be depleted • Could create earthquakes
Geothermal Sites in the United States Figure 26, Supplement 8