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17 TH MILLER/SPOOLMAN LIVING IN THE ENVIRONMENT Chapter 16 Energy Efficiency and Renewable Energy

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16-4 What Are the Advantages and Disadvantages of Using Hydropower Concept 16-4 We can use water flowing over dams, tidal flows, and ocean waves to generate electricity, but environmental concerns and limited availability of suitable sites may limit the use of these energy resources.

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We Can Produce Electricity from Falling and Flowing Water Hydropower Uses kinetic energy of moving water Indirect form of solar energy Worlds leading renewable energy source used to produce electricity Advantages and disadvantages Micro-hydropower generators

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Tradeoffs: Dams and Reservoirs Fig. 13-13, p. 328

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Fig. 13-13b, p. 328 Powerlines Reservoir Dam Intake Powerhouse Turbine

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Trade-Offs: Large-Scale Hydropower, Advantages and Disadvantages Fig. 16-22, p. 415

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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

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16-5 What Are the Advantages and Disadvantages of Using Wind Power? Concept 16-5 When we include the environmental costs of using energy resources in the market prices of energy, wind power is the least expensive and least polluting way to produce electricity.

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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

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World Electricity from Wind Energy Figure 12, Supplement 9

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Solutions: Wind Turbine and Wind Farms on Land and Offshore Fig. 16-23, p. 417

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Fig. 16-23a, p. 417 Gearbox Electrical generator Power cable Wind turbine

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Fig. 16-23b, p. 417 Wind farm

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Fig. 16-23c, p. 417 Wind farm (offshore)

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Wind Turbine Fig. 16-24, p. 417

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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

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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

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Trade-Offs: Wind Power Fig. 16-25, p. 418

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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

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United States Wind Power Potential Figure 24, Supplement 8

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16-6 Advantages and Disadvantages of Using Biomass as an Energy Source Concept 16-6A Solid biomass is a renewable resource for much of the worlds population, but burning it faster than it is replenished produces a net gain in atmospheric greenhouse gases, and creating biomass plantations can degrade soil biodiversity. Concept 16-6B We can use liquid biofuels derived from biomass in place of gasoline and diesel fuels, but creating biofuel plantations can degrade soil and biodiversity and increase food prices and greenhouse gas emissions.

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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

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Trade-Offs: Solid Biomass Fig. 16-26, p. 420

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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

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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 CO 2 emissions if managed properly 3.Available now

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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

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Case Study: Is Biodiesel the Answer? Biodiesel production from vegetable oil from various sources 95% produced by the European Union Subsidies promote rapid growth in United States Advantages and disadvantages

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Trade-Offs: Biodiesel Fig. 16-27, p. 421

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Case Study: Is Ethanol the Answer? (1) Ethanol from plants and plant wastes Brazil produces ethanol from sugarcane Environmental consequences United States: ethanol from corn Low net energy yield Reduce the need for oil imports? Harm food supply Air pollution and climate change?

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Case Study: Is Ethanol the Answer? (2) Cellulosic ethanol: alternative to corn ethanol Switchgrass Crop residues Municipal wastes Advantages and disadvantages

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World Ethanol Production Figure 13, Supplement 9

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Bagasse is Sugarcane Residue Fig. 16-28, p. 421

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Natural Capital: Rapidly Growing Switchgrass Fig. 16-29, p. 423

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Trade-Offs: Ethanol Fuel Fig. 16-30, p. 423

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Case Study: Getting Gasoline and Diesel Fuel from Algae and Bacteria (1) Algae remove CO 2 and convert it to oil Not compete for cropland = not affect food prices Wastewater/sewage treatment plants Could transfer CO 2 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

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Case Study: Getting Gasoline and Diesel Fuel from Algae and Bacteria (2) Bacteria: synthetic biology Convert sugarcane juice to biodiesel Need large regions growing sugarcane Producing fuels from algae and bacteria can be done almost anywhere

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16-7 What Are the Advantages and Disadvantages of Geothermal Energy? Concept 16-7 Geothermal energy has great potential for supplying many areas with heat and electricity, and it has a generally low environmental impact, but sites where it can be used economically are limited.

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Getting Energy from the Earths Internal Heat (1) Geothermal energy: heat stored in Soil Underground rocks Fluids in the earths mantle Geothermal heat pump system Energy efficient and reliable Environmentally clean Cost effective to heat or cool a space

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Natural Capital: A Geothermal Heat Pump System Can Heat or Cool a House Fig. 16-31, p. 425

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Getting Energy from the Earths Internal Heat (2) Hydrothermal reservoirs U.S. is the worlds 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

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Geothermal Sites in the United States Figure 26, Supplement 8

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Geothermal Sites Worldwide Figure 25, Supplement 8

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Geothermal Power Plant in Iceland Fig. 16-32, p. 425

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Trade Offs: Geothermal Energy Fig. 16-33, p. 426

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16-8 The Advantages and Disadvantages of Using Hydrogen as an Energy Source Concept 16-8 Hydrogen fuel holds great promise for powering cars and generating electricity, but for it to be environmentally beneficial, we would have to produce it without the use of fossil fuels.

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Will Hydrogen Save Us? (1) Hydrogen as a fuel Eliminate most of the air pollution problems Reduce threats of global warming Some challenges Chemically locked in water and organic compounds = net negative energy yield Expensive fuel cells are the best way to use hydrogen CO 2 levels dependent on method of hydrogen production

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Will Hydrogen Save Us? (2) Net negative energy yield Production and storage of H 2 Hydrogen-powered vehicles: prototypes available Can we produce hydrogen on demand? Larger fuel cells fuel-cell stacks

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A Fuel Cell Separates the Hydrogen Atoms Electrons from Their Protons Fig. 16-34, p. 427

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Trade-Offs: Hydrogen, Advantages and Disadvantages Fig. 16-35, p. 428

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Science Focus: The Quest to Make Hydrogen Workable Bacteria and algae can produce hydrogen through biodegrading organic material Use electricity from renewable energy sources to produce hydrogen Storage options for hydrogen

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16-9 How Can We Make the Transition to a More Sustainable Energy Future? Concept 16-9 We can make the transition to a more sustainable energy future if we greatly improve energy efficiency, use a mix of renewable energy resources, and include environmental costs in the market prices of all energy resources.

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Choosing Energy Paths (1) How will energy policies be created? Hard energy path Soft energy path

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Choosing Energy Paths (2) General conclusions Gradual shift to smaller, decentralized micropower systems Transition to a diverse mix of locally available renewable energy resources Improved energy efficiency Fossil fuels will still be used in large amounts Natural gas is the best choice

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Solutions: Decentralized Power System Fig. 16-36, p. 430

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Small solar-cell power plants Bioenergy power plantsWind farm Fuel cells Rooftop solar- cell arrays Solar-cell rooftop systems Smart electrical and distribution system Commercial Small wind turbine Residential Industrial Microturbines

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Bioenergy power plants Smart electrical and distribution system Small solar-cell power plants Solar-cell rooftop systems Commercial Fuel cells Rooftop solar- cell arrays Residential Small wind turbine Stepped Art Industrial Microturbines Wind farm Fig. 16-36, p. 430

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Solutions: Making the Transition to a More Sustainable Energy Future Fig. 16-37, p. 431

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Economics, Politics, Education, and Sustainable Energy Resources Government strategies: Keep the prices of selected energy resources artificially low to encourage their use Keep energy prices artificially high for selected resources to discourage their use Consumer education

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What Can you Do? Shifting to More Sustainable Energy Use Fig. 16-38, p. 432

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Three Big Ideas 1.We should evaluate energy resources on the basis of their potential supplies, how much net useful energy they provide, and the environmental impacts of using them. 2.Using a mix of renewable energy sources especially solar, wind, flowing water, sustainable biofuels, and geothermal energycan drastically reduce pollution, greenhouse gas emissions, and biodiversity losses.

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Three Big Ideas 3.Making the transition to a more sustainable energy future will require sharply reducing energy waste, using a mix of environmentally friendly renewable energy resources, and including the harmful environmental costs of energy resources in their market prices.