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16-6 Advantages and Disadvantages of Using Biomass as an Energy Source

16-6 Advantages and Disadvantages of Using Biomass as an Energy Source.

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16-6 Advantages and Disadvantages of Using Biomass as an Energy Source

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  1. 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 world’s 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.

  2. 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

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

  4. 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

  5. We Can Convert Plants and Plant Wastes to Liquid Biofuels (2) • Major advantages over gasoline and diesel fuel produced from oil • Biofuel crops can be grown almost anywhere • No net increase in CO2 emissions if managed properly • Available now

  6. We Can Convert Plants and Plant Wastes to Liquid Biofuels (3) • Studies warn of problems: • Decrease biodiversity • Increase soil degrading, erosion, and nutrient leaching • Raise food prices • Reduce water supplies, especially for corn and soy

  7. 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

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

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

  10. Case Study: Is Ethanol the Answer? (2) • Cellulosic ethanol:alternative to corn ethanol • Avoid food vs. biofuel • Switchgrass- higher energy yield, • Requires much more land use • Expensive to break down cellulose

  11. World Ethanol Production Figure 13, Supplement 9

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

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

  14. 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 • Need to lower costs • Open ponds vs. bioreactors • Affordable ways of extracting oil • Scaling to large production

  15. 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.

  16. 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

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

  18. 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

  19. Geothermal Sites in the United States Figure 26, Supplement 8

  20. Geothermal Sites Worldwide Figure 25, Supplement 8

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

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

  23. 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.

  24. 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 • CO2 levels dependent on method of hydrogen production

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

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

  27. 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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