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Alternative Sources – Ch. 20 & 21

Alternative Sources – Ch. 20 & 21. Alternatives to Fossil Fuel. The U.S. relies on fossil fuels. The U.S. relies more on fossil fuels and nuclear power than other countries Conventional alternatives play minor, yet substantial roles, in energy use

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Alternative Sources – Ch. 20 & 21

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  1. Alternative Sources – Ch. 20 & 21

  2. Alternatives to Fossil Fuel The U.S. relies on fossil fuels • The U.S. relies more on fossil fuels and nuclear power than other countries • Conventional alternatives play minor, yet substantial roles, in energy use • The use of conventional alternatives has been growing more slowly than fossil fuels

  3. Nuclear energy • Nuclear energy = the energy that holds together protons and neutrons within the nucleus of an atom • nuclear fission = the splitting apart of atomic nuclei

  4. A typical light water reactor 104 in U.S.

  5. Coal versus nuclear power

  6. Waste stored onsite in pools – expected to be at capacity in 2015

  7. Fusion remains a dream • Nuclear fusion = the process that drives our Sun’s vast output of energy • The force behind hydrogen (thermonuclear) bombs • Involves forcing together the small nuclei of lightweight elements under extremely high temperature and pressure

  8. NIMBY – not in my backyard

  9. Yucca Mountain, Nevada NRDC Testimony on Fukushima

  10. U.S. Total Energy

  11. Renewable Energy

  12. EROI

  13. Biomass energy Biomass = organic material: wood/forestry waste, manure, charcoal, landfill gas 80% of renewable energy use worldwide – heat, cooking, light

  14. Note Scales!

  15. Biomass • Biopower = biomass sources are burned in power plants, generating heat and electricity • Biofuels = biomass sources converted into fuels to power automobiles • Biodiesel • Vegetable Oil mixed with alcohol • Nontoxic, biodegradable, fewer emissions, more expensive than petrodiesel

  16. www.mobiusbiofuels.com

  17. Ethanol = produces as a biofuel by fermenting carbohydrate-rich crops • 20% U.S. corn • Any vehicle will run well on a 10% ethanol mix

  18. B20 = 20% biodiesel 80% petrodiesel B100 = pure biodiesel

  19. Biomass benefits • Carbon-neutral: no net carbon into the atmosphere • If biomass not overharvested • Capturing landfill gases reduces methane emissions • Economic benefits include • Supporting rural communities • Reducing dependence of fossil fuel imports • Improved energy efficiency • Reduces air pollutants such as sulfur dioxide, mercury

  20. Biomass drawbacks • Health hazards from indoor air pollution • Rapid harvesting can lead to deforestation • Conventional growth of crops exerts tremendous impacts on ecosystems • Fertilizers and pesticides • Land is converted to agriculture • Biofuel is competing with food production • Current growth – fossil fuel intensive

  21. Hydroelectric power • 2.2% world electricity • Hydroelectric power = uses the kinetic energy of moving water to turn turbines and generate electricity • Storage technique water stored behind dams – runs through turbine • Run-of-river – water diverted

  22. A typical dam

  23. A run-of-river system

  24. Hydropower Advantages • Renewable • Clean • Efficient

  25. Hydropower Disadvantages • Habitat disruption • Upstream areas are submerged • Downstream areas are starved of water • Natural flooding cycles are disrupted • Thermal pollution of downstream water (more shallow) • Periodic flushes of cold reservoir water can kill fish • Dams block passage of fish, fragmenting the river and reducing biodiversity Predicted to decline as other renewables increase. Dam Removal

  26. Manufacturing, installing, and servicing new renewables labor-intensive = new employment

  27. Energy Incentives 1950 - 2010

  28. U.S. funding 1974- 2005

  29. Solar • Passive – buildings designed to maximize absorption of radiant energy in winter – reduce in summer • Active – radiant energy is focused, moved, stored • Photovoltaic – radiant energy converted to electricity

  30. Passive Mudbrix.com

  31. Active

  32. 21_07.JPG Photovoltaic (active)

  33. 21_08.JPG

  34. Production of PV cells grew sixfold between 2000 and 2005 and prices fell.

  35. 21_09.JPG

  36. 21_10.JPG

  37. Wind EROI = 23:1

  38. 21_12.JPG

  39. 21_13.JPG Fastest growing renewable Future Wind Farms

  40. 21_14.JPG

  41. Geothermal Energy -electricity -hot water

  42. 21_16.JPG Water temperatures 3 km (1.9 mi) below ground. Data from Idaho National Laboratory, 2007

  43. 21_17.JPG Tidal Energy

  44. La Rance in France – 40 years of tidal energy

  45. Hydrogen • Electricity from renewable sources used to produce Hydrogen • H usually bound to other elements – force it to release through electrolysis 2 H2O 2H2 + O2 • Fuel Cells reverse reaction to produce electricity 2H2 + O2 2H2O

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