14 Renewable

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14 Renewable

  1. 1. Renewable Sources of Energy
  2. 2. Resources <ul><li>Non-Renewable : can not be replenished in a reasonable amount of time </li></ul><ul><ul><li>Coal </li></ul></ul><ul><ul><li>Oil (petroleum) </li></ul></ul><ul><ul><li>Natural Gas </li></ul></ul><ul><ul><li>Radioactive Elements </li></ul></ul><ul><li>Renewable : can be replenished in a reasonable amount of time </li></ul><ul><ul><li>Solar </li></ul></ul><ul><ul><li>Wind </li></ul></ul><ul><ul><li>Water (hydroelectric) </li></ul></ul><ul><ul><li>Biomass </li></ul></ul><ul><ul><li>Geothermal </li></ul></ul><ul><ul><li>Hydrogen </li></ul></ul>
  3. 3. Renewables: <ul><li>Biomass </li></ul><ul><li>Hydroelectric </li></ul><ul><li>Solar </li></ul><ul><li>Wind </li></ul><ul><li>Geothermal </li></ul><ul><li>Hydrogen </li></ul>
  4. 4. Biomass Energy <ul><li>Biomass : Consists of the organic material that makes up living organisms </li></ul><ul><li>Biomass Energy : From plant and animal matter, such as charcoal, wood, manure, crops. These can be burned to generate heat or electricity </li></ul><ul><li>Biomass Fuels : some biomass can be converted into fuels: </li></ul><ul><ul><li>Ethanol: from fermentation (corn) -can be added to gasoline and used in “Flex-Fuel” cars </li></ul></ul><ul><ul><li>Biodiesel: from vegetable oil, grease, animal fat-mixed with ethanol, used in diesel engines </li></ul></ul>
  5. 5. Biomass… <ul><li>Methane (as a landfill gas from the anaerobic decomposition of organic matter) </li></ul><ul><li>Biomass can also be vaporized at high temps (anaerobically) to create a mixture of gases: H 2 , CH 4 , CO </li></ul><ul><li>These gases can be used together in a gas turbine to create electricity, or separately, for ex: H 2 </li></ul>
  6. 6. Biomass…. <ul><li>Benefits </li></ul><ul><li>Carbon-neutral (carbon produced from burning it is the same carbon used during its production (recent photosynthesis) </li></ul><ul><li>Geographically balanced </li></ul><ul><li>Inexpensive </li></ul><ul><li>No N 2 or S emissions </li></ul><ul><li>Drawbacks </li></ul><ul><li>Indoor burning creates pollutants </li></ul><ul><li>Competes with crops for food </li></ul><ul><li>Crops require energy to grow </li></ul>
  7. 7. Hydropower: The kinetic energy of moving water can turn turbines and generate electricity <ul><li>Benefits </li></ul><ul><li>Clean </li></ul><ul><li>Renewable </li></ul><ul><li>Drawbacks </li></ul><ul><li>If overused, can become non-sustainable </li></ul><ul><li>Dams create problems for ecosystems, etc </li></ul>
  8. 8. Solar <ul><li>Technologies are still being developed </li></ul><ul><ul><li>Passive solar energy collection : construction that optimizes the sun’s heat and light </li></ul></ul><ul><ul><li>Active solar energy collection : utilizes technology to collect and convert solar energy </li></ul></ul><ul><ul><li>Photovoltaic cell : collects sunlight and converts it into electricity. Can be used directly or stored in a battery. Used in chips, panels, roofing tiles </li></ul></ul>
  9. 9. Solar… <ul><li>Benefits </li></ul><ul><li>Needs no other fuels </li></ul><ul><li>Individuals (not power companies) can control it </li></ul><ul><li>No pollution </li></ul><ul><li>Can sell it back to the grid </li></ul><ul><li>Drawbacks </li></ul><ul><li>Still expensive </li></ul><ul><li>Not all locations have enough sun </li></ul>Sales of PV cells up 63% in Japan, up 25% in the US Storage is still difficult
  10. 10. Solar Panels Solar Roof Tiles
  11. 11. Wind <ul><li>Wind turbines convert kinetic energy of wind into electricity </li></ul><ul><li>Wind is an indirect form of solar energy </li></ul><ul><li>Turbines can be small enough to mount on the roof of a house or have a span of a football field </li></ul><ul><li>Wind speeds offshore are 20% greater </li></ul><ul><li>http://www.bergey.com/ </li></ul><ul><li>http://www.talcoelectronics.com/c-24-wind-power.aspx?gclid=CPHE99b8opcCFRKAxgodawt1dA </li></ul><ul><li>http://www.skystreamenergy.com/ </li></ul>
  12. 12. Wind… <ul><li>Benefits: </li></ul><ul><li>Very efficient </li></ul><ul><li>No fossil fuels needed </li></ul><ul><li>No emissions (except for construction) </li></ul><ul><li>Drawbacks: </li></ul><ul><li>Variable winds </li></ul><ul><li>“ not in my backyard” </li></ul><ul><li>Threat to birds, bats </li></ul>Wind Farm
  13. 13. Geothermal <ul><li>From the decay of radioactive elements, under extreme pressure, deep within the earth, that generates heat </li></ul><ul><li>Underground water can be heated…will rise through natural fissures (cracks) in earth (geysers and natural spas) </li></ul><ul><li>Can drill down to the heated water and pump it up to the surface </li></ul>
  14. 14. Geothermal… <ul><li>Drawbacks: </li></ul><ul><li>Can release gases trapped in the water-- </li></ul><ul><li>Dependent on location </li></ul><ul><li>May not be totally renewable if water is pumped out too quickly </li></ul>
  15. 15. Hydrogen the simplest and most abundant element <ul><li>Fuel Cells use H 2 to produce electricity </li></ul><ul><li>Fuel cells were used by NASA in the 1960’s </li></ul><ul><li>H 2 gas does not exist freely on Earth. </li></ul><ul><li>The atoms must be released from their compounds </li></ul>
  16. 16. Hydrogen from water… <ul><li>Electrolysis : produces pure hydrogen </li></ul><ul><li>Requires *energy input </li></ul><ul><li>2 H 2 O  2 H 2 + O 2 </li></ul><ul><li>Hydrolysis : the reverse process after electricity is produced in the fuel cell </li></ul><ul><li>2 H 2 + O 2  2 H 2 O </li></ul>* Hydrogen production is only as “clean” as the energy used to obtain it. How a fuel cell works: C:Documents and Settings mrecchia Desktopfuel cell video.htm
  17. 17. Hydrogen from other sources… <ul><li>From algae : When certain algae are deprived of light, they produce H 2 at the end of photosynthesis </li></ul><ul><li>From biomass or fossil fuels : </li></ul><ul><ul><li>Can be separated from methane (a form of natural gas): </li></ul></ul><ul><ul><li>CH 4 + 2H 2 O  4H 2 + CO 2 </li></ul></ul>
  18. 18. Hydrogen Economy? <ul><li>Benefits: </li></ul><ul><ul><li>Renewable </li></ul></ul><ul><ul><li>Most abundant </li></ul></ul><ul><ul><li>Clean </li></ul></ul><ul><ul><li>Zero-emission </li></ul></ul><ul><ul><li>As safe as gasoline </li></ul></ul><ul><li>Drawbacks </li></ul><ul><ul><li>Leakage could deplete atmospheric ozone </li></ul></ul><ul><ul><li>Public fear </li></ul></ul>

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