Renewable Energy

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Renewable Energy

• Nov 19

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Wind Power
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Wind Power
Vertical axis machine
Horizontal axis machine
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Wind Power
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(No Transcript)
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Wind Power

• Winds arise from differential heating of the
  Earths surface on a local, regional, or
  worldwide scale.
• Global winds
• Local winds

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Wind Power

• Environmental Impacts
• Visual impact
• Electromagnetic interference potential to
  interfere with radio, tv, and radar signals and
  with microwave communication links
• Ecological impacts
• Noise

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Wave Power

• Water has a higher density than air, so has
  higher energy densities
• Have little effect on general flow of water
  around them
• Central issue economics of harnessing power in
  harsh marine environments
• Need sites with regular waves

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Wave Power
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Wave Power

• Onshore devices
• Must be located in deep water areas adjacent to
  coasts to avoid loss of energy through friction

Tapered channel wave energy converter
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Wave Power

• Offshore devices
• Can produce more energy, but at a higher cost
• Passing waves force joints to pump high-pressure
  oil through hydraulic motors
• Motors then drive the electrical generators to
  produce electricity
• Power is fed from the device via cable to the
  seabed, and then to shore

Pelamis sea snake
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Tidal Power

• The regular rise and fall of the tides represents
  a shifting store of potential energy powered by
  the drag of the moon and sun
• Water collected at high tide and then drained
  through a water turbine to generate electricity
  or use of spin turbine
• The Earth experiences 2 tides a day, allowing
  tidal power dams to be filled every 12 hrs
• More tidal energy in Atlantic Ocean basin than
  Pacific

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Tidal Power
Tidal dam
Spin turbine
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Small-Scale Hydropower

• Doesnt have the environmental and social impacts
  of large-scale hydropower
• Can be used in areas where local geography
  doesnt allow for large dams
• Plant sits on one side of the river
• Little water is held back and diverted, so the
  river is unaffected
• Less powerful

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Small-Scale Hydropower
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Biomass

• Fuel GJ/t
• Grass (fresh-cut) 4
• Domestic waste (as collected) 9
• Straw (baled) 14
• Sugar cane (air-dried stalks) 14
• Wood (air-dried, 20 moisture) 15
• Paper (stacked newspaper) 17
• Commercial wastes ( UK average) 16
• Dung (dried) 16
• Calorific value of various biomass feedstocks
  data from BOY96,p143.

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Biomass
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Geothermal

• Derived from radioactive decay of isotopes deep
  within the Earth or from heat left over from the
  original coalescence of matter that formed the
  Earth
• Heat accessed in 1 of 2 ways
• Hot dry rock technology drill close to
  radioactive sources
• Wet rock technology natural output of energy
  higher because of presence of water

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Geothermal
Wet-rock technology
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Geothermal

• Environmental concerns
• New boreholes would have to built every 10 years
  as local heat is diminished
• Dry-rock technology required water to be pumped
  into the ground
• Odors could be released
• Land subsidence
• Increased seismicity

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Fast Breeders and Fusion

• Fast breeder reactors and fusion reactors use
  uranium more efficiently than thermal nuclear
  reactors
• These expand the worlds resource of uranium from
  70 years to 9930 years
• They do this by producing more fissionable fuel
  than they use
• Also produce less radiation and radioactive waste