Chapter 21: New renewable Energy Alternatives

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Chapter 21 New renewable Energy Alternatives
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Renewable Energy

• sun
• wind
• geothermal
• oceans
• hydrogen

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Solar Energy

• convertion of hydrogen (H) to helium (He)
• each m2 of area receives about one kilowatt of
  solar energy seventeen 60 watt lightbulbs
• therefore each house has enough roof area to
  generate all it needs using solar panels
• passive and active solar energy collection

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Passive Solar Energy Collection

• design of buildings
• construction materials are chosen to
• maximize direct absorption of sunlight during
  winter
• keep the interior cool in summer
• south facing windows
• planting vegetation for shade during summer
• overhangs to block sun in summer
• heat-absorbing contruction materials
• straw, brick or concrete for example

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Passive Solar Energy Collection
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Active Solar Energy

• solar panels
• solar cookers
• photovoltaic cells

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Active Solar Energy

• solar panels
• few on the roof of a house or building
• collection of mirrors
• power tower with molten salt creating steam that
  moves the generator
• tubes with oil which creates steam that move
  turbines

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Active Solar Energy

• photovoltaic cells
• collect sun's energy converting it to electrical
  energy using semiconductors.

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Benefits of PV cell

• PV cells are
• quiet
• safe
• require little or no maintenance
• no moving parts
• no turbine or generator required
• each unit lasts 20-30 years

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Active Solar Energy

• solar cookers
• allows families to cook without having to gather
  fuelwood
• lessens daily workload
• helps reduce deforestation
• helps relieve social and environmental stress

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Benefits of Solar Power

• inexhaustable as energy source
• enough energy to power earth as long as
  technology develops
• allows decentralized control over power
• producing many new jobs
• does not pollute

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Drawbacks of Solar Power

• localization

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Drawbacks of Solar Power

• costs

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Wind Energy

• wind turbines
• windmills have been used for more than 800 years
  in Europe
• drain wetlands
• irrigate crops
• grind grain into flour

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Wind

• first wind turbine was created in the late 1800s
• rural electrification act 1935 killed its
  development promoting dams and coal plants
• not until the oil embargo of 1973 that the idea
  was brought back and funding for research was
  given
• low costs
• kinetic energy converted into electric energy
• different turbines are designed to work at
  different wind speeds
• faster the wind the more energy it generates

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Wind fast growing energy sector
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Offshore Wind Turbines

• more expensive
• more productive
• shallow areas
• maintenance

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Benefits of Using Wind Power

• cleaner
• under optimal conditions it is much more
  effective than any other conventional energy
  source
• small to large scale usage
• farmland can lease a small area and still be
  productive
• once built, the costs are only for maintenance
• as efficiency increases the cost of electricity
  decreases

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Downsides of Wind Power

• wind is intermitent and unpredictable
• good resourse are mostly away from populations
• grid has to be built and that costs money
• conspicuous
• people object to farms due to aesthetics
• not-in-my-backyard syndrome
• threat to birds and bats

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Geothermal Energy

• generated deep within Earth
• from an area of volcanic activity along two
  tectonic plates

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Benefits and Limitations

• Benefits
• reduces emissions relative to fossil fuels
• other pollutants it produces are in very small
  quantities
• filters help control pollutants
• Limitations
• can produce other pollutants like CO2, CH4, NH3
• sources may not be truly sustainable
• limited to area where tectonic plates meet
• water used for energy corrodes equipment
  shortening lifetime of the plant
• chemicals in the water may pollute the air

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Ocean Energy Sources

• tides
• waves
• currents

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Tides

• rising and fallen of the ocean level
• twice each day
• erecting dams across the outlets of the tidal
  basins
• outgoing tide will pass through the turbines
  generating electricity
• no pollution
• high impact on the ecology of estuaries

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• Hydroelectricity from Tidal Waves

La Rance- France
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Wave Energy

• converting mechanical energy to electricity
• harness the motion of wind-driven waves at the
  ocean surface
• greater energy is found in deeper ocean sites
• none are operating yet

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• Wave Energy Generator

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Currents

• marine kinetic energy
• essentially like underwater wind turbines
• are now been tested in Europe

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Hydrogen

• Benefits
• storage of energy generated by sustainable energy
  is a problem, hydrogen fuels cells are promising
• Hydrogen is the fuel and it is abundant
• clan, bonds H2 and O2 making water as final
  product
• Drawback
• to make the fuel (H2) energy is required and
  carbon based pollutants are produced
• possible risk of depleting ozone from
  stratosphere if H2 leaks
• THE END