Environmental Science: Toward a Sustainable Future Richard T' Wright

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Environmental Science Toward a Sustainable
Future Richard T. Wright
Chapter 14

• Renewable Energy
• PPT by Clark E. Adams

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Renewable Energy

• Putting solar energy to work
• Indirect solar energy
• Renewable energy for transportation
• Additional renewable-energy options
• Policy for a sustainable-energy future

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Putting Solar Energy to Work

• Principles of solar energy
• Solar heating of water
• Solar space heating
• Solar production of electricity
• The promise of solar energy

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Terms and Definitions Solar Heating Systems

• Active moves water or air with pumps and blowers
• Passive moves water or air with natural
  convection currents or gravity

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How Photovoltaic Cells Work Part 1

• Each cell consists of two thin mylar layers.
• Lower layer has atoms with single electron in
  outer orbit easily lost.
• Upper layer has atoms lacking one electron in
  outer orbit easily accepts electrons.

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How Photovoltaic Cells Work Part 2

• Kinetic energy from sunlight dislodges electrons
  from lower layer creates an electric potential
  between the two layers.

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How Photovoltaic Cells Work Part 3

• The potential provides the energy for an
  electrical current through the rest of the
  circuit.
• Electrons from lower layer flow through a device
  back to upper side.

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How the Solar-trough Collector Works

• The curved reflector focuses sunlight on and
  heats oil in the pipe.
• Heated oil used to boil water and generate steam
  for driving a conventional turbogenerator.

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Disadvantages of Solar Energy Technologies

• Expense
• Only works during the day
• Requires backup energy sources, e.g., batteries
• Some climates not sunny enough

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Hidden Costs of Traditional Energy Sources

• Air pollution
• Strip-mining
• Nuclear wastes

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Indirect Solar Energy

• Hydropower
• Wind power
• Biomass energy

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Renewable Energy and Transportation

• Biofuels ethanol and biodiesel
• Hydrogen the fuel for the future

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Additional Renewable Energy Options

• Geothermal energy
• Tidal power
• Ocean thermal-energy conversion (OTEC)

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OTEC Benefits or Drawbacks?

• In an average day the heat absorbed by the
  surface water in only one square mile is
  equivalent to the burning of 7,000 barrels of oil
  
• Cost effectiveness to capture and distribute heat
  energy
• Industrial interest in the OTEC alternative

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Policy for a Sustainable Energy Future

• National energy policy
• A clean energy blueprint

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National Energy Policy (True or False)

• Mandates to increase fuel efficiency in cars
• Exploitation of public lands for fossil fuel
  reserves
• Subsidies to producers of solar energy technology
• Research and development on renewable energy
  technologies

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A Clean Energy Blueprint

• Supply side
• Establish a Renewable Portfolio Standard
• Maintain production tax credits
• Extend net metering
• Substantially increase research-and-development
  on renewable energy and efficiency

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A Clean Energy Blueprint

• Demand side
• Improve efficiency standards
• Enhance building codes
• Provide incentives for combined heat and power
  facilities
• Raise fuel economy (CAFÉ) standards
• Increase research and development on
  high-efficiency vehicles (hybrid electric and
  fuel cell vehicles).

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End of Chapter 14