Chp by malj

VIEWS: 16 PAGES: 44

									      Chapter 18
Renewable Energy Sources
     Cleaner Cars, Cleaner Fuels

   Cars release a lot of pollution
   2005
     Bush administration

     7% improvement in
      mileage
     22.2 mpg

   Diesel engines need work
    Cleaner Cars, Cleaner Fuels
   Energy Policy Act of 2005
      Tax credits

      Energy-efficient autos

   Liquid hydrogen as a
    fuel
   What does the future
    hold?
Electrical Generation Costs
         Direct Solar Energy

   Energy directly from the sun
   Tremendous amount
   Always available
   Must be collected
        Active Solar Heating
   Collectors absorb solar energy
   Pumps or fans distribute heat
   Primarily for heating water
         Passive Solar Heating

   No mechanical devices to distribute
    heat
   New home design
   Room temperature
    is steady
   Convection
   Save on heating!
A Passive Solar Home
    Photovoltaic (PV) Solar Cells

   Convert sunlight into electricity
   Thin wafers or films
   No pollution
   Minimal maintenance
    Photovoltaic (PV) Solar Cells
   Can be used in remote areas
   Good choice for developing countries:
    why?
   School, home use
    Photovoltaic (PV) Solar Cells
   Can look like conventional roofing
   Prices are coming down
   Future progress is critical
        Solar Thermal Electric
              Generation
   Sun’s energy concentrated by mirrors,
    lenses
   Heat a working fluid
   Fluid is circulated to
    boil water
   Steam generates
    electricity
       Solar Thermal Electric
             Generation
   Backup system needed
   Very efficient
   No pollution
    produced
   Must be cost-
    competitive
    Hydrogen As A Fuel Source

   Could be the fuel of the future
   Where does the hydrogen come from?
   Electrolysis
   Must use renewable fuel source to
    obtain the hydrogen!
   Few pollutants produced when burned
   Can be used for transportation
    Solar-Generated Hydrogen

   Use PV cells for electrolysis of water
   Currently not very efficient
   Still expensive
   Would need new distribution system for
    transportation
   Future development is critical
     Solar-Generated Hydrogen
   Fuel cells
     Electrochemical cell

     Like a battery

     Major carmakers working on it
        Indirect Solar Energy
   Indirect use of sun’s energy
   Biomass, wind power, hydroelectricity
             Biomass Energy
   Wood, plants, animal wastes
   Potentially renewable: why?
   Burned to release energy
   Half of human population
    relies on
   Cooking, heating
                   Biogas
   Mixture of gases
   Similar to natural gas
   Animal wastes
   Biogas digesters
     Decompose wastes

     Use gas for cooking, lighting

     Solid remains are fertilizer

   Can also be used to power fuel cells
Biogas Digester
      Biomass As A Liquid Fuel

   Methanol, ethanol
   Gasohol: mix gasoline and ethanol
   Biodiesel
     Plant, animal oils

     Becoming more popular

     Burns cleaner than regular diesel
                  Ethanol
   Sugarcane, corn, wood, agricultural and
    municipal wastes
   Government subsidizes
   Good outlet for some wastes
   Problems
      Land and water use

      Soil erosion

      Decreased food production
             Wind Energy
   Fastest growing energy source
   No waste, emissions
   Electricity
   Costs are declining
   Denmark is a world
    leader
   Need steady winds
   Great Plains of U.S.
Wind Power Is On The Rise!
        Wind Energy Problems

   Birds and bats killed by turbines
     Avoid migration routes

     Operate only at certain times

     Monitor the project

   Visual pollution
     Maple Ridge, NY

     Massachusetts coast
                Hydropower

   Flowing or falling
    water spins turbines
   Most efficient way to
    produce electricity
   19% world’s electricity
   2200 U.S. plants
        Hydropower Problems
   Damages ecosystem, species
   Displaces people: Three Gorges Dam
   High construction cost
   Reduces downstream flow
   Reservoirs eventually fill in
   Danger of collapse
   Degrades river
   Increase in waterborne disease:
    schistosomiasis
          Geothermal Energy

   Use energy from Earth’s interior
   Big potential source
   Electricity
     Hydrothermal reservoir: hot fluid

     Bring fluid to surface to generate
      electricity
Geothermal Energy
         Geothermal Energy
   Emits very few pollutants
   Is it truly renewable?
   Land may subside
      Geothermal Heat Pumps

   Used for heating and cooling
   Ground temperature relatively constant
   Underground pipes carry water
   Fluids circulate
   Expensive to install
   Use is on the increase: why?
   Very efficient!
              Tidal Energy

   Use power of the tides to generate
    electricity
   France, Russia, China, Canada
   Very few ideal locations
   May be damaging to ecosystems
      Conservation & Efficiency
   Energy conservation
     Using less energy

     Reduce use, waste

     Carpooling

   Energy efficiency
     Using less energy for a task

     More fuel-efficient cars

   Both very important!
    Energy Consumption Trends

   Use is on the increase
   Greatest increase in developing
    countries: why?
Energy-Efficient Technologies
   Appliances, automobiles, light bulbs,
    furnaces, etc…
   “Superinsulated” buildings
   May cost more, but will save money!
Energy-Efficient Technologies

   National Appliance Energy Conservation
    Act
      Sets national standards

      Much greater efficiency today

   Invest in energy improvements now to
    save money in the long run
        Automobile Efficiency
   Has improved since 1970s: why?
   Increased use of minivans, trucks, SUVs
   Efficiency must continue to improve
              Cogeneration
   Combined heat and power (CHP)
   Recycling “waste” heat
   Generate electricity, use steam before
    cooling it back down
    Electric Companies & Energy
             Efficiency
   Make more money, generate less
    electricity
   Incentives for conservation
   Help consumers save electricity
      Light bulbs, furnaces

   Company doesn’t have to invest in new
    power generation
    Electric Companies & Energy
             Efficiency
   Use cogeneration to save energy
   Improve electricity grids
      Some energy lost in transmission

   Plan for future use
Energy Conservation At Home

   Average household: $1500/year on
    utilities
   Use energy-efficient technologies
   Better insulation, windows
   Seal cracks
   Replace inefficient appliances
Energy Conservation At Home
Case Study: Green Architecture

   Consider the environment when building
   Energy conservation
   Indoor air quality
   Water conservation
   Building materials
Case Study: Green Architecture
   Adam Joseph Lewis Center for
    Environmental Studies, Oberlin College
   Geothermal heat pump
   PV cells for electricity
   Triple-paned windows
   Motion sensors
   Recycle wastewater
   Sustainable wood
   Recycled carpet

								
To top