1. Chapter 19 Alternative Energy and the Environment

2. Introduction to Alternative Energy Sources Alternative Energy –Renewable and nonrenewable energy resources that are alternatives to the fossil fuels Renewable Energy –Alternative energy sources, such as solar, water, wind and biomass, that are more or less continuously made available in a time framework useful to people Nonrenewable Energy –Alternative energy sources, including nuclear and geothermal, that are dependent on fuels or a resource that may be used up much faster than it is replenished by natural processes

4. Solar Energy Passive Solar Energy Systems –Direct use of solar energy through architectural design to enhance or take advantage of natural changes in solar energy that occur throughout the year without requiring mechanical power Active Solar Energy Systems –Direct use of solar energy that requires mechanical power; usually consists of pumps and other machinery to circulate air, water or other fluids from solar collectors to heat sink where the heat may be stored

6. Passive Solar Energy Sunlight through windows strikes specially designed masonry wall painted black Heats up and radiates outward to warm house during day and into evening

8. Provide space heating or heat water Photovoltaic cells: converts sunlight directly into electricity –Remote areas –High cost; limited efficiency; hazardous materials; large areas of land Solar Collectors

9. Photovoltaic Solar Cells

10. Solar Power Tower Focus sunlight in a central collector and generator Heat is used to produce steam to drive turbines and generate electric power

12. Ocean Thermal Conversion Using the ocean as a gigantic solar collector Uses temperature differences to cause another substance (ammonia) to boil Problems: –floating platforms –currents and critters

13. Solar Ponds Shallow pond filled with water and used to generate relatively low-temperature water Salty brine (bottom) traps heat; thermal energy from hot brine

14. Hydrogen High-quality fuel Fuel cells –combines fuel and oxygen in an electrochemical reaction –H is most common fuel type steam combined with CH4 (most economical) electrolysis gasification of biomass –Other fuel types: methanol, ethanol and natural gas

15. Water Power A form of stored solar energy; dictated by climate One of the oldest and most common energy sources Sources vary in size

17. Pump Storage System Off-peak energy is used to store water in an elevated reservoir During light power load (night), water is pumped from low to high pool

18. Power Storage System During peak power load (day), water flows from high pool to low pool through a generator “stored” energy Advantage: timing of energy production to use

19. Future of Water Power Future growth limited –alters streamflow patterns –most economical sites already used –reservoirs: sediment –increased evaporation “Micro” - local sites

20. Tidal Power Form of water utilizing ocean tides in places where favorable topography allows for construction of a power plant Large tidal range; specific shaped shoreline

21. Wind Power Used for centuries Concentrated by topography (vertical convergence) Problems: –noisy –asthethics –bird migration –large area needed

22. Biomass Energy Energy that is recovered from biomass, which is organic material such as plant and animal waste (air pollution)

23. Geothermal Energy Natural heat from the interior of the Earth that is converted to heat buildings and generate electricity

24. Geothermal Energy Plate boundaries Lower sources –space heating –swimming pools –greenhouses Groundwater (13˚ C) –shallow systems to warm/cool houses –use temp. differences Potential Adverse Environmental Impacts –gas emissions –thermal water pollution –induced seismicity –land subsidence