Renewable Energy Sources: Solar, Wind, Fuel Cells, Biomass, and Alternatives, Exams of Geography

Download Renewable Energy Sources: Solar, Wind, Fuel Cells, Biomass, and Alternatives and more Exams Geography in PDF only on Docsity! 1 Alternative Energy Generation Geography 1000 Lecture 24 (Next to last—Hang on!!) Spring 2009 Some Terms from the Lecture and Text forTest!!  Renewable Energy Use in 2005 (Biomass 46.5%, Hydropower 44.5%, Wind 2.3%, Solar 1%) P. 357  Flat Plate solar collector p. 358  Energy Star Program p. 360  Photovoltaic Cells p. 361-362 CSP p. 363  Power tower p. 363, Wind Power p. 367  Biomass again p. 368-370, Biofuels p.370  Fuel Cells –Hywire and FreedomCAR p. 372-373  Tidal barrage p. 375, OTEC p. 375  Importance of a national Energy Policy p. 375-377 Introduction  Alternative energy sources are usually renewable, sustainable or potentially sustainable, and environmentally benign.  The alternative energy sources covered in the lecture include:  Solar Power  Wind  Fuel Cells  Biomass  Geothermal and others  Energy conservation and efficiency improvement is also an effective path to meet our future needs. GROWING ENERGY DEMANDS World energy consumption by fuel source. The graph indicates world energy consumption in quads (1 quad = 1.06 E18 J) for the years 1999 and 2020 (estimate) for various fuel sources. 1) International Energy Outlook 2002 1) Energy Information Administration, Office of Integrated Analysis and Forecasting, International Energy Outlook 2001 , rep. no. DOE/EIA-0484(2001), US Department of Energy, Washington, DC (March 2001). Also available online is International Energy Outlook 2002 at http://www.eia.doe.gov/oiaf/ieo/index.html. World energy consumption by fuel source Renewable-energy Use in the United States 2 Examples of Renewable Energy Sources 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 Solar Heating of Water: Flat-plate Solar Collector Solar Water Heaters Solar Space Heating Solar Building Siting 5 Wind Power: Benefits or Drawbacks?  Level of environmental degradation  Geographical distribution of energy produced  Aesthetics WHAT IS A FUEL CELL  Reversed Electrolysis Device  Pt coated electrodes  Use air as a source of O2 How Does it Work  Electrolyte- proton- exchange-membrane (PEM), Phosphoric Acid  Combines Fuel and Oxygen  Produces H20 (l), heat, CO2 www.howstuffworks.com Still a little fuzzy? DOE’s website: http://fossil.energy.gov/coal_power/fuelcells/fuelcells_howitworks.shtml ADVANTAGES OF FUEL CELLS  EFFICIENCY  Fuel cells can convert as much as 80% of the energy stored in the fuel *  QUIET  NO MOVING PARTS  EXTRA HEAT CAN BE USED * Berinstein, Paula. Alternative Energy: Facts, Statistics, and Issues. Westport, CT, Oryxpress 2001 Graph Courtesy of Mercedes-Benz MORE ADVANTAGES  Low Pollution- Fuel cells produce only water and CO2 depending upon the fuel used  Low Maintenance/Operating cost  Can use conventional fuels - gasoline, methane, propane  Small or large scale uses DISADVANTAGES  Still produce CO2 although with more usable energy.  Expensive: (Pt) It costs about $40,000 to make a fuel cell system for a car.*  (Power plant estimated costs 1999: $800-1200/kWh (The first one in Austin cost about $4000/kW)**)  Hydrogen/Reformer Problem  Clean Fuel * Berinstein, Paula. Alternative Energy: Facts, Statistics, and Issues. Westport, CT, Oryxpress 2001 ** Daily Texan 17.7. 2002 6 FUEL CELL IN AUTOMOBILES  Fuel Cell efficiency~40% (depends on fuel)- recall reformer, up to 80% if heat regenerated  Motor efficiency ~80%  Can be combined with recharging while braking  Overall Efficiency: ~32% REGULAR COMBUSTION ENGINE  A lot of the energy is wasted in the heat of the exhaust as well as in the radiator.  Pollution (NOx , SOx VOC and other)  Has a very low efficiency, about 20-25% .* * Physics Today. April 2002 A BATTERY-POWERED CAR  Battery efficiency: ~90%  Motor efficiency ~80%  TOTAL: 72%  No Pollution ???  Remember that the power had to be generated somewhere else, most likely a conventional coal plant! ~40%.*  Real Efficiency ~29% * Berinstein, Paula. Alternative Energy: Facts, Statistics, and Issues. Westport, CT, Oryxpress 2001 Comparing the Battery and Fuel Cell in automobile  Fuel cell slightly more efficient and without the conventional pollution  Fuel cell design offers convenient ―recharge‖ at a gas station  Fuel cell automobiles are still much more expensive ($80,000  80mpg/52mpg (Toyota Prius-hybrid) IS IT WORTH IT?  The U.S. Department of Energy (DOE) is projecting that if 10% of automobiles used in the US were powered by fuel cells, air pollutants would be cut by one million tons per year and 60 million tons of CO2 would be eliminated yearly. BIG SCALE POWER GENERATION  Fuel Cells could achieve very high efficiency (~80%) if the extra heat produced is used. This might be possible in a large scale commercial plants.  Can use current infrastructure  Large reduction of emissions  High investments are necessary with current technologies. 7 THE MAIN PROBLEM REMAINS  We still need to use natural gas or diesel to burn or another form of energy to be able to generate fuel for the fuel cells.  Carbon dioxide emissions are lowered (higher efficiency) but not at all eliminated. (down 60% for coal, 25% CH4)-DOE Conclusions- FUEL CELLS  in transportation can help significantly reduce emission of many pollutants.  can help lower, not eliminate the amount of CO2.  will not solve long term dependence on fossil fuels, chiefly natural gas and oil. Biomass Energy  Burning firewood  Burning wastes  Burning biogas (methane) Renewable Energy and Transportation  Biofuels: ethanol and biodiesel—THIS may create a really dramatic change in the markets for corn in the US and the world.  Hydrogen: the fuel for the future Additional Renewable Energy Options  Geothermal energy  Tidal power  Ocean thermal-energy conversion (OTEC) Geothermal Energy: Benefits or Drawbacks?  Consistent source  Level of pollution  Cost-effectiveness  Technology required for extraction  Geographical distribution of energy produced