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Renewable Energy Chapter 18 18-1 Renewable Energy Today Objectives 1. List six forms of renewable energy, and compare their advantages and disadvantages. 2. Describe the differences between passive solar heating, active solar heating, and photovoltaic energy. 3. Describe the current state of wind energy technology. 4. Explain the differences in biomass fuel use between developed and developing nations. 5. Describe how hydroelectric energy, geothermal energy, and geothermal heat pumps work. Renewable Energy – energy from sources that are constantly being formed Solar, wind, hydro, and geothermal Solar Energy Most all renewable NRG comes directly or indirectly from the sun ◦Passive Solar Energy Use the sun’s NRG to heat something directly A passive solar home Ceilings heavily insulated Thick walls and floors South-facing double paned windows Shade trees for summer Insulated windows ◦Active Solar Heating Uses collectors to gather the sun’s energy Collectors on roofs capture the sun’s NRG and heat a liquid which flows to a heat exchanger which heats water for the building About 8% NRG used in US is used to heat water Photovoltaic cells convert the sun’s energy into electricity No moving parts Produce a small electric current Need extended periods of sunlight Electricity stored in batteries Provides about 1 million households with electricity Wind Power Converts the movement of wind into electrical energy Faster growing NRG source Biomass When plant material, manure, or any other organic matter is used an NRG source ◦Include wood and dung (can cause air pollution and habitat destruction) ◦ Other source include methane (gas given off by decomposition) and alcohol (ethanol- fermentation of agriculture wastes) Gasohol – blend of gasoline and ethanol; less air pollution then gas Hydroelectricity NRG produced by moving water 20% of the world’s electricity Dams are expensive to build but inexpensive to operate Advantages: No air pollution,Provide flood control, water for drinking, agriculture, industry, and recreation Disadvantages: disrupts ecosystems, people are displaced, dam failure, sedimentation Geothermal NRG from the heat in the Earth’s crust Pump water heated water from rock formations and use the water or steam to power turbines Some homes used geothermal heat pumps US is the world’s larges producer 18-2 Alternative Energy and Conservation Objectives 1. Describe three alternative energy technologies. 2. Identify two ways that hydrogen could be used as a fuel source in the future. 3. Explain the difference between energy efficiency and energy conservation. 4. Describe two forms of energy-efficient transportation. 5. Identify three ways that you can conserve energy in your daily life. Look around the room…..can you find any instances were energy is being wasted?? Alternative energydescribes NRG sources that are still in development Tidal Power Uses the 2 tide changes Tide difference needs to be around 16 m Cost to build is high Ocean Thermal Energy Convection Warm surface water is used to boil sea water ◦Water at lower pressure boils at a lower temperature ◦Boiling water turns turbine ◦Expensive to operate ◦Environmental effects unknown Hydrogen Hydrogen is found in every molecule of living thing Produced water vapor as a byproduct Takes a lot of energy to produce Energy can be stored in fuel cells (produces electricity chemically) Energy Efficiency How do we reduce NRG use?? ◦Lifestyle changes? ◦Increase NRG efficiency The percentage of NRG put into a system that does useful work NRG out/NRG in X 100 More than 40% of NRG produced is wasted Decease dependence on fossil fuels Use public transportation Use more NRG efficient vehicles Hybrid cars Cogeneration ◦The production of two useful forms of NRG from the same fuel source Using wastes for fuel Energy Conservation ◦ SAVING ENERGY! Use energy efficient devices Walk! Carpool Buy products that use less packaging Turn down your thermostat (68 in winter, 78 in summer) Unplug unused electrical appliances Clean vents Water saving devices WHAT CAN YOU DO???
