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
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,Provideflood 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??
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 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???