Renewable Energy Chapters15 Living in the Environment, 12 th Edition, Miller Advanced Placement Environmental Science
Energy Efficiency Solar Energy Hydropower Wind Power Biomass Geothermal Sustainability
Energy Efficiency Increasing energy efficiency of common devices has economic and environmental advantages Reducing oil imports Prolonging fossil fuel supplies Reducing pollution and environmental degradation Saving money Buys time to develop new technology Creating jobs
Efficiency of Some Common Devices Device Efficiency (%) ß ßDry-cell flashlight battery90 ß ßHome gas furnace85 ß ßStorage battery70 ß ßHome oil furnace65 ß ßSmall electric motor62 ß ßSteam power plant38 ß ßDiesel engine38 ß ßHigh-intensity lamp32 ß ßAutomobile engine 25 ß ßFluorescent lamp22 ß ßIncandescent lamp 4
Energy Efficiency percentage of energy input that does useful work in an energy conversion system
Ways to Improve Energy Efficiency Between 1985 and 2001, the average fuel efficiency for new motor vehicles sold in the United States leveled off or declined Fuel-efficient models account for only a tiny fraction of car sales Hybrid-electric cars are now available and sales are expected to increase Fuel-cell cars that burn hydrogen fuel will be available within a few years Electric scooters and electric bicycles are short-range transportation alternatives
Energy use of various types of transportation
Ways to Improve Energy Efficiency Superinsulated house is more expensive than a conventional house, but energy savings pay back the extra cost Strawbale houses have the additional advantage of using an annually renewable agricultural residue, thus slowing deforestation
Ways to Improve Energy Efficiency Existing homes can be made more energy efficient adding insulation plugging leaks installing energy-saving windows wrapping water heaters installing tankless models buying energy-efficient appliances and lights
Energy Efficiency Solar Energy Hydropower Wind Power Biomass Geothermal Sustainability
Solar Energy Buildings can be heated passive solar heating system active solar heating system Solar thermal systems are new technologies that collect and transform solar energy into heat that can be used directly or converted to electricity Photovoltaic cells convert solar energy directly into electricity
Suitability of Solar Usage best when more than 60% of daylight hours sunny
Solar Heating Passive system: Absorbs & stores heat from the sun directly within a structure Active system: Collectors absorb solar energy, a pump supplies part of a buildings heating or water heating needs.
Photovoltaic (Solar) Cells Provides electricity for buildings
Solar Thermal Techniques Solar Two SOLAR%20AMERICA%5B1%5D.ppt/Seminar/ SOLAR%20AMERICA%5B1%5D.
Heliostats ßHeliostats provide concentrated sunlight to the power tower ßThe reflecting mirrors follow the sun along its daily trajectory SOLAR%20AMERICA%5B1%5D.ppt/Seminar/ SOLAR%20AMERICA%5B1%5D.
Power Tower ßSunlight from mirrors are reflected to fixed receiver in power tower ßFluid transfers the absorbed solar heat into the power block ßUsed to heat a steam generator Solar One SOLAR%20AMERICA%5B1%5D.ppt/Seminar/ SOLAR%20AMERICA%5B1%5D.
Solar-Hydrogen Revolution Splitting water can produce H 2 gas If scientists and engineers can learn how to use forms of solar energy to decompose water cheaply, they will set in motion a solar-hydrogen revolution Hydrogen-powered fuel cells could power vehicles and appliances
Basically…… 2 H2O O2 + 4 H+ + 4 e- 2 H2O + 2 e- 2 OH- + H2
Energy Efficiency Solar EnergyHydropower Wind Power Biomass Geothermal Sustainability
– Currently - about 10% of U.S. electricity comes from hydropower. hydroelectric/hydro.pptppt History of Hydroelectric tml
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Tidal Power Plant
Energy Efficiency Solar Energy Hydropower Wind Power Biomass Geothermal Sustainability
Rotary Windmill
Energy from Wind Production of electricity and hydrogen gas by wind farms is expected to increase Western Europe currently leads in the development of wind power Land used for wind farms also can be used for ranching or crops and most profits stay in local communities
Optimization ßLow Torque – Rapid Speed ßgood for electrical generation ßHigh Torque – Slow Speed ßgood for pumping water ßSmall generator ßlow wind speeds ßcaptures small amount of energy ßLarge generator ßhigh wind speeds ßmay not turn at low speeds
Source: American Wind Energy Association
Energy Efficiency Solar Energy Hydropower Wind PowerBiomass Geothermal Sustainability
Energy from Biomass In the developing world, most people heat homes and cook by burning wood or charcoal Plant materials and animal wastes also can be converted into biofuels, Biogas Liquid ethanol Liquid methanol ßUrban wastes can be burned in incinerators to produce electricity and heat
Types of Biomass Fuel
Conversion Processes Biomass Feedstock – – Trees – – Forest Residues – – Grasses – – Agricultural Crops – – Agricultural Residues – – Animal Wastes – – Municipal Solid Waste Fuels: Ethanol Renewable Diesel Methanol Hydrogen Electricity Heat Products – – Plastics – – Foams – – Solvents – – Coatings – – Chemical Intermediates – – Phenolics – – Adhesives – – Fatty acids – – Acetic Acid – – Carbon black – – Paints – – Dyes, Pigments, and Ink – – Detergents – – Etc. Biorefinery - - Acid Hydrolysis/Fermentation - - Enzymatic Fermentation - Gas/liquid Fermentation - Thermochemical Processes - Gasification/Pyrolysis - Combustion - Co-firing
Energy Efficiency Solar Energy Hydropower Wind Power BiomassGeothermal Sustainability
Geothermal Energy Geothermal energy can be used to heat buildings and to produce electricity Geothermal reservoirs can be depleted if heat is removed faster than natural processes renew it, but the potential supply is vast
Technology ßGeothermal Heat Pumps ßshallow ground energy ßDirect-Use ßhot water can be piped to facilities ßPower Plants ßsteam and hot water drive turbines geothermal/GeothermalEnergy.pptGeothermalEnergyppt
Dry Steam Power Plants ßHydrothermal fluids are primarily steam ßSteam goes directly to turbine ßNo fossil fuels geothermal/GeothermalEnergy.pptGeothermalEnergyppt
Benefits ßClean Energy ßone sixth of carbon dioxide vs. natural gas ßvery little if any nitrous oxide or sulfur compounds ßAvailability ß24 hours a day, 365 days a year ßHomegrown ßRenewable geothermal/GeothermalEnergy.pptGeothermalEnergyppt
Environmental Effects ßOnly emission is steam ßSalts and dissolved minerals reinjected ßSome sludge produced ßMineral extraction ßLittle Visual Impact ßSmall acreage, no fuel storage facilities geothermal/GeothermalEnergy.pptGeothermalEnergyppt
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Future ßOnly tiny fraction is currently used (U.S is the #1 user) ßDry hot rock heated by molten magma ßDrill into rock and circulate water geothermal/GeothermalEnergy.pptGeothermalEnergyppt
Energy Efficiency Solar Energy Hydropower Wind Power Biomass GeothermalSustainability
Suggestions to make the transition to a more sustainable energy future.