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

hydroelectric/hydro.pptppt

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

rebasics_geothermal.html

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.