http://physics.colorado.edu/phys3070The Betz LimitWind power parametersWind power parametersThe future of wind energyOcean thermal energy conversionBiomass – fuel from plantsBiomass – fuel from plantsBurning garbageBurning garbageGeothermal energyGeothermal energyEnergy from the ocean tidesWhat are possibilities?Judah Levine, 3070L19 1http://physics.colorado.edu/phys3070http://physics.colorado.edu/phys3070Judah LevineJudah LevineJILA SJILA [email protected]@colorado.edu303 492303 492--7785 (27785 (2--7785)7785)M,F 11M,F 11--Noon, W 1Noon, W 1--3 pm3 pmalso by appointmentalso by appointmentPower point files for all lectures Power point files for all lectures now on the course web pagenow on the course web pageJudah Levine, 3070L19 2Term paper outline and abstract due next Friday. E-mail ok.Judah Levine, 3070L19 3The Betz LimitThe Betz LimitVbVapowerinputpowerExtractedvvba27163==Judah Levine, 3070L19 4Wind power parametersWind power parameters59.02716max6.023===efficiencymwattsvareapowerSuppose wind speed is 50 km/hr, diameter ofwindmill is 3 m, efficiency is 75% of maximumpossible value. How much power is generated?A: 2806 WattsB: 3172 WattsC: 4502 WattsD: 5041 WattsE: 8621 WattsJudah Levine, 3070L19 5Wind power parametersWind power parameters59.02716max6.023===efficiencymwattsvareapowerSuppose wind speed is 50 km/hr, diameter ofwindmill is 3 m, efficiency is 75% of maximumpossible value. How much power is generated?wattsPmAAPsmkmmshrhrkm504107.771307.75.171375.059.09.136.09.13110003600150223=×====×××==××πAns=DJudah Levine, 3070L19 6The future of wind energyThe future of wind energyQQXcelXcelWind source programWind source program––Rebates: $0.86 in Jan, $0.15 in FebruaryRebates: $0.86 in Jan, $0.15 in FebruaryQQOffOff--shore wind farmsshore wind farmsQQSignificant local oppositionSignificant local oppositionJudah Levine, 3070L19 7Ocean thermal energy conversionOcean thermal energy conversionQQHeat engine driven by thermal gradient Heat engine driven by thermal gradient between surface and deeper layersbetween surface and deeper layers––Very small Very small CarnotCarnotefficiencyefficiencyQQTurbine driven by ocean currentsTurbine driven by ocean currents––Potentially serious environmental impactsPotentially serious environmental impactsQQVery large capital costsVery large capital costsJudah Levine, 3070L19 8Biomass Biomass ––fuel from plantsfuel from plantsQQBurn stuff directlyBurn stuff directly––Wood, wood chips, Wood, wood chips, ……QQConvert to liquid fuel or additive (yeast)Convert to liquid fuel or additive (yeast)––Alcohols are carbon chains with OH replacing HAlcohols are carbon chains with OH replacing H••EthanolEthanol••MethanolMethanol––Diesel fuel mixturesDiesel fuel mixtures––Gasoline mixturesGasoline mixturesQQConvert to methane (natural gas)Convert to methane (natural gas)––Natural decayNatural decayJudah Levine, 3070L19 9Biomass Biomass ––fuel from plantsfuel from plantsQQDoes farming produce more energy than it Does farming produce more energy than it uses?uses?––Fertilizers, water transport, farm machineryFertilizers, water transport, farm machinery••Estimate in the text based on solar energy conversion is Estimate in the text based on solar energy conversion is not the main issuenot the main issueQQCan we grow enough plant material to make Can we grow enough plant material to make a difference?a difference?––SwitchgrassSwitchgrass, other non, other non--food cropsfood crops––Change to more vegetarian dietChange to more vegetarian dietQQShould we divert agricultural products from Should we divert agricultural products from food to fuel?food to fuel?Judah Levine, 3070L19 10Burning garbageBurning garbageQQRequires separation to remove the bad Requires separation to remove the bad stuff, filtering of fly ash, stuff, filtering of fly ash, ……––Dioxin, other bad stuff not completely Dioxin, other bad stuff not completely removedremoved••Dioxin=carcinogen formed when organic Dioxin=carcinogen formed when organic material burned in presence of chlorinematerial burned in presence of chlorineJudah Levine, 3070L19 11Burning garbageBurning garbageQQJustified more for garbage disposal Justified more for garbage disposal than for energy productionthan for energy production––Where do we put the stuff?Where do we put the stuff?••Boulder county landfill filled years agoBoulder county landfill filled years agoQQLocal oppositionLocal oppositionJudah Levine, 3070L19 12Geothermal energyGeothermal energyTectonic motionSteam vent, geyser, …Solid crustMolten materialWaterPlastic crustHot spotJudah Levine, 3070L19 13Geothermal energyGeothermal energyEnergy transport to the surface is quite slowConvection of high-viscosity materialEnergy extraction must be slow to maintain equilibriumThe Geysers area in Northern California will be depleted because energy is being extracted too quicklyJudah Levine, 3070L19 14Energy from the ocean tidesEnergy from the ocean tidesQQLimited to a few locations where the Limited to a few locations where the tides are large enough tides are large enough QQIrregular periodicityIrregular periodicityJudah Levine, 3070L19 15What are possibilities?What are possibilities?QQHydroelectricHydroelectric––Growth probably mostly outside of USGrowth probably mostly outside of USQQWindpowerWindpowerQQBiomassBiomassQQSolar cells Solar
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