Post on 15-Dec-2015
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Chapter 13Chapter 13Renewable Energy and Renewable Energy and ConservationConservation
Overview of Chapter 13Overview of Chapter 13
Direct Solar EnergyDirect Solar Energy Indirect Solar EnergyIndirect Solar Energy
WindWind BiomassBiomass HydropowerHydropower GeothermalGeothermal TidalTidal
High and Low Technology Energy High and Low Technology Energy SolutionSolution
Direct Solar EnergyDirect Solar Energy Perpetually availablePerpetually available Varies with latitude, season, time of Varies with latitude, season, time of
day, and cloud coverday, and cloud cover
Heating Buildings and WaterHeating Buildings and Water
Passive solar energyPassive solar energy System of putting the sun’s energy to use System of putting the sun’s energy to use
without requiring mechanical devices to without requiring mechanical devices to distribute the collected heat distribute the collected heat
Certain design features can enhance Certain design features can enhance passive solar energy’s heating potentialpassive solar energy’s heating potential South facing windows (in N. hemisphere)South facing windows (in N. hemisphere) Well insulated buildingsWell insulated buildings Attic ventsAttic vents Overhangs and solar sunspacesOverhangs and solar sunspaces
Solar Solar SunspaceSunspace Utilizes passive Utilizes passive
solar energy to solar energy to heat and cool heat and cool homeshomes
Can be added Can be added to existing to existing homeshomes
Typically used to Typically used to heat waterheat water 8% of energy in 8% of energy in
US is used to US is used to heat waterheat water
This technology This technology could supply could supply large amount of large amount of US energy US energy demanddemand
Heating Buildings and WaterHeating Buildings and Water Active Solar EnergyActive Solar Energy
System of collecting and absorbing the System of collecting and absorbing the sun’s energy, and using pumps or fans sun’s energy, and using pumps or fans distribute the collected heat distribute the collected heat
Heating Buildings and WaterHeating Buildings and Water
Solar Thermal Electric GenerationSolar Thermal Electric Generation Means of producing electricity in which Means of producing electricity in which
the sun’s energy is concentrated by the sun’s energy is concentrated by mirrors or lenses to either heat a fluid mirrors or lenses to either heat a fluid filled pipe or drive a Stirling engine filled pipe or drive a Stirling engine
More efficient than other solar More efficient than other solar technologiestechnologies No air pollutionNo air pollution No contribution to global warming or No contribution to global warming or
acid precipitationacid precipitation
Solar Thermal Electric Solar Thermal Electric GenerationGeneration
Photovoltaic Solar CellsPhotovoltaic Solar Cells A wafer or thin film that is treated A wafer or thin film that is treated
with certain metals so that they with certain metals so that they generate electricity when they generate electricity when they absorb solar energy absorb solar energy No pollution and No pollution and
minimal minimal maintenancemaintenance
Used on any scaleUsed on any scale Lighted road signsLighted road signs Entire buildings Entire buildings
Photovoltaic Solar CellsPhotovoltaic Solar Cells
Can be Can be incorporated incorporated into building into building materialsmaterials Roofing Roofing
shinglesshingles TileTile Window Window
glassglass
More economical than running More economical than running electrical lines to rural areaselectrical lines to rural areas
Cost of Electrical Power Cost of Electrical Power PlantsPlants Alternative Alternative
power power sources are sources are becoming becoming competitive competitive with with traditional traditional power power sourcessources
Indirect Solar EnergyIndirect Solar Energy
BiomassBiomass Plant materials, such as wood, crop Plant materials, such as wood, crop
wastes and animal waste, used as fuelwastes and animal waste, used as fuel Wind energyWind energy
Electric or mechanical energy obtained Electric or mechanical energy obtained from surface air currents caused by from surface air currents caused by solar warming of airsolar warming of air
HydropowerHydropower Form of renewable energy reliant on Form of renewable energy reliant on
flowing or falling water to generate flowing or falling water to generate mechanical energy or electricitymechanical energy or electricity
BiomassBiomass
Contains energy from sun via photo-Contains energy from sun via photo-synthesizing plantssynthesizing plants Oldest known fuel to humans - still used by half Oldest known fuel to humans - still used by half
the world’s populationthe world’s population Renewable when used no faster than it can be Renewable when used no faster than it can be
producedproduced
Can convert to Can convert to biogas or liquidsbiogas or liquids Ethanol and Ethanol and
methanolmethanol Clean fuelClean fuel
BiomassBiomass
AdvantagesAdvantages Reduces dependence on fossil fuelsReduces dependence on fossil fuels Often uses waste materialsOften uses waste materials If trees are planted at same rate biomass is If trees are planted at same rate biomass is
combusted, no net increase in atmospheric combusted, no net increase in atmospheric COCO22
DisadvantagesDisadvantages Requires land, water and fossil fuel energyRequires land, water and fossil fuel energy Can lead to Can lead to
DeforestationDeforestation DesertificationDesertification Soil erosionSoil erosion
Wind EnergyWind Energy World’s fastest growing World’s fastest growing
source of energysource of energy Wind results from sun Wind results from sun
warming the warming the atmosphereatmosphere Varies in direction and Varies in direction and
magnitudemagnitude New wind turbines New wind turbines
harness wind efficientlyharness wind efficiently Most profitable in rural Most profitable in rural
areas with constant windareas with constant wind
Wind EnergyWind Energy
No waste - clean No waste - clean source of energysource of energy
Biggest Biggest constraints:constraints: Cost Cost Public resistance Public resistance
(NIMBY)(NIMBY)
Few environmental problems Few environmental problems Kills birds and batsKills birds and bats
HydropowerHydropower
Most efficient energy Most efficient energy source (90%)source (90%)
Most widely used form Most widely used form of solar energyof solar energy 19% of world’s energy19% of world’s energy
Traditional Traditional hydropowerhydropower Suited only to large Suited only to large
damsdams New technologyNew technology
Utilize low flow systemsUtilize low flow systems
HydropowerHydropower
Other Indirect Solar EnergyOther Indirect Solar Energy
Ocean wavesOcean waves Produced by windsProduced by winds Has potential to turn a turbine- and Has potential to turn a turbine- and
create electricitycreate electricity Ocean Temperature GradientsOcean Temperature Gradients
Use difference in temperature of surface Use difference in temperature of surface and deep water to create electricityand deep water to create electricity
Other Renewable Energy Other Renewable Energy SourcesSources Geothermal energyGeothermal energy
Energy from the Earth’s interior for Energy from the Earth’s interior for either space heating or generation of either space heating or generation of electricity electricity
Tidal EnergyTidal Energy Form of renewable energy that relies of Form of renewable energy that relies of
the ebb and flow of the tides to the ebb and flow of the tides to generate electricitygenerate electricity
Enormous energy sourceEnormous energy source 1% of heat in upper 10 km of earth crust 1% of heat in upper 10 km of earth crust
is equal to 500x the earth’s fossil fuel is equal to 500x the earth’s fossil fuel sourcessources
Geothermal EnergyGeothermal Energy
From From Hydrothermal Hydrothermal ReservoirsReservoirs Created by Created by
volcanoesvolcanoes Reservoirs used Reservoirs used
directly for heat or directly for heat or to generate to generate electricityelectricity
Geothermal EnergyGeothermal Energy
From hot, dry rockFrom hot, dry rock Geothermal heat Geothermal heat
pumpspumps Use difference in Use difference in
temperature temperature between surface between surface and subsurfaceand subsurface
Great for heating Great for heating buildingsbuildings
Expensive Expensive installationinstallation
Tidal EnergyTidal Energy
Typical difference between high and Typical difference between high and low tide is 1–2 ftlow tide is 1–2 ft Narrow bays may have greater variationNarrow bays may have greater variation
Potential energy difference between Potential energy difference between low and high tide can be captured low and high tide can be captured with with A dam across a bayA dam across a bay A turbine similar to a wind turbineA turbine similar to a wind turbine
High and Low Technology High and Low Technology Energy SolutionsEnergy Solutions
Most promising “energy sources” are Most promising “energy sources” are energy conservation and energy energy conservation and energy efficiencyefficiency
Energy ConservationEnergy Conservation Using less energy by reducing energy Using less energy by reducing energy
use and wasteuse and waste Energy EfficiencyEnergy Efficiency
Using less energy to accomplish a given Using less energy to accomplish a given tasktask
Hydrogen as a Fuel SourceHydrogen as a Fuel Source
Hydrogen gas (HHydrogen gas (H22)) Comprised of two hydrogen moleculesComprised of two hydrogen molecules Large amounts of available energyLarge amounts of available energy Explodes when combined with oxygen Explodes when combined with oxygen
releasing energy and forming waterreleasing energy and forming water
Hydrogen as a Fuel SourceHydrogen as a Fuel Source
AdvantagesAdvantages Very high energy densityVery high energy density Can be produced from any electrical Can be produced from any electrical
sourcesource Electrolysis (see illustration on next slide)Electrolysis (see illustration on next slide)
No greenhouse gases and few other No greenhouse gases and few other pollutantspollutants
Can be use in vehiclesCan be use in vehicles Disadvantages Disadvantages
Highly volatile (requires special storage)Highly volatile (requires special storage) Relatively inefficientRelatively inefficient
Hydrogen as a Fuel Source -Hydrogen as a Fuel Source -ElectrolysisElectrolysis
Hydrogen Fuel CellHydrogen Fuel Cell
Fuel cellFuel cell Device that directly converts chemical energy Device that directly converts chemical energy
into electricity into electricity Requires Requires
hydrogen from hydrogen from a tank and a tank and oxygen from oxygen from the air the air
Similar to a Similar to a battery, but battery, but reactants are reactants are supplied from supplied from outside sourceoutside source
Future Applications of Fuel Future Applications of Fuel CellsCells Hydrogen Fuel Hydrogen Fuel
Cell VehiclesCell Vehicles Hydrogen is not Hydrogen is not
yet readily yet readily available as a fuel available as a fuel sourcesource 61 hydrogen 61 hydrogen
fueling stations in fueling stations in USUS
Batteries in cells Batteries in cells phones or laptopsphones or laptops
Energy Consumption Trends Energy Consumption Trends and Economicsand Economics
Super-insulated buildings (right)Super-insulated buildings (right) Energy efficient appliancesEnergy efficient appliances AutomobilesAutomobiles Aircraft technologyAircraft technology Compact FluorescentCompact Fluorescent
light bulbslight bulbs Condensing furnacesCondensing furnaces
Energy Efficient Energy Efficient TechnologiesTechnologies
CogenerationCogeneration
Production of two useful forms of Production of two useful forms of energy from the same fuelenergy from the same fuel Most effective on small scale Most effective on small scale
Energy Savings in Energy Savings in Commercial BuildingsCommercial Buildings
Saving Energy at HomeSaving Energy at Home