Alternative EnergyAlternative Energy

Chapter 18Chapter 18

Solar EnergySolar Energy

Renewable Energy SourceRenewable Energy Source Found every where at least part of Found every where at least part of

the year.the year.

Three (3) Types:Three (3) Types:– Passive Solar HeatingPassive Solar Heating– Solar Water HeatingSolar Water Heating– Solar CellsSolar Cells

Passive Solar HeatingPassive Solar Heating

How it works:How it works:– Build your home facing south.Build your home facing south.– Large, double pane windows.Large, double pane windows.– Thick walls & insulation on north side.Thick walls & insulation on north side.– Concrete, adobe or stone construction.Concrete, adobe or stone construction.– Venting for hot air out during summer.Venting for hot air out during summer.– Drapes in winter to keep heat in at night.Drapes in winter to keep heat in at night.– Deciduous trees planted on south sideDeciduous trees planted on south side

Block sunlight in summerBlock sunlight in summer Allow sunlight in winterAllow sunlight in winter

Passive Solar HeatingPassive Solar Heating

Passive Solar HeatingPassive Solar Heating

ADVANTAGESADVANTAGES

– Free energyFree energy

– RenewableRenewable

– CleanClean

– SafeSafe

DISADVANTAGESDISADVANTAGES

– UnattractiveUnattractive

– Is there enough Is there enough available sunlight in available sunlight in all areas?all areas?

– Construction costsConstruction costs

– Requires backup Requires backup heat sourceheat source

Solar Water HeatingSolar Water Heating

How it works:How it works:

– ““Solar Collectors” on roofSolar Collectors” on roof

Pipes with water or anti-freeze are coiled Pipes with water or anti-freeze are coiled through box on roof.through box on roof.

Heated water transferred to basement.Heated water transferred to basement.Heat Heat exchangedexchanged to fresh water; water to fresh water; water

pumped back to roof to be reheated.pumped back to roof to be reheated.

Solar Water HeatingSolar Water Heating

Solar Water HeatingSolar Water Heating

ADVANTAGESADVANTAGES

– Free energyFree energy

– RenewableRenewable

– CleanClean

– SafeSafe

DISADVANTAGESDISADVANTAGES

– UnattractiveUnattractive

– Is there enough Is there enough available sunlight in available sunlight in all areas?all areas?

– Requires a backup Requires a backup hot water sourcehot water source

Solar Cells (Photovoltaics)Solar Cells (Photovoltaics)

How it works:How it works:– Converts sunlight to electricity!Converts sunlight to electricity!– Sunlight strikes semi-conductorSunlight strikes semi-conductor– Electrons are excited and move; creates Electrons are excited and move; creates

electricity.electricity.– Energy can be stored in a chemical Energy can be stored in a chemical

battery for use when sunlight is absent.battery for use when sunlight is absent.

Photovoltaics (Solar Cells)Photovoltaics (Solar Cells)

Solar CellsSolar Cells

ADVANTAGESADVANTAGES

– Free energyFree energy

– RenewableRenewable

– CleanClean

– SafeSafe

DISADVANTAGESDISADVANTAGES

– Expen$ive!Expen$ive!

– Need large surface areaNeed large surface area

– UnattractiveUnattractive

– Is there enough Is there enough available sunlight in all available sunlight in all areas?areas?

– Requires a backup Requires a backup electricity sourceelectricity source

Wind EnergyWind Energy

How it works:How it works:– Sunlight heats Earth’s surfaceSunlight heats Earth’s surface– Warm air rises; cooler air replaces it (wind)Warm air rises; cooler air replaces it (wind)– Wind (mechanical E) turns giant bladesWind (mechanical E) turns giant blades– Connected to a generator; creates Connected to a generator; creates

electricityelectricity

Wind EnergyWind Energy

ADVANTAGESADVANTAGES

– Free energyFree energy

– RenewableRenewable

– CleanClean

– Well developed Well developed technologytechnology

– Electricity is cheaper Electricity is cheaper per watt than coal per watt than coal produced.produced.

DISADVANTAGESDISADVANTAGES

– UnattractiveUnattractive

– Few regions with Few regions with consistent windsconsistent winds

– NoisyNoisy

– Interfere with Interfere with microwave microwave communicationscommunications

– Harm birds & wildlifeHarm birds & wildlife

Wind EnergyWind Energy

HydroelectricityHydroelectricity

How it works:How it works:– Dam is constructed to make a reservoirDam is constructed to make a reservoir– Need height change to create enough Need height change to create enough

power of moving waterpower of moving water– Flowing water through dam turns Flowing water through dam turns

turbines, turns generator, makes turbines, turns generator, makes electricityelectricity

Hoover DamHoover Dam

HydroelectricityHydroelectricity

ADVANTAGESADVANTAGES

– Free energyFree energy

– RenewableRenewable

– CleanClean

– Flood controlFlood control

– Reservoir for recreation Reservoir for recreation & irrigation& irrigation

DISADVANTAGESDISADVANTAGES

– Disrupts ecosystems & Disrupts ecosystems & floods upstream landfloods upstream land

– Tremendous Tremendous environmental damage environmental damage during constructionduring construction

– Dam construction is Dam construction is extremely expensiveextremely expensive

– Limited to areas with Limited to areas with rivers & streamsrivers & streams

Geothermal EnergyGeothermal Energy

How it works:How it works:– Uses Earth’s heat to create steam to Uses Earth’s heat to create steam to

make electricitymake electricity– Hot Dry Rock MethodHot Dry Rock Method

Pump cold water below groundPump cold water below groundTurns to steamTurns to steamExtract pressurized steamExtract pressurized steamTurns turbine, turns generator, creates Turns turbine, turns generator, creates

electricityelectricity

Geothermal EnergyGeothermal Energy

Geothermal EnergyGeothermal Energy

Geothermal EnergyGeothermal Energy

ADVANTAGESADVANTAGES

– Free energyFree energy

– Potentially Potentially Renewable***Renewable***

– No greenhouse gasesNo greenhouse gases

– Minimal environmental Minimal environmental damage during set-updamage during set-up

DISADVANTAGESDISADVANTAGES

– Limited availability on Limited availability on Earth.Earth.

– Earth takes a long time Earth takes a long time to replace the heat.***to replace the heat.***

BiomassBiomass

How it works:How it works:– Burn organic matter to produce heatBurn organic matter to produce heat– Examples:Examples:

Wood (#1 fuel in world usage)Wood (#1 fuel in world usage)Municipal Waste (garbage)Municipal Waste (garbage)Sugar cane (Hawaii)Sugar cane (Hawaii)Chicken droppingsChicken droppings

– Convert to other productsConvert to other productsCorn to ethanol (gasoline additive)Corn to ethanol (gasoline additive)

Waste to Energy PlantWaste to Energy Plant

BiomassBiomass

ADVANTAGESADVANTAGES

– Reduces “wastes”Reduces “wastes”

– RenewableRenewable

– Conserves fossil Conserves fossil fuelsfuels

– Sell extra electricity Sell extra electricity to publicto public

DISADVANTAGESDISADVANTAGES

– COCO22 emissions emissions

– Noxious gases Noxious gases releasedreleased

– Who wants to live Who wants to live near a plant that near a plant that burns trash or burns trash or chicken poop?chicken poop?

Tidal EnergyTidal Energy

How it works:How it works:– Offshore TurbinesOffshore Turbines

Similar to underwater windmillsSimilar to underwater windmills

– Tidal BarrageTidal BarrageSimilar to hydroelectric damsSimilar to hydroelectric dams

Offshore TurbinesOffshore Turbines

Tidal BarrageTidal Barrage

Tidal EnergyTidal Energy

ADVANTAGESADVANTAGES

– Free energy Free energy

– RenewableRenewable

– Clean (non-Clean (non-polluting)polluting)

DISADVANTAGESDISADVANTAGES

– Affects ecosystemsAffects ecosystems

– UnattractiveUnattractive

– Expensive to buildExpensive to build

– Affects shipping Affects shipping

Energy ConceptsEnergy Concepts

& Efficiency& Efficiency

Introductory Energy ConceptsIntroductory Energy Concepts

EnergyEnergy– ““The ability to do work”.The ability to do work”.

KEY CONCEPTKEY CONCEPT!!– The amount of energy in the universe is The amount of energy in the universe is

constant.constant.

Six (6) Forms of EnergySix (6) Forms of Energy MechanicalMechanical

– The energy of moving The energy of moving things.things.

EX: wind, moving EX: wind, moving waterwater

ElectricalElectrical– The energy of moving The energy of moving

electronselectrons

HeatHeat– The energy of The energy of

temperature changetemperature change Hotter temperatures Hotter temperatures

can do more work.can do more work.

Six (6) Forms of EnergySix (6) Forms of Energy LightLight

– The energy of moving The energy of moving photonsphotons

ChemicalChemical– The energy The energy storedstored in the in the

bonds between atoms.bonds between atoms. EX: food, wood, EX: food, wood,

gasoline, batteries, gasoline, batteries, coal, oil…coal, oil…

NuclearNuclear– The energy The energy storedstored

between the subatomic between the subatomic particlesparticles

EX: Nuclear power EX: Nuclear power plantsplants

Kinetic vs. Potential EnergyKinetic vs. Potential Energy

Kinetic EnergyKinetic Energy– The energy of something moving.The energy of something moving.– EX: Ball rolling down a hill.EX: Ball rolling down a hill.

Potential EnergyPotential Energy– Stored energy; can be moved and used Stored energy; can be moved and used

when needed.when needed.– EX: Ball on the edge of a hill.EX: Ball on the edge of a hill.

Kinetic vs. PotentialKinetic vs. Potential

At Top = 100% potentialAt Top = 100% potential

At Bottom = 100% kineticAt Bottom = 100% kinetic

11stst Law of Thermodynamics Law of Thermodynamics

““Conservation of Energy Law”Conservation of Energy Law”– Energy can neither be created nor Energy can neither be created nor

destroyed.destroyed.

Energy in the universe is constant.Energy in the universe is constant. If you can’t destroy energy, you If you can’t destroy energy, you CANCAN change change

its form!its form!

– EX: MatchesEX: Matches– EX: Light BulbEX: Light Bulb

22ndnd Law of Thermodynamics Law of Thermodynamics

““Energy Quality Law”Energy Quality Law”– When energy changes form, some When energy changes form, some

useful energy is always degraded to useful energy is always degraded to lower quality, less useful energy.lower quality, less useful energy.

Low temperature heatLow temperature heat is the least useful is the least useful energy form!energy form!

– EX: 90% of energy in gas (chemical) is EX: 90% of energy in gas (chemical) is changed to heat!changed to heat!

Energy EfficiencyEnergy Efficiency

Net EnergyNet Energy– Total E – (E input & wasted E)Total E – (E input & wasted E)

Energy EfficiencyEnergy Efficiency– % of total E that does work.% of total E that does work.– Wasted energy reduces E efficiencyWasted energy reduces E efficiency

Life cycle costsLife cycle costs– Initial energy costs + lifetime operating costsInitial energy costs + lifetime operating costs

ElectricityElectricity

The movement of The movement of electrons. electrons.

Created by moving a Created by moving a

conducting material conducting material (copper wire) (copper wire) through a magnetic through a magnetic field.field.

““Electric Generator”Electric Generator”

Coal & Turbine PicturesCoal & Turbine Pictures