Alternative Energy SourcesAlternative Energy Sources

Alternative Energy SourcesAlternative Energy Sources

SolarSolar WindWind HydropowerHydropower Tidal PowerTidal Power BiomassBiomass GeothermalGeothermal

Solar PowerSolar Power

Types of Solar PowerTypes of Solar Power

ActiveActive PassivePassive

Active Solar PowerActive Solar Power

Energy from sun is Energy from sun is stored in a stored in a “thermal mass”“thermal mass”

When needed, heat When needed, heat from thermal mass from thermal mass is then pumped is then pumped throughout throughout structurestructure

Active Solar PowerActive Solar Power This also refers to This also refers to

electrical generation electrical generation using solar powerusing solar power

Two ways to do this Two ways to do this are photovoltaic are photovoltaic cells and huge cells and huge commercial electric commercial electric facilitiesfacilities

This shows the This shows the diagram for the diagram for the house seen in the house seen in the previous slide. The previous slide. The PV panels are on the PV panels are on the roofroof

Large-scale Solar Electric SiteLarge-scale Solar Electric Site

Large-scale Solar Electric SiteLarge-scale Solar Electric Site

These facilities use solar power to These facilities use solar power to heat water to form steam. The steam heat water to form steam. The steam goes to generate electricity just as in goes to generate electricity just as in fossil fuel or nuclear electric plants.fossil fuel or nuclear electric plants.

No release of air pollutantsNo release of air pollutants No electricity generated at nightNo electricity generated at night They They dodo work on cloudy days, though. work on cloudy days, though.

Passive Solar PowerPassive Solar Power

Works on the Works on the principle that hot principle that hot air rises and cool air rises and cool air sinks air sinks (convection)(convection)

Solar heats air and Solar heats air and it moves through it moves through convection through convection through the structure or to the structure or to thermal massthermal mass

Solar PowerSolar Power

BenefitsBenefits AbundantAbundant No greenhouse No greenhouse

gases, few other gases, few other pollutantspollutants

Simple, minimal Simple, minimal repair neededrepair needed

Cheap over the Cheap over the long termlong term

DetrimentsDetriments Retrofitting needed Retrofitting needed

if structure is not if structure is not already designed as already designed as passive solarpassive solar

Has limitations, Has limitations, night, some locations night, some locations better such as south better such as south rather than north rather than north facing slopesfacing slopes

Initial capital outlay Initial capital outlay can be highcan be high

Some solar power historySome solar power history

Solar power furnace Solar power furnace was used by was used by Lavoisier to Lavoisier to discover elements, discover elements, particularly nitrogenparticularly nitrogen

Solar power water Solar power water distillation used by distillation used by French Foreign French Foreign Legion and still used Legion and still used today!today!

Wind powerWind power

Can be used for mechanical tasks, Can be used for mechanical tasks, e.g. pumping watere.g. pumping water

Can be used for generation of Can be used for generation of electricity for direct use or storage in electricity for direct use or storage in batteriesbatteries

Mechanical Power WindmillsMechanical Power Windmills High torque, low-High torque, low-

speed to pump speed to pump water, grind grain, water, grind grain, saw woodsaw wood

Electrical Power WindmillsElectrical Power Windmills

High speed, low High speed, low torque machinestorque machines

Will turn Will turn themselves off if themselves off if wind speed wind speed exceeds their limitsexceeds their limits

Effects of wind powerEffects of wind power

No greenhouse No greenhouse gasesgases

Few other Few other pollutantspollutants

CheapCheap AbundantAbundant SimpleSimple

Some noise Some noise pollutionpollution

Metal blades Metal blades interfere with TV interfere with TV & radio reception& radio reception

Aesthetic Aesthetic pollutionpollution

No evidence for No evidence for bird death.bird death.

Positive Negative

HydropowerHydropower

Electric Mechanical

How hydropower worksHow hydropower works

Negative effects of Negative effects of HydropowerHydropower

Flooding the land

Displacement of local inhabitants

Local climatic changes

Tectonic activities (Earthquakes)

Loss of species (aquatic & terrestrial)

Loss of normal nutrient flow down river

Changes temperature of water, too

Positive Effects of HydropowerPositive Effects of Hydropower

Can generate electricityCan generate electricity Can do mechanical work, e.g. grind Can do mechanical work, e.g. grind

graingrain No greenhouse gasesNo greenhouse gases Initial construction provides jobsInitial construction provides jobs

Tidal PowerTidal Power

Tidal PowerTidal Power

Essentially entails Essentially entails placing a dam placing a dam across an ocean across an ocean inlet and harnessing inlet and harnessing the energy as water the energy as water moves in and out moves in and out with the tideswith the tides

Positive & negative Positive & negative effects are same as effects are same as hydropowerhydropower

Tidal dam

Biomass EnergyBiomass Energy

Biomass Pros & ConsBiomass Pros & Cons

Burning biomass Burning biomass gets rid of solid gets rid of solid wastewaste

Creates energyCreates energy Creates new Creates new

markets for cropsmarkets for crops

Burning biomass Burning biomass releases COreleases CO22 and and other gases other gases associated with associated with combustioncombustion

Creates solid waste Creates solid waste from ashfrom ash

May cause more May cause more grasslands to be grasslands to be planted to corn planted to corn

An energy mixAn energy mix

Using more than one form of energy Using more than one form of energy to meet needs is an important way to to meet needs is an important way to ensure long-term energy needs will ensure long-term energy needs will be metbe met

Just as in ecosystem ecology, we find Just as in ecosystem ecology, we find that Diversity = Stabilitythat Diversity = Stability

Depending on only one form of Depending on only one form of energy leaves nation vulnerable to energy leaves nation vulnerable to all sorts of problemsall sorts of problems