therese camilleri vsl st. michael school scout group alternative energy sources
TRANSCRIPT
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