Energy and Energy and the the EnvironmentEnvironment

Science 30: Unit DScience 30: Unit DChapter 2: Sustainable Chapter 2: Sustainable energyenergy

2.2- Forms of Solar 2.2- Forms of Solar EnergyEnergy

Solar Energy is recovered in 2 forms:Solar Energy is recovered in 2 forms:

1.1. Passive: Energy is absorbed and Passive: Energy is absorbed and distributed with no need of a distributed with no need of a mechanical device.mechanical device.

2.2. Active: Energy is absorbed but needs a Active: Energy is absorbed but needs a device to pump heat to other parts of device to pump heat to other parts of the device.the device.

Solar Energy

1) Passive Energy1) Passive Energy Passive solar design uses many features Passive solar design uses many features

to maximize solar energy:to maximize solar energy: South facing windows to absorb energy.South facing windows to absorb energy. Concrete floors to absorb radiation and Concrete floors to absorb radiation and

transfer to other sections using conduction.transfer to other sections using conduction. Convection currents created due to Convection currents created due to

temperature differences.temperature differences. Energy efficient building materials.Energy efficient building materials. Roof overhang to prevent overheating in Roof overhang to prevent overheating in

summer.summer.

2) Active technologies: 2) Active technologies: Solar heat collectorSolar heat collector

Uses flat, black boxes to capture Uses flat, black boxes to capture energy--- pipes inside have antifreeze energy--- pipes inside have antifreeze that heats up ---pumped to collector--- that heats up ---pumped to collector--- heat exchanger = energy released to heat exchanger = energy released to water tank.water tank.

Converts solar energy to thermal energy.Converts solar energy to thermal energy.

3) Earth energy systems 3) Earth energy systems (geothermal)(geothermal)

Similar to solar panels but use a loop of Similar to solar panels but use a loop of piping in the ground to collect heat.piping in the ground to collect heat.

Pipes filled with antifreeze --- heat from Pipes filled with antifreeze --- heat from earth’s core --- used to heat building.earth’s core --- used to heat building.

Used from the 1940’s on.Used from the 1940’s on. Expensive to install but little energy Expensive to install but little energy

needed to operate = savings!needed to operate = savings!

Energy Sources

4) Photovoltaic cells4) Photovoltaic cells Converts EMR into electric energy.Converts EMR into electric energy. Photon absorbed--- electrons ejected Photon absorbed--- electrons ejected

(brighter source = more electrons).(brighter source = more electrons). Disadvantages:Disadvantages:

Electric current is weak = used in small devices Electric current is weak = used in small devices or hook many together to create a large or hook many together to create a large current.current.

Only work in the light (not at night).Only work in the light (not at night). Produce only DC currentProduce only DC current Expensive to produce.Expensive to produce.

5) Hydroelectric Power5) Hydroelectric Power Moving water possess’ kinetic energy; Moving water possess’ kinetic energy;

hydroelectricity generates 19% of worlds hydroelectricity generates 19% of worlds electricity = renewable resource.electricity = renewable resource.

95% of Quebec’s energy comes from 95% of Quebec’s energy comes from water.water.

Original source of energy is the sunOriginal source of energy is the sun→ → water heated by sun evaporates → water heated by sun evaporates → carried by air currents → forms carried by air currents → forms precipitation and falls at higher altitude. precipitation and falls at higher altitude. Creates potential energy.Creates potential energy.

a) Hydroelectric Damsa) Hydroelectric Dams

Convert gravitational potential energy into Convert gravitational potential energy into electricity.electricity.

Store water in reservoir Store water in reservoir → higher the → higher the reservoir level = more kinetic energy reservoir level = more kinetic energy created.created.

Force of water pushes against turbine Force of water pushes against turbine blades → blades turn and generator blades → blades turn and generator convert kinetic energy into electrical convert kinetic energy into electrical energy. Transformers increase voltage.energy. Transformers increase voltage.

Abraham Lake Dam

Bighorn dam:

-90m high

-33km reservoir

-Lake level fluctuates 40 m.

Wave Energy

b) Hydroelectric Powerb) Hydroelectric Power

Provide 5% of Energy in Alberta.Provide 5% of Energy in Alberta. Power must be assessed based on economic, Power must be assessed based on economic,

environmental and social concerns:environmental and social concerns: Renewable, emission free and 80% efficient, low per Renewable, emission free and 80% efficient, low per

kWh cost.kWh cost. Land loss due to reservoir filling (impedes movement Land loss due to reservoir filling (impedes movement

of nutrients = of nutrients = ↓ fertility).↓ fertility). Leaching of metals into water = ↓ quality.Leaching of metals into water = ↓ quality. Loss of current cities/archeology sites.Loss of current cities/archeology sites. Interactions with aquatic ecosystem/species.Interactions with aquatic ecosystem/species.

6) Wind Energy6) Wind Energy Wind travelling through a smaller opening (tunnel) Wind travelling through a smaller opening (tunnel)

generates lots of kinetic energy.generates lots of kinetic energy. SW corner of AB is well suited for this.SW corner of AB is well suited for this.

Solar energy converted to thermal energy = kinetic Solar energy converted to thermal energy = kinetic energy in air increasesenergy in air increases→ kinetic energy of turbine → kinetic energy of turbine → electrical energy of generator.→ electrical energy of generator.

Convection currents create Westerly's that flow Convection currents create Westerly's that flow across Alberta.across Alberta. Pincher Creek, Fort Macleod, Lethbridge are prime Pincher Creek, Fort Macleod, Lethbridge are prime

spots for wind power due to wind patterns.spots for wind power due to wind patterns.

a) Wind energy a) Wind energy limitationslimitations Fastest growing form of electricity Fastest growing form of electricity

generation in Canada; sun provides energy generation in Canada; sun provides energy source (renewable).source (renewable).

Versatile (used for cities and homes).Versatile (used for cities and homes). Limitations:Limitations:

Limited usage due to required conditions.Limited usage due to required conditions. Variable energy source.Variable energy source. Inefficient conversion (30%) to electricity.Inefficient conversion (30%) to electricity. Land loss for wind farms.Land loss for wind farms.

7) Biomass7) Biomass Biomass = amount of dried plant matter.Biomass = amount of dried plant matter. Chemical potential energy from recently Chemical potential energy from recently

living organisms.living organisms. Uses and effects:Uses and effects:

Waste wood is combusted to create Waste wood is combusted to create electricity (via turbines and generators).electricity (via turbines and generators).

COCO2 2 produced is absorbed by plants = carbon produced is absorbed by plants = carbon neutral process.neutral process.

Sustainable resource as Carbon is Sustainable resource as Carbon is replenished.replenished.

Natural Resources

a) Biofuelsa) Biofuels Convert biomass into a biofuel= produced Convert biomass into a biofuel= produced

from renewable resources.from renewable resources. Common types: methane (biogas), ethane Common types: methane (biogas), ethane

(ethanol) and mixture (biodiesel).(ethanol) and mixture (biodiesel). Composition of fuels:Composition of fuels:

Methane= decomposing organics (landfills), Methane= decomposing organics (landfills), human waste and manure.human waste and manure.

Biodiesel = waste organics from industry (oil).Biodiesel = waste organics from industry (oil). Ethanol = fuel wood, waste wood, manure, Ethanol = fuel wood, waste wood, manure,

fuel crops (corn, soy) and plant waste.fuel crops (corn, soy) and plant waste.

Ethanol in GasolineEthanol in Gasoline Produced using yeast to ferment sugars in plants Produced using yeast to ferment sugars in plants

= alcohol!= alcohol! Ethanol blends with gasoline up to 10%; newer Ethanol blends with gasoline up to 10%; newer

vehicles can use up to 85% blend.vehicles can use up to 85% blend. Renewable source (crops regrown).Renewable source (crops regrown). Benefits and concerns:Benefits and concerns:

New crops absorb CONew crops absorb CO22; create alternate energy ; create alternate energy source.source.

Land taken from crop growing for food; fertilizers used Land taken from crop growing for food; fertilizers used can harm environment.can harm environment.

Inefficient creation of fuel (low energy molecules Inefficient creation of fuel (low energy molecules created, high concentrations of ethanol = toxic).created, high concentrations of ethanol = toxic).

Cow Power

Landfill gasLandfill gas

Methane released in landfills as bacteria Methane released in landfills as bacteria digest organic waste.digest organic waste.

Collect fuel to create biogas.Collect fuel to create biogas. Clover Bar Landfill (Edmonton) = Clover Bar Landfill (Edmonton) =

produces enough biogas for electricity to produces enough biogas for electricity to 4600 homes.4600 homes.

Renewable source.Renewable source.

Biofuel Energy

Hydrogen fuelHydrogen fuel Hydrogen fuel cell functions as an electrochemical Hydrogen fuel cell functions as an electrochemical

cell does; reactants supply circuit with constant cell does; reactants supply circuit with constant energy.energy.

Hydrogen enters at an electrode, oxygen enters at Hydrogen enters at an electrode, oxygen enters at the opposite the opposite → hydrogen reacts and provides → hydrogen reacts and provides electrons (electricity) and ions that complete flow electrons (electricity) and ions that complete flow of charge.of charge.

Flameless combustion reaction.Flameless combustion reaction. Usage limited by high cost of catalysts/Hydrogen Usage limited by high cost of catalysts/Hydrogen

avaliability; very efficient and produce only water avaliability; very efficient and produce only water vapor as byproduct.vapor as byproduct.

Hydrogen Cars

Transforming the EconomyTransforming the Economy

Alberta is currently a Carbon economy Alberta is currently a Carbon economy (dependant on non-renewable (dependant on non-renewable resources).resources).

Scientists predict that in the next 20 Scientists predict that in the next 20 years, carbon economies will switch to years, carbon economies will switch to hydrogen economies (dependant on hydrogen economies (dependant on renewable resources).renewable resources). Requires creative combinations of energy Requires creative combinations of energy

sources.sources. Eco City