VCE Environmental Science

VCE Environmental Science
Revision Lecture Area of Study 1 Energy and Global Warming Katie Reed Eltham High

Understanding Area of Study 1
Principles of Energy Definition of fossil and non-fossil, renewable and non-renewable Forms, availability, extraction, refinement, energy conversions of: Coal Gas Petroleum Uranium Solar Wind Hydro Geothermal Biomass Natural/EnhancedGreenhouse Effect Non-Government Strat. Earth Hour Carbon Sinks Carbon Offset Government Strat. Carbon Tax Building Design Public Awareness International Strat. Kyoto Protocol UNFCCC IPCC International Technological Initiative What is it? Our use of Energy over time Difference between potential & kinetic energy. Measuring energy. Laws of Thermodynamics Exothermic and Endothermic Reactions Combustion Energy Efficiency Layers of the Atmosphere EM Spectrum & light behaviour Greenhouse Gases Natural GHE & Climate Change Enhanced GHE Fossil Fuels & Alternatives Policies

Principles of Energy

Most of the Energy on Earth is derived from the Sun.
In scientific terms, Energy is the ability for a system to do work. Note: Work means to apply a force, or transfer energy to a system Systems are any objects that contain components (inputs & outputs), for example, Human Body Machines Tectonic Plates Weather Most of the Energy on Earth is derived from the Sun.

The Two Types of Energy Potential Energy is stored energy in a system
Kinetic Energy is moving energy; energy due to motion

Unit 3 Exam, 2007 Question 4 What type of energy does the water behind the dam represent? A. Kinetic B. Potential C. Electrical D. Chemical

Mechanical Energy Mechanical Energy is the total available energy in the system (both the potential and the kinetic).

FIRST Law of Thermodynamics
Energy can neither be created or destroyed, it is simply transformed from one system to the next.

Unit 3 Exam, 2007 Question 5 The law of conservation of energy means that the hydroelectric power station A. Converts all of the water’s energy into electricity. B. Efficiently transforms one type of energy into another. C. Converts all the water’s energy into different forms of energy D. Conserves the environment by generating no greenhouse gases

SECOND Law of Thermodynamics
Entropy (the ‘chaos’) always increases Consequences: Useable energy in a system decreases with each transformation Heat energy always flows from higher to lower energy levels (hot to cold) Most energy is lost in systems through heat.

Exothermic & Endothermic Reactions
Exothermic Reactions: Release energy by breaking bonds Lose heat to the environment Example: combustion Endothermic Reactions: Require energy to proceed Absorb energy (recording a temperature drop)

Unit 3 Exam, 2007 Question 9 The term ‘exothermic’ refers to a reaction A. In which heat is given out. B. In which heat is absorbed. C. Which proceeds very rapidly. D. Which requires high temperatures before it begins

Combustion Combustion is an exothermic reaction in which a substance reacts with oxygen to give heat and light. The heat energy (exploding energy) in these reactions is usually used to do work (example a car).

Energy Efficiency Calculating Energy Efficiency
Energy Efficiency is critical to sustainable growth. Reducing heat loss, reduces the ‘wasted’ energy in a system. This can be accomplished by: Reducing friction Reducing heat output (bulbs) Increasing combustion efficiency (car engines) Calculating Energy Efficiency 100 X Energy Efficiency (%) Total Energy Input Useful Energy Output = Example 1: For every 100J put into a car engine (unleaded petrol) 30J of work is done by the driveshaft, what is the efficiency of the car? Example 2: In getting petrol to a fuel station, energy is ‘lost’. Petrol extraction is 96% efficient; refining is 87% & distribution in 97%. What is the efficiency of getting petrol to a station? Overall Efficiency (%) Decimal efficiency = X Decimal efficiency Example 2: Energy Efficiency = 0.96*0.87*0.97 = 0.81 Example 1: Energy Efficiency = 100/100*30 = 30%

Unit 3 Exam, 2007 Question 10 Each kg of hydrogen gas used (with excess oxygen) contains approx kJ of chemical energy, and in the fuel cell produces 3,500kJ of electrical energy. The percentage efficiency of conversion of the fuel cell is: A. 0.27% B. 7.3% C. 27% D. 73%

Fossil Fuels & Alternative Sources

Fossil Fuels & Non-Renewables
Definition Fossil Fuels & Non-Renewables The term ‘Fossil Fuel’ refers to coal, oil & natural gas deposits on Earth, which Are combusted to release their chemical energy for work. Were formed over millions of years from the compression and heating of beds of decomposing matter (carboniferous fossils) Coal formed from decomposed plant matter. Oil products from decomposed marine animals. Fossils fuels are non-renewable as they can be replaced over geological time, but not within the span of human civilisation.

Coal - Formation Coal is formed when decomposing plant materials remains under pressure and heat for millions of years. The more pressure the plant material is put under the denser and more ‘carbon pure’ it becomes. There are many grades of coal based on purity. The denser the coal, the hotter it burns. Brown coal (most common in Australia) is a low grade coal with about 70% carbon.

Availability & Use of Coal
Globally coal is highly available as historically conditions to create it were wide spread. There is currently enough coal to last until 2100 at current consumption rates. Australia has large resources of black and brown coal, especially along the eastern seaboard. Use In Victoria brown coal is used exclusively to provide 6555MW of electricity (approx. 67% of total generation) In Australia coal is used to supply 80% of electricity required Globally coal fired power stations provide 40% of electricity world wide.

Extraction of Coal Preferred mining of coal
Open pits Adjacent to power station or within infrastructure network (reduce transport costs) Open cut mining only possible when seam is near the surface and at a low angle. Historically coal mining has taken place underground, following the seams. Dangerous Natural gas pockets. Rock collapse Coal dust destroys lung tissue Whilst open cut mining more economic and safer it has a devastating effect on the environment, which rarely recovers. Pike River Coal Explosion in New Zealand in 2010 claimed 29 miner’s lives. Their bodies are still trapped in the mine.

Coal Processing & Energy Transformations
38-50% Efficient Coal is crushed in a mill before being combusted in a furnace in order to heat water in a boiler. The high pressure steam is used to turn a turbine, which is attached to an electrical generator. The steam is condensed and cooled before being recycled through the system. The electricity is passed over high voltage wires across the coverage area before being stepped down at transformer stations in order to be used in factories and homes. Chemical Energy > Heat Energy (combustion of coal) > Heat Energy (Steam) > Kinetic Energy (turn turbines) > Electrical energy (electromagnetic flux)

Electricity From Coal Advantages Disadvantages
Burning coal is one of the cheapest ways to generate power at the moment. Coal power stations can be built anywhere where there are good transport links and a plentiful supply of cooling water The world has many coal reserves. Coal can be safely transported. Burning coal produces carbon dioxide, which contributes to the greenhouse effect. It also produces sulphur dioxide, (forms acid rain) Coal is not renewable. There are limited supplies which will run out one day Coal-fired power stations need huge amounts of fuel. Maximum 50% efficiency

Formation of Oil Products
Decaying marine are covered by layers of sediments. The pressure and temperature of being deeply buried creates a greasy fluid. The fluid rises (less dense than water) through a porous rock. If it is trapped by a cap rock can be extracted as oil.

Extraction & Refining Extracting oil requires drilling through cap rock and siphoning oil products. Generally the oil in the well is under pressure and will naturally come to the surface. Refining oil is done through fractionation Boiling off different products at different temperatures. In 1 barrel of oil 50% petrol 40% other fuels 10% shopping bags, moth balls etc.

Availability & Use of Oil
Oil formation requires special conditions, thus rarer. The middle east has the largest oil fields and reserves 1239 Billion Barrels of oil are in reserve. In 2008 globally 82.1 Million barrels were being produced per day. An oil barrel contains 41 gallons, (1 gallon = 4 litres) Within Australia there 3 main oil fields (Bonaparte, Gippsland and Perth Basins) Oil is used most readily as fuel (diesel, petrol and aviation fuel) for transport, though can be used in an oil-powered power plant (rare).

Energy Conversions 38% Efficient
Oil is piped into the power station where it is burnt in boilers to heat water. High pressure steam is produced and piped to the turbines. The steam turn the turbines Turbines run electrical generators that create electricity Remember for the exam: When talking about electricity transformations and how it gets to houses it travels over low-loss high voltage wires and is stepped down by transformers at sub-stations. 38% Efficient

Oil Generation Advantages Disadvantages
Oil is easy to transport by pipeline or ship Oil-fired power stations can be built anywhere where there are good transport links and where there is a plentiful supply of cooling water A large amount of electricity can be generated from one power station quickly. Burning oil produces carbon dioxide, which contributes to the greenhouse effect It also produces other emissions eg sulphur dioxide Oil is not renewable. The world’s supply of oil is running out quickly Using oil is very expensive compared to coal and gas. The mining and production of oil is a politically charged issue (i.e. oil wars)

Formation, Reserves & Extraction of Gas
Natural Gas used for energy is methane. Fossil fuel methane is generated from the decomposing matter. There are usually large quantities of methane in both coal pits and oil fields. Natural gas is also formed when oil fields are ‘over cooked’. Globally there are large gas supplies in the Middle East and Europe. Australia has large natural gas fields in all of its oil basins. Hydraulic fracturing is a common way of extracting gas. You drill into the gas laden strata and use water to hydraulically crack the rocks and release gas. NOTE: Natural gas and biogas are the same product (methane) however, have VERY DIFFERENT sources. Natural gas from fossils is NOT-RENEWABLE.

Unit 3 Exam, 2007 Question 7 Which one of the following is an advantage of natural gas? A. It is renewable. B. It is non-renewable. C. There are many sources world wide. D. It producers no carbon dioxide emissions.

Up To 80% Efficient with cogeneration
Energy Conversions NOTE: Gas is an efficient energy production option as it employs co-generation (CHP – Combined heat & power), that is the use of the by-product of heat energy to further make more useful electrical energy. Gas is combusted in a turbine, turning them. Turbines drive electrical generators Hot exhaust from gas is used to heat boiler & make steam. Steam is used to further turn turbines to produce electrical energy. Up To 80% Efficient with cogeneration

Gas Generation Advantages Disadvantages
Gas is light and easy to transport by pipeline Large amounts of electricity can be generated from one gas-fired power station Gas-fired power stations are normally built near rivers and the gas pipeline network but they can be built anywhere Burning gas produces carbon dioxide, which contributes to the greenhouse effect Natural gas is not renewable. There is a limited supply, which will eventually be used up, however we can make renewable biogas. The UK is importing most of its gas. This means that our energy supplies may become quite costly if wholesale prices rise

Uranium Reserves For Nuclear Energy
Uranium is used in nuclear fission reactors as a source of electricity generation. Uranium is a heavy metal element found in rocks. It is not a fossil fuels, though is also non-renewable (there is a limited supply that cannot be replaced). Uranium is generally found in old rock, predominantly in Australia. Australia has multiple uranium ore reserves in central Australia.

Extraction, Refinement & Use
The difficulty with Uranium is that it is found at extremely low concentrations. Uranium ore must be crushed and undergo an ‘enrichment process’ including: Milling, concentrating and converting. Extremely energy intensive. Uranium is only used in Australia for medical use (Lucas Heights Reactor) Nuclear Power Stations Provide about 15% of the World’s Electricity. U.S, France and Japan are largest users of Nuclear Power Case Study: Nogent Nuclear Power Station, France 78% of all electricity in France is produced via nuclear power. Much of this energy is exported to central Europe and the U.K. Nogent Nuclear Power Station is located 120km South East of Paris Provides electricity to just under 4 million people in the Ile-de-France region 2 reactors produce 1363MW each

How Nuclear Power Work – Nuclear Fission
Neutrons are fired at Uranium fuel rods causing the Uranium atom to spit. The fission process releases energy (as bonds break) , neutrons and alpha particles. Control rods (of boron) are used to stop the cascade of neutrons and a ‘meltdown’ reaction

Energy Conversions 30% Efficient
Uranium fuel rods added to a core with control rods. Neutrons are fired at the fuel rods causing decay of the uranium which releases heat. The heat is used to boil water and generate steam. The steam is used to drive turbines, The turbines create electical energy that is transferred via high voltage wires 30% Efficient

Nuclear Generation Advantages Disadvantages
Uranium is readily and cheaply available, and nuclear fuel is easily stored. A small amount of nuclear fuel produces a lot of electricity. Uranium can meet a growing global energy demand whilst alternative energies support/are being developed. Nuclear power stations do not produce any carbon dioxide from nuclear fission and thus do not contribute to greenhouse gases. Nuclear power stations may be unpopular with people who are concerned about how safe they are. It is a cultural and historical issue. Nuclear energy is not renewable. When uranium runs out it cannot be replaced. Nuclear energy produces radioactive waste which is difficult to store and has a half life of 4.47 billion years. Nuclear power stations cannot be switched on and off easily

Renewable Energy Sources
Definition Renewable Energy Sources Renewable energy is energy that is derived from sources that can be replenished within the human civilisation time span. Generally, renewable energy includes: Solar Energy (From Sun) Wind Energy (From general spinning of turbines) Hydro Energy (From Sea, Rivers and Dams) Geothermal (From the heat of the planet’s core) Biogas (methane gas generated from renewable sources) Renewable energy generation is a current fast expanding field. Projects currently being worked on include: Fusion Kite Wind Energy

Unit 3 Exam, 2007 Question 1 Which one of the following is a non-fossil energy source? A. Coal B. Oil C. Uranium D. Natural Gas

Solar Energy Formation
Note: 51% of the solar energy reaching the surface is 10,000 times all of the commercial energy used each year. Two ways to capture sun’s energy at the moment: Photovoltaic (solar cells) Using semi-conductive material to move electrons (current) High energy beams of light, and using this energy to heat water. Solar Thermal High Energy Note: also research about using this type of energy to create hydrogen gas (from water). The term photovoltaic refers to energy collected by solar panels (exclusively). In contrast solar energy is the collective name for all energy derived from the sun.

Photovoltaic Solar panels are made of multiple layers of semi-conductive material. Photons (packets of light) hit the semi-conductive material. Electrons move freely through this material in one direction. Moving electrons are a current (electricity). As the current generated in a PV cell is very small many panels are placed together. Electricity must be immediately used or stored in batteries. 15% Efficient

High Energy Solar 50% Efficient
High Energy Thermal condenses light rays from the sun using mirrors that are centralised on a point (usually a tower). The tower contains a crystalline substance that can melt (i.e. NaCl), this melted substance is used to heat water to generate steam and drive a electric turbine. Also can heat the tower to create a wind tunnel. The U.S. Had many prototypes of this energy source (especially in California) which have been decommissioned with the G.F.C. Spain currently uses this source to generate a component of its power 5-10MW If the U.S. was to use this source exclusively they would require 60,000km2 of land. ½ the land mass of strip mining Uranium for 30 years of nuclear Can’t use this land for other uses as with wind farms. Unsure about reliability of power source. 50% Efficient

Global Use of Solar Energy
Users of Solar Thermal Energy China (180PJ) US (62PJ) Japan (23PJ) Users of Solar Electrical Energy Germany 3.1 TWh US (0.7 TWh) Spain (0.5 TWh) Potential Use in Australia Australia has a naturally large solar radiation value Max kwh/m2 day in central and northern Australia Min 2.75 kwh/m2 in Tasmania and Melbourne Globally all of Australia is exposed to more radiation per day than Europe or most of Canada and Alaska. 58 million PJ of solar radiation falls on Australia every year (Australia uses 5800PJ per year). Currently solar energy equals 0.1% of total primary energy consumption. It is expected to increase to 5.9% (24 PJ p.y. in 2030)

Solar Energy Advantages
Solar energy is renewable and the Sun’s heat and light are free Solar energy can be used to generate electricity in remote places where other electricity supplies are hard to come by It does not produce any carbon dioxide, which contributes to the greenhouse effect Energy is usually generated at or near to the location it will be used. This keeps transmission and distribution costs to an absolute minimum. It can work in conjunction with other forms (coal plants) e.g. Adding energy to the grid in Melbourne for credit. Disadvantages PV cells do not work so well when it is cloudy and do not work at night. They also vary seasonally and based on location. Large scale solar energy plants has a high capital costs. In Australia the largest volume of solar radiation is in the northwest, which is not connected to the grid, infrastructure will be required to enable large scale solar production. We cannot store large amounts of solar produced energy for more than a few hours.

Definition Wind Energy
80% Efficient Wind energy harnesses the kinetic energy of the wind by making it turn turbines. The electrical power available= velocity of wind3 If the wind speed doubles, the power generated is multiplied by eight. The length of the blades on the rotor also determine the amount of power produced, the longer the blade, the more wind it can harness. A wind turbine that produces 1 MW (common) could provide sufficient electricity to power approximately 300 homes, and save over 2000 tonnes of greenhouse gas emissions per year (NSW Gov.)

Use In Australia For wind farms to be viable an area requires frequent high velocity wind speeds. In Australia these regions include South west coast of WA Entire southern coast of Australia Southern S.A. Bass Straight and Tasmania All of the Victorian and Southern NSW Coastline. There are 16 current wind farms in Australia producing over 10 MW of electrical power. In total Australia produces 1877 MW electrical energy (1.3% of our demand) Case Study: Portland Wind Farm Located in Portland, Victoria(38°21′8.74″S 141°35′14.4″E) One of the largest in Australia, four sites totalling 98 turbines. 195MW production at a cost of $330 million AUD Provides 500 GWh annually, power 125,000 homes (Geelong area). Provides 7% of Victoria's electrical energy

Global Use of Wind Energy
Case Study: Brazos Wind Farm, Texas Located in Texas, United States. Globally U.S. Has most wind farms, produce 2 % of yearly electricity. Wind farm consists of 160 turbines, each producing 1 MW. This farm provides 30, 000 homes with electricity in Texas. Texas weather is highly variable, however, have consistent winds. Highest wind potential state in U.S. Lots of flat farming land that wind farms can co-inhabit with. Globally we have a huge wind resource 72TW. This is 5 times world energy demand. Currently wind energy accounts for 2% of the global electrical energy needs. Denmark, Ireland, Portugal (all14%), Germany (8%) & Spain (11%) are large producers and users of electrical energy generated from wind.

Wind Energy Advantages
The land required for wind farms can still be used for farming, housing, industry etc. (co-land use) maximising land efficiency and the areas where wind farms can be installed. No greenhouse gases or pollution generated. Low running cost and upkeep once a facility is established. Disadvantages The wind farms can be noisy. Expensive to produce and install, require in many instances to lease access to land. Some people feel they decrease the aesthetic value of an area. Some research and suggestion that they can be dangerous for bird life. Some people feel they impact negatively on natural environments – disrupt biodiversity. Not a constant or predictable source of energy.

Unit 3 Exam, 2007 Question 8 Which one of the following is an disadvantage of wind power? A. It is renewable. B. It is non-renewable. C. It producers no carbon dioxide emissions. D. It will only produce electricity part of the time.

Definition of Hydro Energy
80% Efficient Hydroelectricity is electrical energy that is generated from: Water Stored or moving through reservoirs, flowing rivers, streams, waterfalls etc. It falls from a height (gravitational potential energy) and is channelled through turbines in order to spin them and generate electrical electricity.

Global Use The use of hydroelectricity in a country relates directly to its: Availability of water Topography to provide potential energy. Water runoff and storage potential Globally, approximately 16% of energy is produced by hydroelectricity. China has the highest hydroelectricity potential of any nation. Also has the largest single hydro project – thrree gorges provides 18,200 MW at the moment, predicted to provide MW when complete. Case Study: Three Gorges Dam, China Three Gorges Dam spans the Yangtze River in the Hubei Province in China 26 turbines, each with a capacity of 700MW exist at the moment, with a plan to push it to 32 turbines. When built it was planned to account for 10% of China’s electricity needs, however China’s growth is so fast that by the time it is fully operational it will only account for 3% of the nations needs. Exceptional renewable energy project that is predicted to have reduced China’s emmisions by 100 million tonnes per year, HOWEVER, it also: Displaced 1 million people Serious environmental impact to region, including sedimentation and deforestation.

Suitability & Use in Australia
Australia currently has 108 operating hydroelectric plants providing 7.8GW of power. Around 4.5% of all energy generation in Australia is provided by hydroelectricity. Suitability Most of Australia receives under 900mL of rain a year. The areas with more rain (north Australia) are not necessarily suitable due to topography (flat or not suitable for damming).

Hydro Energy Advantages
Once the plant is built, operating costs are very low so the energy produced is virtually free It does not produce any carbon dioxide, reducing effect on EGE It is sustainable and renewable Dams store water so we can control when electricity is made Power output can be increased very quickly to meet sudden demand Electricity can be generated constantly as long as there is enough water Disadvantages Dams are very expensive to build. Valuable land is flooded when a reservoir is made: homes and wildlife habitats can be lost A good site for a hydroelectric power plant, such as a mountainous region, are not always near towns where energy is needed.

A B Definition Ocean energy includes:
Wave Tidal Ocean Thermal Sources Wave energy systems channel waves through turbines to generate electrical energy. Tidal energy systems rotate like ‘wind turbines’ clockwise as the tide approaches and anti-clockwise as it recedes. B

Use and Viability in Australia
Australia has only a few localised regions where the tidal energy is great enough to warrant a tidal energy facility. Few in areas where damage to environment is warranted. There are no active commercial tidal plants providing to Australia’s electrical energy production Only 4 pilot plants currently exist (contributing less than 1MW)

Global Use Only a few tidal energy sites are in operation around the world. Together they have a total capacity of less than 250 MW. Potential for tidal energy is immense; potential global tidal power exceeds 450 terawatts, most of it in Asia and North America. Station Capacity (MW) Country Location Comm Annapolis Royal Generating Station 20 Canada 44°45′07″N 65°30′40″W 1984 Jiangxia Tidal Power Station 3.2 China 28°20′34″N 121°14′25″E 1980 Kislaya Guba Tidal Power Station 1.7 Russia 69°22′37″N 33°04′33″E 1968 Rance Tidal Power Station 240 France 48°37′05″N 02°01′24″W 1966 Strangford Lough SeaGen 1.2 United Kingdom 54°22′04″N 05°32′40″W 2008 Uldolmok Tidal Power Station 1.0 South Korea 34°32′07″N 126°14′06″E 2009

Tidal Energy Advantages Tides are predictable
Once the plant is built, operating costs are very low, so the energy produced is very cheap It does not produce carbon dioxide or waste Tidal current turbines should have low environmental impacts. Disadvantages The plants can only produces power when the tide is flowing in or out – around 20 hours a day Barrages can be very expensive to build There is no one leading tidal stream device at the moment Compared to river dams, tidal barrages are very expensive and can affect a wide area upstream and downstream. Tidal barrages reduce the time mud flats are exposed and covered and therefore affect bird and other wildlife and fisheries. The relatively low head of water above the turbines restricts the capacity of individual generators to about 25—50 megawatts. All components and machinery must be able to withstand salt water and moving silt and sand.

Definition Geothermal energy is heat derived from the Earth.
There is a constant flow of heat from the inner core (5000°C) to the surface of the Earth and into space. The heat is generated from the decay of radiogenic materials. Comes in two types: Hot Rocks Hydrothermal 3 basic requirements for geothermal energy A persistent heat source A heat transfer medium Permeability in the rock

Use and Viability in Australia
Australia has considerable Hot Rock geothermal energy potential. Areas over 200°C at 5km are potential sites for geothermal facilities. There are no commercial ventures at the moment, only prototypes (labelled on map)

Global Use 10,715 MW of geothermal power in 24 countries is online.
Case Study: Iceland 25 % of all of Iceland’s electricity is generated by geothermal energy. 5 geothermal powerstations provide electricity as well as heating. The remaining electricity is provided by hydroelectricity plants utilising dammed water which is piped to underground turbines. 87% of all of the buildings in Iceland are heated using geothermal energy. Iceland is uniquely situated along a mid-oceanic ridge making geothermal energy accessible and viable. Less than 0.1% of all of Iceland’s electricity comes from fossil fuels. 10,715 MW of geothermal power in 24 countries is online. Generated 67,246 GWh of electricity in 2010. The thermal efficiency of geothermal electric plants is low, around 10-23%

Geothermal Energy Advantages
Geothermal energy does not produce any pollution in the form of greenhouse gases. Running costs for a geothermal power station are very low. Disadvantages It is difficult to find suitable sites to put a geothermal power station. If not carefully managed, a borehole can ‘run out of steam’ and may not be useable for several decades. Dangerous gases and minerals can come out of a borehole, which may be difficult to dispose of.

Definitions Bioenergy is the broad term given to energy generation from recent organic material (biomass). It is used for: Power (biogas) Heat energy (biomass). Fuel (Biofuel) Biomass is any living material (animal fats, plants etc.) grown and harvested materials for energy production. Generally the combustion of this material releases carbon dioxide (CO2) and small amounts of other greenhouse gases when it is converted into another form of energy. Biogas is composed principally of methane and CO2 produced by anaerobic digestion of biomass. It is currently captured from landfill sites, sewage treatment plants, livestock feedlots and agricultural wastes.

Biogas Example (Electrical Energy Production)

Greenhouse Effect

The sun is the primary source of energy for Earth.
The sum emits the entire electromagnetic spectrum of light through fusion reactions (fusing of two atoms together eg. 2 hydrogens to 1 helium) The sun is the primary source of energy for Earth. The sun emits light energy of all wavelengths at Earth. Different wavelengths of light interact with the different layers in the atmosphere.

Electromagnetic Spectrum
The light that surrounds us is called ‘visible light’. It is comprised of a tiny band of the EM spectrum that the human eyes (our rods and cones) can perceive. There is much more ‘light’ than we can perceive; some animals can see broader spectrums (eg. The snake senses IR, humans skin receptors can also ‘sense’ IR). The EM Spectrum is a continuum of light energy. Light behaves both as a wave and a particle. A packet of light energy is called a photon. Photons have frequencies which relate to how much energy they have. All photons are pure energy, they all travel at the speed of light, though have varying energy intensities (associated wave functions). The longer the wave length the less energy the photon has. For example: Radio waves vary in width from the size of a building to a mountain and have relatively ‘low’ energy levels. Gamma wavelengths are smaller than an atoms nucleus and are very energetic. They are called ionising as if they hit an atom they cause it to form into an ion by removing its electrons. The atmosphere is opaque (does not allow through) certain wave frequencies. Only wavelengths smaller than the largest wavelengths of UV get through Earth’s atmosphere. VIDEO: The electromagnetic spectrum is the range of wavelengths present in light. There is a relationship between the wavelength and energy. The shorter the wavelength the higher the energy of the photon.

Ionosphere Mesosphere Stratosphere Troposphere
Earth’s Atmosphere Ionosphere the very top layer is where atoms are ionised, causes auroras. 200km Ionosphere There are very few gases in the mesosphere to stop radiation, however this layer does slow meteorites plummeting to Earth 88km Mesosphere Ozone Layer Layer contains most of Earth’s ozone, responsible for blocking UV radiation 50km Stratosphere Nearly all of the Earth’s atmosphere gases are in this lowest 10km thick layer. This layer provides a global blanket, keeping the temperature stable and warm. All weather occurs in this layer. 10km Troposphere

Natural Greenhouse Gases Enhanced Greenhouse Gases
The (Natural) Greenhouse Effect Is a natural process Caused by the ‘blanket’ of greenhouse gases that absorb and re-emits IR radiation (& heat) within the troposphere. Provides a stable, relatively warm mean surface temperature on Earth. Essential for life The Enhanced Greenhouse Effect The additional release of GHG due to human activity (primarily burning of fossil fuels) increases the ‘thickness’ of the blanket. Increases the absorption and re-emission of radiation and heat at surface of Earth. Natural Greenhouse Gases Include: Water Vapour Carbon Dioxide Enhanced Greenhouse Gases Include: Additional Carbon Dioxide Methane CFCs Nitrous Oxide

Radiation In The Atmosphere
Radio Micro IR Visible UV X-Rays & Gamma 200km Ionosphere 88km Mesosphere Ozone Layer 50km Stratosphere 10km Troposphere

Radiowaves & Microwaves
Radio and microwaves can are reflected and emitted into space. Every radio and microwave transmission is out there travelling at the speed of light through space.

1 2 O Heat C O IR energy is absorbed by the bonds in greenhouse gases
IR energy is remitted back into the troposphere as well as heat

The reason we can see Earth from space is because most of the visible light is reflected back into space.

Example: Black Car On A Hot Day
Some Visible Light is Absorbed By Surface Objects and Re-emitted as Infrared Radiation 1. Infrared & Visible light radiation is absorbed by the paint pigment molecules of the car Example: Black Car On A Hot Day 2. Infrared radiation re-emitted. Humans feel this as the heat radiated from something. 3. Some of the visible light energy is lost is the absorption process. Most of this energy is re-emitted as IR radiation (felt as heat) This is why: The car is black, as it absorbs all of the wavelengths of visible light. The black car gets so hot on a summer’s day. You can feel the heat radiate off objects

How Is UV Reflected By Ozone?
The high energy wavelengths of Ultraviolet radiation break apart the covalent bonds between oxygen molecules. The free oxygen collides with another oxygen molecule reforming ozone. Most UV radiation is transformed in this manner in the ozone layer. Some UV radiation penetrates the troposphere (that is what burns us on a cloudy day). Note: The ‘Hole in the Ozone Layer’ has nothing to do with rising global temperatures.

What is the hole in the ozone layer?
The hole in the ozone layer refers to the depletion of stratospheric ozone. Caused by the man made greenhouse chlorofluorocarbons (CFCs). The chlorine molecule is released by UV, destroys ozone molecules and upsets the balance between O2 and O3. One chlorine molecule persists in the atmosphere for 100 years. Decreased ozone increases UV reaching the surface. The warming effect of UV is negligible as it does not interact with greenhouse gases. It does destroy biological material (i.e. us). NOTE: The hole in the ozone layer and increased temperatures are not related, every year examiners will test this!

Summary of Greenhouse Gases In Atmosphere
Wavelength of Light Energy Level Penetrates Absorbed & Re-emitted By Contribution to Greenhouse Effect X-rays & Gamma Radiation Very High, very small wavelength Not even Ionosphere Water vapour in highest levels of atmosphere Nill Ultraviolet Light (UV) High, small wavelength Ionosphere & Mesosphere Ozone and oxygen molecules ONLY in ozone layer at top of stratosphere Negligible UV radiation is not absorbed & remitted by Visible Light Average wavelength and energy All layers to surface Not absorbed by greenhouse gases Absorbed by surface objects Some re-emitted as IR Only re-emitted IR will interact with greenhouse gases Infrared (IR) Low energy, wavelength the size of human -Absorbed by CO2, CH4, N2O Contributes significantly to greenhouse effect Radio & Microwaves Low, very large wavelengths - Not absorbed by greenhouse gases, reflected back to space Does not contribute

Natural Greenhouse Effect
Visible IR 200km Natural greenhouse gases (water vapour & carbon dioxide) keep the temperature on the surface of the Earth warm and stable. IR radiation is absorbed and re-emitted repeatedly by greenhouse gases every time giving off heat. 88km 50km 10km Heat Heat

Enhanced Greenhouse Effect
Visible IR 200km Activities and land use of man cause additional greenhouse gases to be emitted into the atmosphere Additional greenhouse gases increase the instances of absorption and re-emission of IR radiation, and thus heat released, increasing overall temperature of surface 88km 50km Heat Heat Smog Smog Smog Smog 10km Smog Heat

There appears to be a strong correlation between carbon dioxide and temperature

Consequences of the Enhanced Greenhouse Effect

Enhanced Greenhouse Effect Policies

Non-Government Responses
Earth Hour Global event, where people turned off their lights for 60min. Marketed as making a positive change for the climate Started in Australia Occurs Each March (26th March 2011) Australia is 50% coal generated electricity, Does Earth Hour... Reduce emissions? What was the real intention of an event like this? How effective are these events?

Replacing the Carbon Sinks
Groups like Landcare Australia, ‘Friends of’ community groups, Greenpeace etc. Rehabilitates forests. Purchases ‘green wedges’ Provides community training programs Promotes ‘carbon footprint reductions’

Wiping Your Carbon Footprint
Some companies offset carbon as a part of the service. For those that don’t there are general sites Specialist companies whose product is eliminating your carbon footprint, by equating a $ cost to remove the carbon dioxide you pump into the air by putting money towards research and carbon sink projects.

Government Initiatives
Governments can: Invest in climate change research and initiatives Federal funded and supported renewable energy schemes. CSIRO Australian Department of Climate Change Infrastructure Incentives Solar cells Insulation Mandate policy to reduce EGE Carbon tax Carbon scrubbing Land use Fuel and Energy Efficiencies Types of legal cars and transport Local building law Increase public awareness Black balloons campaign Energy efficiency systems Making Climate Change Education an official component of the national curriculum.

Kyoto Protocol The Kyoto Protocol is an international agreement linked to the United Nations Framework Convention on Climate Change. The major feature of the Kyoto Protocol is that it sets binding targets for 37 industrialized countries and the European community for reducing greenhouse gas (GHG) emissions. These amount to an average of five per cent against 1990 levels over the five-year period The major benefit of the protocol is that it commits countries to meet their targets (by international law). Note: The Kyoto Protocol is listed in you study design as an examinable component. It is slightly out of date, though you must know it (Even though gov. are working with other policy frameworks)

Unit 3 Exam, 2007 Question 11 The Kyoto Protocol is an agreement that ultimately aims to reduce the A. Amount of carbon dioxide emissions. B. Energy efficiency of motor vehicles. C. Use of renewable energy resources. D. Number of coal-fired power stations.

Copenhagen Accord Document formed at the 2009 Copenhagen United Nations Framework Convention on Climate Change . The Accord is not legally binding and does not commit countries to agree to a binding successor to the Kyoto Protocol, whose present round ends in 2012 Endorses the continuation of the Kyoto Protocol. Underlines that climate change is one of the greatest challenges of our time emphasises a "strong political will to urgently combat climate change in accordance with the principle of common but differentiated responsibilities and respective capabilities“ Recognizes "the scientific view that the increase in global temperature should be below 2 degrees Celsius", in a context of sustainable development, to combat climate change. The Australian Government committed to reduce emissions by 5 to 25% by 2020.

VCE Environmental Science

Similar presentations

Presentation on theme: "VCE Environmental Science"— Presentation transcript:

Similar presentations

About project

Feedback

Log in

Auth with social network:

VCE Environmental Science

Similar presentations

Presentation on theme: "VCE Environmental Science"— Presentation transcript:

Similar presentations

About project

Feedback