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CHAPTER 16: NON-RENEWABLE ENERGY RESOURCES (Fossil Fuels (COAL (Makes up…
CHAPTER 16: NON-RENEWABLE ENERGY RESOURCES
Renewable Energy Resources
Resources that can last indefinitely without any reduction in their supply. They are inexhaustible as they are able to be replaced through natural processes quicker than they are being used.
Resources are considered renewable only if they are managed in a sustainable in manner.
Non-renewable energy resources
Resources that exist only in limited deposits in various parts of the Earth. They can be replaced, but only over long periods of geological time. They are exhaustible because we are using them at a much faster rate than they are being replaced.
Examples: Coal and oil
Producing Electricity
Both use renewable and non-renewable sources of energy
Electricity is produced when fuel or other sources of energy are used to drive generators or turbines.
Electric generator is a device for converting mechanical energy into electrical energy.
Has a magnet at the end of a rotating shaft; when the magnet rotates it induces an electric current. The shaft is attatched to a turbine.
In a power plant, the blades of the turbine may be turned by steam (created by combustion of fuel such as coal or gas) , wind, or moving water.
Electricity:
Flow of electrons. When an outside force upsets the balancing force between protons and neutrons an atom may gain or lose an electron. The free movement of these elecrons creates an electric current.
Energy Times
Peak energy times: Hours when electricity is most in demand.
Off peak times:When the last energy is being used. Generally overnight when most people are sleeping.
Distributors may charge higher rates for electricity at peak time to encourage consumers to spread the demand to off peak times.
Fossil Fuels
Examples: Coal, petroleum (oil) and natural gas.
Formed from dead and decaying organisms trapped below layers of sediments or rocks.
Coal
formed from ancient forests that were buried 300-400 million years ago. Over time, the amount of rock and sediments above the buried forest increased and the pressure and the temperature. The plant material became fossilised and compressed and eventually converted into coal.
Petroleum and natural gas are formed from aquatic plants and animals that died and sank to the bottom of oceans, lakes and estuaries. The dead organisms were decomposed by bacteria and sediments were deposited over them, increase the temperature and pressure, and the organisms were converted into oil and natural gas.
All fossil fuels produce useful energy through the process of combustion. Combustion releases carbon dioxide.
COAL
Makes up about 94% of Australia's fossil fuel energy resources, and provides 62% of our total energy production.
Locally, black coal is used to mainly generate electricity.
Despite having this available resource, we must weigh up the benefits of using brown coal for electricity against the impacts it has on the environment.
The overall efficiency of coal (from extraction to use) is approx 25%-30%.
Australia has about 8% of the world's total coal reserves.
3/4 of our black coal production is exported, mainly to Japan.
Formation:
Begins with layers of decaying trees and other vegetation in swamps. The bottom layers become compressed and use some water. This form is called peat, which can be dried and used as a fuel. Further deposits can increase the pressure and heat in the peat and convert it into a soft coal called brown coal, or lignite. Overtime, brown coal can be transformed into anthracite, or black coal, by further deposition of sediments and subsequent increases in temp and pressure.
Sub-bituminous coal and bituminous coal are intervening stages between lignite and anthracite.
Anthracite contains less oxygen and moisture and more carbon than other forms of coal, and provides much more heat when it burns.
PETROLEUM
Crude oil pumped from the ground is a heavy, sticky black substance.
It is heated in a refinery and different product are extracted at different temperatures.
These products range from bitumen, through to diesel oils, kerosene, petrol and gas.
All petroleum products are primarily hydrocarbons, that is, they are made up of carbon and hyrdogen atoms.
Oil is a more convenient fuel than coal as it is easier to transport, it has a higher energy content and it burns more cleanly and produces less smoke.
These advantages along with the development of the internal combustion engine, led to the increased use of petroleum products during the 20th centruy, particularly in transport
About 75% of the oil consumed in Australia is used for transport. The remaining oil is used by industry in processes such as heating, and in the production of plastics, paints and bitumen for roads.
NATURAL GAS
Often occurs with oil reserves
Constitutes about 20% of the world's, and of Australia's energy use.
Australia has about 1% of the world's reserves of natural gas.
With the development of high-pressure pipes and improved welding and pipe-laying techniques, natural gas began to be used.
Natural gas is a mixture of hydrocarbon gases: it is mostly methane, but also contains small amounts of ethane, propane and butane.
The combustion of methane releases energy and forms carbon dioxide and water; other hydrocarbon gases burn in the same way.
The combustion of natural gas is cleaner as it produce pollutants like sulphur dioxide and nitrous oxide (in addition to CO2).
It is used in homes for heating and cooking, and by industry for heating and manufacturing.
It has an overall energy efficiency of approx 30% for electricity production and 90% for heating.
Coal Seam Gas (CSG)
Natural gas that collects in underground coal seams and bonds to the surface of coal participles.
The coals seams are generally filled with water and it is the pressure of the water that keeps the gas as a thin film on the surface of the coal.
Australia has large coal seam gas reserves.
It is considered an unconventional gas due to methods used to extract it.
Hydraulic fracturing (fracking)
The process involves high pressured injections of sand, water and chemicals into the coal seam gas well. The injection causes fractures in the coal seam, allowing the gas to flow to the surface of the well.
Causes concern in Australia and the world due to the potential for fugitive gases to contaminate water sources and possible seismic activity and tremors associated with the drilling process.
In 2016, the Vic Gov was the first Australian state to ban coal seam gas and fracking.
URANIUM (NUCLEAR FISSION)
Not a fossil fuel. It is a non-renewable energy resource.
Used in nuclear reactors to produce heat, which is then used to generate electricity.
Make use of nuclear fission chain reactions to release energy.
A fission reaction is initiated by a neutron striking the nucleus of an atom with a large mass number and splitting that nucleus into smaller nuclei. Each reaction liberated energy and additional neutrons, which can continue the reaction by striking other large nuclei. Uranium 235, an isotope of uranium, is an example of an atom the nuclei of which can take part in nuclear fission reactions.
In these reaction, a small amount of mass from the nuclei is converted into energy.
Nuclear Energy is a highly efficient fuel source with a total energy efficiency of approx 90%
It produces about 15% of the world's electricity
The rate of growth in nuclear power has slowed as result of accidents in nuclear power plants and growing concerns about the safety of the plants, the health risks associated with nuclear radiation and the difficulties of nuclear waste disposal.
Also the problem that nuclear proliferation leads to an increase in fissionable material, which could be used for nuclear weapons.
Nuclear Fusion
Another type of nuclear reaction.
Energy is released when two atoms are forced together.
Fusion is a source of clean, sustainable energy for the future.
The fuels for a future fusion power source are the heavy hydrogen isotopes deuterium and titrium. (these are so abundant that, even if not technically renewable, it could meet the world's electricity needs for millions of years)
However, controlled fusion reactions have occurred only on a small scale in the lab.
Limits to Non-Renewable Fuels
Fossil Fuel Depletion
Fossil fuels take hundreds of millions of years to form within the Earth but only days or months to extract from the ground in large quantities to power our activities.
Our rate of extraction and use of fossil fuels is far greater than the rate that fuels can be replenished.
Factors considered in estimating fossil fuel depletion:
Future energy demands
Technological advanced in use and extraction methods
Estimates of remaining reserves
Peak Oil
Concept that the rate of oil extraction will reach a peak and then decline.
Reasons why oil production has not reached peak yet:
new 'unconventional' oil sources being developed
The effect of oil prices (affecting both consumption and the economic viability of extraction)
Policies to move away from fossil fuel use (e.g requiring more efficient car engines)
Many economists, environmentalists and petroleum industry experts believe, because oil is a limited resource, that we will hit a limit to our oil production at some time.
In response, many governments are encouraging renewable energy and energy efficiency to reduce their economy's dependence on oil and move to a green company.
STUDY DESIGN:
Fossil Fuels
• timeframes and processes required for the formation of fossil fuels
• uncertainty in calculating remaining fossil fuel deposits
• changes in the rate of the use of fossil fuels over time, including the concept of peak oil.
Comparison of Different Energy Sources
• the characteristics of renewable and non-renewable energy sources, including biomass, solar, hydro-electric,wind, tidal, oil, coal, natural and coal seam gas, nuclear, geothermal
• the impact on the environment and society of accessibility, extraction, conversion, transport, processing and use of energy resources ???
• the extent to which different energy sources can supply current energy needs and projections of future energy needs.
