Energy Fossil Fuels
Energy Production
Introduction
Globally, the demand for energy is increasing, especially in developing countries. However, it is the rich industrialised countries that use most of the world's energy production.
The USA has about six per cent of the world's population but consumes around thirty per cent of the world's energy production. In contrast, India has about twenty per cent of the world's population but consumes only two per cent of the world's energy production.
In the 1990's oil, coal and natural gas, known as fossil fuels, accounted for ninety per cent of the world's energy production. Fossil fuels were formed from plants that have decomposed and over millions of years have been converted into coal, oil, gas and other materials such as peat.
As they take so long to form, they are considered as being non renewable. Until now, fossil fuels have been relatively easy to obtain and cheap to use. Unfortunately, they are major polluters of the natural environment.
Nuclear energy production uses uranium. This is not a fossil fuel and sometimes is considered as non renewable. However, nuclear energy production uses only small quantities of uranium and therefore should take a very long time to consume the known global resources. In addition, nuclear fuel can be recycled to some extent so it could be regarded as a renewable resource.
In many parts of the developing world wood is used, by individuals, to provide energy. It provides more than a third of the developing world's energy requirements.
Energy sources that are considered to be sustainable are known as renewable. Currently only the use of running water, to produce hydro electric power, is a source of renewable energy used on the global scale.
Other potential renewable sources of energy include:
- the sun (solar power)
- the wind
- waves on the sea
- changes in sea level due to tides
- heat from the Earth (geothermal)
- energy from vegetable waste (biomass).
As the supply of fossil fuels runs out, these renewable sources will be used more and more. Although these sources do not produce waste products such as carbon dioxide, sulphur dioxide and nitrogen oxides it should be understood that all methods of energy production have some effects on the environment.
Non renewable energy sources
- Fossil fuels
At the moment coal, oil and gas are the most widely used sources of energy. However, they will not last for more than a few hundred years at current consumption rates.
- Coal
Coal, the longest used fossil fuel, still produces about a quarter of the world's energy. Now there is a reducing demand for producing power from coal. It is not just the burning of coal that affects the environment. Extraction of coal leads to dereliction of land, subsidence and water pollution. Mining operations also produce huge amounts of waste. As more easily accessible deposits are used up production costs are rising.
Advantages of using coal
- Coal is found in many locations around the world.
- Coal reserves are predicted to last another 300 - 400 years.
- Coal produces a wide range of by products.
Disadvantages of using coal
- Burning coal produces carbon dioxide which causes global warming.
- Burning coal produces sulphur dioxide which causes acid rain.
- Emission of fumes and particles cause human health problems.
- Oil
Oil has been the main source of energy since the Second World War. It now provides about one third of the world's energy production. Its distribution around the world is uneven. It is often found in remote areas such as deserts or under the sea. Pollution is caused by burning oil and from spillages during transportation.
Advantages of using oil
- Oil is transported easily over land by means of pipelines.
- Oil burns more efficiently than coal.
- Used in various forms in internal combustion engines to provide transport.
Disadvantages of using oil
- Oil not evenly distributed around the world - supply is politically vulnerable.
- Burning oil produces carbon dioxide which causes global warming.
- Burning oil produces carbon monoxide and unburnt hydrocarbons which cause health problems and smog.
- Natural gas
Natural gas is often found in the same locations as oil. Currently there is a world surplus and supplies are, therefore, relatively cheap. Natural gas provides about sixteen per cent of the worlds total energy production at present.
Non renewable energy sources
Advantages of using gas
- Gas burns more efficiently than oil and coal.
- It is less damaging to the atmosphere than oil or coal.
- Gas is transported easily over land by means of pipelines.
Disadvantages of using gas
- Gas combustion releases methane which adds to the greenhouse effect.
- Gas combustion releases nitrogen and sulphur oxides leading to acid rain.
- Gas is not evenly distributed globally - supply is politically vulnerable.
- Nuclear power
Nuclear power is produced by the fission of atoms using radioactive uranium. The process does not release smoke, sulphur / carbon / nitrogen oxides into the air. However, there is a risk of releasing radioactivity into the environment. In some industrialised countries such as France and Japan (where fossil fuels are in short supply) governments are using nuclear power despite concerns about its safety.
Advantages of using nuclear power
- It does not cause air pollution
- It does not contribute to the greenhouse effect.
- Only small amounts of uranium are used.
Disadvantages of using nuclear power
- Power stations are very expensive to build.
- There will be extremely high decommissioning costs.
- Risk of radioactive waste contaminating the environment.
- Fuelwood
Trees are being removed at an increasing rate in underdeveloped parts of the world. They are needed for shelter as well as for fuel. Collecting fuelwood is a time consuming task. People have to walk many miles each day to find enough wood to cook their food. As populations grow this leads to removal of all trees resulting in desertification. Alternative energy sources are badly needed in these areas.
Renewable energy sources
Potential renewable sources of energy include running water (hydroelectric), the sun (solar power), the wind, waves on the sea, changes in sea level due to tides, heat from the Earth (geothermal) and energy from vegetable waste (biomass).
- Hydroelectric power (HEP)
At present HEP accounts for approximately six percent of the world's energy consumption. However, in some countries it accounts for much higher proportions, E.g. Norway generates ninety five percent of its electricity in this way.
Renewable energy sources
Advantages of using hydroelectric power
- It does not usually contribute to the greenhouse effect, smog or acid rain
- It does not cause water or land pollution.
- Reservoirs can also be used for water supply and recreation.
Disadvantages of using hydroelectric power
- Construction requires enormous capital expenditure.
- Large areas of farmland and wildlife habitats may have to be flooded.
- People may have to be relocated if settlements are drowned.
- Wind power
Modern wind turbines have good efficiency, but need to be located in areas which have high and regular wind speed - usually found in upland areas and exposed coastlines. However, about 7000 wind turbines would be needed to replace a nuclear power plant. Wind turbines are usually built in groups to form a 'wind farm'.
Advantages of using wind power
- It does not usually contribute to the greenhouse effect, smog or acid rain.
- It does not cause water or land pollution.
- It does not depend on sunshine - operates night and day.
Disadvantages of using wind power
- Wind does not blow all the time.
- Wind farms spoil the visual appearance of the countryside.
- Wind farms cause noise pollution in areas which would otherwise be quiet.
- Geothermal energy
Geothermal means heat from the Earth. In some parts of the world, such as Iceland, where there are active volcanoes, heat from the interior of the Earth is accessed from the surface. This is a source of energy in the form of very hot water or steam.
Advantages of using geothermal energy
- It provides a constant supply of heat.
- It is not a major source of pollution.
- It is cost efficient in suitable locations.
Disadvantages of using geothermal energy
- Construction requires large capital expenditure.
- Emissions of sulphurous gases cause pollution.
- Its use is limited to volcanic areas.
- Energy from the sea
The harnessing of wave and tidal power has not been extensively used. Many rivers around the world have a tidal range which could generate electricity. Many designs to extract energy from waves have been tested. These involve nodding, bobbing, pushing and pulling mechanisms either on the surface or submerged.
Renewable energy sources
Advantages of using energy from the sea
- It is clean, safe and reliable.
- Tidal barrages can provide areas for recreational activities and fish farming.
- Upstream areas are protected from tidal surges.
Disadvantages of using energy from the sea
- Construction of tidal barrages requires large capital expenditure.
- Problems with reliability of machinery to harvest energy from waves.
- Tidal barrages destroy wildlife habitats.
- Solar power
Solar energy can be used to generate electricity either directly, using photovoltaic cells or indirectly using solar cells to heat water. Its potential in developing countries is enormous.
Advantages of using solar power
- It is renewable and free from pollution.
- It is safe and efficient.
- It has low maintenance costs.
Disadvantages of using solar power
- It is of limited use in cloudy areas.
- Initial costs are relatively high.
- Energy is only produced during the day.
- Energy from biomass
This involves the production of energy from organic materials that is placed in a 'digester' to produce 'biogas' which is mainly methane. In the UK, landfill sites produce methane from the decomposition of household waste.
Advantages of energy from biomass
- It is renewable and cheap.
- Sometimes the digester residue can be used as a fertiliser.
- There is little pollution.
Disadvantages of energy from biomass
- There can be pollution from methane and carbon dioxide and particulates.
- Crops grown for fuel may take the place of food crops.
- Collecting enough biomass fuel could be difficult.
References
www.wasteonline.org.uk/resources/InformationSheets/Energy.htm
www.wikipedia.org/wiki/Renewable_energy
www.wikipedia.org/wiki/Fossil_fuel
www.wikipedia.org/wiki/Nuclear_power
www.schoolscience.co.uk/content/4/physics/nirex/wastecharts1.html
Assessment
Energy Production
Questions 1 to 5 - Select the correct response for the following questions :
1.What percentage of the world's energy production is consumed in the USA?
A2%
B6%
C20%
D30%
2.In the 1990s, what percentage of global energy production was obtained from coal, oil and gas?
A72%
B84%
C90%
D60%
3.Which of the following is not classed as a renewable method of energy production?
AHydro electric power
BNuclear power
CWind power
DSolar power
4.Which of the following is not considered to be a non renewable energy source?
ACoal
BGas
CBiomass
DOil
5.What is the usual minimum number of wind turbines in a wind farm for it to be economical?
A25
B15
C 8
D 1
Questions 6 to 10 - Decide whether each statement is True (T) or False (F).
6. i)Nuclear energy production uses uranium. This is not a fossil fuel and sometimes is considered as non renewable.
ii)However, nuclear energy production uses only small quantities of uranium and therefore should take a very long time to consume the known global resources.
Which option best describes the two statements?
Ai)Tii)T
Bi)Tii)F
Cii)Fii)T
Dii)Fii)F
7. i)Approximately one quarter of the world's energy is produced by burning coal.
ii)Oil now accounts for only 10% of the world's energy production.
Which option best describes the two statements?
Ai)Tii)T
Bi)Tii)F
Ci)Fii)T
Di)Fii)F
8. i)Natural gas supplies 31% of the world's energy production.
ii)Known gas reserves should last another 120 years at current usage.
Which option best describes the two statements?
Ai)Tii)T
Bi)Tii)F
Ci)Fii)T
Di)Fii)F
9. i)A disadvantage of nuclear energy production is that it contributes to the greenhouse effect.
ii)Hydro electric power production requires little capital expenditure.
Which option best describes the two statements?
Ai)Tii)T
Bi)Tii)F
Ci)Fii)T
Di)Fii)F
10. i)Currently it would take approximately 7000 wind turbines to replace one nuclear power station.
ii)Solar power production is renewable and free from pollution.
Which option best describes the two statements?
Ai)Tii)T
Bi)Tii)F
Ci)Fii)T
Di)Fii)F
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