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9.6 Option — Organic geology: 6. The search for alternative sources of energy
| Syllabus
reference (October 2002 version) |
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6. The search
for alternative sources of energy |
Students learn to:
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Students: |
Extract from Earth and Environmental Science Stage 6 Syllabus
(Amended October 2002). © Board of Studies,
Prior learning: Science Stages 4–5 syllabus: Outcome 5.11 (content 5.11.1 a and b) and (content 5.11.2 b).
Background: As Greenhouse gases are causing an increase in global temperatures with accompanying sea level rise and loss of species, we should be investigating alternative energy sources as, apart from the consequences of global warming, fossil fuels will eventually run out.
gather information from a secondary source to investigate alternative sources of energy
- Investigate several secondary sources to find the
best one for the information. The Internet and an up to date text book should
be good sources.Alternative Energy Sources, California (AES
)
has some really good information. Just click on which section you are interested
in, eg wind or solar. A NSW source on wind energy is Energy, Wind power NSW Department of Industry and Investment - When you have decided on the source or sources of information gather the appropriate information in a book or folder. Which energy sources are going to be more important in the shorter term? Why? You will need to consider factors such as availability, cost and benefit to the environment.
identify and discuss alternative sources of energy - solar, wind, hydro-electric, nuclear, synthetic oil, ethanol, wave power - and evaluate the relative importance and future potential of each as an alternative source for local communities
Alternative sources of energy include solar, wind, hydro-electric, nuclear, wave, geothermal and biofuels, including ethanol.
Solar
- Solar energy can be either solar thermal, e.g. solar hot water that can be heated to high temperatures to form steam to turn a turbine in a power station or solar photovoltaic cells where solar energy is converted directly to electricity.
- Solar energy has the advantages of being clean and reliable(even on cloudy days some electricity will be generated).
- Current disadvantages of solar PV energy include; the expense and energy required to make the solar cells, the inefficiency of the process changing solar to electrical energy and the large areas required by solar collectors to obtain a reasonable amount of power.
- However technology is quite advanced for solar (photovoltaic or PV) energy and it is currently being used as an alternative to diesel generators, especially in remote areas where there is no power grid to connect to. The cost will become less with economies of scale as it becomes more popular and as technology improves.
- Solar thermal is looking more promising as a permanent source of energy with the energy being stored in an ultra battery, a hybrid energy storage device made up of a super capacitor integrated with a lead-acid battery cell UltraBattery: no ordinary battery. CSIRO, Climate Change, Reducing greenhouse gas emissions
- Wind turbines are used to generate electricity. It is a clean energy source and cheap once it has been set up.
- Sites for instillation of the turbines must be chosen carefully to supply maximum wind.
- Disadvantages of wind include expensive to set up, turbines are sometimes noisy and a suitably windy location must be found.
- However some have been established in Australia, e.g
Australia’s first grid connected wind farm was built at Crookwell,
NSW, Southern Tablelands of NSW and there are now wind farms in NSW at Blayney, Hampton Park, Bungendore and Kooragang
Island.
- Water released from dams provides the energy to turn power producing turbines. This is a clean power source as no emissions are produced.
- Disadvantages of hydro-electric power include alteration of plant and animal habitat when a lake or dam is formed and not enough water to generate a lot of electricity as Australia is a fairly dry country. Canada has a lot more hydro-electricity as snow melting means a continuous supply of a lot of water all year round.
- Uranium is most commonly used.
- Uranium nuclei are split and release energy. This process is called nuclear fission.
- One kilogram of uranium can produce as much energy as burning 2800 tonnes of coal.
- Disadvantages of nuclear fission include; safety, waste storage and fuel availability.
- Similar principle to hydro-electricity.
- Constant motion of waves and tidal movement greater than 12m can be converted to electricity using turbines.
- Can interfere with aquatic life and could be destroyed by very rough seas as occurred in the North Sea off the English coast.
- Earth’s internal heat source surfaces as hot springs, geysers and active volcanoes.
- Temperature increases with depth at a rate of 3oC/100m.
- Geothermal energy is concentrated along active plate margins and in mantle plumes but harnessing this energy is currently not economical.
- In Australia a possible source of geothermal energy
is Hot Dry Rock. The rock in the Hunter Valley geothermal anomaly may have
the right temperatures, rock properties and stress conditions at a depth of
two kilometres. This would be in the core of the anomaly. Research is currently
being done. Geothermal energy Energex, positive energy
- Coal can be liquefied into synthetic oil by adding hydrogen to the coal to increase the hydrogen carbon ratio until it matches that of oil. This process was developed by the Germans during WWII.
- It is easier to purify synthetic fuels derived from coal than it is to purify coal itself. Synthetic oil derived from coal contains fewer impurities and burns much more cleanly than coal, and in some cases more cleanly than normal oil. The byproducts of the process can be made environmentally inert or can be themselves converted into industrial products.
- The costs of coal derived oil have come down from $50 per barrel in the 1970s, but is still slightly higher than standard oil. Technology is being developed to reduce the cost to the targeted US$21 per barrel price.
- Produced by fermentation of crops.
- Can be used to extend petrol by combining ethanol with the petrol.
- Requires a large amount of energy to distil to a pure substance, making it not practical unless you use waste such as sugar cane waste. Then much of the energy would be used in production of the sugar cane which is sold. Only a small amount more energy is used in the final process to produce the ethanol.
- Environmental damage would be done if countries like Brazil cut down forests to grow grain for ethanol to sell to countries such as USA.
- The problem you need to solve is which alternative energy sources to test.
- Consider which energy source it is practical to test
in the classroom, including what energy source you could easily access and
how you will be able to test its energy efficiency. You could consider solar
and wind as alternative energy sources. A non-fossil fuel could be biomass to produce ethanol. Wood waste or sugar cane waste could be sources of biomass. If these aren't available you could obtain other plant material.
Cellosic ethanol Wikipedia. Does the school have the equipment to test these? If not could
you go to a lab such as one at a university or the CSIRO? You could do some
background reading or talk to scientists about how you can compare the efficiency
of different energy sources.
- When you have enough information and have the correct equipment perform the investigation.
- Windows need to be able to be opened to make maximum use of conditions outside, rather than windows that are permanently sealed for air conditioning. Materials such as masonry and water can store heat energy for extended time. This prevents rapid temperature fluctuations in the house and saves on heating bills.
- Buildings have north facing walls with large windows for maximum absorption of heat from the sun in winter when the sun is low.
- Low energy light globes
- Solar hot water systems on the roof
- Photovoltaic cells on the roof that generate electricity
- You can save energy in the home by simple things like putting on an extra jumper instead of turning the heater on
- Turning lights off when they are not being used
- Not leaving TV, video and computer on standby
- The most effective designs are based on specific understanding of a building site's wind patterns, terrain, vegetation and solar exposure.
- To evaluate these methods, consider which ones are the easiest to implement and which do not need a huge outlay of money to establish the method. However which one will save the most energy and therefore money in the long term is also important
Wind
Hydro-electric
Nuclear
Wave and tidal
Geothermal
Synthetic oil
Ethanol
solve problems and perform first-hand investigations to test the energy efficiency of various non-fossil fuels and alternative energy sources
describe and evaluate methods of conserving energy, including architectural design
Look at the website of About.com
Build to Save Energy by Jackie Craven, About.com:architecture
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