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9.6 Option — Organic geology: 5. The environmental impacts of fossil fuel use
| Syllabus
reference (October 2002 version) |
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5. The environmental
impacts of fossil fuel use - complete versus incomplete combustion |
Student learn to: | Students:
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Extract from Earth and Environmental Science Stage 6 Syllabus
(Amended October 2002). © Board of Studies, NSW.
Prior learning:Science Stages 4–5 Syllabus: Outcome 5.11 (content 5.11.1 b and 5.11.2b)
identify data sources, select equipment, plan and perform a first-hand investigation to distinguish between the products of complete and incomplete combustion
- Identify data sources with information on the
products of complete and incomplete combustion. Look in text books and on
the Internet. If you are using a search engine you could type words such as
combustion, carbon monoxide, incomplete.
- When you have done the literature search decide what
investigation you will do, then select the equipment you will need,
keeping in mind any risks involved in the investigation and addressing any
hazards that may arise.
- Perform the investigation carefully, recording results accurately. Repeat the experiment to see if the results are similar. Make sure that any gases produced are collected satisfactorily and not allowed to escape.
The following information may help you get started with your literature search.
All fuels contain hydrocarbons (CxHy).
The general equation for the combustion
of a hydrocarbon is;
CxHy + O2
CO2 + H2O
+ energy
To burn completely, any fuel needs
a sufficient supply of oxygen.
Incomplete combustion (insufficient
oxygen) produces carbon monoxide (CO) and carbon (soot).
identify data sources, analyse information and use available evidence to determine the effects of fossil fuel combustion products, using a variety of media
- Identify data sources by looking for CD ROMs
on the environment and issues concerning air quality, on the Internet (you
could check the EPA, NSW site, the Australian Conservation Foundation or use
a search engine) and in books and journals.
Combustion
Wikipedia. Scroll down to Types, Complete vs. incomplete.
Car exhaust - air pollutants Alpha online.
- Put the information you have gathered in a table, with the first column being the product, and the second column being the effect of the product. You will need to consider the fact that different fossil fuels have slightly different products of combustion. Also consider who they may have an effect on, e.g children’s brains can be affected if they inhale too much lead from the burning of leaded petrol.
analyse and evaluate the types and effects of products of burning fossil fuels - gases, water, particulates
- The combustion of fossil fuels for transport, electricity
generation and industrial processes can result in the emission of significant
amounts of pollution.
- The major combustion products of fossil fuels are
various nitrogen oxides – (written as NOx, where x can
represent several different numbers, depending on which nitrogen oxide gas
it is), sulfur dioxide -SO2, carbon monoxide - CO, carbon dioxide
- CO2 and methane - CH4.
- The 1990s have proved to be the warmest decade since
high-quality records commenced in 1910, and contained five of the 10 warmest
years on record. The 1980s were the second warmest decade since 1910. It has
been estimated that global temperatures increased by approximately 0.58OC
in the 20th century. In its last report, IPCC stated that average surface
temperature is projected to increase by 1.4 to 5.8 Celsius degrees over the
period 1990 to 2100. Sea level has risen approximately 0.1-0.25 metres in
the last hundred years and is projected to rise by 0.1 to 0.9 metres over
the same period. The wide range in predictions is based upon several different
scenarios that assume different levels of future CO2 emissions.
Each scenario then has a range of possible outcomes associated with it. The
most optimistic outcome assumes an aggressive campaign to reduce CO2
emssions, while the most pessimistic is a "business as usual" scenario. The
more realistic scenarios fall in between.
- These effects are global and are not confined to national
boundaries. Consequently, international responses are required to reduce global
greenhouse gas emissions.
- SO2 is produced from the combustion of
high sulfur coals. SO2 reacts with water and sunlight to form sulfuric
acid, which produces acid rainfall. Australian coals tend to contain low levels
of SO2.
- NOx is produced as a result of nitrogen
reacting with oxygen in the combustion chamber. NOx contributes
to ozone depletion.
- CO2 is a by-product of all combustion of
fossil fuels and is thought to trap infra - red radiation that would normally
escape into space, thus resulting in the greenhouse effect.
- Particulates, mostly dust, soot or unburnt carbon,
and smoke are released into the atmosphere as a result of burning of fossil
fuels. Particles greater than 10 micrometres (µm) are not inhaled into the
lungs and so are not considered a health hazard but fine particles about 2.5
µm and smaller are. These are dangerous as not only can they be inhaled but
they penetrate deep into the lungs. They have been known to cause respiratory
difficulties and in some cases have resulted in a reduced life expectancy.
Particulates are not usually included when the costs of burning fossil fuels are
considered but they increase the cost of the health bill for society. These types
of issues should be evaluated.
- Water vapour is also given off during the burning of fossil fuels. Water vapour is about 60% to 70% of the gas that causes the natural Greenhouse Effect. However the incresed water vapour in the atmosphere due to fossil fuel burning is negligible to the enhanced Greenhouse Effect. Instead increased water vapour in the atmosphere is largely due to warmer suface temperatures causing increased evaporation from rivers, lakes and oceans. Also these warmer temperatures increase the amount of water vapour the atmosphere can hold.
analyse the dependence of modern society on fossil fuels and assess attempts to limit emissions
- The use of alternative fuel sources has increased
slowly, with incentives from state governments.
- Alternative fuel sources are still not economically
viable to run as a dominant energy source in comparison to fossil fuels, however
as the price of fuel increases and the cost of alterrnative sources goes down,
the alternative energy sources become more competitive.
- The NSW Environmental Protection Authority (EPA) in
conjunction with the other states and the Federal Government is part of a
world wide scheme to limit emissions.
- The NSW
EPA lists in detail all initiatives taken to reduce the amount of emissions
from fossil fuel combustion. Scroll down to 'Response to the Issue' and look at the different categories.
You could also scroll to the top to read some background information.
- A world wide attempt to limit emissions is the Kyoto
Protocol. This is an international convention, drawn up in Kyoto, Japan in
1997, in which countries would commit to reduce their greenhouse emissions
by 2012. The Australian Government successfully argued that their commitment
to reduce emissions shouldn’t be as great as the conference suggested
as the government would be planting millions of trees (carbon sinks) but in 2007 when the Labor government won office they ratified the treaty. In 2001
the Bush administration refused to ratify the protocol as it ‘would
harm US businesses’ but in 2009 the new US government had not ratified it.
- International energy outlook
2010 , Energy Information Administration, Department
of Energy, Washington DC, USA.
- Do you think attempts to limit emissions have been successful?
analyse information from secondary sources concerning the enhanced greenhouse effect
- There is a lot of information on the Internet, on
CD ROMs and in books and journals on the enhanced greenhouse effect but many
references just refer to it as the greenhouse effect so clarify what the article
is referring to when researching. You could put the information you gather
into two columns, one for information concerning the harm to the environment
caused by the enhanced greenhouse effect and one for evidence that the enhanced
greenhouse effect doesn’t exist and so there is no harm. Note the people
and/or organisations that are commenting on the for or against arguments.
Consider which ones are more reputable and so are more believable.
- A separate table could include the different changes the enhanced greenhouse effect could result in and the consequences to different countries if these changes occur.
describe and evaluate arguments concerning the greenhouse debate
The greenhouse effect
- Some of the infra -red radiation from the Earth's surface is trapped by Greenhouse gases and is reflected back to the Earth.
- This results in a higher average surface temperature and a narrower range of temperatures.
- It is a naturally occurring and life-sustaining process.
The enhanced greenhouse effect
- Additional infra-red radiation from the Earth's surface is trapped due to an increased concentration of greenhouse gases (CH4, CO2, CO, H2O, NOx).
Possible consequences
- An increase of 0.8 - 2oC in the Earth's surface temperature by the year 2030.
- Changes in the climate.
- Rise of sea level (not due to melting of polar ice).
- These consequences have been developed by climate modellers.
- Some scientists believe that the degree of global warming due to the enhanced green house effect is not solely due to greenhouse gas emissions; but due to a combination of emissions and the Earth's natural greenhouse cycle. Whatever the case most scientists feel strongly that more should be done to reduce greenhouse gases to reduce the impact on people and the environment. What do you think?
analyse information and use available evidence to predict the economic and environmental effects of removing all sources of fossil fuels
- Consider economic and environmental effects separately. The two main fossil fuels to consider are coal and oil.
- You will have to gather information to be able to analyse it. Consider stationary energy first. Australia relies heavily on coal to produce electricity but solar, wind and hydroelectricity produce a small but growing percentage of our electricity. Consider though if all coal fired power stations were closed down immediately. Some countries have less dependence on coal. Examples are New Zealand with a high proportion of geothermal electricity, France has approximately 80% of their electricity produced by nuclear power and in Canada hydroelectricity is very important.
- Although transport could be adapted to run on alternative energy it will take some time to develop
The Alternative Energy and Transportation Expo
Santa Monica, California, USAA website A World Without Fossil Fuels
Barbelith Underground has postings of some of the consequences of a world without fossil fuels.
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