Chapter 23 Fossil Fuels

Energy Sources Today “Human history becomes more and more a race between education and catastrophe” H.G. Wells, The Outline of History (1920)

How much energy do we use? Energy is measured in joules (J). Large amounts of energy are commonly expressed in kilojoules (kJ) or mega joules (MJ). A kJ = 1000 J, a MJ = 1,000,000 J A petajoule (PJ) is a useful unit for discussing national energy needs 1 PJ = 1 x J

How much energy do we use? Each person in our modern society uses on average nearly 1000MJ per day. This figure is one hundred times greater than the body’s basic requirement. The bulk of our energy is use if for transport, heating and domestic purposes. The national energy budget is somewhat higher. Australia uses about 2000 PJ of energy per year, for mining, manufacturing, commercial services, farming etc. Look at the picture at the bottom of page 367.

Meeting Our Energy Needs In ye olde days what did people used to use to get energy?? Why can’t that sustain us now?? What did we now use instead?? Can that sustain us??

Meeting Our Energy Needs Fossil fuels provide nearly 90 % of the worlds energy needs. This include coal, oil and natural gas There is a growing pressure to reduce our future dependence on these fuels because – Increasing concern over the effects of gases released into the atmosphere as a by-product of the combustion of fossil fuels. – Fossil fuels are non-renewable and will eventually run out – Demand for petroleum as a raw material for polymers, pains and other petrochemical products.

Meeting Our Energy Needs Can you think of any other reasons why we should try and limit our use of fossil fuels? What might this picture tell us?

Energy Converters Conversions of energy of one form to another involves ‘losses’ This is usually in the form of thermal energy

Energy Converters The engine in a car is an energy converter. It converts the chemical energy in petrol to thermal energy by combustion. Petrol is mostly octane The combustion of octane is a redox reaction 2C 8 H 18 (g) + 25O 2 (g) → 16CO 2 (g) + 18H 2 O(g) Turn to page 369 to see how energy is lost in a car engine

Fossil Fuels Non-renewable energy sources are those used at a faster rate than they can be produced. Fossil fuels and uranium are fuels of this type. We will eventually run out. Sustainability is all about meeting the long term ongoing needs of society. As well as the short-term and intermediate needs. The concept includes the needs of the environment as well as the economical and social well being of future generations

Fossil Fuels Does Australia have any nuclear power plants?? Figure 23.6 Electricity production by fuel source. The size of the block represents a region’s energy use. Energy use in the world is far from equal. Source: ‘Nuclear Energy Prospects in Australia’, Nuclear Issues Briefing Paper 44, April 2005, Uranium Information Centre Ltd.

Fossil Fuels Coal, oil and natural gas formed form primitive plants and animals When we burn these we are burning the remains of plants and animals that lived million’s of years ago. Chemical energy in fossil fuels can be considered as trapped solar energy. Why?

Now Its Your Turn In groups you are going to learn about one fossil fuel and your job is to do a PowerPoint thing like I do and summarise one fossil fuel for the class. There is lots of info in your text book, and you can look up more if you have to. Shayna, Charlie and Lauren – Oil Ben, David and Simon – Coal Andrew and Alex – Natural Gas

Fossil Fuels may cost the earth Many fossil fuels are used as raw materials in the chemical industry. Plastics, fibres and pharmaceuticals have all originated from fossil fuels. Can we afford to keep using fossil fuels for transport and energy if we need this precious resource for other things?

Fossil Fuels may cost the earth What about the environmental cost? What happens when we burn wood and coal? Could this contribute to the Greenhouse effect?

What are governements doing They are exploring possible energy sources such as: Production of biofuels Production of hydrogen from natural gas Solar-generated electrolysis of water to produce hydrogen and oxygen Solar power Wind power Geothermal power Nuclear power

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