Sources of Fuels

Photosynthesis People in industrialised societies use large amounts of energy and most of it comes from fossil fuels. This energy comes directly or indirectly from the sun via photosynthesis. Photosynthesis is the process in which plants use solar energy to convert carbon dioxide from the air and water from the ground into carbohydrates such as glucose, sucrose, starch and cellulose, which are compounds containing carbon, oxygen and hydrogen: Carbon dioxide + water + light→ glucose + oxygen 6CO2 (g) + 6H2O (l) + light → C6H12O6 (aq) + 6O2 (g) 

Photosynthesis is an endothermic reaction.

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It is a multistep reaction brought about by the green pigment chlorophyll

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Solar energy is converted into chemical energy and is stored.

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Carbohydrates in plants are the energy source for animals, including humans.

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They are high energy compounds as they release large amounts as they release large amounts of energy during respiration or combustion.

Cellular respiration is essentially the reverse process to photosynthesis. It converts the stored chemical energy into a form which the organism is able to then use: Glucose + oxygen → carbon dioxide + water + energy C6H12O6 (aq) + O2 (g) → 6CO2 (g) + 6H2O (l) The amount of energy released during respiration is the same as what was absorbed during photosynthesis, which is 2830 kJ per mole of glucose used.

Fossil fuels Normally when plants and animals die, insects, fungi, worms and bacteria called decomposers, convert them back into carbon dioxide, water and nutrients, releasing the stored energy into the environment. In some locations and under certain conditions, over geological time scales, the decay processes were interrupted resulting in some plant material only being partially decomposed. This partially-composed material remains stored in the form of rich compounds that are called fossil fuels. All of these compounds are carbon-based since living matter is composed of carbon. Through the processes of mining, and burning fossil fuels, the energy content of these materials can be used as a power source for transportation and for generating electricity for homes, schools and businesses. Some fossil fuels include: 

Coal

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Crude oil

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Natural gas

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Oil shales

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Tar sands

Australia has an abundance of fossil fuel resources, in particular its immense supplies of coal and natural gas, but has limited reserves of crude oil. As a result Australia uses lots of fossil fuels to produce electricity, and exports some of these resources overseas in particular to big consumers such as China or India.