Chemistry - Energy from Fuels

Advantages of Coal

• Cheap and extant throughout the world

• Longest lifespan in comparison to other fuels

• Can be converted to synthetic liquid fuels and gases

• Safer than nuclear power

• Ash produced can be used in making roads

Advantages of Petroleum

• Easily transported in pipelines or by tankers

• Volatile and thus convenient for use in cars, burns easily

• High enthalpy density

• Sulfur Impurities can be removed easily

Advantages of Natural gas

• Higher specific energy

• Clean and produces fewer pollutants per unit energy

• Easily transported in pipelines and pressurized containers

• Does not contribute to acid rain

Disadvantages of Coal

• Contributes to global warming due to CO₂

• Contributes to acid rain, SO₂

• Produces particulates (electrostatic preceptors can remove most of them)

• Difficult to transport

• Waste can lead to visual and chemical pollution

• Mining is dangerous

Disadvantages of Petroleum

• Limited lifespan and uneven world distribution

• Contributes to acid rain and global warming

• Transport leads to pollution

• Carbon monoxide is a local pollutant produced by incomplete combustion of gasoline in internal combustion engines

• Photochemical smog is produced as secondary pollutant due to recations of primary pollutants (nitrogen oxides and hydrocarbons) released from internal combustion engines.

Disadvantages of Natural Gas

• Limited Supplies

• Contributes to Global warming

• Risk of explosion due to leaks

Energy density

Specific energy

Photosynthesis

6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂

Fermentation

C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂

Combustion

2C₂H₅OH + 6O₂ → 4CO₂ + 6H₂O

Advantages of Biofuels

• Cheap and readily available

• If crops and trees are replanted, they can be a renewable and sustainable source

• less polluting than fossil fuels

Disadvantages of Biofuels

• Uses land which could be used for other purposes such as growing food

• High cost of harvesting and transportation in large volumes

• Takes nutrients from soil/uses large amounts of fertilizers

• Lower specific energy than fossil fuels