Biofuels

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The question of whether biofuels could make a real impact on reducing greenhouse emissions without creating other environmental problems is not simple.

The theory is that the plants used to manufacture biofuels take the greenhouse gas CO2 (carbon dioxide) out of the atmosphere while they are growing and only produce the same amount of CO2 when they burn in the engines of vehicles. So there is no net addition of CO2 to the atmosphere.

There are other factors in the equation, though, such as the amount of energy needed for:

• Farming the crops
• Manufacturing fertilizers
• Transporting biofuels.

The fuels used in these processes also produce CO2, as well as other pollutants.

Technology is improving, so second generation biofuels will probably be produced less expensively and more efficiently, using a greater range of plants and plant waste. However, biofuels themselves are not as efficient as fossil fuels – the energy content of ethanol is only two-thirds that of petrol – so they are added to petrol or diesel, rather than replacing them.

Finally, even champions of biofuels acknowledge that, while they reduce some dangerous emissions, such as carbon monoxide (CO), they may produce higher levels than traditional fuels of some dangerous compounds, such as nitrogen oxides.