Dear Tamilselvan,

One of the major reasons for producing biofuels is to reduce greenhouse gas emissions and to mitigate the effects of global warming produced by fossil fuels. However, according to the Food and Agriculture Organisation of the UN, some unintended impacts of biofuel production are on land, water and biodiversity.

The principle behind biofuels is essentially the same as that behind fossil fuels such as oil. Both biofuels and fossil fuels have stored the energy of the Sun in the form of biologically-produced chemicals called hydrocarbons. The energy stored in the fuels results from the ability of plants to carry out photosynthesis – the manufacture of sugar, starch and other complex organic molecules using sunlight.

However, unlike fossil fuels, biofuels have the potential to be carbon neutral, meaning that the loss of carbon dioxide to the atmosphere caused by burning them is offset by the absorption of carbon dioxide by the biofuel plants when they are growing. (The carbon locked up in fossil fuels was put there by plants that lived and photosynthesised millions of years ago.)

If this were true – that there is a perfect balance between absorption and production of carbon dioxide – then burning biofuels would not cause an overall increase in levels of atmospheric carbon dioxide, one of the principal greenhouse gases. Unlike fossil fuels, biofuels therefore have the potential to help to prevent global warming if they could replace the burning of oil-based fuels such as gasoline and diesel. They also have the added advantage over fossil fuels in that they are renewable.

It sounds like the perfect answer to all our worries

Yes it sounds like it, but the truth is not so straightforward. There are many problems with biofuel production that can significantly change the carbon balance sheet.

For a start, biofuel crops often need fertilisers and pesticides which are made from oil. The machinery used to grow, transport and process the crop is also often powered by fossil fuel. Then there are the tracts of pristine forests that are cut down to grow biofuel crops. This results in the loss of natural "carbon sinks" that are invaluable in the fight against climate change. In short, biofuels are not the universal panacea that some people believe them to be.

Please have a look at these useful researchgate links for said query.

https://www.researchgate.net/publication/264441003_Evaluation_of_environmental_impact_and_gaseous_emissions_of_biodiesel_fuels_and_blends_of_selected_feed-stocks

https://www.researchgate.net/publication/260288597_Sustainability_and_environmental_impact_of_ethanol_as_a_biofuel

https://www.researchgate.net/publication/281510408_The_emission_effects_by_the_use_of_biodiesel_fuel

https://www.researchgate.net/publication/236142938_Impacts_of_biodiesel_combustion_on_NOx_emissions_and_their_reduction_approaches

https://www.researchgate.net/publication/308354277_Environmental_impact_and_sustainability_study_on_biofuels_for_transportation_applications

Article Evaluation of environmental impact and gaseous emissions of ...

Article Sustainability and environmental impact of ethanol as a biofuel

Article The emission effects by the use of biodiesel fuel

Article Impacts of biodiesel combustion on NOx emissions and their r...

Article Environmental impact and sustainability study on biofuels fo...