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Biodiesel – Friend or Foe?

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Biodiesel: Friend or Foe? Is it good for your car and can you avoid it?

Biodiesel and biofuel are substitutes for diesel and petrol respectively.

They are produced from different types of biomass.

This article will focus on biodiesel, which is commonly made from rapeseed oil and used cooking oil.

Biodiesel can be made from bacteriaE. coli bacteria ‘can produce diesel biofuel’……read more here

In theory, they will run in every diesel car, though it is normal for biodiesel to be used in a blend with actual diesel, though the proportions of the blend may differ significantly (from 5% biodiesel to 100% biodiesel!)

Get more of the chemistry…

Benefits of Biodiesel:

The most appealing quality of biodiesel is that it is carbon neutral.

During combustion within the diesel engine it releases exactly as much CO2 as was absorbed by the plant during its life. In this era of concern for our carbon footprints, it feels great to be able to drive diesel cars without the guilt of adding substantially to pollution.

Furthermore, biodiesel is a completely biodegradable and non-toxic substance.
Any spillages that might occur will not be a problem, and not endanger wildlife in the way that oil and its refined diesel could.
On top of this, the flash point of biodiesel is higher than that of diesel, making it safer to transport and use.

The Dark Side of Biodiesel:

The problem with the idea of carbon neutrality is that it does not take into account the carbon costs of its production.

If combustion releases exactly as much carbon as has been absorbed, then it follows that any amount of carbon in the production of this diesel substitute will mean a larger amount than has been absorbed.

However, even with this emission surplus, biodiesel is still estimated to produce between 50-60% fewer emissions than its diesel counterpart.

The Trouble with Biofuels ……read morethe downside of biofuels

Another big issue surrounding biodiesel as a replacement for diesel oil lies in the need for land to grow the plants that can be turned into them.

This results either in the destruction of natural habitats or switching from the production of food plants; both of which are far from ideal.

This also increases the costs associated with the production of biodiesel, which are already significant.

One bright side, however, is that the government has introduced incentives to switch to biofuels, and so the cost is not borne by the drivers.

An additional problem that can be associated with used cooking oil as a biodiesel is that in the cold winter months, it has been known to freeze within the tanks of cars.

Obviously, this is a major drawback to replacing diesel, particularly the further North you travel.

Biodiesel in Cars:

The use of biodiesel is on the rise, and no small part of that is due to the UK’s Renewable Transport Fuels Obligation (RTFO) which necessitates all road transport fuels to contain a proportion of biofuels.

From April 2013 that has been a minimum of 5%. Biodiesel production increased by a factor of four between 2000 and 2005, although in recent years there has been a trend towards the biofuel ethanol compared to biodiesel.

The following car manufacturers have approved their diesel car range to run on 100% RME biodiesel (which is biodiesel made from rapeseed):

  • Volkswagen

  • SEAT

  • Audi

  • Skoda

The Green Car Website is here



Despite its lack of complete carbon neutrality, it cannot be argued that biodiesel is not advantageous to the environment, with carbon emissions being substantially lower than their fossil fuel counterparts.

As an added benefit, you may find it is cheaper to run your diesel car on biodiesel, due to the government incentives to do so, resulting in a win-win for both the planet and you.

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