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Biofuel - the pros and cons

As more environmentally conscious drivers search for ways to reduce their carbon dioxide emissions and therefore reduce their negative impact on the environment, many are considering biofuel.

What is biofuel?

Broadly speaking, biofuel refers to any solid, liquid or gas fuel that has been derived from biomass. It can be produced from any carbon source that is easy to replenish - such as plants.

One of the main challenges when producing biofuel is to develop energy that can be used specifically in liquid fuels for transportation. The most common strategies used to achieve this are:

  • Grow plants – Plants that naturally produce oils include oil palm, jatropha, soybean and algae. When heated resistance (viscosity) is reduced they can be burned within a diesel engine or they can be processed to form biodiesel.
  • Grow sugar crops or starch – These include sugar cane, sugar beet, corn and maize which are then turned into ethanol through the process of yeast fermentation.
  • By-products – By-products such as wood chippings can be converted into biofuels including methanol, ethanol and woodgas.

What are the different types of biofuel?

There are many different biofuels available in the UK. One of the most common worldwide is E10 fuel, which is actually a mixture of 10% ethanol and 90% petroleum. This formula has been improved in recent years with the introduction of E15 fuel (15% ethanol, 85% petroleum); E20 fuel (20% ethanol, 80% petroleum); E85 fuel (85% ethanol, 15% petroleum); E95 fuel (95% ethanol, 5% petroleum) and E100 fuel which is ethanol with up to 4% water.

In Europe, biodiesel is the most popular form of biofuel - it can be used in any diesel engine when mixed with mineral diesel. This is produced from oils and fats and is now readily available at many petrol stations. Like ethanol, biodiesel is available in a number of mixes including B5 (5% biofuel, 95% diesel), B10 (10% biofuel, 90% diesel), B20 (20% biofuel, 80% diesel), B80 (80% biofuel, 20 diesel) and B100 (100% biofuel).

In the UK, the Renewable Transport Fuels Obligation (RTFO) obliges that all road transport fuels-petrol and diesel-sold in the UK, must contain a percentage of biofuel. This amount, currently around 3 per cent, increases annually until April 2013 when it will reach 5 per cent. Thereafter, it will remain at that level for subsequent years.

There are many sources of biofuel including vegetable oil, which is used in many older diesel engines; butanol, which is seen as a replacement for petroleum; and biogas which is produced from biodegradable waste materials.

This technology has been expanded with the introduction of 'second generation' biofuels - which use biomass to liquid technology. Examples include biohydrogen, biomethanol and mixed alcohols.

Third generation biofuels are also known as algae fuels. They have many advantages including have a low input and a high yield level – they produce 30 times more energy per acre than land – and are also biodegradable. As a result, they are relatively harmless to the environment if spilled.

Where are biofuels used?

Biodiesel can, in theory, be used in all diesel engines. However, due to the parts attached to the diesel engine, some manufacturers do not approve engines running on higher biofuel blends of biodiesel.

Volkswagen, SEAT, Audi and Skoda all approved their cars built from 1996-2004 running on 100% RME biodiesel - that is biodiesel made from rapeseed - on the condition that it meets specification EN14214.

Generally speaking, it is recommended that you use a combination of biodiesel blended with regular diesel. Indeed at the majority of petrol stations, a mix up to 5 per cent biofuel is already included in diesel, thanks to the RTFO. It is also worth bearing in mind that biodiesel made from waste cooking oil can freeze in the winter - and so no more than a 50 per cent blend is recommended.

Between 2000 and 2005 ethanol production doubled, and biodiesel production quadrupled, so biofuels are clearly on the rise.

What are the advantages of biofuels?

The aim of all biofuels is to be carbon neutral. They have the potential to reduce greenhouse gas emissions when compared to conventional transport fuels but whether they live up to this depends on the way they are produced and managed.

In reality, biofuels are not carbon neutral simply because it requires energy to grow the crops and convert them into fuel. The amount of fuel used during this production (to power machinery, to transport crops, etc) does have a large impact on the overall savings achieved by biofuels. However, biofuels could potentially still prove to be substantially more environmentally friendly than their fossil alternatives.

In fact, according to a technique called Life Cycle Analysis (LCA) first generation biofuels can save up to 60% of carbon emissions compared to fossil fuels. Second generation biofuels offer carbon emission savings up to 80%. This was backed by a recent UK Government publication which stated biofuels can reduce emissions by 50-60%.

Another advantage of biofuels is that they save drivers money. The UK Government in particular has introduced many incentives to drivers of 'green cars' based on emissions - with reduced taxation dependent on how environmentally friendly your vehicle is. With petrol prices on the rise, replacing petroleum with a renewable energy source should also offer significant savings at the pump in the long term, particularly when biofuels are more readily available.

However, there are arguments though that biofuel production has contributed to the destruction of natural habitats to make room for it. Also in some cases they are reported to have displaced valuable food production and contributed to rising food prices. Developing countries seem particularly vulnerable to the potential negative impacts of the production of first-generation biofuel crops . More on these problems is below. But on a positive note, it is hoped that tightening environmental requirements in Europe, the US and other developed countries coupled with the development of more advanced, non-food source biofuels will help stamp out these problems experienced  while importing first-generation biofuels.

What are the disadvantages of biofuels?

Updated: August 2012.

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Paul Lucas

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