Bioethanol – the advantages and disadvantages

You’ve probably heard of bioethanol as an alternative to petroleum and diesel. However, how does it work and how green is it? The guide to bioethanol will shed some light.

What is bioethanol and how is it produced?

Bioethanol refers to ethanol liquid which is made from common crops including sugar cane and corn. It is considered an alternative to petroleum and diesel and its popularity is emerging as a fuel for cars – it is particularly well established in Brazil.

Production of bioethanol involves the conversion of a feedstock crop into fermentable sugars through enzyme amylases. Yeast is then added to ferment the sugars into alcohol and carbon dioxide. The main crop used in bioethanol production varies throughout the world – in Brazil, sugar cane is preferred, in the USA its corn and across Europe it’s predominantly wheat and barley.

What cars use bioethanol?

Bioethanol can be handled in a similar manner to petrol and is often used as a low percentage blend to save on fuel costs – E10 is 10% ethanol and 90% petrol.

However, bioethanol can be suitable in much larger quantities and can produce excellent high-performance results – it is already used in motor racing. Yet it is generally necessary to adjust the car to accept these larger quantities such as through the fitting of a larger fuel tank and an adjustment of the ignition timing. Pure ethanol is also difficult to vaporise which can make starting a car in cold weather difficult and that is why most fuels retain at least a small amount of petrol – such as E85 cars with 85% ethanol and 15% petroleum.

Bioethanol is on the increase as a fuelling alternative. Already Ford, Saab and Volvo produce Fuel-Flex Vehicles (FFVs) that can run on an ethanol blend up to E85.

What are the advantages of bioethanol?

The overwhelming advantage of bioethanol for the environment is its potential to be carbon neutral on a lifecycle basis – meaning the carbon dioxide (CO2) emitted during its use is offset by the absorption from the atmosphere during its growth.

With emissions of CO2 and nitrous oxide taken into account, some studies suggest that lifecycle greenhouse gas emissions can be reduced by 90% with bioethanol compared to petrol. This is a best-case scenario however, using sugar cane as the crop and large amounts of bagasse (the remaining wood fibres after the juice is extracted) used for heat energy. Nevertheless, even by current European standards the emission reductions are significant – around 35-65% depending on the processing method.

Bioethanol also has the advantage of lower taxation. The UK government has reduced fuel duty on bioethanol which offsets the higher production costs. The first supermarkets in the UK selling E85 offered it at around 2p cheaper than conventional petrol but typically you would use much more bioethanol per mile than traditional fuel – around 50% more if you’re using 100% bioethanol.

What are the disadvantages of bioethanol?

There are many concerns over the use of bioethanol as a long-term alternative in the fuelling of cars. These include:

  • Biodiversity – A large amount of arable land is required to grow crops. This could see some natural habitats destroyed including rainforests.
  • The food V fuel debate – There is concern that due to the lucrative prices of bioethanol some farmers may sacrifice food crops for biofuel production which will increase food prices around the world.
  • Carbon emissions – There is debate over the neutrality of bioethanol when all elements are taken into consideration including the cost of changing the land use of an area, transportation and the burning of the crop.

There are also concerns over the fuel systems used. Too many older cars are currently unequipped to handle even 10% ethanol while there is concern that using 100% ethanol decreases fuel economy by around 15-30% compared with 100% petroleum.

How can you run a bioethanol car?

Finding bioethanol is still difficult in the UK as there are very few filling stations that sell high percentage bioethanol fuels although this number is on the rise.

In 2008, the Government’s Renewable Transport Fuel Obligation stated that 2.5% of all fuel must be from renewable sources and this number will rise to 5% by 2010. Bioethanol is therefore being used already, alongside other renewable fuel sources, when we visit a petrol station.

The number of green cars using bioethanol predominantly is set to grow as part of the BEST (Bioethanol for Sustainable Transport) project.



0 #1 the vales sengkang 2015-04-26 08:53
You actually make it seem so easy with your presentation but I
find this matter to be really something which I
think I would never understand. It seems too complex andd very broad for
me. I am looking forward for your next post,
I'll try to get the hang of it!
Quote | Report to administrator

Add comment

Comments are for viewing by everyone in the general public.

We require you to consider this when posting comments as we do not allow defamatory remarks or comments of a demeaning nature.

The comments system is purely to allow comments on a particular article or subject being covered.

We reserve the right not to publish any comments we feel have broken our policies.

Security code