What Is Biofuel? - Definition, Advantages, Examples and Uses

Biofuel is defined as any fuel sourced derived from biomass, otherwise known as organic matter. This includes any plant or algae material (including wood), as well as animal waste. Since these types of fuels are continually being replenished naturally by the cycle of life, they are considered as renewable sources of energy.

That makes them an attractive alternative to fossil fuels like coal, oil and natural gas. These substances must be developed over the course of millennia and extracted from deep under the ground using expensive and environmentally damaging processes. They are also being consumed at a far faster rate than they are being produced, meaning that sooner or later the planet’s supplies of fossil fuels will be completely exhausted – especially if we continue to deplete them at the current rate.

What are biofuels?

Simply put, biofuel is a catch-all term which refers to all fuel sources created from organic matter. However, not all biofuels are created equal. In fact, there is a clear distinction between primary biofuels and secondary biofuels, which separates them based upon how they are produced but also influences how they are normally used.

What are the different types of biofuels?

Primary biofuels are defined as organic materials that are deployed as an energy source immediately, without any prior treatment or processing. Some examples of primary biofuels include timber, wood chips, pellets and other types of wood that is traditionally used for heating and cooking purposes, especially in developing countries where no other fuel source is available. Although not as common, primary biofuels can also be used to generate electricity.

Secondary biofuels refer to any form of biomass that is used to generate energy after it has been processed. Examples of secondary biofuels include liquid biofuels that are becoming increasingly popular in the transportation industry, such as bioethanol and biodiesel. These are also used in industrial processes and biomass power plants, as well.

The vast majority of biofuel consumption takes place in domestic settings – usually in impoverished countries where no other sources of energy are available – to heat water for cooking, washing and cleaning, or to heat the home itself. 80% of all biofuels consumed today are devoted to this purpose. 18% of known biofuels are used in industrial settings, while just 2% of biofuels are used as a feedstock for vehicles in the transportation industry. However, this latter application is becoming increasingly popular as individual drivers, automotive manufacturers and national governments become more cognisant of the need to improve the emissions ratings of their cars.

How are biofuels made?

There is no complicated scientific process behind how primary biofuels are made. Since there is no processing involved, they are simply cultivated, harvested and combusted. Secondary biofuels, on the other hand, are a much more complex beast. To simplify matters, it may be helpful to concentrate on the two most common liquid biofuels that are used in the transport industry.

Bioethanol is made in much the same way that the alcohol found in beverages is, which is unsurprising given that ethanol is the same entity as the alcohol in whisky, vodka, beer, wine and many more alcoholic beverages. The substances involved are subjected to chemical reactions, fermentation and heat to ensure that the starch in the plants turns first into sugars, then into alcohol. This alcohol is then refined using a sophisticated process to ensure it is viable for use the engine of vehicles.

Biodiesel is a little different. The first part of the process is the same – the raw materials are forced to react with certain chemicals, then fermented and heated to create the alcohol. At this point, the alcohol is mixed with either animal fat or vegetable oil to turn it into biodiesel. There are a wide variety of different oils that can be used, from coconut oil to rapeseed oil to many others.

What are biofuel’s pros and cons?

Biofuels have been touted by environmental groups and commercial interests as a sustainable alternative to fossil fuels, and it’s certainly true that they hold a number of benefits in comparison to oil, gas and coal. However, no fuel source is perfect, which means that they also carry several drawbacks, as well. Here’s a rundown of the advantages and disadvantages associated with biofuels:

Why are biofuels good?

• Renewable. As mentioned above, fossil fuels are a finite source of energy which will eventually run out. Since biofuels can easily be replaced by simply generating more organic matter, they are theoretically renewable.
• Carbon. Since biofuels are created from organic matter such as plants, and plants remove carbon from the air, they’re inherently better for the environment than fossil fuels. However, this argument isn’t quite as convincing as might be expected once the emissions savings are offset by the costs and emissions incurred during the fertilisation, transportation and processing are factored into the equation.
• Cost-effectiveness. Producing bioethanol is cheaper than producing petrol, so combining the two could be a great way to cut expenses in the transportation industry. The same goes for biodiesel and diesel. What’s more, as stocks of fossil fuels run low, their prices will inevitably rise. The sustainable nature of biofuels makes their pricing more stable.
• Fuel efficiency. In comparison with fossil fuels, bioethanol and biodiesel contain smaller concentrations of chemicals like chlorine and sulphur. This means that when mixed with petrol or diesel, they can dilute the level of these contaminants in the fuel source and produce cleaner emissions. For more information on how this process works, the article Ensure Accurate Results for Sulfur and Chlorine Analysis in Biodiesels contains much useful information.
• Locality. Finally, biofuels can be produced locally, creating jobs in the same region where they will be consumed and reducing the transportation costs and emissions associated with shipping to them to the point of sale.

Why are biofuels bad?

• Resource use. The amount of energy produced by biofuels is considerably smaller than that generated by fossil fuel combustion, meaning far more land, water and fertiliser is needed to meet the energy demands of the same number of people. That’s especially true with regard to primary biofuels.
• Delicate ecosystems. The oils needed to produce biodiesels often derive from endangered habitats such as rainforests or other biodiverse locations. Harvesting the land in this way displaces animal populations, destroys ecosystems and discourages biodiversity.
• Suitability. Not all biofuels are suitable for all vehicles. In the UK, this is particularly prevalent, since the engines of many car models are not equipped to handle 100% biofuel mixes. Meanwhile, biodiesel is not suitable for use in the aviation industry, due to its poor oxidative stability and high freezing point. The article Analysing Jet Fuel for Biofuel Contaminants - Safety First gives more information on this particular point.
• Emissions. When primary biofuels are combusted to create heat (as happens most commonly in developing countries), they produce greater amounts of local emissions than other forms of heating.

Are biofuels good for the environment?

As hinted at above, there are both environmental pluses and negatives associated with biofuels. Though they can offer a variety of eco-friendly benefits for our planet, they can also entail detrimental consequences. Much depends on the specific type of biofuel in question, how it is produced and how it is consumed. It’s advised to read up on the biofuel you have in mind before committing to its use as an everyday fuel source.

What is E10?

In March of 2020, the UK government announced it would be replacing the current bioethanol option (E5) with a new upgrade (E10). As the name suggests, E10 contains a 10% mix of bioethanol (alongside 90% petrol) and is believed to reduce carbon emissions by 2%. According to the government, replacing E5 with E10 across the country will lead to emissions reductions equivalent to taking 350,000 vehicles off British roads.

The only drawback to this strategy is that all cars built before 2011 may not be equipped to deal with E10, due to the fact that it can leave behind residue in the engine and lead to blockages in the system. It’s estimated that up to one million cars will be adversely affected in this manner. Those drivers are recommended to switch to super unleaded petrol if they want to reap the same environmental benefits – but the downside is that super unleaded is more expensive than standard petrol, while E10 is cheaper.

In any case, the debate on bioethanol and biodiesel being used in the transportation industry has a limited shelf-life in Britain. That’s because the UK government has already set a deadline of 2035 for the sale of new petrol, diesel and hybrid cars, after which it will not be possible to buy new models.

Can biodiesel replace diesel?

Internationally, biodiesel can be used as a direct replacement for diesel in many vehicles. However, in the UK, biodiesel is only available in a blended format, since there are not many manufacturers who have approved their engines for 100% biodiesel use. As mentioned above, biodiesel is not a viable substitute for diesel in jet engines and other aviation purposes.