While the popularity of hybrids and electric vehicles is on the rise, the majority of cars still run on petrol and diesel. But what about biofuels - which vehicles are compatible, and what are the benefits of using biofuels? The obvious advantage is helping to reduce greenhouse gas and carbon emissions, though there are a number of other benefits too. We’ve explored biofuels in more detail below:

What are Biofuels?

Biofuels are a type of fuel that have been made from natural products, rather than fossil fuels. This means that they are a renewable source of energy. Biofuels are generally blended with either petrol or diesel, which can reduce the level of carbon emissions the fuel creates. 

There are two main types of biofuel, when it comes to running a vehicle. These are bioethanol and biodiesel. The former is an alcohol that’s produced through the fermentation of sugars and starches from particular crops. These include corn, wheat and sugar beets. Biodiesel is also produced through food products, though usually the waste, such as waste cooking, rapeseed, palm and vegetable oils. 

What is the Legislation on Biofuels?

Within Europe, there are a few directives that encourage the use of biofuels. These include the 2009 Renewable Energy Directive (RED), which provides legal requirements for the use of renewable fuels, as well as targets for the reduction of greenhouse gas emissions. The 2009 Fuel Quality Directive (FQD) focuses solely on transport fuels, and requires fuel suppliers to meet percentage reductions in terms of greenhouse gas emissions. 

In the UK, the main piece of legislation to take note of is the Renewable Transport Fuel Obligation (RTFO) order. This only applies to fuel suppliers who are providing more than 450,000 litres of fuel a year. A percentage of this fuel has to come from sustainable, renewable sources.


What Percentage of Ethanol is in Biofuels?

The fuel specifications defined by European Standards state that up to 5% Ethanol in petrol won’t cause any compatibility problems with vehicle fuel systems. Therefore, the pumps won’t be marked to indicate that this petrol may contain biofuels. This doesn’t mean that petrol always has some level of biofuel mixed in, but it might contain anywhere between no biofuel and 5% biofuel. 

You can also get petrol with higher concentrations of Ethanol, but this will always be clearly labelled. You’ll see this at filling stations as ‘E10’. There could potentially be compatibility issues with E10, though according to the AA, more than 90% of petrol vehicles are compatible. For the most part, cars made after the year 2000 should be compatible with E10.

It’s also important to note that even if your car isn’t technically compatible with higher concentrations of Ethanol based fuel, one accidental fill isn’t cause for alarm. You won’t need to drain the tank if you fill up once with E10 rather than regular petrol, though continued use is likely to cause problems down the line. 

Pros of Ethanol and Biodiesel

The advantages of ethanol and any other type of biofuel are obvious - they are a sustainable source of energy, and reduce both CO2 and HC (Hydrocarbon) emissions. In fact, biodiesel can decrease greenhouse gas emissions by up to 86%, which is the equivalent of planting almost two billion trees.

Both biodiesel and Ethanol have good combustion properties too, which means that they are safe to use, readily available, and don’t produce toxic or unpleasant gases when releasing energy. 

biofuel fuel boiler

Disadvantages of Biofuels 

Unfortunately, biofuels come with a number of disadvantages. Though bear in mind that these cons are in relation to ‘first generation’ biofuels - they don’t necessarily all apply to advanced biofuels, which are currently being developed.

Limitations of Ethanol

Perhaps the biggest disadvantage of Ethanol is that it can cause erosion. As it has a higher solvency than petrol, it can lead to erosion in things like aluminium, zinc, brass, copper and lead. So over time, you may need to replace parts of your car due to erosion. 

Another limitation of Ethanol is that it has a lower energy density than conventional petrol - around two thirds. Fuel consumption will therefore be higher. 

Another thing to remember with Ethanol is that in low temperatures, it may cause starting problems with your vehicle. So perhaps avoid using it in the winter!

Limitations of Biodiesel 

Biodiesel has similar disadvantages to Ethanol - your fuel consumption will be higher due to a lower energy density, it has a high solvency so can lead to erosion, and it may be impacted by low temperatures.

On top of this, biodiesel also increases tailpipe emissions of NOx (Nitrogen Oxides). NOx contribute to things like acid rain, so are harmful to the environment. 

Advanced Biofuels

There are a few concerns about the sustainability of ‘first generation’ biofuels, including the worry that there isn’t enough farmland to produce both food and plant matter for biofuels. But second generation, or advanced, biofuels are made from non-edible sources, like wood chips and agricultural waste, such as husks, stems and leaves. The characteristics of this fuel should also be more like those of regular petrol and diesel. Unfortunately it will be some time before production of advanced biofuels can begin on an industrial scale, but the future looks promising!