First of all, what is biofuel? Well, essentially biofuel is a renewable fuel made from an organic product – such as wheat straw, sugar beet or even algae – which can be used as an alternative to petrol or diesel.
How do you make biofuel?
Some biofuels are made from specially grown crops. In Europe, some of the most commonly used are wheat, maize, sugar beet, rapeseed and soybean(1) – crops chosen for their high natural energy content. However, a downside to growing crops specifically to make biofuel is that it uses up valuable agricultural land, which is needed to grow food.
To tackle this issue, ExxonMobil is working with others to research how to make biofuel that doesn’t compete with food production. One way to approach this is by making cellulosic biofuel, using agricultural residue – like wheat straw. This is complementary to vegetable farming, because it makes use of the leftovers from the harvest.
Another avenue we are pursuing is working out how to make biofuel from algae. Algae can be grown in waste water and brackish water – in fact, it can even purify polluted water – so it doesn’t use up agricultural land or fresh water.
What kind of cars can use biofuels?
When relatively small amounts of bioethanol – a common type of biofuel –is added to unleaded petrol, many cars (generally speaking those made after 2002(2)) can use it without any engine modifications.
If you live and drive in the UK, France, Germany, Finland or Belgium(3)(4) you may have already put some biofuel in your car. Unleaded ‘SP95-E10’ fuel is labeled ‘E10’ because it contains 10 percent bioethanol – and it’s widely available in continental Europe. In September 2017 E10 was found to be the best-selling fuel in France(5).
In the UK, up to 5 percent bioethanol has been added to petrol for over 10 years(3). It’s recently been labeled ‘E5’ and British diesel contains up to 7 percent biodiesel – labelled ‘B7’.
The fuel in many pumps across Europe contains small amounts of biofuel and the amount is labeled. In the UK for example, diesel contains up to 7 percent biodiesel and is now labelled ‘B7’.
Fuel labeled ‘E85’ is also available at some European service stations. This fuel blends up to 85 percent bioethanol with 15 percent petrol, but only ‘flexible fuel’ vehicles can use E85, meaning it isn’t suitable for ordinary cars without engine modifications. Bioethanol-unleaded petrol blends are popular in Brazil, where 80 percent(6) of the light vehicle fleet have flex fuel engines.
Biodiesel made from algae can be used by ordinary diesel cars without making major changes to engines or infrastructure. However, we’ve still got a long road ahead before we’re able to make algae biodiesel at a commercial scale. For the time being, all we can say is that the research is moving ahead smoothly!