Biofuels are greener, more environmentally-friendly alternatives to regular fuels such as petrol and oil, made from natural and renewable materials such as wood, grass and food scraps.
Biofuels are playing a particularly important role in the transport industry, as cars, buses and planes are largely dependent on finite fossil fuels such as petrol. Transport is also responsible for a large amount of greenhouse gases, and biofuels have the potential to reduce this carbon footprint.
It might seem, then, that biofuels are a relatively recent concept, but they actually go back a long way.
In the 13th century explorer Marco Polo noted that the Chinese used covered sewage tanks to generate power. Meanwhile in the late 1800s Rudolf Diesel created an engine powered by vegetable oil. That was before petroleum-based diesel fuel – then much cheaper – became so widely available.
Commonly made from vegetable oil, animal fat and recycled grease (including used cooking oil), biodiesel can be used in most things that take regular diesel, such as cars, trucks, machinery and ships, however it’s usually used as a blend to reduce the pollution emitted from diesel-powered cars.
Also known simply as ‘ethanol’, this type of biofuel is simply an alcohol made by fermenting sugar and plants such as crops and sugarcane. Ethanol can be used as a fuel for vehicles – in particular high-performance cars – but it’s usually blended with regular gasoline to help reduce emissions.
Biogas is a by-product of anaerobic digestion that can be used domestically, or to generate electricity. When organic waste such as manure, sewage waste and agricultural waste breaks down it creates a mixture of methane gas and carbon dioxide. This is called anaerobic digestion.
Anaerobic methane digesters trap large amounts of this waste at high temperatures with reduced oxygen to speed up the breakdown process. This creates the gases more quickly than natural decomposition.
The clever technology then traps the resulting gas, which can then be used for the same purposes as natural gas: heating, cooking and so on. Some vehicles even use the gas as an alternative fuel.