Shell Global Solutions process for ethanol production
Biofuels are a renewable energy source, made from organic matter or wastes, that can play a valuable role in reducing carbon dioxide emissions. Biofuels are one of the largest sources of renewable energy in use today. In the transport sector, they are blended with existing fuels such as gasoline and diesel. In the future, they can be particularly important to help decarbonize the aviation, marine, and heavy-duty road transport sectors.
What are biofuels?
Biofuels can be produced from organic matter, or biomass, such as corn or sugar, vegetable oils, or waste feedstocks.
As biofuels emit less carbon dioxide (CO2) than conventional fuels they can be blended with existing fuels as an effective way of reducing CO2 emissions in the transport sector. The use of biofuels has grown over the past decade, driven largely by the introduction of new energy policies in Europe, the USA, and Brazil that call for more renewable, lower-carbon fuels for transport. Today biofuels represent around 3% of road transport fuels in use around the world.
Types of biofuels
Today, most biofuels are produced from agricultural crops and are called conventional biofuels. New technologies and processes that produce fuels from waste, inedible crops, or forestry products are being developed and these fuels are known as advanced, or second-generation biofuels. Advanced biofuels are likely to become the primary form of biofuels in the future as they can improve their sustainability.
The two main types of biofuels are ethanol and biodiesel.
Ethanol is produced by fermenting sugar or starch from products such as sugarcane, maize or wheat. It is used in blended fuels with petrol, either at low levels in regular vehicles (up to 10%) or at higher levels in cars that have been adapted to take both petrol and ethanol, known as “flex-fuel” vehicles.
Biodiesel and HVO
Biodiesel is produced from vegetable oils, fats, or greases. It is blended with diesel, generally at low levels (up to 7%).
HVO, or Hydrotreated Vegetable Oil, differs from biodiesel in the way it is produced and in the quality of the final product. HVO is produced through the hydroprocessing of oils and fats. It can typically be blended with diesel without a blending limit. HVO is also commonly referred to as renewable diesel.
Advanced or second-generation biofuels
A variety of waste feedstocks can be used to produce transport fuels that contribute to reducing CO2 emissions when compared to traditional fossil fuels. Some of these biofuels can be blended with conventional fuels and others are fully compatible with current vehicles and so can be used as complete replacements for conventional fuels.