A huge amount of research and innovation has gone into the search for sustainable biofuels that could reduce carbon emissions from private and commercial transport. However, with electric vehicles increasingly seen as the main route to decarbonizing private transport, is there any role left for biofuels?
It is estimated that biofuels could save an average of 83% of GHG emissions compared to fossil fuels. However, only 2% of biofuels are currently used for transportation. 80% are used for residential heating and 18% in industry.
Both fossil fuels and biofuels are made from organic material biomass (the remains of plants and animals). Whilst the finite supply of fossil fuels has taken millions of years to form, biofuels can be produced in a much shorter time span. Furthermore, biofuels emit just 39kg of CO2 per megajoule of energy generated, compared to 75.1kg for fossil fuels.
The Committee on Climate Change says, “There is no universal answer to the question as to whether biomass is low carbon.” This is because there is a wide range of different biofuels, the science behind their production is evolving rapidly and the methods of production determine the carbon footprint.
Biofuels can be categorized into four generations of biofuel.
The first generation is made from food crops such as wheat and sugar, which is converted into gas or liquid and blended with conventional fuel such as petrol or diesel to reduce its carbon content. The production of first-generation biofuel is well established, but altogether relies on roughly 2-3% of the global water and land used for agriculture.
The second generation of biofuels is made from non-food crops and residue from forestry and agriculture, such as straw, grass and fast-growing woody crops. This avoids conflict with food production and makes use of waste streams from other industries.
The third generation is made from specially modified energy crops like grass, algae, and engineered microorganisms. Any CO2 resulting from production is captured directly, and the production does not require any change in land use. These biofuels can be processed into a range of fuels, including diesel, petrol, and jet fuel. They also have potential to be carbon neutral.
The most recent generation of biofuels (the fourth generation), not only generate sustainable energy, but capture and store CO2. Biomass raw materials are processed into fuel using similar processes to generations two and three but absorb CO2 during the growth process – making them carbon negative.
Achieving net zero will require all passenger vehicles to transition to clean fuels, and in the UK, a switch to electric vehicles (EVs) has been the key focus of government policy. In 2023, a new £381 million Local Electric Vehicle Infrastructure fund was announced, alongside £15 million in funding for the On-Street Residential Charging Scheme.
However, heavy investment in electric vehicle infrastructure does not mean that biofuels have no role to play in road transport decarbonization. The UK government has been warned by the House of Commons Transport Committee not to ‘put all its eggs in one basket’ through overreliance on EVs to reduce transport-related carbon emissions.
The House of Commons Transport Committee’s ‘Fuelling the Future’ report argues that alternative fuel vehicles could provide a ‘socially equitable’ alternative for motorists. Either for those unable to purchase an electric vehicle, or for those living in rural or isolated communities beyond the reach of charging infrastructure.
There is also an argument that scrapping the nation’s current car stock to replace them with EVs also comes at a cost in materials and embedded carbon. Biofuels could help to reduce the impact of cars without sending them to the scrapheap prematurely.
The Committee also recommends that the UK government move beyond its ‘deliberately technology agnostic’ approach for the rest of the transport network. While the rail network is moving towards electrification, there could be a role for biofuels in aviation, maritime, and heavy goods vehicles.
The use of biofuels to power heavy goods vehicles is already fairly advanced. Their weight and distance travelled makes frequent battery charging impractical, and some businesses have already transitioned to biofuels. One high-profile example is the Mercedes Formula 1 freight fleet which has switched to biofuels, saving 88% on emissions. Jersey has adopted vegetable oil-based biofuels for more than 37% of its vehicles, with a plan to phase out combustion engines entirely in coming years. Aldi has also announced that biomethane-powered HGVs will be used in its UK fleet.
The aviation and maritime industries will also see a transition to alternative fuels over time, as batteries are likely to prove too heavy and too carbon intensive to produce at the scale required. Synthetic fuels and biofuels could well be set to take up the slack.
Standards have a vital role to play in supporting innovation and assisting in the application of biofuels. Whether it’s measuring carbon output, finding shared definitions to assist with collaboration or exploring the application of a new technology, standards can help.
Standards that may be of interest include:
PAS 2060 Specification for the demonstration of carbon neutrality
BS EN ISO 14064-2 Greenhouse gases - Specification with guidance at the project level for quantification, monitoring and reporting of greenhouse gas emission reductions or removal enhancements
BS EN ISO 17225-1 Solid biofuels – Fuel specifications and classes – Part 1: General requirements
PAS 7060 Electric vehicles. Safe and environmentally conscious design and use of EV batteries
Achieving Net Zero in transportation is likely to be the result of a range of different measures, rather than finding a straight single replacement for fossil fuels. While electrification has received much of the recent government attention and infrastructure investment in recent times, biofuels might also have an important role to play. As the technology behind sustainable transport develops and progresses, standards can help find the right balance between biofuels, electrification, and other low-carbon options.
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