Biofuels – types and use in sustainable transportation
What Are Biofuels and How Are They Produced
Biofuels are renewable energy sources derived from biological materials such as crops, waste oils, or organic residues. Unlike fossil fuels, which take millions of years to form, biofuels can be produced on a much shorter timescale, offering a more sustainable alternative for powering vehicles and reducing carbon emissions.
Production of biofuels involves converting raw organic matter into usable energy forms. Bioethanol, for instance, is made through the fermentation of sugars and starches from crops like wheat, sugar beet or maize. It is blended with petrol and used in standard combustion engines. Biodiesel, on the other hand, is created from vegetable oils or animal fats via a process known as transesterification and is blended with regular diesel.
There are also advanced biofuels, produced from non-food feedstocks such as agricultural residues, waste oils or even algae. These are often referred to as second- and third-generation biofuels. They reduce the environmental impact further by avoiding the food-versus-fuel conflict and making use of materials that would otherwise be discarded.
In the UK, biofuels have become a key element in decarbonising the transport sector. With government mandates in place and growing awareness of climate change, the role of biofuels is steadily increasing within the national energy mix.
Types of Biofuels Used in Transport
A variety of biofuels are now in use across the UK to reduce reliance on fossil fuels and meet climate targets. These fuels are particularly important in decarbonising sectors where electrification is not yet fully viable.
Bioethanol is blended into petrol sold at UK petrol stations. Since September 2021, the standard grade has been E10, which contains up to 10% bioethanol. This change was made to reduce carbon emissions from petrol cars, which still make up a large share of vehicles on British roads.
Biodiesel is commonly made from used cooking oil, tallow, and rapeseed oil. It is often blended with diesel in different proportions, such as B7 (7% biodiesel), the current standard for road diesel in the UK. Biodiesel is used in a range of applications, from cars and lorries to buses and agricultural machinery.
Another increasingly prominent option is hydrotreated vegetable oil (HVO), a type of renewable diesel that is chemically very similar to fossil diesel. It can be used in existing diesel engines without modification and is gaining popularity for commercial fleets and off-road use.
Biomethane, a purified form of biogas, is being trialled in several public transport systems and by logistics companies. It can power specially adapted vehicles and is a low-emission alternative to compressed natural gas (CNG).
These diverse biofuels allow the UK to take advantage of waste streams, local agriculture, and existing vehicle technology to accelerate the shift towards cleaner transport.
Environmental Benefits of Using Biofuels
One of the strongest arguments in favour of biofuels is their environmental benefit compared to conventional fossil fuels. Their use can significantly reduce greenhouse gas emissions, especially when produced from waste materials or sustainable feedstocks.
Biofuels are considered carbon neutral in theory because the carbon dioxide released during combustion is offset by the carbon absorbed during the growth of the original biomass. While this cycle is not perfect—due to emissions from cultivation, processing and transport—it offers a lower carbon footprint overall than petrol or diesel.
In addition to climate benefits, biofuels help improve local air quality. They tend to emit less sulphur dioxide, particulate matter and nitrogen oxides than fossil fuels, leading to better public health outcomes, particularly in densely populated urban areas with high traffic levels.
Furthermore, biofuels promote waste reduction. For example, biodiesel produced from used cooking oil repurposes a material that would otherwise be discarded. Similarly, biomethane production from food waste or manure reduces the volume of waste going to landfill and prevents methane emissions from decomposition.
Finally, biofuels support energy security by reducing reliance on imported crude oil. The UK can produce a significant portion of its biofuel needs domestically, creating jobs in rural communities and supporting the circular economy.
Challenges and Drawbacks of Biofuel Implementation
Despite their advantages, the implementation of biofuels presents several challenges that must be addressed to ensure their long-term sustainability and effectiveness.
A key issue is the competition with food production. First-generation biofuels are derived from crops like maize, wheat and rapeseed, which can also be used for human consumption. Large-scale diversion of such crops for energy purposes can affect food prices and raise ethical concerns, especially during times of global supply shortages.
Land use change is another concern. Expanding biofuel feedstock cultivation can lead to deforestation or the conversion of biodiversity-rich areas into farmland. This not only undermines the climate benefits of biofuels but also harms ecosystems and wildlife.
Economically, biofuels can be more expensive to produce than fossil fuels, especially in the absence of subsidies or incentives. This can limit their competitiveness in a free market and make them vulnerable to oil price fluctuations.
There are also technical limitations. While lower blends such as E10 and B7 are compatible with most vehicles, higher blends or pure biofuels may require engine modifications. Additionally, cold weather performance, fuel stability and storage issues need to be managed carefully.
To mitigate these drawbacks, policy must focus on sustainable sourcing, support for advanced biofuels, and clear standards for emissions and land use. Public awareness and corporate responsibility also play a vital role in ensuring that biofuels contribute positively to environmental and energy goals.
Alternative Fuels Compared to Petroleum-Based Fuels
As the UK transitions away from fossil fuels, various alternative energy sources are being explored alongside biofuels. Each has distinct characteristics and applications across different transport modes.
Electric vehicles (EVs) are becoming increasingly common, particularly for private passenger transport. They produce zero emissions at the point of use and are supported by growing government incentives and charging infrastructure. However, concerns remain about battery production, mineral sourcing, and range limitations for long-distance or heavy-duty use.
Hydrogen fuel cells are promising for long-haul freight and buses, offering fast refuelling and high energy density. The UK government has launched several hydrogen trial programmes, but large-scale infrastructure is still lacking and green hydrogen remains expensive.
Compressed natural gas (CNG) and liquefied natural gas (LNG) are also used, especially in freight and public transport. While cleaner than diesel, they are still fossil fuels unless derived from renewable sources such as biomethane.
Compared to these, biofuels offer a major practical advantage: they are compatible with existing engines and distribution networks. This makes them an ideal transitional solution, especially in sectors that cannot electrify rapidly, such as aviation, maritime transport, and heavy goods vehicles.
Global Success Stories in Sustainable Transport
Around the world, many countries have successfully adopted biofuels as part of their transport decarbonisation strategy, showing that real change is possible with the right policies and investments.
Brazil has long been a global leader in ethanol use, producing it from sugarcane and integrating it widely in the fuel supply. Most cars are flex-fuel and capable of running on high ethanol blends, which has significantly reduced the country’s reliance on oil.
In Sweden, biogas derived from organic waste is widely used in buses and taxis. Stockholm’s public transport system is a pioneer in low-emission mobility, and the country continues to innovate in advanced biofuel production.
Germany has invested heavily in biodiesel and renewable diesel, encouraging their use through subsidies and sustainability mandates. The country is also testing algae-based biofuels for aviation.
The UK has its own success stories as well. Through the Renewable Transport Fuel Obligation (RTFO), suppliers must include a minimum share of renewable fuel in the fuel they supply. Organisations such as Transport for London (TfL) have incorporated biodiesel from used cooking oil into bus fleets, while logistics companies are trialling biomethane for freight transport.
These examples demonstrate how a combination of regulation, innovation, and infrastructure development can facilitate the transition to low-carbon transport systems.
Biofuel Policy and Legislation in the UK
In the United Kingdom, the main legislative framework governing biofuels is the Renewable Transport Fuel Obligation (RTFO). Introduced in 2008, it requires fuel suppliers to ensure that a certain percentage of the fuel they supply comes from renewable sources.
Under the RTFO, which is administered by the Department for Transport (DfT), obligated suppliers must achieve an annually increasing target. As of 2024, the target stands at 12.6% by energy, rising each year to align with the UK’s Net Zero by 2050 goal. Suppliers can meet this obligation through bioethanol, biodiesel, biomethane and other advanced fuels.
The UK government also supports development fuels, which include advanced biofuels made from waste, residues or non-food crops. These fuels benefit from double counting towards RTFO targets, encouraging their adoption over first-generation fuels.
Sustainability criteria are built into the RTFO, ensuring that biofuels must meet greenhouse gas savings thresholds and avoid negative land use changes. Feedstock sourcing and production practices must comply with stringent environmental and social standards.
Beyond the RTFO, the government provides funding for research and pilot projects, including support through the Green Fuels, Green Skies programme for sustainable aviation fuel (SAF) development.
Despite this progress, challenges persist: policy uncertainty, the need for infrastructure investment, and public scepticism about biofuels. Continued support, transparency and clear regulation will be crucial to expanding biofuel use responsibly.
The Future of Energy in Sustainable Transport
The UK’s path to sustainable transport will involve a combination of technologies and fuels. While electric mobility will play a central role, biofuels will remain essential for specific sectors where batteries are impractical.
Aviation, shipping, and heavy road transport all pose electrification challenges. Here, advanced biofuels offer an immediate solution with the potential to deliver significant carbon reductions. Sustainable aviation fuel (SAF), for example, could cut emissions from flights by up to 80% compared to fossil jet fuel.
Further investment in second- and third-generation biofuels—such as those made from waste materials, algae, or lignocellulosic biomass—will reduce the pressure on food systems and enhance overall sustainability.
To realise this potential, collaboration between government, industry, and academia will be vital. Innovation in feedstocks, more efficient processing technologies, and well-designed policy will drive the biofuel sector forward.
As the UK works towards its climate targets, biofuels will remain an indispensable part of the toolkit—bridging the gap between current infrastructure and the fully decarbonised transport system of the future.
Frequently Asked Questions (FAQ)
1. What biofuels are used in the UK?
Mainly bioethanol (in petrol) and biodiesel (in diesel), with growing use of renewable diesel and biomethane in fleets and logistics.
2. Is there a legal requirement to use biofuels in the UK?
Yes. The Renewable Transport Fuel Obligation mandates suppliers to include a rising share of renewable fuels.
3. Can I use biofuels in a regular car?
Most cars can use E10 and B7 without issue. Higher blends may require modifications or specific engine compatibility.
4. Are biofuels environmentally friendly?
When produced sustainably, yes. They emit fewer greenhouse gases and reduce reliance on fossil fuels, especially if made from waste.
5. What’s the future of biofuels in the UK?
They will remain key in sectors like aviation, freight, and maritime, where full electrification is not yet feasible.