Drop-in fuel blends: A cleaner path for heavy-duty transport

UCL Ph.D. student Sunita Sisodiya is pioneering research on innovative fuel blends to decarbonise heavy-duty transport. Her work on pyrolysis bio-oils and hydrotreated vegetable oils (HVO) shows their potential to reduce emissions and maintain engine efficiency.

Exploring the role of Pyrolysis Bio-Oils and hydrotreated vegetable oil in decarbonising the transport sector

The transportation sector, particularly heavy-duty vehicles, is a major contributor to global CO2 emissions. As the world moves toward a more sustainable future, new fuel solutions are being explored to reduce the carbon footprint of existing fleets. Fast-pyrolysis bio-oils (FPBOs), hydrotreated vegetable oils (HVO), and fuel blends are emerging as promising alternatives to conventional diesel fuels, offering near-term solutions for decarbonising heavy-duty transport.

The role of Pyrolysis Bio-Oils and HVO in combustion

Research conducted by Sunita Sisodiya, a Ph.D. student at UCL, has explored how pyrolysis oils behave when tested as neat fuels and in blends with HVO and standard diesel (EN590-B0). Her findings highlight key differences in combustion profiles between these fuels, with pyrolysis oils igniting slower but releasing energy more rapidly during the early stages of combustion, while HVO ignites earlier but has a longer burn duration. When blended, these fuels offer a combustion profile that closely resembles that of conventional diesel.

Sisodiya’s work also points to the potential of using these drop-in fuel blends to address both emissions and fuel efficiency concerns. By optimising fuel blends with higher renewable content, particularly pyrolysis oil, and maintaining stable combustion, these fuels could play a key role in transitioning the heavy-duty transport sector to a lower-carbon future without compromising engine performance.

Sisodiya’s work also points to the potential of using these drop-in fuel blends to address both emissions and fuel efficiency concerns. By optimising fuel blends with higher renewable content, particularly pyrolysis oil, and maintaining stable combustion, these fuels could play a key role in transitioning the heavy-duty transport sector to a lower-carbon future without compromising engine performance.

Doctoral researcher Sunita Sisodiya recently published an article in SAE Magazine highlighting her experiences of testing low-carbon drop-in fuels for decarbonising heavy-duty transport. In collaboration with bp, her research explores how the molecular structure of renewable fuels used in heavy-duty engines impacts energy release during combustion and emissions, including those toxic to human health such as exhaust particulate matter.

Sunita’s work aims to develop sustainable fuel solutions that can be integrated into existing transport systems and infrastructure, providing a near-term strategy to reduce greenhouse gas emissions whilst transitioning to zero-emission technologies and supporting the circular economy by utilising waste by-products as feedstocks for renewable fuel. In this SAE Magazine article, Sunita discusses her experiments with fuels made from waste wood, exploring how the energy invested into the upstream fuel production processes influences performance in a heavy-duty diesel engine.

 

A pathway to decarbonisation and waste valorisation

In addition to their environmental benefits, drop-in fuel blends present an opportunity for waste valorisation, turning agricultural and forestry residues into valuable fuel. As the demand for HVO feedstocks (such as waste cooking oil) grows, alternative sources like pyrolysis oils provide a more sustainable and scalable option. Furthermore, the lifecycle greenhouse gas emissions of these fuels can be minimised through careful feedstock selection and fuel processing, making them a crucial part of the broader strategy to decarbonise the transport sector.

The development of these innovative fuel blends represents an important step in meeting global climate targets and reducing air pollution. With heavy-duty vehicles accounting for a significant share of transportation emissions, finding cleaner alternatives to diesel is critical. As Sisodiya continues her research, she aims to better understand the molecular characteristics of these fuels and their impact on engine performance and emissions, contributing to a cleaner and more sustainable transport future.

For more information on this research and the role of drop-in fuel blends in decarbonising heavy-duty transport, see pages 18-23.

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