Representative image. Wikimedia commons
A Finnish researcher has found that fuels derived from waste and industrial by-products have the potential to provide a cleaner and more practical alternative for powering high-demand marine and off-road engines.
Michaela Hissa, PhD, a project researcher at Finland’s University of Vaasa, examined renewable naphtha made from crude tall oil and marine gas oil refined from recycled lubricants as part of her dissertation research.
She discovered that both could serve as viable alternative fuels, especially since electric and hybrid propulsion systems are not a practical option for the high-power engines used in marine and off-road applications.
The findings could provide an important bridge toward decarbonization while electric and hybrid propulsion systems continue to advance.
“When blended with fossil diesel, renewable naphtha burns efficiently and reduces smoke emissions,” Hissa revealed, adding that marine gas oil, in contrast, reduces hydrocarbon and carbon monoxide emissions. Meanwhile, both fuels significantly cut particulate matter, a pollutant linked to severe health risks.
The fuels are derived from industrial side streams. Renewable naphtha is processed from crude tall oil, which is a by-product of the pulp industry. In turn, marine gas oil is made from used lubricating oils classified as hazardous waste.
According to Hissa, scaling up their use will require a functioning collection and refining infrastructure; however, the raw materials are abundant. “Lubricating oils are needed in a wide range of rotating machinery, from power plant turbines and paper machines to engines in vehicles, off-road machines, and ships.”
Because they are drop-in fuels, renewable naphtha and marine gas oil can be used in existing engines without significant modifications. “Large volumes of used oil are generated globally,” Hissa explained.
This makes them particularly attractive for sectors with large heavy-duty engines, where full electrification or fleet replacement is not yet practical.
However, the scientist pointed out that the number of existing marine and off-road engines is substantial, and replacing them won’t happen overnight. “To reduce emissions, it is essential to find solutions that support the transition without requiring the replacement of the entire infrastructure.”
Hissa believes that wood-based residues are likely to play a significant role as raw material for renewable fuels manufactured from organic waste.
Still, while the country’s forest industry provides a strong foundation for its development and use, availability, cost-effective production, and competitive pricing remain key challenges for large-scale deployment.
“In the future, engines will need to adapt to an increasingly diverse range of fuels, the researcher stated in a press release. “More research is needed to understand how different fuels behave in engines.”
As per Hissa, both fuels proved technically ready for internal combustion engines, whether used alone or blended with other fuels. “A concern, however, is how the availability of raw materials for both fuels will affect their supply and price,” she concluded.
Hissa’s PhD dissertation, ‘Ignition and combustion studies of alternative engine fuels,’ was published in the Acta Wasaensia series by the University of Vaasa.
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