In the pursuit of sustainable energy solutions, the reliance on traditional fossil fuels continues to pose significant environmental challenges, especially in sectors like marine and off-road transportation that require high-power engines. While electric and hybrid propulsion systems are advancing rapidly, their current limitations prevent them from effectively replacing these engines in heavy-duty applications. Addressing this critical gap, researcher Michaela Hissa from the University of Vaasa explores innovative alternative fuels derived from industrial by-products and waste streams that have the potential to substantially reduce harmful emissions without necessitating drastic changes to existing engine infrastructure.
Hissa’s doctoral dissertation meticulously investigates the combustion and ignition characteristics of two promising renewable fuels: naphtha derived from crude tall oil and marine gas oil produced from recycled lubricants. These fuels, classified as “drop-in” alternatives, can be blended directly with conventional fossil diesel and used in current engine technologies without requiring significant modifications. This attribute is particularly valuable because it enables an immediate reduction in emissions while the global energy landscape gradually shifts toward greener propulsion methods.
Renewable naphtha, a valuable fraction obtained from the refining of crude tall oil — a by-product of the pulp and paper industry — exhibits efficient combustion properties when mixed with fossil diesel. Notably, it contributes to reducing smoke emissions, which are a persistent environmental and health concern. On the other hand, marine gas oil derived from the sophisticated reprocessing of used lubricating oils significantly curtails hydrocarbon and carbon monoxide emissions, pollutants closely linked to environmental toxicity and respiratory ailments. Importantly, both fuels have demonstrated substantial decreases in particulate emissions, a pollutant known for its detrimental effects on human health and atmospheric quality.
The source materials for these alternative fuels underscore the importance of a circular economy. Crude tall oil, being a biomass derivative, leverages sustainable forestry resources, while recycled lubricants come from globally generated waste streams. Used lubricating oils, ubiquitous across various industries — including power generation turbines, paper manufacturing machinery, and diverse engines in vehicles and ships — present both an environmental hazard and an untapped resource for energy recovery. Establishing robust collection and refining systems for these materials is paramount for scaling their production and integration into fuel markets.
From a technical viewpoint, the combustion behavior of these fuels within existing Diesel engines is of significant interest. Renewable naphtha’s chemical composition allows swift ignition and cleaner burning, which translates to smoother engine operation and lower emissions profiles. Similarly, marine gas oil’s unique hydrocarbon makeup facilitates cleaner combustion, reducing the formation of harmful intermediates such as unburned hydrocarbons and carbon monoxide. These findings open avenues for fine-tuning fuel blends to achieve optimal environmental benefits without compromising engine performance or durability.
Finland’s robust forest industry offers a strategic advantage in pioneering wood-based renewable fuels. The country’s abundant forestry residue supplies a consistent feedstock for developing biofuels like crude tall oil derivatives. However, challenges remain in ensuring the cost-efficiency of large-scale production and maintaining competitive pricing relative to fossil fuels. Success in overcoming these hurdles will depend on advancements in refining technologies, infrastructural development, and policy frameworks encouraging renewable fuel adoption.
The current energy transition in marine and off-road sectors demands interim solutions that bridge conventional and futuristic propulsion systems. Given the extensive global installation base of high-power engines, wholesale replacement is neither economically feasible nor logistically expedient. Here, drop-in fuels derived from renewable and recycled sources emerge as practical and scalable interventions to significantly curtail emissions, mitigate environmental impact, and facilitate compliance with increasingly stringent regulations.
Moreover, as engine technologies evolve to accommodate diverse renewable fuel types, comprehensive combustion research remains crucial. Michaela Hissa’s doctoral work underscores the necessity of understanding fuel ignition properties, combustion kinetics, and emission profiles across various engine conditions. Such scientific insights enable informed development of optimized fuel blends and engine calibrations, ensuring that environmental gains are realized without compromising efficiency or reliability.
The versatility of renewable naphtha and recycled marine gas oil as fuel components also illustrates the potential of integrating waste valorization with energy needs. This approach embodies the principles of sustainability by transforming hazardous by-products into valuable resources, thus reducing environmental contamination risks while supporting energy demand. Consequently, industries generating substantial waste streams are incentivized to participate actively in circular economy models that prioritize resource efficiency.
Furthermore, the application of these alternative fuels aligns with global climate goals by targeting emission reductions in sectors that traditionally lag behind in decarbonization efforts. Marine and off-road engines, often operating in challenging conditions, contribute disproportionately to particulate matter and toxic gas emissions. Adoption of renewable, drop-in fuels provides a pragmatic pathway to alleviate such impacts promptly while supplementary electrification and hybridization technologies continue their maturation.
Scaling the production and use of these biofuels will require coordinated actions among policymakers, researchers, industry players, and infrastructure developers. Facilitating the establishment of collection channels for used lubricants, expanding refining capacities, and integrating supply chains are critical steps toward commercial viability. Additionally, public and private sector investments in fuel quality monitoring, engine compatibility testing, and emissions certification will bolster market confidence and regulatory acceptance.
In conclusion, the research spearheaded by Michaela Hissa offers an insightful advancement in combustion science and sustainable energy. Her detailed exploration of alternative engine fuels derived from industrial by-products not only highlights innovative solutions to pressing environmental challenges but also provides a viable roadmap for integrating these fuels into the current energy ecosystem. As the world intensifies efforts to combat climate change, such interdisciplinary and application-oriented research underscores the importance of leveraging existing resources and infrastructures for an ecologically responsible energy future.
Subject of Research: Ignition and combustion characteristics of alternative engine fuels derived from waste and industrial by-products.
Article Title: Ignition and Combustion Studies of Alternative Engine Fuels: Bridging the Gap in High-Power Engine Emissions.
News Publication Date: Not specified (Dissertation defense scheduled for 20 August 2025).
Web References: Publication pdf
References:
Hissa, Michaela (2025). Ignition and Combustion Studies of Alternative Engine Fuels. Acta Wasaensia 558. Doctoral dissertation. University of Vaasa.
Image Credits: University of Vaasa
Keywords: Refuse derived fuels, Alternative energy, Energy resources, Fuel, Renewable energy, Engines, Marine engineering
