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author = {Srikakolapu, S and Manjunath, H and Thatoi, D and Santhosh, M and Rajgor, M and Kumari, A and Priya, K},
title = {Clean Energy Pathways for Marine Engines: Technological and Environmental Insights into Biodiesel–Alcohol Blends},
journal = {Clean Energy},
year = {2026},
month = {feb},
publisher = {Oxford Academic},
volume = {10},
number = {1},
pages = {36--55},
doi = {10.1093/ce/zkaf059},
url = {https://academic.oup.com/ce/article/10/1/36/8281744},
keywords = {Microalgae, Wastes and Byproducts, Biodiesel (FAME), Ethanol, Chemical Upgrading, Blending and Fuel Mixtures, Engine Testing and Performance, Fuel Properties and Characteristics, Lifecycle Assessment (LCA) and Air Emissions, Ocean-going Vessels},
}
RIS
TI - Clean Energy Pathways for Marine Engines: Technological and Environmental Insights into Biodiesel–Alcohol Blends
AU - Srikakolapu, S
AU - Manjunath, H
AU - Thatoi, D
AU - Santhosh, M
AU - Rajgor, M
AU - Kumari, A
AU - Priya, K
T2 - Clean Energy
AB - The maritime industry is responsible for the emission of ∼940 million tonnes of CO 2 on an annual basis, accounting for roughly 2.9% of the total global anthropogenic greenhouse gas emissions. Achieving the decarbonization objectives set forth by the International Maritime Organization for the years 2030 and 2050 requires an expedited transition towards low-carbon marine fuel alternatives. This review presents a concentrated and quantitative assessment of biodiesel and biodiesel–alcohol blends as viable near-drop-in substitutes for marine gas oil. Non-edible feedstocks, including Jatropha curcas , Pongamia pinnata , used cooking oil, and microalgae, produce biodiesel with heating values ranging from 37 to 42 MJ kg −1 and cetane numbers between 47 and 58, thereby conforming to ISO 8217 specifications. The incorporation of alcohols, most notably n-butanol, in concentrations of 10–20% enhances atomization and ignition properties, resulting in a reduction of CO and hydrocarbon emissions by 50–60% and particulate matter by as much as 70%, accompanied by a modest increase in NO x emissions of 8–15%. A comprehensive meta-analysis of 18 studies representative of marine conditions has corroborated that blends containing 20% biodiesel and 10%-butanol-20% biodiesel maintain brake thermal efficiency ( g = −0.03, P > 0.05) while simultaneously decreasing CO, hydrocarbon, and particulate matter emissions by 16–21%. Lifecycle assessments reveal savings of greenhouse gas emissions ranging from 65 to 85% contingent upon the type of feedstock utilized. At the same time, techno-economic evaluations demonstrate that production costs are competitive with those of marine diesel, particularly when factoring in carbon credits. This review distinctively amalgamates statistical synthesis, insights from lifecycle and techno-economic assessments, and a strategic policy roadmap that aligns with the directives of the International Maritime Organization, the European Union Emissions Trading System, and various Asian maritime frameworks, thereby providing stakeholders with practical guidance for the large-scale implementation and adherence to the objectives of International Maritime Organization Tier III and carbon intensity indicator.
DA - 2026/02//
PY - 2026
PB - Oxford Academic
VL - 10
IS - 1
SP - 36
EP - 55
UR - https://academic.oup.com/ce/article/10/1/36/8281744
DO - 10.1093/ce/zkaf059
LA - English
KW - Microalgae
KW - Wastes and Byproducts
KW - Biodiesel (FAME)
KW - Ethanol
KW - Chemical Upgrading
KW - Blending and Fuel Mixtures
KW - Engine Testing and Performance
KW - Fuel Properties and Characteristics
KW - Lifecycle Assessment (LCA) and Air Emissions
KW - Ocean-going Vessels
ER -
Abstract
The maritime industry is responsible for the emission of ∼940 million tonnes of CO 2 on an annual basis, accounting for roughly 2.9% of the total global anthropogenic greenhouse gas emissions. Achieving the decarbonization objectives set forth by the International Maritime Organization for the years 2030 and 2050 requires an expedited transition towards low-carbon marine fuel alternatives. This review presents a concentrated and quantitative assessment of biodiesel and biodiesel–alcohol blends as viable near-drop-in substitutes for marine gas oil. Non-edible feedstocks, including Jatropha curcas , Pongamia pinnata , used cooking oil, and microalgae, produce biodiesel with heating values ranging from 37 to 42 MJ kg −1 and cetane numbers between 47 and 58, thereby conforming to ISO 8217 specifications. The incorporation of alcohols, most notably n-butanol, in concentrations of 10–20% enhances atomization and ignition properties, resulting in a reduction of CO and hydrocarbon emissions by 50–60% and particulate matter by as much as 70%, accompanied by a modest increase in NO x emissions of 8–15%. A comprehensive meta-analysis of 18 studies representative of marine conditions has corroborated that blends containing 20% biodiesel and 10%-butanol-20% biodiesel maintain brake thermal efficiency ( g = −0.03, P > 0.05) while simultaneously decreasing CO, hydrocarbon, and particulate matter emissions by 16–21%. Lifecycle assessments reveal savings of greenhouse gas emissions ranging from 65 to 85% contingent upon the type of feedstock utilized. At the same time, techno-economic evaluations demonstrate that production costs are competitive with those of marine diesel, particularly when factoring in carbon credits. This review distinctively amalgamates statistical synthesis, insights from lifecycle and techno-economic assessments, and a strategic policy roadmap that aligns with the directives of the International Maritime Organization, the European Union Emissions Trading System, and various Asian maritime frameworks, thereby providing stakeholders with practical guidance for the large-scale implementation and adherence to the objectives of International Maritime Organization Tier III and carbon intensity indicator.