Key areas of decarbonisation in the maritime industry

The study aimed to assess the environmental impacts of alternative fuels in the maritime sector, particularly their potential for global warming, ocean acidification, eutrophication and marine toxicity. To this end, a comparative analysis of different fuels was conducted, including liquefied natural gas, green methanol products, ammonia, biofuels and traditional heavy fuel oil. The results showed that liquefied natural gas, despite its lower CO₂ emissions, had a high climate impact due to methane leaks, with a global warming potential of 0.18 to 0.22 kg CO₂-eq/MJ. Green biofuels, particularly methanol, had the lowest global warming potential (0.016-0.020 kg CO₂-eq/MJ), but their direct CO₂ emissions during combustion remained high. Ammonia, as a carbon-free fuel, reduced CO₂ emissions but produced significant amounts of nitrous oxide (N₂O), which has a significant impact on the climate balance. The ocean acidification potential for heavy fuel oil was 0.18 kg SO₂-eq/MJ, and for ammonia, 0.10 kg SO₂-eq/MJ. Eutrophication analysis showed that ammonia and nitrous oxide emissions significantly increase nitrogen levels in marine ecosystems, which can cause algae growth. The toxicity of different fuels showed that ammonia has the greatest potential to harm marine organisms, even at low concentrations. The practical significance of the results is determined by the need for a comprehensive assessment of the environmental impact of the transition to alternative fuels in shipping, which can be used by maritime transport authorities, environmental agencies, seaports, and companies involved in the development and implementation of technologies for decarbonising shipping and reducing the environmental impact of maritime activities