How do the total methane and CO2 emissions from using LNG as a marine fuel compare to the emissions from using other marine fuels such as heavy fuel oil (HFO), marine diesel oil (MDO), and marine gas oil (MGO)?

Abstract

This master thesis investigates the total methane and CO2 emissions from using Liquefied Natural Gas (LNG) as marine fuel compared to traditional marine fuels, including Heavy Fuel Oil (HFO), Marine Diesel Oil (MDO), and Marine Gas Oil (MGO). The research emphasizes LNG's potential environmental advantages due to its lower emissions of sulphur oxides (SOx), nitrogen oxides (NOx), and particulate matter. However, it also highlights the challenge of methane slip — the release of unburned methane during the combustion process in LNG engines, which complicates its environmental benefits.

This master thesis investigates the total methane and CO2 emissions from using Liquefied Natural Gas (LNG) as marine fuel compared to traditional marine fuels, including Heavy Fuel Oil (HFO), Marine Diesel Oil (MDO), and Marine Gas Oil (MGO). The research emphasizes LNG's potential environmental advantages due to its lower emissions of sulphur oxides (SOx), nitrogen oxides (NOx), and particulate matter. However, it also highlights the challenge of methane slip — the release of unburned methane during the combustion process in LNG engines, which complicates its environmental benefits.

The findings indicate that while LNG significantly reduces SOx and NOx emissions, its methane emissions could offset these benefits due to methane's high global warming potential. This potential detriment makes LNG a complex choice for achieving absolute reductions in greenhouse gas emissions in maritime transport.

The thesis also explores the economic aspects of transitioning to LNG, noting that while operational costs related to fuel and maintenance are generally lower, the initial capital expenditures for retrofitting ships or constructing new LNG-capable vessels are considerable. The study stresses that these economic considerations are crucial for shipping companies as they navigate the evolving landscape of global energy markets and regulatory environments.

Future research is encouraged to focus on long-term and empirical studies to monitor and verify the real-world performance of LNG-fuelled ships. This includes a detailed analysis of lifecycle emissions from LNG and further exploration of alternative fuels like bio-LNG and synthetic LNG, which could potentially offer lower greenhouse gas emissions.

In conclusion, while LNG presents a significant step forward in reducing air pollutants, its role in maritime climate change mitigation remains nuanced. The transition to LNG should be managed strategically with an eye toward future technologies that could provide more sustainable and zero-emission solutions in maritime transport.