The present paper proposes using methanol fuel in ships to meet emissions regulations established by the International Maritime Organization. An analysis of the use of twin fuel engines operated by diesel and methanol has been conducted from environmental and cost-effective viewpoints. As a case study, a tanker vessel operated by two fuels was investigated. The environmental results showed decreases in SOx, NOx, PM, CO2, and CO pollutant emissions by 90%, 76.80%, 83.49%, 6.43%, and 55.63%, respectively. A selective catalytic reduction (SCR) measure is installed onboard the vessel to decrease NOx emissions in case diesel fuel is used. Economically, the dual-fuel engine will save on SCR costs. The cost-effectiveness values for using a methanol engine will be $242.3/ton and $764.7/ton for reducing CO2 and NOx emissions, respectively. Finally, the cost-effectiveness for reducing NOx emissions using SCR system is $536.6/ton for the conventional diesel engine.
The majority of all cargo delivered worldwide is transported by sea (Zhou et al. 2020; Aarflot et al. 2022). Petroleum and other liquid fuels are the dominant sources for transporting this cargo. According to the International Maritime Organization (IMO), worldwide ships consume 309 million tons of fuel annually. These fuel consumptions result in yearly emissions of 11 million tons of sulfur oxides (SOx), 22 million tons of nitrogen oxides (NOx), 1.71 million tons of particulate matter (PM), 1056 million tons of carbon dioxide (CO2), and 844 million tons of carbon monoxide (CO) (IMO 2020). These emissions contribute to air pollution and climate change, highlighting the need for more sustainable shipping practices.