Biodiesel and Renewable Diesel as a Drop-in Fuel for Decarbonized Maritime Transportation

Some of the biggest problems facing our world on a global scale are global warming, climate change, and air pollution. The transport and logistics sector causes these problems to become even more intractable with the internal combustion engines used, and the role of maritime transport in this regard is substantial. The International Maritime Organization (IMO), which is the United Nations’ (UN) specialized agency for regulating maritime transportation, began its studies on the topic of greenhouse gas within the scope of the UN’s sustainable goals for the future and announced the initial greenhouse gas (GHG) strategy plan in April 2018. In these ongoing studies, the importance of alternative marine fuels becomes more and more critical day by day. There are many types of alternative marine fuels with different properties, such as liquefied petroleum gas, liquefied natural gas, methanol, ethanol, and biofuels. Each alternative fuel has its own characteristics, which leads to some advantages and disadvantages in terms of use. During the transition to alternative fuels from conventional fuels, drop-in fuels such as biodiesel and renewable diesel can be used to meet the reduction target of the IMO Initial GHG Strategy. The advantage of these biofuels is that it can be used with the existing fuel system and a diesel engine without any retrofit requirement or can be used with minor modifications. The purpose of this study is to state the steps that IMO has taken for decarbonization and then to explain the properties, raw materials, and production methods of biodiesel and renewable diesel, an alternative marine fuel, and to determine its usability and suitability by comparing it with other promising alternative fuels and revealing their pros and cons for decarbonizing the maritime industry.