Study on the Potential Impact of Biofuels on the Operation and Maintenance Durability of Marine Main Engine Components

The maritime transportation industry is under pressure to reduce the level of emissions generated annually by commercial vessels. In order to achieve this objective, regulatory bodies, both national and international, have imposed strict limitations on the industry, and thus major changes have to be made in a tight time frame. In the last decade, engineers and ship designers have been searching for alternatives to traditional fuels, but it is not easy to find a perfect balance between operational costs and economic efficiency. Many potential solutions are being studied, with some of them already proven and implemented, such as liquefied natural gas, solar and wind power, electric propulsion, and many more. One solution might be biofuels, and this study aims to assess the potential impact of their use on the energy performance and durability of a typical marine propulsion engine, namely the MAN B&W 6S70MC-C7, fitted on board many types of ships including large oil tankers, container ships and bulk carriers. The main topic is approached through a progressive structure, starting from the analysis of general characteristics of these fuels and the engine installation, comparative simulations, operational experience, and technical recommendations. The comparative assessment is focused on two traditional types of fuels and two biofuel types. The aim is to identify a viable solution that can sustain the operational efficiency of this main engine without a major impact on its maintenance cycle and without additional costs on the components. Even if these biofuels are more expensive than the traditional ones, in the long run, they could prove to be a better choice in terms of operational costs and compliance with regulation.