The main subject of research involves the characteristics and assessment of the already ongoing process of maritime shipping radical decarbonization. There were identified and analyzed international legal and administrative regulatory measures as well as a package of technical, technological, operational and economic solutions, including the possibility of choosing alternative low-emission fuels that are necessary to achieve the already set targets by 2050. This research aimed to indicate and assess the most promising types of measure which are to be applied to achieve the required reduction of CO₂ emissions in global shipping as well as developing a potential roadmap leading to their implementation. In the conducted research work, mainly qualitative analyses were applied, i.e., factor analysis (FA), comparative analysis (CA), and a series of consultations with representatives of the maritime industry were carried out, following the procedure typical for the Delphi technique. The main result of the research work is the development of a scenario for potential supply and distribution of fuels to the maritime shipping market by 2050. The basic conclusion is that shortages in manufacturing, commercialization, and supply of low and zero-emission fuels to the shipping market may be the main obstacle hampering the reaching of the targets of shipping industry decarbonization. Such a scenario could significantly slow down the stepping up process of greening the global supply chains.

The goal of reducing the climate impact of shipping requires many different activities. To reduce greenhouse gas emissions, the International Maritime Organization prepared some proposals to meet and fulfill the requirements. It sets out the provisions of the International Convention for the Prevention of Pollution from Ships 73/78 Annex 6—Prevention of the Air Pollution from Ships (1997) with the amendments and the future objectives set. The main objective is to achieve climate neutrality from shipping by 2050. One method is the decarbonization of marine fuels. The types of fuels that are transient fuels, with the final target fuel being hydrogen, are shown. Carbon dioxide emissions depend on the chemical composition of the fuel, its Lower Heating Value and the engine efficiency. The aim of the manuscript is to demonstrate that the use of fuels with lower carbon content is a transitional process enabling the hydrogen era to take place. An analysis of this problem is presented as a review of the subject along with the author’s comments and observations. The development of technologies for adapting potential fuels to combustion requirements in marine diesel engines and gas turbines, together with their storage and bunkering capabilities, are the main barriers to their limited use. The efficiency of marine diesel engines reaches a value of about 50%, while that of fuel cells are close to 100%. It seems that hydrogen will be the fuel of the future, including in shipping. Its basic use is in fuel cells, the efficiency of which is almost twice that of current thermal internal combustion engines.

This article presents the initial processes of changing ship fuels aimed at reducing emissions of carbon dioxide and other greenhouse gases. A significant reduction in GHG emissions is only possible by using carbon-free fuels. The process of reducing CO₂ emissions was forced by legal regulations introduced in recent years by the International Maritime Organization and the Parliament of the European Union. The year 2050 was set as the target year for achieving the intended goals, but intermediate goals should be achieved already in 2030 and 2040. This article attempts to analyze the ongoing changes in the fuel market in maritime transport on the way to achieving the threshold of climate neutrality with this form of transport. A number of hopes related to this were indicated but also so were obstacles that may slow down this process. In 2023, there was an increased interest among shipowners in adapting ship engines to burn more ecological ship fuels. However, it is far from our expectations. Meeting the gradually increasing emission limits through imposed regulations was possible in the years 2020–2023 by using dual-fuel engines in which gaseous fuels, mainly LNG and LPG, were used for long periods of operation. The next step is the use of biofuels or synthetic fuels, which, however, will not meet the requirements after 2030. Interest is moving towards the use of ammonia and, ultimately, after 2040, hydrogen. The aim of this article is to analyze the ongoing processes and assess the directions of changes that justify the sense of the actions taken.

Paper discusses the problem of pressure drop in the process of working medium flow through combustion chamber of gas turbine. The pressure loss is an internal disadvantage of combustion chamber depends on many parameters, especially the chamber design and working gas flowrate. There is a problem to calculate the parameters of working medium in characteristic points of gas turbine thermodynamic cycle because the total pressure before and after combustion chamber is not known. There is a lack of information from manufacturer about it and in publications as well (mainly no experimental data, only theoretical considerations). It will be important information because the pressure drop has an meaningful influence on gas turbine performance. The paper presents an estimation of decreasing the performance of gas turbine from discussed reason. Author of that manuscript recognized the necessity of showing the importance of that parameter and turning the attention to not fully recognized problem.

The article presents the regulations of the International Maritime Organization aimed at reducing carbon dioxide emissions from international shipping. One of the main objectives is to search the alternative to fossil fuels. The main problem is the lack of indication of the target fuel for...

The paper analyzes the reasons for the interest in natural gas as a potential marine fuel to replace the existing fuels derived from crude oil. The increase of environmental awareness and the effects of human activity caused the process of searching for more environmental friendly fuels. Naturally, interest has been shifted to a well-known energy source commonly found on Earth, in quantities much larger than crude oil. This fuel in the form of liquefied natural gas seems to be an attractive substitute for the currently dominant types of marine fuels. The technologies of its extraction, liquefaction, storage and transport were mastered and marine engines were adopted to its combustion as dual-fuel engines. The regulations introduced by the International Maritime Organization and the European Parliament, forcing the reduction of emissions harmful substances into the atmosphere from the combustion of marine fuels, require taking action to meet them. The proposals in individual next 30 years are given. Due to introduction of regulations to reduce carbon dioxide emissions, it is necessary to switch to fuels with a lower or zero carbon content or the use of biofuels recognized to be more environmental friendly. Due to only 25% lower carbon content in methane with its higher lower heating value, it is possible to reduce the direct emission from this gas by about 30%. However, in the processes from natural gas extraction to energy effect in engines as a fuel, methane leaks occur, significantly worsening its image as an ecological fuel. Researches indicate that with current technologies, natural gas should not be recognized as an ecological fuel until gas leaks are significantly reduced. The article justifies why LNG should be considered as a transient marine fuel, with the need to switch to other synthetic fuels, ammonia, and finally hydrogen.