Innovation trends and evolutionary paths of green fuel technologies in maritime field: A global patent review

As global environmental issues become increasingly prominent, the maritime industry faces an urgent imperative to curtail carbon emissions and mitigate environmental impact. Green marine alternative fuels are actively addressing these challenges. Global patent data are collected, and four sub -technologies of green fuel technologies in the maritime field are extracted based on Natural Language Processing. To evaluate the innovation trends and evolutionary paths of these technologies, the Main Path Analysis is employed to identify the evolution path of technologies and the evolution situation of major innovative entities, while the Social Network Analysis was used to present the results visually. These four sub -technologies (Hydrogen & Fuel Cell, Methanol & Ethanol, Ammonia, and LNG & LPG) have occupied the mainstream of fuel technology in maritime over the past five years, with 34.6% of patents, 38.3% of patent citations, and 93.9% of technological influence, accounting for 27.4%, 20.5%, 16.7% and 44.3%, respectively. Ammonia, and Hydrogen & Fuel Cell are springing up like mushrooms after rain, while the development of LNG & LPG, Methanol & Ethanol is relatively mature. Each of these technologies showcases distinct developmental paradigms. We elaborated on developmental paradigms and future research priorities of each technology in the conclusion. In addition, new technological opportunities are also created through the cross-fertilization of technologies. In particular, integrated systems for hydrogen production, storage, and combustion on LNG ships, and maritime hybrid power systems driven by ammonia and hydrogen have opened a new window for the green development of maritime fuels.