Various endeavors are undertaken by the maritime industry, academia, and policy-makers to reduce greenhouse gas emissions. These include the search for feasible technologies that could be used onboard merchant vessels and are propelled by international legal and social initiatives. To this end, this study aimed to critically analyze the research trends pertaining to the active methods of reducing the negative environmental impact of shipping. The research is focused on alternative fuels and renewable energy systems with respect to the related policy-making and existing legal framework. Therefore, a bibliometric approach was applied to a sample of 234 scientific papers indexed in the SCI-EXPANDED in Clarivate Analytics Web of Science Core Collection. The results indicate that the scientific efforts were made more on alternative fuels, while renewable energy sources only recently became a popular research subject. Moreover, the environmental benefits of prospective technologies are more investigated than their financial aspects. The research effort on alternative maritime fuels was made in parallel with the legal one, both aiming to combat global climate change and magnifying each other.
