Is electric battery propulsion for ships truly the lifecycle energy solution for marine environmental protection as a whole?

This paper was inspired to answer the fundamental question on whether electric battery powered ships can ultimately be a promising solution for future maritime environmental protection. The overall process was designed to demystify the holistic environmental benefits and harms of 14 primary energy sources for electricity production in consideration of the national-specific cases of 33 countries. A series of comparative analyses between the diesel as the reference fuel and the battery-electric propulsions were conducted with 27 short-route ferries engaged in Scotland coastal areas. A key message obtained from the analysis results were that the impact of battery application was far from the zero-emission shipping in the lifecycle perspective. Moreover, the same vessels were found to yield completely different environmental performances, depending on how those countries produce electricity. In some Asian countries heavily relying on fossil-based power generation, the environmental impact of battery operation was estimated far greater than that of diesel operation in the UK. Case studies were, then, scaled-up to about 5500 marine vessels presently engaged in international voyages. In general, consistent results were found. Research findings distinctively demonstrated the misguidance of current maritime policies for encouraging battery-powered ships and identified that these shortcomings would stem from the limitations of current practices of maritime environmental assessment. Lastly, it strongly suggested to the marine industry and stakeholders that the environmental protection from shipping activities would be not only a matter of ships but also a matter of how the national power grid develops.