Life Cycle Carbon Footprint Assessment and Emission Reduction Analysis of Marine Lithium-Ion Battery Propulsion Systems

Objectives To address the limitations of the International Maritime Organization carbon emission accounting framework, which is not suitable for life-cycle assessment of electric vessels, a life-cycle carbon footprint accounting model for lithium battery-powered ship propulsion systems was developed. Methods Based on the Life Cycle Assessment methodology, the model incorporates the stages of battery manufacturing, electricity consumption, and end-of-life treatment. A 400 TEU river-sea direct container vessel was selected as a case study, and comparative analyses were conducted using the Ecoinvent database and China's grid carbon footprint factor. Results Results show that, when using the Ecoinvent database, the carbon footprint of the electric propulsion system at a speed of 10.8 knots was 30.6% higher than that of the diesel propulsion system. However, when applying China's grid carbon footprint factor and additionally for the manufacturing of spare rotation batteries and electric motors, the electric propulsion system achieved 3.3% carbon emissions at operating speeds of 10.8 knots. Conclusions Among the various factors affecting the carbon footprint of lithium battery propulsion systems, the grid energy mix and battery performance exhibit relatively high sensitivity. Under China’s current grid conditions, lithium battery propulsion systems already demonstrate a certain carbon reduction advantage, and their carbon reduction potential is expected to further increase with grid decarbonization and advances in battery technology.