Year: 2026
Type: dissertation
Abstract: Global shipping is undergoing a critical transition as it strives to meet the International Maritime Organization’s target of reaching net-zero greenhouse gas emissions by 2050. Achieving this ambition requires a coordinated transformation of energy technologies, powertrain architectures, and circular economy practices. As the maritime sector advances toward electrification, choices in propulsion, energy-storage, and fuel systems will determine both environmental performance and long-term economic viability. This research explores the techno-economic and environmental feasibility of sustainable energy pathways for marine vessels, focusing on alternative fuels for high-power ships and on circular economy strategies for large-scale lithium-ion batteries. It integrates three complementary areas: sustainable fuel options for icebreakers, experimental analysis of first- and second-life battery performance, and life-cycle cost modelling of marine energy storage systems. The investigation integrates laboratory-scale ageing experiments, life-cycle and total cost-of-ownership modelling, and ship-level techno-economic simulations based on operational data from the Polaris icebreaker and Ellen e-ferry. Comparative assessments encompass fossil fuels, electrofuels, and nuclear energy systems, while the circular economy framework quantifies the reuse and salvage value of propulsion batteries across diverse market and cost conditions. The results identify small modular reactors and renewable methanol and ammonia as the most promising long-term energy solutions for icebreakers. The Small Modular Reactor (SMR) offers near-zero operational emissions and approximately €15 million lower life-cycle costs than the next best alternative. In the energy storage studies, retired electric vehicle batteries retained substantial capacity for reuse in lower-stress stationary applications, with first-life cycling intensity having only a limited effect on second-life degradation once repurposed at approximately 80% state of health. Second-life batteries can achieve payback periods between three and six years in frequency control or stacked grid services when procured at half the cost of new systems. Battery reuse and material circulation further reduce ferry life-cycle costs by 1–2%, improving battery capital efficiency by about 20%. Future research should focus on optimising hybrid fuel–battery configurations, conducting more comprehensive techno-economic analyses of small modular marine reactors, developing policy-driven life-cycle models to refine decarbonisation pathways for a broader range of vessel types, and enhancing the logistics of large-scale battery repurposing.
Source: Aaltodoc (Aalto University)
Author: Lehmusto, Mika
Institution: Lappeenranta-Lahti University of Technology
Language: English
Subfield: Environmental Engineering
Field: Environmental Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7152948773