Environmental impacts of zero-emission high-speed passenger vessels

A life cycle assessment (LCA) was conducted to compare environmental impacts of high-speed passenger vessels powered by internal combustion engines, battery-electric systems and low-temperature proton exchange membrane fuel cell/battery hybrids. The analysis accounted for changes in energy demand and carbon fibre composite hull material use associated with zero-emission propulsion systems and included supporting infrastructure as an extension. Results show that battery-electric and fuel cell systems can reduce climate change and other impacts compared to combustion engines, depending on energy carrier pathway. However, trade-offs were observed in various impact categories, such as resource use and freshwater toxicity. Propulsion energy demand was the key impact contributor across systems, with fuel cell hybrids especially sensitive to energy needs due to high energy conversion losses. Accurately reflecting specific energy demands across propulsion systems with changes in hull and design choices is therefore necessary for fair comparisons. While the carbon fibre composite hull production itself had limited impact contribution for the baseline vessel, the contribution for low-carbon vessel systems was more relevant across all impacts, particularly when energy for carbon fibre production was increased to an industry reported maximum. Similarly, infrastructure was a key contributor to several impact categories, and to all impact categories for the battery-electric vessel option with low-carbon charging electricity, and should therefore be considered in future assessments. The study is based on Norwegian vessels and routes, but findings offer broader insights applicable to international high-speed passenger vessel transitions. • Zero-emission systems had substantial well-to-tank impact category contributions. • Differences in propulsion energy demand between systems are essential to include. • Hull and infrastructure can be key contributors and belong within system boundaries. • Fuel-cell systems are sensitive to hydrogen production pathway and energy losses. • Zero-emission systems offer impact reduction potential, depending on energy carrier.