Life cycle GHG emissions distributed over production of propulsion system, use phase, and disposal of propulsion system.

A new report commissioned by NCE Maritime CleanTech gives important insight into the life cycle GHG emissions of alternative propulsion systems for express boats.

The transport sector is the largest source of direct GHG emissions in Norway, with nearly one third of total national emissions. The Norwegian Government has implemented ambitious target to reduce emission from short sea shipping and wants to contribute to using “low- or zero emission solutions” for all county municipal ferries and express boats.

“Well-to-wake” emissions

It is debated both on EU and IMO level whether maritime emissions should be measured from “tank-to-wake” or from ”well-to-wake”. EU argues that by taking into account emissions related to the production cycle of fuels, a “well-to-wake” approach could enable a more complete picture of the environmental performance of alternative fuels. NCE Maritime CleanTech share this opinion that the challenge of achieving net zero carbon emissions should be shared along the supply chain, and not be placed on shipowners alone.

Several counties in Norway has initiated the development of tender processes for zero emission fast ferries, addressing the topic of “well-to-wake” emissions. NCE Maritime CleanTech requested Asplan Viak AS to do a comparative life cycle assessment (LCA) study of alternative express boat propulsion systems. The results were presented to cluster partners in a webinar on June 25th.

Express boat analysis: 15 alternative propulsion systems
In the analysis, LCA was used to estimate CO2 equivalents in emissions from 15 alternative propulsion systems for a fictitious express boat operating a route between Bergen and Selje. The crossing is 150nm with a crossing time of 4.5 hours. The well-to-wake GHG emissions were calculated for a 10-year period of operation and considered the most relevant components as well as fuels and energy carriers. NCE Maritime CleanTech and cluster partners Norled, BKK, Brødrene AA and Corvus Energy have provided input to the analysis.

– The various technology options are at different technology readiness levels, but the preliminary results provide useful insights. It highlights important aspects of the life cycle GHG emissions of alternative propulsion systems for express boats such as batteries, hydrogen and biofuels, says NCE Maritime CleanTech CEO, Hege Økland.

The analysis shows that the operational phase is generating most emissions. However, this is not the case for battery electric solutions, were the production phase generate most emissions. In general, electric propulsion has low GHG emissions. But the levels differ heavily  on what source the electric power is generated from (e.g. hydropower).

Two wide categories of propulsion technologies were considered for the express boat: internal combustion engine and electric motor. While the electric propulsion systems show great potential as a measure to reduce GHG emissions from express boats, both the battery electric and hydrogen electric propulsion systems have low gravimetric and volumetric energy densities, which may limit their applicability in express boats. Both ammonia and hydrotreated vegetable oil (HVO) are alternative fuels for combustion engines that may offer lower lifecycle GHG emissions compared to MGO, but their emissions profile strongly depends on their production pathways. For HVO, the limited supply may also be an issue.

Report available for cluster members

The full report will be shared with members of NCE Maritime CleanTech, as well as a recording of the webinar. More information on membership in NCE Maritime CleanTech here. The work with the report has received financial support from Vestland County Council.