Analysis of energy efficiencies of in-port ferries and island passenger-ships and improvement policies to reduce CO emissions.

This study focuses on estimating CO emissions and analysing energy efficiencies using the Energy Efficiency Operational Index (EEOI) for ferries sailing within an urban port of Taiwan and passenger-ships operating on island routes surrounding Taiwan. A comparative analysis of energy efficiency parameters showed that hybrid diesel-electric ferries had a 12% improved efficiency compared to the traditional full-diesel ferries, while high-speed passenger ships had up to 79% lower efficiency than medium-speed passenger ships. Some potential policies for reducing CO emissions from in-port ferries and island passenger-ships are presented based on these results. The estimated CO emissions from in-port ferries sailing within the urban port could be reduced by 10% when employing hybrid diesel-electric ferries instead of traditional full-diesel ferries. Emissions from island passenger-ships operating on island routes could be reduced by 11-26% through utilising small medium-speed passenger ships instead of small high-speed passenger ships and large passenger ships.