20. Performance Evaluation of an Inland Pusher

In order to meet the future exhaust gas emission standards on European inland waterways, ship owners are facing challenges when selecting the optimal power configuration and/or retrofit option. While there are many variations of power configurations for an inland vessel, a typical ship owner is not certain which of those possibilities is the best one. To help tackling these challenges, a comprehensive study has been carried out where various power configurations have been evaluated against the operational profile of an inland pusher on river Rhine. The operational profile was obtained by measuring the fuel rack position and ship speed during the period of 6 months. Comparing the transport efficiency (i.e., fuel consumed versus cargo transported) with the recorded water levels it was shown that the transport efficiency doubles in deep water periods. Furthermore, it was argued that a more flexible power configuration, with an additional shaft line, could contribute to the total efficiency. Based on the operational profile, seven alternative power configurations have been selected. They include: diesel-direct, diesel-electric, gas engine-electric, and a combination of diesel-direct and diesel-electric. Afterwards, an estimate of the total exhaust emissions during one typical voyage was made for all alternative configurations using dynamic models. For the investigated vessel, the diesel direct configuration still is the most efficient configuration regarding the energy consumption. However, regarding NOx and PM the performance of power configurations based on gas engines is superior. As an alternative for NOx reduction, the effect of SCR installation was also considered which appears to be practical solution for retrofitting as well.