On behalf of the Belgian Federal Public Service Mobility and Transport, the Maritime Technology Division of Ghent University had performed a scientific investigation to assess potential technical measures to increase the energy efficiency of inland vessels, and the costs and benefits – including environmental aspects – resulting from these measures. The results of this study can be applied to the design or reconversion of inland vessels to reduce the energy consumption and emission of greenhouse gases and noxious materials.
The study consists of a literature study, an analysis of the present inland vessel fleet, and the study of available data concerning resistance and propulsion, to determine measures that can lead to an optimization of the design of an inland vessel by:
_ Reducing the hull resistance;
_ Increasing the hydrodynamic efficiency of the propeller by improving the design and selection of an optimal propeller;
_ Increasing the efficiency of the engine;
_ Any other measures (e.g. control devices)
A cost-benefit analysis is carried out by quantifying which financial and environmental advantages can potentially be realized by the considered measures, and by assessing the additional cost due to investments and the loss of cargo capacity.
This analysis only focuses on smaller types of inland vessels (250 – 1350 ton) sailing on the Belgian waterways. Three types of inland ships can be identified in this loading capacity range, the péniche-spits, the Campine barge and Rhine-Herne-Canal ships. The average yearly fuel consumption and emissions are estimated for these three classes of ships, taking into account the operational profile on each of the classes of Belgian waterways.
Several possibilities for reduction of fuel consumption and emissions are investigated. Measures that reduce the ship’s resistance can have a beneficial effect on fuel consumption and emission reduction on the Belgian waterways when mainly the viscous or frictional resistance is reduced. A reduction of wave making resistance is less beneficial due to the low forward speed in confined waters. Only in the case of small inland ships travelling great distance on open water, a large impact in fuel consumption and emissions can be detected if the wave making resistance is reduced.
Optimization of the propeller and/or the installation of a propeller nozzle may induce a large gain in thrust and performance, especially on the older small inland ships, since they have originally been designed for towed operation.
Technical developments aside, it is very important that the skipper is aware of fuel consumption at all time since it is a realtime indication of efficiency. It is therefore recommended to install a fuel consumption indicator on existing small ships. A very important lesson to learn is that all investment in a resistance reducing, or efficiency increasing measure is mainly turned into a greater forward speed and a reduction in travel time and not into a reduction of fuel cost and emissions when no change is made to the operational profile.