Modes of Transport - Inland Waterways
Inland waterways can relieve the burden on port infrastructure - especially in the maritime ports - and on the surrounding rail and road infrastructure, thereby reducing congestion, energy and fuel costs. In terms of energy consumption per tonne of freight, inland shipping is already regarded as one of the most efficient means of transport. Nevertheless, work is constantly being done in Germany on the development of modern, energy-efficient and environmentally friendly vessels for inland waterways in order to achieve energy and cost savings as the volume of freight transported by inland waterways increases.
Modernising the fleet
German firms have not merely developed entirely new types of vessel for use on inland waterways. They also offer various structural alterations, modernisation and refitting for existing fleets:
- Replacement of the main power system in order to improve performance and reduce fuel consumption.
- Replacement of or addition to the propulsion system, e.g. propeller nozzles to make the system more efficient and thus save fuel.
- Redesign of the stern and of thruster tunnels to enhance the efficiency of the system.
- Alteration of the ends of the vessels in push-tow combinations to reduce turbulence between the units and thus resistance.
These actions can result in a drop in specific freight transport costs of between 1 and 8%. A combination ofthese measures boosts energy efficiency even further - e.g. a combination of the first three measures cuts specific transport costs by up to 14%. If these measures are implemented in parallel to regular or exceptionally required (general) overhauls, the potential fuel savings mean that the investment can pay off within a few years. The services described above are marketed by German shipyards. And similar outcomes can be achieved by using appropriate German products.
In addition to the design of the vessel and the propulsion/rudder system, the cross-section of the waterway in relation to the immersed vessel is of crucial importance for the speed-related resistance and thus the power needed by vessels on internal waterways. Trials have shown that, given a sufficient water depth, large inland cargo vessels (more than 1,500 t pay load, 95 - 110 m length) use significantly less energy per laden tonne than smaller units. The deliberate alteration of the fleet structure towards substantially more energy-efficient large cargo vessels can cut fuel consumption by around 9%.
Fuel cell technology
Fuel cell technology is already being used for passenger vessels on inland waterways. For example, the Zemship (Zero Emission Ship), which runs on the Alster in Hamburg, has a hybrid system consisting of two 48 kW fuel cell systems plus a lead gel battery. A smart energy management system co-ordinates the division of the work between the fuel cells and the battery. The fuel cell hybrid drive is the main power source. The vessel is fuelled with gaseous hydrogen by the world's very first hydrogen boat fuelling station at Hamburg's Stadtpark. Up to 50 kg of the gaseous hydrogen is stored on board in 350-bar pressure tanks, providing enough energy for three days of operations. The passenger vessel generates 100 kW of output and saves roughly 73 t of CO2 emissions a year.