Reference report: diesel-electric drive for freight ship ENOK

The regulations for emissions are set to become ever stricter in the coming years and the price for marine diesel will increase steadily. It’s time to rethink and to invest in more efficient drive concepts. 

The challenge

The stricter emission regulations in force since 2015 and the continuous increase in the price of mandatory marine diesel necessitate the development of new efficient drive concepts. A diesel-electric s ships drive make this possible but until now did not fulfil the requirements for size and weight.Many promise reductions in emissions and consumption but only few can actually keep this promise. The challenge with the freight ship ENOK, the first ship with High Torque Power-Drive (HTP), was to reduce fuel consumption by 25%. And this taking into account that the ship was 55 years old and possible problems during conversion could not be foreseen.

The solution

In the converted inland waterway freight ship four diesel power units with four 230kW permanent magnet generators deliver the power for four torque motors on the ship propulsion. Several torque drives are coupled on one drive train to ensure fail-safe operation. The HTP system is considerably superior to other systems. The fast current control from ARADEX means that the power of the diesel power unit can be utilized even during acceleration time. This in turn reduces the required capacity in the DC link. The diesel power units always run at the ideal speed and therefore with high efficiency. The power units deliver only the required amount of energy. This means apart from ideal emission values a fuel consumption reduction of 25%.

The project

Many promise savings but only few actually keep them. Claus-D. Christophel was aware of this. For this reason the ENOK started a comparison journey after the last tests had been completed. The GMS started from Torgau near to Magdeburg in Germany on 8th September 2010. The ENOK had 1230 t of wheat on board and travelled to Holland, arriving 7 days (or 69.5 hours) later in Wormerveer near to Amsterdam. With the new diesel-electric drive system total fuel consumption was 3,300 litres. Captain Koopmans had already completed the same journey in 2005 when the ENOK was driven by two diesel engines. This journey also took 7 days (67.5 hours) with a fuel consumption of  4,460 litres. The new diesel-electric drive system consumed 1,160 litres less than the old system – a saving of 26%. But not only fuel consumption was reduced; the CO² emissions were reduced by 3,082 kg. 


  • 25% reduction in fuel consumption
  • CO² emissions reduced by 3,082 kg
  • Ideal emission values
  • Considerably improved fail-safe operation of the motors
  • Fast current control due to “diesel-electric power management”
  • Precise manoeuvring even at speeds as low as 20 rpm
  • Compact and modular devices

" We achieved our goal to reduce fuel consumption by 25% "

Claus-D. Christophel

Torque Marine IPS GmbH & Co. KG.

Torque propulsion drive, diesel power unit-generator combination and VP600 inverter

Reference report: diesel-electric drive for freight ship ENOK

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