This written project is based upon an internship done onboard the pelagic fishing vessel HG 264 Ruth. The internship is part of the 6th and final semester in the Marine and Technical Engineer education at Aarhus School of Marine and Technical Engineering. The written project is also the final bachelor project. The internship covered over 2 months of active duty whilst fishing for herring in the North Sea, and offloading in Sassnitz, Germany. The intern has been working with electrical, mechanical and refrigeration systems onboard, and in general been a part of the technical department onboard.
The aim of this project is to uncover the possibilities for generating electrical power at a higher efficiency than it is currently being generated, particularly during the ships layover periods. The end product of this project can be used to make a viable economical assessment on whether to invest in some of the solutions or not. At this point, Ruth is already equipped with 2 diesel generators á 903 kVA which are used when the ship is lying still, or the main engine is switched between high- and low step. During offloading, one diesel generator is running at around 50 % load. This is due to the refrigeration system, offloading pumps and other various loads.
Due to the nature of pelagic fishing, the ship is laid still for up to 4 months a year (112 days in the spring of 2012). During these layover periods, the electrical load is very low, and one of the current diesel generators is running at 10-15 % load. This is where it is expected that some other option would deliver the power in a more efficient manner, thereby decreasing the price per kilowatt-hour.
Through correspondence with the ships technical department, it has been established that a new diesel generator should have a peak power output of around 250 kW. This would cover the basic power consumption of the vessel and allow for the running of a single hydraulic pump, so that deck cranes and other hydraulic equipment can be used without the need for starting up one of the large diesel generators. The project also looks at the possibility of installing a smaller generator, only to cover the basic power consumption of around 80 kW at a very high efficiency.
An alternative to installing a new diesel generator, is to use shore power from Hirtshals Ports own electrical supply. This has not been used yet, due to the high cost of 1,67 DKK per kilowatt-hour.