Reducing shipboard emissions – Assessment of the role of electrical technologies

Saving fuel and reducing emissions are major drivers in the marine industry, with a large number of potential modifications and machinery options available to enable the greening of shipping. Assessing which technology and what combination of solutions gives favourable economic results needs careful consideration of the vessel's operational profile. Electrification of shipboard systems introduces operational flexibility, offering the potential for fuel savings and emission reductions. Auxiliary drives, energy storage and onshore power supply are three approaches which address the issues of ship fuel consumption/emissions, specifically during in-harbour operation of vessels. In this paper, the impact of these three technologies on ship environmental performance and energy consumption is assessed by considering a real case RoRo vessel sailing a real operational profile. Models of the resultant system are built such that the machinery configurations can be analysed separately or in conjunction with each other. The results stress the importance of the operational profile of the vessel, showing significant fuel and emissions reductions during in-harbour operations but relatively small savings when considering operation through a complete return voyage. The sensitivity of the results to fuel and utility costs are also considered and shown to have a large impact on the economic feasibility (or otherwise) of different solutions.