Ship Energy Efficiency and Underwater Radiated Noise

Abstract

The report presents the results of a review of means for technical and operational measures which can: a) increase the Energy Efficiency and reduce Greenhouse Gas emissions from ships, and/or b) mitigate underwater radiated noise (URN) from ships, which can have damaging effects on marine animals of many types. In some cases, measures may have desirable outcomes for both aspects, while in others they may conflict. The report highlights when each of these may apply. The report text introduces some of the key issues related to Energy Efficiency, Greenhouse Gas and URN, and to the current initiatives at the International Maritime Organization (IMO) which relate to these. Measures are consolidated in the matrix that provides an overview of each measure, and a summary of its effectiveness for Energy Efficiency, Greenhouse Gas and URN. Other aspects of each measure are also outlined, to define the advantages and benefits to the ship’s design and operations; disadvantages and challenges; technology readiness level; cost impacts for implementation and operation; and applicability to different ship types. A wide range of mitigation measures are available. All will incur some level of cost, but in most cases there are co-benefits between Energy Efficiency and URN that may offset some or all of this disadvantage. Main recommendations are: There is a need for increased data collection and knowledge dissemination. For both Energy Efficiency/Greenhouse Gas and URN there is a lack of high-quality, measured data on the effectiveness of many of the methods that have been proposed. This increases risk and uncertainty for owners who wish to improve the performance of their ships, and will delay any improvement of the overall global fleet. IMO, and its member administrations, should take and encourage steps to improve this situation.