Towards improving energy efficiency regulations of bulk carriers

The introduction of the Energy Efficiency Design Index (EEDI) by the International Maritime Organization (IMO) caused an upsurge in activities for increasing the energy efficiency and reducing CO2 emissions of new vessel designs. However, application of the EEDI is not expected to further advance future design improvements partly owing to the fact the majority of the new buildings already comply with EEDI requirements and particularly since EEDI only considers a single operating point. In addition, the EEDI does not effectively assess a realistic improvement of measures for increasing the ship operating energy efficiency as they can be quite effective in the considered operating point for the EEDI but their performance greatly varies in the real operating conditions. In this study, a more realistic definition of the EEDI is proposed, which is based on a number of representative vessel operating points. The application of the proposed approach for the case of bulk carriers is investigated and the results are discussed in order to reveal its advantages against the currently used approach. The proposed approach can be employed by IMO for improving the energy efficiency regulatory framework.