Research On Ship Energy Efficiency Operational Indicator

Energy Efficiency Operational Indicator (EEOI) is promoted by IMO to measure the energy efficiency of ships. From the indicator definiation, formula derivation and data calculation, the paper does in-depth analysis of EEOI, obatains related conclusion and proposes some recommendations.Indicator definiation: The paper points out that EEOI is defined as the quatity of CO2 emmission on the basis of unit transportation turnover. EEOI is superior when compared with other indexes.Formula derivation: The formula and concept of voyage EEOI, EEOI theriotical calculation and unit time turnover EEOI is proposed. The paper also derivates the conversion formula between container ship's two types of EEOIs and derivates precise, estimated and forcast CO2 emmission formulas of water-transportaion.Data calculation: The paper analyses EEOI theriotical calculation formula and points out that EEOI is influnced by ship factors, engine factors and operation factors. The results show that energy efficiency is higher for larger ships and energy efficiency of container ships is lower than that of bulk ships and oil tankers. Through sensitivity analysis of operation factors, the paper finds that reducing ship speed and raising full rate are the two best ways to improve energy efficiency. Increasing voyage distance and shortening berthing time are also useful, but their influnces are not significant. Unit time turnover EEOI formula is used to compute the optimal ship speed. The energy efficiency gap between container ships and other two types of ships is narrowed obviously on the basis of unit time turnover EEOI.Recommendations: CO2 emmission factor is not necessary to be amended. Use conversion turnover and passenger-cargo conversion factor to calculate EEOI of Ro-ro passenger ships. Appeal shipping companies to establish effective EEOI statistical methods. Suggest EEOI be used in the calculation of CO2 emmission of water-transportaion. Propose unit time turnover EEOI be used to correct speed influence in order to reflect ship energy efficiency in an objective and overall manner.