Attained EEDI ≤ Required EEDI
EEDI =
P x SFC x C F DWT x V REF
Where : P = 75 % of the rated shaft power , SFC = the specific fuel consumption ,
C F
= a conversion factor giving the amount of CO 2 produced from the particular type of fuel used , DWT = represents the deadweight tonnage of the ship , and
V REF
= the vessel speed at design load .
Figure 1 : Required EEDI Calculation
the ship ’ s type and size . The regulation stipulates that the attained EEDI must not be greater than the required EEDI , in which , IMO has calculated the required EEDI values ( see Figure 1 ), based on reference lines developed using averaged energy efficiency data from ships built between 2000 and 2010 ( MEPC . 203 ( 62 ), 2011 ).
The regulation stipulates that the required level of EEDI be further strengthened every five years as part of the effort to reduce carbon dioxide emissions per tonne mile from ships . As can be seen from Table 2 , IMO has set rate of reduction of carbon dioxide emissions until the period of 2025 and beyond , whereby most types of ships need to be 30 % more efficient compared with the baseline . Here , the role of ship designers and builders are essential , and they are free to choose the most cost-effective solution , as long as the required level of energy efficiency is achieved . This encourages new ships to be more technologically advanced and ultimately , promote innovation at the ship design stage . New technologies and alternative fuels such as LNG , LPG , methanol , biofuel , and hydrogen are listed as some of the most promising solutions ( DNV . GL , 2019 ).
The implementation and enforcement of an Energy Efficiency Existing Ship Index ( EEXI ) which broadly follows the EEDI , including survey and certification , will contribute to reducing GHG emissions . This Attained EEXI should be less than a specific Required EEXI , taken as a percentage relative to the EEDI baseline . Both the Attained and the Required EEXI will be included in each ship ’ s International Energy Efficiency Certificate ( IEEC ).
Ship Energy Efficiency Management Plan
SEEMP is intended as a practical tool to help ship owners manage the environmental performance of each ship . Under the regulation , all vessels , new or existing , with 400 gross tonnage and above , are required to keep a specific SEEMP on board . A SEEMP provides a structured approach for monitoring and improving a ship ’ s performance and therefore , improving fleet efficiency performance over time . This is done through improvements to the ship ’ s operational efficiency by reducing fuel consumption and in turn , lowering GHG emissions .
Part I of the SEEMP is to provide a mechanism that can improve the energy efficiency of each ship in operation and that of the company ’ s fleet in total . It encourages the implementation of ship specific energy efficiency measures that result in reduced fuel consumption on board . There is a variety of options to improve efficiency , such as , speed optimisation , weather routing and hull maintenance depending on ship type , cargoes , routes , and other factors . There is no “ one size fits all ” solution , so it is important that the SEEMP be ship specific .
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