Energy Efficiency Design Index (EEDI)

Its technical measure and it aims at promoting the use of more energy efficient (less polluting) equipment and engines. 

It requires a minimum energy efficiency level per capacity mile (e.g. tonne mile) for different ship type and size segments. 

It became mandatory from 1 January 2013, following an initial two year phase zero when new ship design will need to meet the reference level for their ship type, the level is to be tightened incrementally every five years.

The EEDI is a non-prescriptive, performance-based mechanism that leaves the choice of technologies to use in a specific ship design to the industry. 

As long as the required energy efficiency level is attained, ship designers and builders are free to use the most cost-efficient solutions for the ship to comply with the regulations.

The EEDI provides a specific figure for an individual ship design, expressed in grams of carbon dioxide (CO2) per ship’s capacity-mile (the smaller the EEDI the more energy efficient ship design) and is calculated by a formula based on the technical design parameters for a given ship.

The CO2 reduction level (grams of CO2 per tonne mile) for the first phase is set to 10% and will be tightened every five years to keep pace with technological developments of new efficiency and reduction measures. 

Reduction rates have been established until the period 2025 to 2030 when a 30% reduction is mandated for applicable ship types calculated from a reference line representing the average efficiency for ships built between 2000 and 2010. 

The EEDI is developed for the largest and most energy intensive segments of the world merchant fleet and will embrace 72% of emissions from new ships covering the following ship types: oil tankers, bulk carriers, gas carriers, general cargo, container ships, refrigerated cargo and combination carriers. 

For ship types not covered by the current formula, suitable formulas are expected to be developed in the future addressing the largest emitters first.

Attained EEDI

EEDI shall be calculated for:

• Each new ship
• Each new ship which has undergone a major conversion
• Each new or existing ship which has undergone a major conversion, that is so extensive that the ship is regarded by the Administration as a newly constructed ship

The attained EEDI shall be specific to each ship and shall indicate the estimated performance of the ship in terms of energy efficiency, and be accompanied by the EEDI technical file that contains the information necessary for the calculation of the attained EEDI and that shows the process of calculation.

The attained EEDI shall be verified, based on the EEDI technical file, either by the Administration or by any organization duly authorized by it.

The attained EEDI shall be calculated taking into account guidelines developed by the Organization.

Required EEDI

• For each
• new ship
• new ship which has undergone a major conversion
• new or existing ship which has undergone a major conversion that is so extensive that the ship is regarded by the Administration as a newly constructed ship

Attained EEDI ≦ Required EEDI = (1-X/100) × Reference line value

where X is the reduction factor specified in Table below for the required EEDI compared to the EEDI Reference line.

Reduction factors (in percentage) for the EEDI relative to the EEDI Reference line

Ship type	Size	Phase 0 1 Jan 2013-31 Dec 2014	Phase 1 1 Jan 2015- 31 Dec 2019	Phase 2 1 Jan 2020- 31 Dec 2024	Phase 3 1 Jan 2025 and onwards
Bulk carrier	20,000 DWT and above	0	10	20	30
	10,000 – 20,000 DWT	N/A	0-10	0-20	0-30
Gas carrier	10,000 DWT and above	0	10	20	30
	2,000 – 10,000 DWT	N/A	0-10	0-20	0-30
Tanker	20,000 DWT and above	0	10	20	30
	4,000 – 20,000 DWT	N/A	0-10	0-20	0-30
Container ship	15,000 DWT and above	0	10	20	30
	10,000 – 15,000 DWT	N/A	0-10	0-20	0-30
General Cargo ships	15,000 DWT and above	0	10	20	30
	3,000 – 15,000 DWT	N/A	0-10	0-20	0-30
Refrigerated cargo carrier	5,000 DWT and above	0	10	20	30
	3,000 – 5,000 DWT	N/A	0-10	0-20	0-30
Combination carrier	20,000 DWT and above	0	10	20	30
	4,000 – 20,000 DWT	N/A	0-10	0-20	0-30

The Reference line values shall be calculated as follows:

Reference line value = a ×b ^-c

Where a, b and c are the parameters given in Table

Ship type	a	b	c
Bulk carrier	961.79	DWT of the ship	0.477
Gas carrier	1120.00	DWT of the ship	0.456
Tanker	1218.80	DWT of the ship	0.488
Container ship	174.22	DWT of the ship	0.201
General Cargo ships	107.48	DWT of the ship	0.216
Refrigerated cargo carrier	227.01	DWT of the ship	0.244
Combination Carrier	1219.00	DWT of the ship	0.488

If the design of a ship allows it to fall into more than one of the above ship type definitions, the required EEDI for the ship shall be the most stringent (the lowest) required EEDI.

EEDI Calculation Formula

EEDI(gCO₂/tonne. Nm)=

           : Main Engines Emissions

          : Auxiliary Engines Emissions

          :Shaft Generators/ Motors Emissions

fi Capacity .Vref fw: Efficiency Technologies
fi Capacity .Vref fw:Transport work

In where:
PME: Main Engine Power (kW);
PAE: Auxiliary Engine Power (kW);
SFC: Specific fuel consumption (g/kW);
C: Fuel to CO2 factor (g CO2/ g Fuel) (nearly 3);
Capacity: for Cargo ships DWT, for Passenger ships GT;
Vref: Reference speed (nm/hour);
fi: Correction factor for capacity;
fw: Correction factor for performance in real weather;
fi: Correction factor for efficiency.


Not applicable to a ship having diesel-electric propulsion, turbine propulsion and hybrid propulsion except for:
Cruise passenger ships and
LNG carriers

In General EEDI formula can be written as,
EEDI = (CO2 from Propulsion system+CO2 from Auxiliary–CO2 emission reduction) / DWT. Speed


EEDI Calculation Formula

EEDI(gCO2/tonne. Nm)=

EEDI condition
EEDI is calculated for a single operating condition of the ship. This will be referred to as EEDI Condition.

The EEDI Condition is as follows:
Draft: Summer load line draft.
Capacity: Deadweight (or gross tonnage for passenger ships) for the above draft (container ship will be 70% value).
Weather condition: Calm with no wind and no waves.
Propulsion shaft power: 75% of main engine MCR (conventional ships) with some amendments for shaft motor or shaft generator or shaft-limited power cases.
Reference speed (Vref ): is the ship speed under the above conditions.

Verification stages
Survey and certification of the EEDI should be conducted on two stages:

1. Preliminary verification at the design stage, and 
2. Final verification at the sea trial. 

Preliminary verification
For the preliminary verification at the design stage, the following should be submitted to the verifier:

• An application for an initial survey 
• An EEDI Technical File containing the necessary information 
• Other relevant background documents 

Tank test aspects
The power curves used for the preliminary verification should be based on results of tank test.

A tank test for an individual ship may be omitted based on technical justifications such as availability of the results of tank tests for ships of the same type.

In addition, omission of tank tests is acceptable for a ship for which sea trials will be carried under the EEDI Condition

Model tank test should be witnessed by the verifier.

Additional information
The verifier may request the submitter for additional information such as:

• Descriptions of a tank test facility. 
• Lines of the model and the actual ship for the verification of the similarity of model and actual ship. 
• Lightweight of the ship and displacement table for the verification of the deadweight; 
• Detailed report of the tank test; this should include at least the tank test results at sea trial condition and under the EEDI Condition. 
• Detailed calculation process of the ship speed
• Reasons for exempting a tank test, if applicable, plus relevant information

Final Verification
Sea trials

• Sea trial conditions should be set as EEDI Conditions, if possible. 
• Prior to the sea trial, the following should be submitted to the verifier: 
• Test procedure to be used for the speed trial, 
• Final displacement table and the measured lightweight, or a copy of the survey report of deadweight, 
• NOx Technical File as necessary. 
• The test procedure should include, as a minimum, descriptions of all necessary items to be measured, measurement methods

The verifier should attend the sea trial and confirm:

• Propulsion and power supply system, 
• Particulars of the engines, and other relevant items described in the EEDI Technical File; 
• Draught and trim; 
• Sea conditions; 
• Ship speed; and 
• Shaft power and RPM of the main engine. 

Parameters to be checked

Draught and trim: should be confirmed by the draught measurements taken prior to the sea trial.
Sea conditions: Sea conditions should be measured in accordance with ITTC
Ship speed: Should be measured in accordance with ITTC
The main engine output: Should be measured by shaft power meter or a method which the engine manufacturer recommends and the verifier approves.

Speed trial – Power curve

• The submitter should develop power curves from results of sea trial. 
• The effect of wind, current, waves, shallow water, displacement, water temperature and water density in accordance with ITTC
• The submitter should compare the power curves obtained as a result of the sea trial and the estimated power curves at the design stage. 
• In case differences, the attained EEDI should be recalculated.