During the 62nd session of the MEPC (11–15 July 2011), at IMO Headquarters in London, the represented Parties to MARPOL Annex VI adopted amendments to Annex VI Regulations for the prevention of air pollution from ships. Considered the first regulation to establish CO2 standards across a global sector, the Energy Efficiency Design Index (EEDI).
In terms of CO2 emissions, shipping contributes to about 2.5% of the world’s emissions and the emission rate will increase by 75% in the next 15 years due to demand and growth in global trade.
What is EEDI mean?
The EEDI is used to calculate a vessel’s energy efficiency. This is based on a complex formula, taking the ship’s emissions, capacity, and speed into account. The lower a ship’s EEDI, the more energy-efficient it is and the lower its negative impact on the environment.
EEDI = (Power · Specific Consumption · Carbon Factor) / (Capacity · Speed)
This essentially translates into (number of grams of CO2 emissions) per tonne per nautical mile.
IMO regulations stipulate that ships must meet a minimum energy efficiency requirement, so their EEDI must not exceed a given threshold – ngưỡng giới hạn.
The EEDI regulation applies to new cargo ships greater than 400 gross tons (GT) and
varies with ship type, size, and function. The categories of ships covered include oil and gas tankers, bulk carriers, general cargo ships, refrigerated cargo carriers and container ships.
Note that the Reference line is different with type of ships.
How to reduce EEDI?
From the IMO EEDI formula, as the smallest possible EEDI, thus small numerator and large denominator.
Solution 1: Reduce the Carbon factor
Solution 2: Optimize the Hull to get Bigger DWT and Higher Speed, Minimize Resistance.
Note this solution is almost carried out by Japan and Korea experts.
Pls see the SHIP HULL OPTIMUM MAIN DIMENSION
Solution 3: Lowering Power require by using Energy Saving Devices
How to make Certification of EEDI?
For the preliminary verification at the design stage, a Ship Owner or a Shipbuilder is to submit to a verifier (3rd party) an EEDI Technical File containing the necessary information for the verification and other relevant background documents. EEDI Technical File, which is to be developed by either a Ship Owner or a Shipbuilder, is to include at least but not limited to:
Dead weight and shaft power of main and aux. Engines;
Ship speed on deep water in the maximum design loaded conditions at the 75% of the maximum continuous rate (MCR) for the main engine;
Specific fuel consumption (SFC) of the main engine at 75% MCR and auxiliary engines;
Principal particulars, overview of propulsion system and electricity supply system on board;
Estimation process and methodology of the power curves at design stage;
Description of energy saving equipment; and
Calculated value of the Attained EEDI.
The verifier is to issue the report on the preliminary verification of EEDI after verifying the attained EEDI at design stage.
Sea Trials Stage
Prior to the sea trial, a Ship Owner is to submit the final displacement table and the measured lightweight, or a copy of the survey report of dead weight, as well as a copy of NOx Technical File as necessary.
The verifier is to attend the sea trial and confirm:
Propulsion and power supply system;
Particulars of the engines;
Other relevant items described in the EEDI Technical File;
Draft and trim, sea conditions; and
Ship speed, shaft power of the main engine.
The verifier is to issue the report on the verification of EEDI after verifying the attained EEDI after the sea trial and it is proposed to issue an International Energy Efficiency (IEE) certificate.