Friday, March 9, 2012
IMO’s MEPC 63 held from from 27th February to 2nd March approved a number of revisions to guidelines on the method of calculation of the attained EEDI for new ships.
Reproduced courtesy of a brief roundup of the week's events put together by ABS, the revisions included oil tankers built to the class societies’ Common Structural Rules (CSR) for which a capacity correction factor is applied to the Attained EEDI to account for increased lightship weight and the corresponding reduction in deadweight capacity.
For ship‐specific structural enhancements, a correction factor (proportional to the ratio of the minimum design dwt and the enhanced design dwt) is applied to account for increased lightship, for example, due to increased longitudinal strength, structural class notations, bow slamming reinforcement and collision strength.
On chemical carriers – a cubic correction factor (dwt/cubic cargo capacity) is applied to the Attained EEDI to take into account the increased lightship due to the greater number of cargo tanks and increased scantlings of those tanks to carry the higher density cargoes relative to oil tankers, both of which need to comply with the same Required EEDI. This was achieved with the help of IPTA’s input.
For large ice‐classed tankers, as an option to applying a weather factor of 1.0, EEDI can be determined by conducting the ship‐specific simulation on its performance at representative sea conditions in which case 'Attained EEDIweather' is assigned to the ship.
The Committee did not decide on proposals for minimum design speed and minimum power and agreed to further consider the proposals at MEPC 64 in October 2012.
New MARPOL VI regulation 21.2 requires the installed propulsion power of a ship to be not less than the propulsion power needed to maintain its manoeuvrability under adverse conditions, as defined in the guidelines under development.
An informal group, which convened during IMO’s intersessional working group on energy efficiency, tentatively proposed that a practical means of complying with this regulation would be to specify minimum design speeds for various ship types.
They proposed a minimum design speed of 14 knots for small and medium size ships and 14.5 knots for ships greater than 100,000 dwt, recognising that slow speed ships, including tankers are the most vulnerable.
IACS confirmed that it intended to submit a proposal (minimum power versus deadweight reference lines) to MEPC 64 containing both an interim approach and the basis for a longer term solution.
Of great importance and to stop further arguments, the committee unanimously agreed that the EEDI will not be applied to existing ships.
As for market based measures, despite some delegates recommending that energy efficiency design based market based measures (MBM) should not be submitted to the agreed MBM impact assessment study, others considered that there should be some means to compare the energy efficiency of existing ships.
Accordingly, all MBM proposals, with any refinements based on MEPC 63 discussions, can be submitted to MEPC 64 in October for consideration by the impact assessment study upon finalisation of the study’s terms of reference in October 2012.
The Committee also approved revisions of the ‘Guidelines for Ships Energy Efficiency Management Plan (SEEMP)’ in three areas.
Perhaps most importantly, SEEMP should recognise that the vessel’s trade may determine the feasibility of the efficiency measures under consideration.
The committee also adopted guidelines for the survey and certification of the Attained EEDI. The process is conducted in two stages:
Preliminary verification is carried out at the design stage, which should include model tests for determining the ship’s power curves. This leads to the development of an EEDI Technical File (which contains the details of the parameters used to calculate the Attained EEDI). Details are provided as to the determination of the parameters in the Technical File.
Final verification of the EEDI Technical File is carried out at the sea trials consistent with the parameters used in the method of calculation of the attained EEDI. Specifications for sea conditions, ship speed and shaft power and rev/min of the main engine are provided.
As for the question of regional reception facilities, the committee adopted amendments to MARPOL Annexes I, II, IV and V to allow small island developing states to develop regional arrangements for port reception facilities, both inside and outside of special areas.
Such arrangements may be achieved through regional arrangements based on guidelines approved by the committee where, because of such states' unique circumstances, regional arrangements are the only practical means to satisfy MARPOL’s requirements.
A unique arrangement was agreed under MARPOL Annex II for the discharge requirements of prewash residues in chemical carriers.
The revision now allows the discharge of prewash residues to be made to a regional ship waste reception centre specified in the applicable regional reception facility plan as an option to the port of unloading.
The committee adopted revisions to the NOx Technical Code which, on entry into force on 1st August 2013, allows for an alternative approach (Scheme B) to be used to certify engines fitted with selective catalytic reduction (SCR) units.
Scheme B allows certification of engines, which cannot be pre‐certified either on a test bed, or on board under the NOx Code’s standard requirements, by allowing for analytic modelling to estimate the effect that the proposed SCR design and arrangement will have on the NOx emissions from the engine to which it is to be fitted.
This modelling is to be validated by testing that can be undertaken using a scaled bench top mock‐up operating on synthetic exhaust gas.
The entire Engine Group (engines that require minor on board adjustments and modifications) would not be approved until the NOx reduction efficiency, relative to the parent engine NOx Technical File, has been demonstrated with the SCR installed on board.
Twelve months after entry into force of the BWM Convention all ships ≥ 400 gt will need to be surveyed and certificated to comply with the convention. As a minimum, ships must have on board an approved Ballast Water Management Plan and a ballast water record book.
To provide for an adequate phase‐in period for survey and certification in advance of the compliance date, the committee agreed to allow the issuance of BWM certificates prior to entry into force of the convention.
The committee also agreed that BWM plans approved under A.868(20) remain acceptable until such time as the ship is required to comply with the biological standards in regulation D2 of the BWM convention.