Page 30: of Maritime Reporter Magazine (September 2011)

30Maritime Reporter & Engineering News MARINE PROPULSIONE EEDCarbon dioxide CO2 greenhouse gasemissions are directly related to shipsfuel efficiency and fuel consumption of the engines, and is thus relates directly tothe total transport efficiency of ships and to engine manufacturers D work for fuel efficiency. The basic idea behind the energy-efficiency regulations is that an Energy Efficiency Design Index (EEDI) be calculated for each new ship in the de- sign phase.This value consists of the relation be- tween the amount of carbon dioxide pro-duced by the ship?s engines and the amount of cargo it carries. The calcula- tion assumes that a ship is moving at a speed corresponding to 5 percent of its engine power. It measures a vessels in- herent fuel efficiency and compares CO2 emissions to transport work. A reference EEDI is determined by IMO for eachtype of ship, e.g. for tankers, bulk carri- ers, container ships etc.MEASUES EDUCE In July, the Parties to MAPO Annex VI represented in the Marine Environ- ment Protection Committee (MEPC) ofthe IMO, adopted mandatory measures toreduce emissions of greenhouse gases(s) from international shipping. his is the first eer andatory global greenhouse gas reduction regie for an international industry sector. The amendments to MAPO Annex VI egulations for the prevention of air pollution from ships, add a new chapter to Annex VI on egulations on energy ef- ficiency for ships to make mandatory the EEDI, for new ships, and the Ship Energy Efficiency Management Plan (SEEMP) for all ships. Under SEEMP, new and ex- isting ships will have to keep on board a ship-specific energy use management plan during operation. It sets out bestpractices for the fuel efficient operation of ships as well as provides guidelines for the voluntary use of the Ship Energy Ef- ficiency Operational Indicator (EEOI) for new and existing ships which enables op- erators to measure the fuel efficiency in grams of CO2 per ton-mile of a ship. he regulations apply to all ships of a gross tonnage of and aboe and are epected to enter into force on 1 anuary 1. owever, the Adminis- tration may waive the requirement for new ships of 00 gross tonnage and above from complying with the EEDI re- quirements. This waiver may not be ap- plied to ships above 00 gross tonnage for which the building contract is placed four years after the entry into force dateof chapter ; the keel of which is laid or which is at a similar stage of constructionfour years and six months after the entryinto force; the delivery of which is after six years and six months after the entryinto force; or in cases of the major con-version of a new or existing ship, four years after the entry into force date. The new chapter includes a regulation on Pro- motion of technical co-operation andtransfer of technology relating to the im-provement of energy efficiency of ships, which requires Administrations, in co- operation with IMO and other interna- tional bodies, to promote and provide, as appropriate, support directly or throughIMO to States, especially developing States, that request technical assistance.It also requires the Administration of a Party to cooperate actively with other Parties, subject to its national laws, regu- lations and policies, to promote the de-velopment and transfer of technology and exchange of information. The MEPC agreed a work plan to con- tinue the work on energy efficiency measures for ships, to include the devel- opment of the EEDI framework for ship types and sies, and propulsion systems, not covered by the current EEDI require- ments and the development of EEDI and SEEMP-related guidelines. The MEPC agreed to the terms of reference for an in-tersessional working group on energy ef- ficiency measures for ships, scheduled to take place in February/March 2012. For each individual ship, the attained EEDI shall not exceed the proposed ref- erence (baseline) line value agreed by the IMO for each ship type. Under the pro-posal agreed at MEPC 62, the EEDI ref-erence line will be reduced by 10 for ships built between 2015-2019; by 15- 20 (depending on ship type) for ships built between 2020 and 202 and 0 for ships delivered after 202. The de- sign process of a novel Aframax crude oil tanker describes well the development process of today, of which propulsion is an integrated part. The classification so- ciety ermaischer loyd () points out that the reason behind the development project was that the oil tanker design has not evolved enough since the introduc- tion of double hull concept. ittle atten- tion has been paid to the products performance over the lifecycle and, in particular the fuel efficiency has not im- proved in the last 20 years despite the general improvements in systems and their efficiency, said. The recently developed Energy Effi- ciency Design Index (EEDI) is a simple but accurate measure of a vessel?s inher- ent fuel efficiency, which compares CO2 emissions to transport work. said that although oil tankers are considered to be among the most energy efficient vessels today, with an EEDI value ranging from 2 to 6g CO2/(tnm), they emitted ap- proximately 115 million tons of CO2 in2009. The current share of oil tanker CO2 emissions is approximately 12 percent ofthe total CO2 emissions from interna- tional shipping. and the echnical Uniersity of Athens teaed up in to deelop this noel Afraa tanker design con- cept.The ideas from the market were in- corporated in the new design concept called BEST-plus. The hull form was hy- drodynamially optimied to reduce fuel consumption and emissions using Com-putational Fluid Dynamics.The design concept targets the typical Aframax oil tanker trades in the Caribbean Sea. Facilities in the main U.S. ports and the U.S. Emission Control Area (ECA) set the operating conditions. If aMexican ECA would be implemented as well, approximately 0 percent of the total transit distance for this trade would be inside an ECA. The current design as- sumes the use of MO as fuel when sail- ing in an ECA. N as ship fuel, or the use of scrubbers, are the alternatives. The need for a relatively high speed in this trade was considered with regard to the upcoming EEDI requirement to ensuresuperior competitiveness of the vessel. The design approach used an advanced optimiation environment, which inte- grates tools to predict required propul-sion power, stability, oil outflow index, cargo capacity and hull structural scant- lings according to IACS CS. Cost of transport normalied with respect to the reference design, was used as the primary target function for the optimiation. The reference design for comparingcost of transport is an existing pre-CS tanker. Compared to the reference design, Many new developments have taken place regarding the ship propulsion machinery and systems, and also re- garding the methods used to find the best design parameters for an energy efficient vessel. Increasing environ- mental considerations, set into practice by global and regional regulations and by public opinion, combined with a higher fuel price, continue to push designers towards better products. By Henrik Segercrantz Advances in Marine Propulsion FEATURE