Trans RINA, Vol 152, Part A4, Intl J Maritime Eng, Oct-Dec 2010


India and Bangladesh to Japan and Korea. The scrap imported is generally from sources other than ships (i.e. cars, cans, motor blocks and turnings, steel scrapped infrastructure or buildings etc.).


from


Our example of Japan importing scrap from India was used for the purpose of showing a direct cycle. In the real world scrap used for


steelmaking, and therefore


shipbuilding, the preponderance of which is in the Far East would travel longer distances thus creating overall greater emissions if looked at from a global perspective.


We acknowledge Dr. Mikelis’s point regarding Tables 5 and 6. In our scenario we have assumed that scrap metal in Bangladesh is hauled to China to be used in a steel mill. If scrap metal is used locally in Bangladesh, raw materials would have to be hauled to the Japanese, Korean or Chinese mills for shipbuilding steel production from an unspecified location, and that would also require energy


and produce emissions which have to be


accounted for. In that sense, and for the examined scenario, Tables 5 and 6 are correct in accounting emissions


generated by carrying scrap metal to Bangladesh, from


Bangladesh to China (as per our illustrative example). What is indeed missing is an account of the emissions generated by importing raw materials or scrap from an unspecified location


3. We understand that NOx will increase the level of ozone but reduces Methane life time thus giving a net


cooling to cover the


difference between ship A and B as regards scrap metal generated, to cover the needs of Bangladesh in steel. However, this quantity is estimated to be rather small and very unlikely to change the final results of our paper. One could actually also attempt to estimate the additional emissions generated by building the extra ships necessary for this additional transport of


raw materials, the


additional emissions generated by air transport for flying the crews of these extra ships, the additional emissions generated by manufacturing the extra aircraft necessary to fly these crews, and so on. But one has to stop somewhere.


Regarding finally Dr. Mikelis’s point on rolled steel, we agree that including this into the analysis would make no significant difference.


Coming now to John Kokarakis’s comments, we first note that NOx and SOx emissions are outside the scope of our paper. NOx and SOx emissions from ships, according to all studies, appear to have a cooling effect on the environment. Still, we do not believe that the environmental impact of a ship can be normalised to CO2 equivalence index to describe its overall contribution to global climate change at this point in time when full understanding of the climatic effects of ship emissions is not available. Eventually something along these lines may be able to be approximated in the future.


Ship engine emit Sulphur oxides (SOx), Nitrogen oxides (NOx), Particulate matters (PM) and Carbon dioxide (CO2).


Papers we have seen have different and sometimes conflicting views. Measures taken for land effect. Additionally altering or


redesigning two stroke engines to reduce NOx emissions will increase their fuel consumption (a fuel penalty as it has been referred to in IMO by about 5% if not more); therefore the overall ship related CO2 emissions will increase.


4. In terms of ocean acidification, nitric acid, formed from NOx, and sulphuric acid formed from SOx emissions contribute a few percent compared to carbolic acid created by CO2 on a global scale.


In December 2008 the Hellenic Chamber of Shipping, realising the conflicting information,


organised a


working group that comprised six (6) internationally acclaimed environmental experts as well as experts from the Greek government and the shipping community who considered that further investigation was required to understand the extent of the impact of shipping on the climate. This is clearly stated in recent papers [19 & 20]. These


papers and going ships so other sometimes conflicting


information, appear to indicate that more should be known to fully understand the effect of the emissions of ocean


proposed move in the right direction. The solution should not create more problems that it solves.


Regarding Jack Devanney’s comments, one can certainly write volumes regarding EEDI, the analysis of which is outside the immediate scope of this paper. In our opinion, EEDI is an index that has a variety of problems, some of which have


been


Greece’s recent submissions to the IMO (documents MEPC 60/4/15, MEPC 60/4/16 and MEPC 60/4/17, among others). One major concern is


the push for that whatever measures are


1. To reduce potential health and acid rain related problems, low sulphur distillates may be appropriate on or close to shore as acknowledged by IMO with the establishment of Emission Control Areas in sea areas


based pollution may be inappropriate for pollution out at sea. For example:


of Northern Europe meeting specific


environmental criteria. On the other hand for the production of these distillates, refineries will need to emit at least 15% more CO2 and other pollutants depending on the level of purification required. If such fuels are not required at sea the world would have a net saving in CO2 emissions. Furthermore the high cost of the distillates in SECAs could cause modal shifts of cargo, resulting in more emissions and congestion from less efficient transport systems.


2. Studies show that sulphate aerosols act as a sun shield. Together with BC they appear to be five to six orders of magnitude more potent than CO2 which should counter weigh their shorter lifetime.


described by


A - 228


© 2010: The Royal Institution of Naval Architects


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