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Q TECHNICAL PAPER


Plot shows the aggregated tracks of the 100 ships sampled that carry


between 8,000- 11,999 TEU. The coloured areas indicate the extent


of regional emissions control areas


and buffer zones 1


Extraction of AIS data for all vessels that can be identified as container ships and aggregation of that data per vessel and hour over the course of the year 2012.


58 2 3


Uploading of that data in CartoDB and selection of all vessels with messages


occurring in all four time-area combinations.


Tagging and exporting of those messages that lie within the buffer zone and ECA (but


not California Waters). Every single message takes the format: IMO number, time stamp, speed, area.


4 5


Discarding of all messages where speed is lower than half the vessel’s design


speed (which we use as a proxy for minimal sailing speed).


Calculation of average (arithmetic mean) sailing speed within all four time-area combinations (a1), (a2), (a3) and (a4) for each single vessel.


6 7


Calculation of the difference in average speeds when present in the buffer zone as


opposed to the (future) ECA for both time frames, i.e. (January-July - JJ)=(a3)-(a1) and (August-December - AD)=(a4)-(a2).


Calculation of the relative difference between the January-July and August-


December difference of the previous step to find out whether vessels slow down (or accelerate) more between areas in the first or second time period, i.e. (rel diff) = (AD)-(JJ) for each vessel.


8


Aggregation of the calculated values by vessel size.


Analysis and results


In Step 1 we extract data from 4,785 container ships and aggregate it into hourly readings for each vessel. This resulted in around 15 million messages, as we observe the vessels only


Emissions Control Areas as stipulated under MARPOL Annex VI Geographic zone


sBaltic Sea sNorth Sea


sNorth American sUS Caribbean Sea


Emissions SOx


SOx


SOx & PM SOx & PM


Adopted


September 1997 July 2005


March 2010 July 2011


Maximum allowable sulphur content in fuel oil (mass percentage) Geographic zone


sOutside ECA s Inside ECA 4.5% m/m


before 1 Jan 2012 1.5% m/m


before 1 Jan 2010


sCalifornian waters** 1.5% (0.5%) m/m from 28 Jun 2009


from 1 Jan 2012 1.0% m/m


from 1 Jan 2010 1.0% (0.5%) m/m


from 1 Aug 2012 * subject to revision ** California specified MGO and MDO (in brackets) limits separately


about every three hours. The filtering in Step 2 leads to a set of 895 vessels for which we have 3.1 million messages. CartoDB (an open source web mapping framework) allows us to easily plot this data, and we extracted two ‘sailing networks’ by different size bins. The image above displays the route from


100 vessels that fall into size bin 6, i.e. that carry between 8,000 and 11,999 TEU. These vessels cover much longer distances, and typically go to major ports in Asia and Europe. Vessels from smaller size bins travel much


shorter distances, e.g. vessels from size bin 1 (not shown here) sail predominantly in the Gulf of Mexico and Caribbean Sea, only a few vessels venture to islands farther out in the oceans or to Asia and Europe. For vessels with tagged and exported


Entered into effect May 2006


November 2007 August 2012 January 2014


messages we discard low-speed readings, calculate individual average sailing speeds within the four time-area combinations, and the absolute speed difference between the areas in the months January to July and August to December (Steps 3-6). We find that over 75% of vessels sail slower


Sulphur limits and validity dates 3.5% m/m


in the (future) ECA than they do in the buffer zone, irrespective of time. In order to estimate the effect that the introduction of the ECA has on sailing speeds, we compute the relative difference for each single vessel (Step 7). Our calculations show that the medians of


0.5% m/m


from 1 Jan 2020* 0.1% m/m


before 1 Jan 2015 0.1% (0.1%) m/m


before 1 Jan 2014


the relative speed difference in all seven bin sizes is very close to zero. This means that about half of vessels are sailing slower (on average) inside the ECA as opposed to the buffer zone than they did before 1 August 2012, and about half the vessels are sailing faster than in previous comparisons .


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