International survey of fuel consumption of seagoing ships at berth

International survey of fuel consumption of seagoing ships at berth

International survey of fuel consumption of seagoing ships at berth

CNSS March 2014 CNSS Work package 5, Quantfication of the current contribution of ships to air pollution International survey of fuel consumption of seagoing ships at berth

International survey of fuel consumption of seagoing ships at berth

2 INTERNATIONAL SURVEY OF FUEL CONSUMPTION OF SEAGOING SHIPS AT BERTH Section 1 International survey of fuel consumption of seagoing ships at berth 3 Section 2 Survey of fuel consumption of seagoing tankers at berth in Rotterdam 36 Contents Photo: www.mediaserver.hamburg.de/C. Spahrbier

International survey of fuel consumption of seagoing ships at berth

3 Summary On behalf of the INTERREG IVB Clean North Sea Shipping (CNSS) project a survey of energy consumption and fuel use on board seagoing ships was performed in close cooperation with the Port of Hamburg and Bremerhafen, the Port of Antwerp, the Port of Rotterdam and the Port of Bergen.

The current understanding of fuel consumption and associated emissions from seagoing ships at berth is based on a survey conducted in 2003. The aim of this latest survey was to provide an updated assessment of fuel consumption and emissions. The survey produced a comprehensive dataset of information gathered from 175 ships, including fuel consumption data, engine power, duration of usage and so on.

This report presents a first analysis of the survey data with respect to fuel usage at berth and the consequences for emissions. The analysis has already resulted in new recommendations for the calculation of fuel consumption at berth for nine ship types. In cases where the survey failed to produce sufficient data, combinations of existing data were used. The fuel distribution over auxiliary engines and boilers has been partly revised based on the results of the questionnaires. Compared with the 2003 survey, relatively less fuel seems to be used in boilers. This change in fuel usage has resulted in a relative increase of NOx, VOC and CO emissions.

As a result of current EU regulations, 90 percent of fuel used on board of ships was proven to have a sulphur content of or below 0,1%. This has resulted in a significant reduction of SO2 emissions and a stabilization of PM10 emissions. Tankers are an important source of emissions for some large ports. However, as the available data for this category of ship are of relatively poor quality, this report recommends a dedicated survey to assess tanker fuel usage. Any new survey should consider the role and importance of the boilers during the entire berthing procedure. Since the emission profiles of boilers and ship engines vary considerably, a detailed understanding of relative fuel consumption is essential if emissions are to be estimated accurately.

Two other categories of ships that still lack sufficient fuel consumption data are ROPAX ships and Cruise ships. International survey of fuel consumption of seagoing ships at berth Compiled by: ir. J.H.J. Hulskotte, TNO, ir. B. Wester and ing. A.M. Snijder, DCMR Milieudienst Rijnmond, dr. V. Matthias, HZG

International survey of fuel consumption of seagoing ships at berth

4 INTERNATIONAL SURVEY OF FUEL CONSUMPTION OF SEAGOING SHIPS AT BERTH The authors of this report would like to express their gratitude and acknowledge the contribution of all those who have assisted with this project. First of all we want to thank all the hard working harbour staff who organised the ship visits at very short notice. Secondly, we would like to thank the students who boarded the ships to complete the questionnaires and analysed the results. Finally, we are grateful to the teachers who prepared, accompanied and assisted the students during the project.

Rotterdam Main Port University of applied sciences Students: Inger van Vuuren, Timothy van Heest, Kasper Renes, Michael Krul, Alex van den Berg, Oskar Dasselaar, Daan Groenewegen,Chris Hanemaayer, Anya Koch, Sander Lohoff Teachers: Peter van Kluyven, Monique van der Drift, Aat Hoorn .

. Wasserschutpolizei Hamburg In general and in particular Thorsten Koops . . Antwerp Maritime Academy (Hogere Zeevaartschool Antwerpen) Tom Moelans, Cedric Kegels, Stijn Andries, François Requier, Amos Sebrechts, Nicolas Saintenoy . .

Hordaland County Council Marte Steinskog . . Port of Rotterdam Authority in general and particularly Martin Pastijn, Wachtchef Inspectie Divisie Havenmeester (DHMR) Acknowledgements

International survey of fuel consumption of seagoing ships at berth

5 1 Introduction 6 2 Preparation 7 3 Data collection 8 4 Analysis of fuel consumption at berth 10 4.1 Hourly fuel consumption as a measure of emissions 10 4.2 Calculation of hourly fuel consumption 10 4.3 Selection of valid data 11 4.4 Results of hourly fuel consumption 12 4.5 Fuel distribution over engine types 26 4.6 Fuels and sulphur content 27 5 Consequences of this research for emissions 30 5.1 Activity data and emission factors 30 5.2 Reference emissions 31 5.3 Emissions based on results of this study 31 6 Conclusions and recommendations 33 7 References 34 Table of contents

International survey of fuel consumption of seagoing ships at berth

6 INTERNATIONAL SURVEY OF FUEL CONSUMPTION OF SEAGOING SHIPS AT BERTH Ports suffer from air pollution not only as a result of ships arriving and departing but also as a result of emissions produced by ships during their time at berth. A thorough assessment of ship emissions at berth is a crucial first step to understanding the impact of those emissions on air quality and public health in harbour cities. In addition, the impact of abatement measures such as shore-side electricity and/or restrictions in sulphur content for shipping fuel to be used in ports must also be understood.

A survey of energy consumption and fuel use on board 175 seagoing ships was undertaken in conjunction with the Port of Hamburg and Bremerhafen, the Port of Antwerp, the Port of Rotterdam and the Port of Bergen.

The survey was based on on a questionnaire designed and tested in 2003 (referred to as EMS study) on behalf of the Netherlands National Emission Inventory (Hulskotte et al., 2003). Some parts of the questionnaire were modified to clarify the answers, meet the goals of the CNSS project and to collect information on any emission reduction technologies already installed on board the ships. 1 Introduction

International survey of fuel consumption of seagoing ships at berth

7 Before boarding the ships to complete the survey, some preparatory work had to be undertaken. The first stage was to arrange access to the ships. After the responsible organisations had been contacted, it transpired that each harbour had its own conditions for obtaining access to ships. The questionnaire had to be modified for the current survey and to meet the objectives of the CNSS project. The partners of the CNSS project gave several suggestions to modify the questionnaire that were incorporated in the version that is been used. Some initial data checks were performed on the digital version of the questionnaire (MS Excel® format).

However, some of the students had access to different versions of MS Excel® and some were unfamiliar with that particular software package. To avoid any inconsistencies, a printed version of the questionnaire was produced for on board data collection. The decision to modify the survey procedure was made after testing the questionnaire in the “machinery simulation room” of the Rotterdam Main Port University of Applied Sciences. With one of the teachers acting as the captain of a ship, a student tried to fill out the questionnaire on a laptop computer. As a result of this test, the sequence of questions was modified slightly and it was agreed that using a paper version of the questionnaire would speed up the data collection process and facilitate better communication with the crew on board the ships being surveyed.

The data would subsequently be transferred to digital format (MS Excel®) once the questionnaires had been completed, with all data fields named sequentially to facilitate the transfer process.

In final preparation for the survey, all interviewers were invited to attend a meeting, hosted by representatives from the CNSS project, during which the goals and the purpose of the project were explained. The meeting also involved some instruction for the interviewers on how to complete the survey and some practical recommendations on how to behave on board ship. Each interviewer was also required to complete an online test. Before beginning the survey, the captain of each ship involved received a letter from the CNSS project advising them that any data collected would only be used for anonymous environmental research, and that no information about individual ships would be published.

2 Preparation Port of Antwerp

International survey of fuel consumption of seagoing ships at berth

8 INTERNATIONAL SURVEY OF FUEL CONSUMPTION OF SEAGOING SHIPS AT BERTH On arrival on board the ships at berth, the questionnaires were completed by different individuals, recruited and trained in advance by the CNSS project. In Hamburg and Bremerhaven the ships were visited by officials from the “Wasserschutzpolizei”. The ship visits in Antwerp, Rotterdam and Bergen were undertaken by students from the Maritime Academy (Hogere Zeevaartschool Antwerpen) the Netherlands Maritime University (STC-NMU) and the University of Bergen, respectively.

In most cases the answers for the questionnaires were provided by the chief engineers and the captain or a master who were able to read the metering instruments on the bridge and in the machinery room. Once the paper versions of the questionnaires were completed, the data were transferred to MS Excel® format. The classification of ships was primarily based on categories provided by the Maritime Connector website (http://maritime-connector.com/). The EMS types (Hulskotte et al., 2003) were added manually, partly based on information that was taken from registered data records. In most cases this information was available on the websites of ship classification companies.

Table 1 Classification of ships EMS shiptype Type in Maritime Connector Remark Number Bulk carrier BULK CARRIER 13 Chem.+Gas tanker CHEMICAL TANKER 1 LPG TANKER 1 OIL/CHEMICAL TANKER 21 Container ship CONTAINER SHIP 66 General Dry Cargo CARGO 11 GENERAL CARGO 4 Oil tanker, crude CRUDE OIL TANKER 5 OIL PRODUCTS TANKER crude 3 Passenger PASSENGERS SHIP ferry 1 RO-RO/PASSENGER SHIP ferries 2 Reefer REEFER 6 RoRo Cargo / Vehicle RO-RO CARGO 5 RO-RO/PASSENGER SHIP Vehicle carriers 8 VEHICLES CARRIER 8 Tug/Supply ANCHOR HANDLING VESSEL 15 MULTI PURPOSE OFFSHORE VESSEL 2 OFFSHORE SUPPLY SHIP 1 TUG/SUPPLY VESSEL 2 Grand Total 175 3 Data collection

International survey of fuel consumption of seagoing ships at berth

9 Table 2 Types of ships visited by harbour location, number EMS shiptype Antwerpen Bergen Bremerhafen Hamburg Rotterdam Grand Total Bulk carrier 10 3 13 Chem.+Gas tanker 1 6 16 23 Container ship 7 4 37 17 65 General Dry Cargo 5 9 1 15 Oil tanker, crude 1 7 8 Passenger 2 2 4 Reefer 2 3 1 6 RoRo Cargo / Vehicle 3 5 9 4 21 Tug/Supply 20 20 Grand Total 15 25 9 75 51 175 The figures in Table 2 indicate that container ships were the most frequent visitors, followed by chemical and oil product tankers and general dry cargo ships. Although crude oil tankers and passenger ships are under- represented in the questionnaire, their possible share of emissions has been taken into account.

Photo: www.mediaserver.hamburg.de/C. Spahrbier

International survey of fuel consumption of seagoing ships at berth

10 INTERNATIONAL SURVEY OF FUEL CONSUMPTION OF SEAGOING SHIPS AT BERTH 4.1 Hourly fuel consumption as a measure of emissions The most generally applicable measure for estimating ship emissions at berth is probably the hourly fuel consumption rate. A measure of energy consumption may be less applicable when specific fuel consumption has been shown to vary considerably. The time spent at berth may also vary considerably between ships and harbours. Therefore the hourly fuel consumption rate was chosen as the central focus of the analysis.

4.2 Calculation of hourly fuel consumption In addition to other data collected in the questionnaire, the following information about the usage of engines and power equipment at berth were collected.

Running hours [AEx_activeatberth_hours] Fuel rate [AEx_fuelatberth_kgperhour] Actual power [AEx_poweratberth] Measure of actual power [AEx_unitpower_berth] Estimated Load factor [AEx_LF_berth] Total hours at berth [Total_time_at_berth_hours] Ships gross tonnage [Grosstonnage_GT] The information above was collected for Main Engines (when applicable), Auxilliary Engines (maximum three), Gas turbines and Boilers (both when applicable). If information on time and fuel consumption per hour per engine was available, the aggregated fuel consumption based on individual engines was taken as the total fuel consumption per call.

If the usage time per engine was not known, the total time at berth was used to estimate the fuel consumption of a particular engine.

[Total_FC] =∑1..x ([AEx_activeatberth_hours] * [AEx_fuelatberth_kgperhour]) When [AEy_activeatberth_hours] not filled in [Total_FC] = [Total_time_at_berth_hours]* [AEy_fuelatberth_kgperhour]) + ∑1..x x ([AEx_activeatberth_hours] * [AEx_fuelatberth_kgperhour]) To calculate average hourly fuel consumption, the total hourly fuel consumption was divided by the total time at berth. [FCh] = [Total_FC] / [Total_time_at_berth_hours] In some special cases where no time data were available (anchor handling vessels), the hourly fuel consumption was measured by adding all the hourly fuel consumptions of different engines: [FCh] =∑1..x([AEx_fuelatberth_kgperhour]) To compare with previously published results (Hulskotte et al,2003 and Hulskotte & Denier van der Gon, 2010), hourly fuel consumption was divided by the gross tonnage (GT) times 1000.

FCs = [FCh]/( [Grosstonnage_GT] * 1000) 4 Analysis of fuel consumption at berth

11 4.3 Selection of valid data In preparation for further analysis, the validity of the data was assessed and a subset of deviating data was discarded, based on specific criteria. If the hourly fuel consumption divided by 1000GT (FCs) differed by more than a factor of three from previous published data (Hulskotte et al,2003 and Hulskotte & Denier van der Gon, 2010) for the same ship type, the data were discarded. Data were considered as deviant if [FCs]/[FCps]>3 or if [FCs]/[FCps]

12 INTERNATIONAL SURVEY OF FUEL CONSUMPTION OF SEAGOING SHIPS AT BERTH 4.4 Results of hourly fuel consumption This section will review the hourly fuel consumption results for the various ship types. By presenting hourly fuel consumption values potted against ship volumes measured as gross ton (GT), it is possible to observe whether there is a relationship between ship volumes and the hourly fuel consumption of a certain ship type. The slope of the regression lines in the graph (multiplied by 1000) will give an indication of the fuel consumption expressed as kg/GT*1000.hour. In the EMS-protocol (Hulskotte et al., 2003) fuel consumption was estimated by taking the total fuel consumption divided by total GT*1000.hour as the estimated value for total fuel consumption.

4.4.1 Container ships Figure 1 indicates a strong relationship between fuel consumption and ship volume expressed in gross tonnes (GT). It seems that smaller ships have relatively higher fuel consumption than bigger ships. By drawing a regression line (see Figure 2) with the fuel consumption as a function of GT to a certain power (power function) multiplied with a coefficient a higher value of R2 is obtained. This may indicate that a power function is a better approximation of the relationship between GT and hourly fuel consumption of container ships as was already shown by Hulskotte & Denier van der Gon, 2010.

Figure 1 Total hourly fuel consumption of container ships as a function of ship volume

13 There is little difference between the EMS data (Hulskotte et al., 2003) and the data collected as part of this study. However, as the EMS results were only based on the data collected from 12 ships, the data in this study (48 data samples) are probably are more representative and accurate. There was always a risk that valid fuel consumption data could be excluded when the deviant data were discarded. Therefore a parallel check was performed on the values of the SFOC of the first auxiliary engine (see Table 4).

Figure 2 Total hourly fuel consumption of container ships as a function of ship volume (power function) Table 3 Summarized results of fuel consumption of container ships Parameter EMS This work N=12 N=48 Total fuel/Total GT.h (kg/GT.h/1000) 5.0 6.0 Intercept (I) (kg) + Slope (S) (kg/GT.h/1000) I=134;S=4.3 Power function: Slope (S) and power (p) S=0.41; p=0.83

14 INTERNATIONAL SURVEY OF FUEL CONSUMPTION OF SEAGOING SHIPS AT BERTH Table 4 clearly indicates that there is an overwhelming correspondence between deviant fuel consumption and SFOC values that lie beyond the reasonable range. Where deviant data and out of range SFOC values coincide, the hourly fuel consumption was probably not recorded correctly in the questionnaires. A selection of valid data from the questionnaires, for all ship types, was rechecked. In Table 4 the SFOC percentages do not add up to 100 percent. There may be one or more ships with alternative SFOC calculation(s), which explains the SFOC value within the reasonable range.

However, for reason of transparency it was decided not to take these alternative calculations of SFOC into account. In the following sections, this discrepancy will recur in similar tables.

4.4.2 General dry cargo (GDC), RoRo cargo and vehicle carriers In the analysis of fuel consumption data, merging two EMS-types (general dry cargo and RoRo cargo) did not introduce any discrepancies when deriving accurate fuel consumption values for ships within these categories. Table 4 Results of data filtering compared with check on SFOC values of container ships Filter criteria number percentage SFOC OK1 SFOC X1 Deviant 17 26% 12% 82% Not deviant 48 74% 85% 8% 65 1 When SFOC OC + SFOC X in the same row do not add to 100% alternative explanation for non-deviating SFOC may be valid. However for clarity reasons this is not accounted.

Figure 1 Total hourly fuel consumption of container ships as a function of ship volume Figure 3 Total hourly fuel consumption of general dry cargo and RoRo cargo ships as a function of ship volume

15 Table 6 shows that the majority (79%) of valid data has a corresponding SFOC value that is within a reasonable range. However 5 out of 12 deviant fuel consumption recordings (42%) also show SFOC values within a reasonable range. This may indicate that in reality fuel consumption figures may vary more widely than anticipated. 4.4.3 Bulk carriers In most cases bulk carriers don’t need special equipment for energy production, which explains why their fuel usage at berth is relatively low. Although self- unloading bulk carriers could be the exception to this observation, no such bulk carriers were part of this survey.

Table 5 Summarized results of fuel consumption of general dry cargo and RoRo cargo ships Parameter EMS This work N=3 N=24 Total fuel/Total GT.h (kg/GT.h/1000) 5.4 6.1 Intercept (I) (kg) + Slope (S) (kg/GT.h/1000) I=18;S=5.6. Table 6 Results of data filtering compared with check on SFOC values of general dry cargo and RoRo cargo ships Filter criteria Number percentage SFOC OK1 SFOC X1 Deviant 12 33% 42% 50% Not deviant 24 66% 79% 17% 36 1 When SFOC OC + SFOC X in the same row do not add to 100% alternative explanation for non-deviating SFOC may be valid. However for clarity reasons this is not accounted.

Comparing the EMS data (Hulskotte et al., 2003) to data collected in this study suggests there are no significant differences between the two datasets for general dry cargo and RoRo cargo ships. However, as the EMS study was only based on 3 ships and the current study included 24 data samples, these latest results provide a more robust confirmation of the earlier results. Data used in this study are probably more representative and accurate.

16 INTERNATIONAL SURVEY OF FUEL CONSUMPTION OF SEAGOING SHIPS AT BERTH Figure 4 Total hourly fuel consumption of bulk carriers as a function of ship volume Figure 3 Total hourly fuel consumption of general dry cargo and RoRo cargo ships as a function of ship volume Table 7 Summarized results of fuel consumption of bulk carriers Parameter EMS This work Total fuel/Total GT.h (kg/GT.h/1000) 2.4 3.1 Intercept (I) (kg) + Slope (S) (kg/GT.h/1000) I=7;S=3.1 This study included eight valid bulk carrier data samples; the EMS study (Hulskotte et al.,2003) had 10 data samples. The results of this study are not significantly different from EMS results.

17 Table 8 shows that all not deviant fuel consumption data have SFOC values within reasonable range while the majority of deviant fuel consumption data show SFOC values beyond reasonable range. The used data filter seems therefore to be justified. 4.4.4 Oil tankers There were a limited number of data samples for crude oil tankers collected as part of this study. As a result, the data collected in this study (8 data samples) were merged with EMS data (15 data samples). Figure 5 Total hourly fuel consumption of crude oil tankers as function of ship volume (green=this survey, n=8, blue/green=EMS-data, n=15) Table 8 Results of data filtering compared with check on SFOC values of bulk carriers Filter criteria Number percentage SFOC OK SFOC X Deviant 5 38% 40% 60% Not deviant 8 62% 100% 0% 13 Figure 5 (includes valid and deviant data) indicates that the size and the relatively high fuel consumption rate of oil tankers results in an hourly fuel consumption rate that may be as much as 10 times higher than that of other ships (see other graphs).

The EMS study (Hulskotte et al.,2003) contained 33% deviant data, while this study included 50% deviant data.

18 INTERNATIONAL SURVEY OF FUEL CONSUMPTION OF SEAGOING SHIPS AT BERTH Table 9 Summarized results of fuel consumption of crude oil tankers Parameter EMS This work N=15 (N=8) Total fuel/Total GT.h (kg/GT.h/1000) 19.3 11.6 Intercept (I) (kg) + Slope (S) (kg/GT.h/1000) I=34;S=16.9 Intercept taken from chemical tankers Having obtained only eight new data samples, this survey does not provide a definitive insight into crude oil tanker fuel consumption. The slope of the regression line in Figure 5 probably provides the best provisional estimation of fuel consumption of crude oil tankers. A more thorough and dedicated survey of this type of ship is recommended.

Table 10 Results of data filtering compared with check on SFOC values crude oil tankers Filter criteria Number percentage SFOC OK SFOC X Deviant 4 50% 75% 25% Not deviant 4 50% 75% 25% 8 The lack of difference in plausibility of SFOC values between deviant and valid data was another reason for not filtering data samples.

19 4.4.5 Oil products, chemical products and gas tankers As the data for the group of oil products, chemical products and gas tankers contained a relatively high percentage of deviant data and unrealistic SFOC values, the latest data were merged with the original EMS data (including valid data).

Table 11 Summarized results of fuel consumption of Oil products/chemical and gas tankers Parameter EMS This work+EMS N=10 N=12 Total fuel/Total GT.h (kg/GT.h/1000) 17.5 14.5 combined 12.1 this work Intercept (I) (kg) + Slope (S) (kg/GT.h/1000) I=34;S=13.8 In total, 12 data samples were collected for this survey in comparison to the 10 data samples collected for the EMS project. As in the case of oil tankers, a more thorough and dedicated survey of this type of ship is required. Because both ship types (oil products/chemical and gas tankers as well as crude oil tankers) require inert gas production results of these types could be compared carefully to each other.

Figure 6 Total hourly fuel consumption of oil products/chemical and gas tankers as a function of ship volume (green=this survey,n=12, blue/green=EMS-data,n=10) Figure 6 indicates that in general the values collected in the latest survey are a little lower than in the original EMS data (Hulskotte et al,2003).

20 INTERNATIONAL SURVEY OF FUEL CONSUMPTION OF SEAGOING SHIPS AT BERTH Table 12 shows that the majority of valid data had SFOC values within a reasonable range and that the deviant data had more SFOC values beyond that reasonable range. However about 1/3 of deviant fuel consumption data showed SFOC values that are within a reasonable range. 4.4.6 Reefers A refrigerated (or reefer) ship is a type of ship typically used to transport perishable commodities that require a temperature-controlled environment, such as fruits, meat, fish, vegetables, dairy products and other foods (Wikipedia). The energy consumption required for cooling means this type of ship uses relatively more energy than, for example, general cargo ships.

As only five valid reefer data samples were obtained in this project, it was decided to merge the data with the data of the EMS project. This produced 11 data samples for analysis.

Table 12 Results of data filtering compared with check on SFOC values Filter criteria number percentage SFOC OK1 SFOC X1 Deviant 11 48% 36% 55% Not deviant 12 52% 58% 25% 36 1 When SFOC OC + SFOC X in the same row do not add to 100% alternative explanation for non-deviating SFOC may be valid. However for clarity reasons this is not accounted. Figure 7 Total hourly fuel consumption of reefers as a function of ships volume (green=this survey,n=5, blue/green=EMS-data, n=6)

21 4.4.7 RoPax ferries As part of this study, passenger ships were split into different categories with two RoRo passenger ships being designated as “RoPax ferries”.

Data were collected from only three RoPax ferries. The study revealed that a large proportion of RoRo passenger ships in fact are pure car carriers (PCC), which were classified under 'RoRo cargo/vehicle'. In the data analysis this type of ships was reclassified under the category “General Dry Cargo” (see 4.4.2). When the EMS data (Hulskotte et al.,2003) were re- analyzed it emerged that of the 10 ships labelled as 'Ferries/RoRo', only three could be considered as RoPax ferries. To get the maximum number of RoPax ferries for the analysis, the data from this study (3 ships) were merged with three selected ships from the EMS project.

Table 13 Summarized results of fuel consumption of reefers Parameter EMS This work N=6 N=5 Total fuel/Total GT.h (kg/GT.h/1000) 24.6 19.6 Intercept (I) (kg) + Slope (S) (kg/GT.h/1000) I=41;S=18.8 Table 14 Results of data filtering compared with check on SFOC values Filter criteria number percentage SFOC OK1 SFOC X1 Deviant 1 17% 0% 100% Not deviant 5 83% 80% 0% 6 1 When SFOC OC + SFOC X in the same row do not add to 100% alternative explanation for non-deviating SFOC may be valid. However for clarity reasons this is not accounted. Although according to the current study reefer fuel usage seems to be lower, no firm conclusions can be derived due to the low number of data samples.

The energy consumption of these ships is probably related to ambient temperature. The EMS data (Hulskotte et al., 2003) were collected during the summer time while data in this study were collected in autumn.

22 INTERNATIONAL SURVEY OF FUEL CONSUMPTION OF SEAGOING SHIPS AT BERTH With only six ships in the study, the database of RoPax ferries is rather weak. Comparison with EMS data is further complicated because the ship categories are not the same. For RoPax ferries it is plausible that the energy consumption rate may be very dependent on the season; in summer air conditioning may contribute to the energy consumption of these ships while in winter space heating may be an important energy consumer. When actual power was not collected as part of the questionnaire, the SFOC calculation for this ship type was performed using an alternative formula.

[SFOC] = [AEx_fuelatberth_kgperhour] / [AE_totalpower] * [AE1_LF_berth]/[Auxilliary_engines_Number] Figure 8 Total hourly fuel consumption of RoPax ferries as a function of ship volume (green=this survey,n=3, blue/green=EMS-data,n=3) Table 15 Summarized results of fuel consumption of RoPax ferries Parameter EMS This work (N=10) (N=6) Total fuel/Total GT.h (kg/GT.h/1000) 6.9 8.9 Not comparable Intercept (I) (kg) + Slope (S) (kg/GT.h/1000) I=91;S=7.6

23 Two of three SFOC values were in a reasonable range. The only value that was out of range could be classed as OK if the average power of the auxiliary engines was considered. 4.4.8 Tug and supply ships The category of tug and supply ships is in fact a mixed category of all kinds of ships serving various purposes. As this is a heterogeneous group, results may also vary considerably. Ships in this category included in the survey were mostly service vessels that perform various tasks in the Norwegian offshore industry. Figure 9 Total hourly fuel consumption of tug and supply ships as a function of ship volume The actual power of the auxiliary engine in these cases was estimated by taking the average power of all auxiliary engines and multiplying it with the load factor.

Table 16 Results of data filtering compared with check on SFOC values Filter criteria number percentage SFOC OK SFOC X Not deviant 3 100% 66% 33%

24 INTERNATIONAL SURVEY OF FUEL CONSUMPTION OF SEAGOING SHIPS AT BERTH Where actual power was not available for tug and supply ships, the SFOC calculation was performed with an alternative formula. [SFOC] = [AEx_fuelatberth_kgperhour] / [AE_totalpower] * [AE1_LF_berth]/[Auxilliary_engines_Number] The actual power of the auxiliary engine in those cases was estimated by taking the average power of all auxiliary engines and multiplying it with the load factor. It should be noted that within the EMS project (Hulskotte et al.,2003) only three data samples were available, whereas the latest study produced 14 new data samples.

For the category of supply ships, the data samples are probably representative. It is not clear whether the relationship between GT and fuel consumption is valid for dedicated tugs. Table 17 Summarized results of fuel consumption of tug and supply ships Parameter EMS This work Total fuel/Total GT.h (kg/GT.h/1000) 9.2 15.6 (other ships) Intercept (I) (kg) + Slope (S) (kg/GT.h/1000) I=10;S=14.6 Table 18 Results of data filtering compared with check on SFOC values Filter criteria number percentage SFOC OK SFOC X Deviant 6 30% 17% 83% Not deviant 14 70% 64% 36% 20 Again it can be seen that most of the valid fuel consumption values correspond to plausible SFOC values, whereas most deviant fuel consumption values have SFOC values beyond a reasonable range.

25 4.4.9 Summary Table 19 lists the fuel consumption of all ship types discussed in the preceding sections (4.4.1 to 4.4.8). Table 19 Résumé of results of fuel consumption at berth Ship type EMS This work This work: Regression line Fuel Coefficient Slope Intercept (kg/1000 GT.h) (kg/1000 GT.h) (kg/h) Crude oil tankers 19.3 11.6 16.9 34 Chemical/gas tankers 17.5 14.5 13.8 34 Bulk carriers 2.4 3.1 3.1 7 Container ships 5.0 6.0 4.3 134 GDC/RoRo cargo 5.4 6.1 5.6 18 RoPax ships Mix: 6.9 8.9 7.6 91 Reefers 24.6 19.6 18.8 41 Tug/supply 9.2 Supply: 15.6 14.6 10 As was explained in paragraph 4.4.4 and 4.4.5, the fuel consumption data of crude oil tankers and chemical tankers have to be considered as provisional results.

A better understanding of the fuel usage for these ship categories would be desirable. In addition, the fuel consumption of RoPax ships deserves more attention in the near future. Other categories of passenger ships that have not been included in this study include cruise ships and cruise ferries. This omission was due to the fact that the study was undertaken outside the regular cruise ship season. Since the energy consumption of cruise ships is expected to be high, their inclusion in future studies is considered a matter of importance.

26 INTERNATIONAL SURVEY OF FUEL CONSUMPTION OF SEAGOING SHIPS AT BERTH 4.5 Fuel distribution over engine types The information that emerged from the questionnaires regarding fuel consumption in boilers was rather limited. For this reason it is not possible to perform detailed analysis of fuel usage in boilers. Table 20 compares the share of fuel used in boilers of this study with the results from the EMS project. Table 20 indicates that the amount of fuel used in boilers seems to be considerably lower than results from the EMS study (Hulskotte et al.,2003). Several non-verified explanations are possible.

One explanation is that ships are no longer allowed to use residual fuel at berth. As a consequence, it is possible that the day tank (filled with ready to use residual fuel) is kept at lower temperatures. This in turn could mean lower fuel usage by the boilers.

Another explanation for tankers is that the tank degassing procedure is performed in the last phase of the berthing procedure, when inert gas is produced. It is possible that the degassing procedures, involving the use of boilers, did not take place during the interviews and were therefore not recorded. These explanations may account for the lower boiler fuel usage percentages with respect to the EMS project (Hulskotte et al.,2003). The results of this project suggest changes for boiler fuel usage at berth, but questions remain as to their applicability. On the other hand the new data do not appear to be completely realistic.

For the emission calculations, a percentage of fuel usage in boilers had to be assumed as actual data seemed to be absent. As a provisional solution, new values that represented a compromise between EMS data (Hulskotte et al.,2003) and the data gathered in this project are proposed. Further dedicated research into tanker fuel usage in boilers will be necessary to provide better data.

Table 20 Share of fuel used in boilers Ship type EMS This work Advice Crude oil tankers 63% 33% 50% Chemical/gas tankers 73% 32% 50% Bulk carriers 36% 10% 10% Container ships 54% 29% 30% GDC/RoRo cargo 33% 11% 10% RoPax ships 32% 0% 30% Reefers 21% 6% 10% Tug/supply 1% 0% 0%

27 In contrast to the EMS data, the results from the questionnaires indicate that main engines are seldom used at berth. Therefore an assumption of zero fuel used by main engines at berth should be adopted when calculating emissions. 4.6 Fuels and sulphur content The information derived from the questionnaires regarding fuel types and sulphur content was generally of high quality, and the analysis of the data was performed on all questionnaire responses as the differences between ship types would probably be random.

For the purposes of this analysis, only complete data from the questionnaires were used, i.e. data where the amount of fuel, the type of fuel and the sulphur content were recorded. Although this limits the amount of available data, it allows for further analysis. Table 21 Count of ships with answers with high and low fuel sulphur percentage Engine type Low S (0.1% S) High S% Main Engine 5 2 29% Aux Engine1 118 14 11% Aux Engine 2 37 10 21% Aux Engine 3 6 7 54% AE-total 161 31 16% Boilers 62 4 6% Table 21 shows that the vast majority of ships follow the European Sulphur directive (Directive 1999/32/EC).

It also shows that larger ships, with more auxiliary engines, seem to use fuels with high sulphur content. Some inconsistencies in the questionnaires were identified with respect to fuel sulphur percentage and fuel types. When MDO (marine diesel oil) was recorded as a fuel type, the sulphur percentage was listed as 0,1 percent or below.

28 INTERNATIONAL SURVEY OF FUEL CONSUMPTION OF SEAGOING SHIPS AT BERTH This could indicate a misunderstanding of the word MDO because the sulphur content of MDO in most cases is more than 0,1 percent. In some other, less frequent, cases when marine gas oil (MGO was recorded it was given a sulphur percentage of 0,5% or more which is improbable. To calculate SO2 emissions the actual sulphur content of fuels must be known. For the purposed of this analysis, it was assumed that the sulphur percentages given in the questionnaires were correct.

Table 22Count of ships with answers with certain fuel types Engine type Low S: High S: High S% MGO;LSMGO IFO;HFO; MDO; RMG380-10 Main Engine 4 3 43% AE1 103 29 22% AE2 33 14 30% AE3 4 9 69% AE-total 140 52 27% Boilers 66 3 4%

29 To keep the emission calculations simple and transparent, it is advisable to assume that 90% of MGO is used with an average sulphur content of 0.1 percent and 10% of HFO with an average sulphur content of 1 percent. The weighted average sulphur content then becomes exactly 0.19%, reflecting the values recorded in the questionnaires. In a recent report (Bloor et al., 2013) it was confirmed that ship compliance with Directive 1999/32/EC is certainly not 100 percent. Furthermore it is advisable to assume that fuel used in all engines/machinery at berth has the same sulphur content.

Table 23 Volume weighted average sulphur content of fuels, % S Engine type Low S (0.1% S) Volume Count weighted based Average Average Main Engine 0.03% 0.98% 0,27% 0,30% AE1 0.09% 0.95% 0,15% 0,18% AE2 0.08% 0.93% 0,28% 0,26% AE3 0.07% 0.96% 0,56% 0,55% AE-total 0.09% 0.95% 0,19% 0,23% Boilers 0.09% 0.95% 0,11% 0,14% Overall volume weighted average 0.19% Groningen Seaports

30 INTERNATIONAL SURVEY OF FUEL CONSUMPTION OF SEAGOING SHIPS AT BERTH 5.1 Activity data and emission factors Based on the fuel consumption data in Table 19, the distribution of fuel usage between engines and boilers in Table 20 and sulphur content in paragraph 4.6, new emission calculations for the port of Rotterdam with the EMS model for ships at berth have been performed. To establish a point of reference calculations were performed on 2008 data, the last year for which data in the correct format were available. Activity data of ships at berth in Rotterdam for the year 2008 are presented in Table 24.

5 Consequences of this research for emissions Table 24 Activity data of ships at berth in Rotterdam in 2008 Ship type Visits GT (average) Total GT Oil tankers (crude) 1668 53563 8,93E+07 Other tankers (chemicals, fruit juices) 5619 9412 5,29E+07 Bulk carriers 1044 53332 5,57E+07 Container ships 7207 28365 2,04E+08 General dry cargo (GDC) 6377 3673 2,34E+07 Ferries / RoRo 4048 31038 1,26E+08 Reefers 266 10271 2,73E+06 Other ships 630 4211 2,65E+06 Source: Statistics Netherlands Table 25 Emission factors for different fuels depending on engine type/machine,(g/kg fuel) Substance MGO/MDO HFO BOILER AE3 ME4 BOILER AE3 ME4 VOC 0,76 2,5 2,7 0,76 2,5 2,7 SO2 21 /202 21 /202 21 /202 20 20 20 NOx 3,5 68 90 4,1 68 90 CO 2 12 13 1,6 12 13 CO2 3173 3173 3173 3173 3173 3173 PM10 0,7 2,1 2,2 1,2 2,5 4,6 1 Marine Gas Oil (MGO), 2 Marine Diesel Oil (MDO), 3 Auxiliary Engine, 4 Main Engine (Emission factors were taken from Oonk et al., 2003.) Emission factors of SO2 and PM10 (Duyzer et al., 2006) were adapted in accordance with the lowered sulphur content of fuels of 0,1 percent sulphur for MGO and 1 percent sulphur for all other fuels (see paragraph 4.6).

31 5.2 Reference emissions Comparing Table 24 with Table 19 highlights some mismatches between ship types. The old category 'Other tankers (chemicals, fruit juices)' is a broader category than 'Chemical/Gas tankers'. The old category 'General dry cargo' is contained in the new category 'GDC/RoRo cargo'”, which now also contains RoRo-cargo ships. The old category 'Ferries/RoRo' contained more than the new category 'RoPax'. The old category 'Other ships'” is similarly much broader than the new category 'Tug/Supply'. Despite these differences in definitions, provisional emission calculations using the data from table 24 have been performed since no activity data are available for the new ship categories.

Table 26 Emissions of ships at berth at Rotterdam based on EMS data (reference), ton/year Ship type CO2 NOx SO2 PM10 VOC CO Oil tankers (crude) 153213 1476 416 75 69 274 Other tankers (chemicals, fruit juices) 70486 476 141 23 27 99 Bulk carriers 22049 313 139 13 13 58 Container ships 68110 716 429 35 33 138 General dry cargo (GDC) 10033 147 46 5 6 27 Ferries / RoRo 66015 981 212 36 40 181 Reefers 6612 122 42 5 5 21 Other ships 3562 82 22 3 3 14 Totals 400080 4314 1447 195 196 812 In Table 26 reference emissions are presented for the EMS ship categories, which have been calculated with existing EMS fuel consumption data, existing EMS fuel distribution data and emission factors presented in Table 25.

5.3 Emissions based on results of this study In Table 27 emissions are presented for the new ship categories with new fuel consumption data and new fuel distribution data. The fuel consumption underlying the results in Table 27 is based on a function with non- zero intercept and slope, and not (as before) by multiplication of GT with the overall fuel coefficient. Explained in formulas: Fuel consumption = [Visits { [ Intercept] + [average GT/1000] * [Slope]} (formula 1), used for Table 27. Fuel consumption = [total GT] * [Fuel Coefficient EMS] (formula 2), used for Table 26.

Since the categories of ship activity data do not completely match the new fuel consumption and new fuel distribution data, the results are provisional and should be used with caution.

32 INTERNATIONAL SURVEY OF FUEL CONSUMPTION OF SEAGOING SHIPS AT BERTH Table 27 Emissions of ships at berth at Rotterdam based on new data (this project), ton/year Ship type CO2 NOx SO2 PM10 VOC CO Crude oil tankers 139170 1572 91 55 71 302 Chemical/Gas tankers 70121 792 41 28 36 152 Bulk carriers 29682 577 36 19 22 104 Container ships 74893 1151 88 41 46 212 GDC/RoRo cargo 19508 379 16 12 14 68 RoPax ships 100759 1548 121 55 62 285 Reefers 6125 119 7 4 4 21 Tug/supply 6573 141 6 4 5 25 Totals 446831 6279 406 217 261 1170 Differences 12% 46% -72% 11% 33% 44% Several reasons exist for the differences in emissions between Table 27 and Table 26.

As CO2 emissions can be considered as a proxy for fuel consumption, the first conclusion from the CO2 emissions is that total fuel consumption has risen by only 12%. Although RoPax ships are responsible for the greatest increase of fuel consumption, this increase is probably not realistic since a large proportion of Ferries/RoRo visits, as presented in Table 24, are more likely to be 'GDC/RoRo cargo' ships. The increase of CO2 emissions in the category 'GDC/RoRo cargo' is mostly due to the use of the non- zero intercept. Very small ships do not produce any emissions according to formula 2, while many small ships can produce significant emissions according to formula 1.

The increase of CO2 emissions in the category 'Tug/Supply' is due to higher fuel consumption, which may not be completely applicable to the corresponding category 'Other ships'. Also using formula 2 instead of formula 1 has probably resulted in the increase values reported.

Differences in NOx emissions have to be compared with differences in CO2 emissions. Although CO2 emissions for some ship categories are lower or almost equal in Table 27 compared to Table 26, some NOx emissions are higher. This applies to 'Crude oil tankers', 'Chemical/Gas tankers' and 'Container ships' and is a result of much more fuel being used by auxiliary engines instead of boilers. Auxiliary engines have much higher NOx, VOC and CO emission factors (see Table 25). The same trends can be observed in VOC and CO emissions.

The dramatic decrease of SO2 emissions is solely due to compliance with the EU regulation (Directive 1999/32/EC), which forbids the use of fuels with a sulphur percentage of more than 0,1 percent at berth.

In the EMS data (Hulskotte et al., 2003) greater amounts of HFO and MDO were found to be used at berth, which explains the much higher SO2 emissions in Table 26 compared to Table 27. The differences in PM10 emissions are a balance between the differences in fuel consumption and the differences in emission factors caused by both the fuel type and the engine/apparatus. Auxiliary engines have higher emission factors than boilers but low sulphur fuels have lower emission factors than high sulphur fuels both in engines and boilers.

33 6 Conclusions and recommendations This new survey completed on behalf of the CNSS project and involving several European ports, has provided an updated and improved assessment of the fuel consumption of ships at berth. The data from the survey has been used to produce a first tentative emissions calculation. Although differences in fuel consumption by individual ship types have been observed, overall the differences in fuel consumption are small. This is reflected in the fact that total CO2 emissions have not changed much. As expected, there has been a profound decrease in SO2 emissions.

Minor quantities of high sulphur fuels were still encountered. Emissions of NOx, calculated from the survey results, are substantially higher because a lower amount of fuel is used in boilers than was previously the case.

The amount of fuel used in tanker boilers (Crude oil tankers and Chemical/Gas tankers) turned out to be quite different to the previous study. Since more data quality issues occurred for these specific data samples, it was assumed that a boiler usage value that lies in between the new data and the existing data. For all other ship types, except RoPax ships, a boiler usage value was derived from the new data. Since there is still scope to improve the data, a dedicated survey of tanker fuel usage is recommended. A new study should focus on the fuel usage in auxiliary engines during the entire stay at port and all activities that require fuel, such as the role and importance of fuel usage in boilers for making inert gas and other processes (pumping and warming) on board.

Other ship categories that lack sufficient fuel consumption data are RoPax ships and Cruise ships. Before embarking on a survey of these ships, a literature research on studies about shore based power supply may provide some insights on their fuel consumption. Although some fuel may still be used in the boilers, this would not be recorded in this type of study.

34 INTERNATIONAL SURVEY OF FUEL CONSUMPTION OF SEAGOING SHIPS AT BERTH Bloor, M., S. Baker, H. Sampson, and K. Dahgren, 2013: Effectiveness of international regulation of pollution controls: the case of the governance of ship emissions.

Duyzer, J., Hollander, K., Voogt, M., Verhagen, H., Westrate, H., Hensen, A., Kraai, A., Kos, G., 2007. Assessment of Emissions of PM and NOx of Seagoing Vessels by Field Measurements. TNO-report 2006-A- R0341/B Hulskotte, J. H. J., H. A. C. Denier van der Gon, 2010: Fuel consumption and associated emissions from seagoing ships at berth derived from an on-board survey. Atmos.Environ., 44, 1229-1236. 7 References

35 Hulskotte, J., Bolt, E., Broekhuizen, D., November 2003. EMS-Protocol Combustion Emissions by Seagoing Ships at Berth (in Dutch). Ministry of traffic and transport Oonk, H., Hulskotte, J., Koch, R., Kuipers, G., Ling van, J., 2003. Emission Factors of Seagoing Ships on the Purpose of Yearly Emission Calculation (in Dutch). TNO-report R 2003/438 version 2 Port of Antwerp

36 SURVEY OF FUEL CONSUMPTION OF SEAGOING TANKERS AT BERTH IN ROTTERDAM Summary This report presents the results of an extensive survey of seagoing tanker fuel consumption and associated emissions in the Port of Rotterdam in July 2013.

The study follows on from an earlier survey by Hulskotte et al., 2013, which indicated that data on seagoing tankers were inconsistent. The chief engineers of twenty seagoing tankers were interviewed on board by an experienced ships inspector who questioned the engineers regarding fuel consumption by the tanker’s equipment during unloading or loading and during hotelling. Due the excellent cooperation received from the crew, a survey response of 100 percent was attained.

The responses were initially recorded on paper questionnaires and subsequently transferred to MS Excel® format by the interviewer within one week of the interview. Together with specific data about fuel consumption, the details of each ship were requested and received in all cases. Both sets of data, the questionnaire responses and ship details, were initially checked and corrections made where necessary. Subsequent analysis of the data resulted in renewed recommendations for the calculation of tankers hourly fuel consumption rates.

The consequences of the fuel consumption recommendations for crude oil tanker emissions in the Port of Rotterdam were calculated and compared with published results.

Finally conclusions about the application of the results of this survey were added. Compiled by: ir. J.H.J. Hulskotte, TNO and dr. V. Matthias, HZG. Survey of fuel consumption of seagoing tankers at berth in Rotterdam

37 1 Introduction 39 2 Preparation 39 3 Data collection and validation 40 3.1 Data collection 40 4 Analysis of fuel consumption at berth 41 4.1 Hourly fuel consumption as a measure of emissions 41 4.2 Data validation 41 4.3 Calculation of hourly fuel consumption 43 4.4 Unweighted fuel consumption per type of equipment 44 4.5 Recommendations for the calculation of hourly fuel consumption 49 5 Emissions from tankers in the port of Rotterdam 50 5.1 Activity data and emission factors 51 5.2 Conclusions and recommendations 52 6 References 53 Appendix Inertgas Systems 54 Contents

38 SURVEY OF FUEL CONSUMPTION OF SEAGOING TANKERS AT BERTH IN ROTTERDAM We gratefully acknowledge the kind cooperation of the Port of Rotterdam.

In particular, the assistance of Martin Pastijn (wachtchef inspectie) was indispensible in the preparation of this project. Inspector Leen de Korte was able to elicit more information than expected due to his easy going but persistent and unflappable character. Acknowledgements Inspector Leen de Korte ready to visit one of the tankers

39 1 Introduction Ports suffer from air pollution not only as a result of ships arriving and departing but also as a result of emissions produced by ships during their time at berth. A thorough assessment of ship emissions at berth is a crucial first step to understanding the impact of those emissions on air quality and public health in harbour cities. In addition, the impact of abatement measures such as shore-side electricity and/or restrictions in sulphur content for shipping fuel to be used in ports must also be understood.

In 2012 a survey of energy consumption and fuel use on board 175 seagoing ships was undertaken by the Clean North Sea Shipping (CNSS) project.

This built on work previously undertaken in 2003 (Hulskotte and Denier van der Gon, 2010). The project involved close cooperation with the Ports of Hamburg and Bremerhaven, the Port of Antwerp, the Port of Rotterdam and the Port of Bergen. The results of this survey were subsequently presented in a report (Hulskotte et al., 2013). One of the conclusions in the report noted that the information gathered for tankers was at odds with data that had been collected previously, and no credible explanation was provided to explain the discrepancies. The report recommended conducting an additional survey on tanker fuel consumption.

This report contains the results of the second survey, undertaken in July 2013 by a ships inspector employed by the Port of Rotterdam, on 20 seagoing tankers. Some sections of the questionnaire used in the 2012 survey (Hulskotte et al., 2013) were modified with the berth phase split into two phases— unloading/loading and preparation for unloading/loading/leaving. In addition, the questions about the usage of oil-fired boilers were clarified and new questions regarding inert gas generators were added. A copy of the each ship's technical specification was also requested; this was provided by all ships involved in the survey.

2 Preparation Before starting the survey the contents of the questionnaire were discussed with a colleague of the ships inspector who would be conducting the interviews. During this discussion the technical procedures of unloading and loading of tankers were reviewed, with special attention paid to the usage of steam driven cargo pumps, the production of inert gas by oil-fired boilers and inert gas generators and the crude oil washing (COW) procedures. Concerns were raised about the inert gas status and overpressure in the cargo rooms being maintained in all circumstances to avoid any explosion risk.

As a result of this discussion, the questionnaire was adapted for usage on tankers.

As a final validation, the first author of this report visited two tankers to assess the suitability of the questionnaire. In addition, an extract from a technical specification for inert gas systems was provided (Appendix A), detailing the process of inert gas production and application in tankers.

3 Data collection and validation 40 SURVEY OF FUEL CONSUMPTION OF SEAGOING TANKERS AT BERTH IN ROTTERDAM 3.1 Data collection Twenty tankers at berth in the harbour at the Port of Rotterdam (14 crude oil tankers and 6 oil products/chemical tankers) were visited in the second week of July 2013 by an experienced ships inspector employed by the Port of Rotterdam.

During each visit, the purpose of the survey was explained to the captain and a formal request for cooperation was made to the captain and the chief engineer. In addition a letter written by TNO was given to each captain, which provided reassurances that any information provided would be treated confidentially and no data identifying individual ships would be reported.

On board the responses to the questionnaires were initially captured on paper and within one week after the completion of the survey, the data for each ship were transferred to MS-Excel® datasheets. In addition, a paper version of the ship's technical specification was requested; specifications for all 20 tankers were received. Table 1 provides an overview of the survey, documenting the ship types and volumes, the cargo and the laytime at berth. The information provided shows that dedicated crude oil tankers can generally accommodate more volume than oil products and oil/chemical tankers. Table 1 also suggests that there are, at least in some cases, no fundamental restrictions to transporting crude oil in an oil/chemical tanker and vice versa (a dedicated crude oil tanker can transport an oil product like kerosene).

Table 1 Overview of ship types, cargo, ships volumes and time at berth in the survey Shiptype*) Cargo Grosstonnage#) Time at berth (hours) CRUDE OIL TANKER Ligt Crude 56200 24 CRUDE OIL TANKER Fuel Oil 57100 16 CRUDE OIL TANKER Crude Oil 57100 26 CRUDE OIL TANKER Crude oil 58100 14 CRUDE OIL TANKER Crude Oil 59600 26 CRUDE OIL TANKER Crude Oil 61300 36 CRUDE OIL TANKER Kerosene 61700 48 CRUDE OIL TANKER Crude oil 62300 10 CRUDE OIL TANKER Fuel 62400 26 CRUDE OIL TANKER Fuel oil 62800 60 CRUDE OIL TANKER Russian Blend 63500 28 CRUDE OIL TANKER Crude 83800 38 CRUDE OIL TANKER Fuel Oil 110400 36 CRUDE OIL TANKER Fuel Oil 160300 200+) OIL PRODUCTS TANKER Crude Oil 26900 24 OIL PRODUCTS TANKER Fuel Oil 43100 30 OIL/CHEMICAL TANKER Crude Oil 13800 22 OIL/CHEMICAL TANKER Nafta 21300 26 OIL/CHEMICAL TANKER Fuel Oil 23200 28 OIL/CHEMICAL TANKER Gasoil 42000 24 Average 59300 29 *) Ship type as indicated in Maritime Connector #) Gross tonnage rounded on hundreds +) Considered as outlier and disregarded in average

41 4 Analysis of fuel consumption at berth 4.1 Hourly fuel consumption as a measure of emissions The most generally applicable measure for estimating ship emissions at berth is probably the hourly fuel consumption rate. A measure of energy consumption may be less applicable when specific fuel consumption has been shown to vary considerably. Also the time spent at berth may vary widely between ships and harbours (Palsson et al., 2008). As a result, the hourly fuel consumption was initially chosen to be the central focus of the analysis. The fuel consumption of the boilers and inert gas generators in a tanker is directly related to unloading and loading cargo.

A tanker may remain at berth longer for various reasons after completing unloading or loading. For this reason, the current survey split the residence time at berth into two phases (in contrast to previous surveys): I. Unloading and loading time II. Time before actual unloading or loading takes place and the time after finishing unloading or loading before departure 4.2 Data validation 4.2.1 Auxiliary engines Prior to starting the analysis, some data validation checks were performed. With respect to the fuel consumption of the auxiliary engines, these checks focused on the specific fuel oil consumption (SFOC).

SFOC is calculated as the hourly fuel consumption rate divided by the actual used power. As at least two components are involved in calculating the SFOC, both must be correct if the results are to be reliable. The checks revealed that only 7 out of 20 questionnaires reported plausible SFOC values between 0,18 and 0,3 kg/kWh.

The questionnaire asked what the actual used power was. Independent checks on the responses were possible in most cases by inspecting the ship's specification, which listed the power and number of individual auxiliary engines. By combining the estimated load factor, also collected in the questionnaire, with the maximum power of the auxiliary engine, the actual used power value collected in the questionnaire could be verified. In 7 of 20 cases the actual used power number given in response to the questionnaire seemed to be the total power of one auxiliary engine. By combining of total power and the load factors of the auxiliary engines, actual used power could be recalculated for these seven cases.

As a result of this recalculation, the SFOC values reported in another six questionnaires were subsequently considered plausible.

Checks on fuel consumption reported in the questionnaires were less straightforward to validate but in some cases mistakes were easily identified and corrected. Two types of recalculations were applied: a. If different load factors were given for the two phases but the reported fuel consumption for both phases was equal, the unreliable fuel consumption was adapted linearly with the load factor (3 cases); b. In two cases the reported fuel consumption was divided by the number of auxiliary engines and in one case the total fuel consumption of all auxiliary engines was noted for each individual auxiliary engine.

In these three cases fuel consumption data were corrected. The changes in fuel consumption of these six cases resulted in another six questionnaires reporting plausible SFOC-values.

For one ship the actual used power did not match with total power of the auxiliary engines noted in the ship specification and the load factor reported in the questionnaire. In this case the actual power was recalculated with the total power reported in the specification.

42 SURVEY OF FUEL CONSUMPTION OF SEAGOING TANKERS AT BERTH IN ROTTERDAM Table 2 documents the average load factor and the average specific fuel oil consumption of the auxiliary engines. This is based on the corrected data from the questionnaires. In all cases one auxiliary engine was running while cargo was unloaded or loaded, in 19 cases two auxiliary engines were running and in two cases three auxiliary engines were running.

For two cases the load factors were not reported in the survey. Table 2 Load factor and specific fuel oil consumption (SFOC) of auxiliary engines (corrected data) Data Item Load factor SFOC SFOC SFOC (kg/kWh) (kg/kWh) (kg/kWh) Aux 1,2 Aux1 Aux2 Aux3 Average 60% 0.221 0.227 0.302 Std.dev. 7% 0.029 0.045 0.030 Number 18 20 19 2 Table 3 Calculation of fuel oil consumption of oil-fired boilers when data were lacking Calculation of oil consumption Phase I Phase II No (data directly used) 16 12 Yes 4 3 It can be concluded from these results that both the load factors and the specific fuel oil consumption data are within an acceptable range.

The standard deviation of the SFOC values is relatively low compared to the average SFOC values; this indicates that the spread in the data is rather low. 4.2.2 Oil-fired boilers and inert gas generators The validation of fuel usage by oil-fired boilers and inert gas generators was problematic because activity data requested in the questionnaire were not reported. It also seems that there was a lack of understanding as to what was meant by the activity rate. For example, steam production in tons/hour for oil-fired boilers was requested. From some of the responses received it seemed that cargo pumped in tons/hour was provided instead.

In one case the amount of inert gas produced (m3 /hour) was quoted. The misunderstandings as to what was requested may be attributable to the diverse nationalities of the crews and the questionnaire being written in English.

In some cases the fuel consumption of oil-fired boilers has been calculated with data taken from other marine boilers where that information was lacking in the questionnaire responses. Steam production could be inferred from the ships specifications and the load factor reported in the questionnaire (see Table 3).

43 Table 4 confirms that during phase I (unloading and loading) more fuel is needed by the boilers than during phase II (arriving or leaving). 4.3 Calculation of hourly fuel consumption In this survey the residence time at berth was split into two phases (in contrast to previous surveys): I.

Unloading and loading time II. Time before actual unloading or loading takes place and the time after completing unloading or loading before departure From the answers reported in the questionnaire, a clear distinction could be made with respect to the level of fuel consumption in both phases. However the precise timing of phase II could not be accurately determined by the chief engineers. As a general rule it was reported that phase II takes about one hour before actual unloading or loading starts and about one hour to leave after unloading or loading.

This implies that the time to complete phase I is estimated to be total time at berth minus two hours and that phase II in all cases is estimated to be two hours. In addition to other items in the questionnaire, the following data about the usage of equipment (Eqx) at berth were collected. Running hours [Eqx_activeatberth_hours] Fuel rate [Eqx_fuelatberth_kgperhour] Actual power [Eqx_poweratberth] Measure of actual power [Eqx_unitpower_berth] Estimated load factor [Eqx_LF_berth] Total hours at berth [Total_time_at_berth_hours] Ships gross tonnage [Grosstonnage_GT] Cargo unloaded/loaded [Cargo_Volume] Table 4 Load factors of oil-fired boilers in during phase I and phase II, % Data item Phase I Phase II 50% 31% Std.dev.

20% 17% Number 16 11 In the calculation of fuel oil consumption it was assumed that for the production of 1 ton of steam 75 kg of fuel is needed. The thermal efficiency of the marine boilers is in the order of approximately 80 %. This number was taken from the specifications for the Mitsubishi MAC-series of marine boilers (Mitsubishi, 2007). In one case the oil consumption of phase II was downscaled linearly with the ratio of the amount of steam produced in phase II and phase I. Although the steam production of oil-fired boilers data were often lacking, the load factors were reported in most cases (see Table 4).

44 SURVEY OF FUEL CONSUMPTION OF SEAGOING TANKERS AT BERTH IN ROTTERDAM The Eqx information above were collected for auxiliary engines (maximum three), oil-fired boilers and inert gas generators (when applicable). The results of the survey were presented in three formats: 1. Unweighted fuel consumption per type of equipment 2. Time weighted fuel consumption per type of equipment 3. Linear regression of fuel consumption against ships volumes (expressed as GT) 4.4 Unweighted fuel consumption per type of equipment Unweighted fuel consumption per type of equipment was calculated by adding all the hourly fuel rates per type of equipment and dividing those totals by the sum of ships gross tonnage divided by 1000.

formula [1]: ∑ ([Eqx_fuelatberth_kgperhour [ Grosstonnage_GT]/1000) To calculate the total fuel rate, the fuel rate of the two phases (I and II) was weighted by time.

formula [2]: [Eqx_fuelatberth_kgperhour] = ([Eqx_fuelatberth_kgperhour]phase I * (average([[Total_time_at_berth_hours])-2 )+ 2 * [Eqx_fuelatberth_kgperhour]phase II )/ average([[Total_time_at_berth_hours]) The results of the survey as expressed in formula [1] and [2] are given in Table 5. Table 5 Unweighted fuel consumption per type of equipment Equipment Fuel Consumption (kg/GT*1000.hours) Share Auxiliary engines 4.3 18% Oil-fired boilers 15.8 79% Inert gas generators 0.7 3% Total 20.8 Table 5 illustrates the large contribution oil-fired boilers make to a tanker's fuel usage. The number of inert gas generators in the types of tankers that were surveyed was very low.

4.4.1 Time weighted fuel consumption per type of equipment Time weighted fuel consumption per type of equipment was calculated by taking the sum of hourly fuel rates multiplied by total hours at berth (estimation of total fuel usage). This total was divided by the sum of ships gross tonnage multiplied by each ships total hours at berth divided by 1000. formula [3]: ∑ ([Eqx_fuelatberth_kgperhour] phase I * ([Total_time_at_berth_hours]-2) + 2* Eqx_fuelatberth_kgperhour] phaseII ( [Grosstonnage_GT]* [Total_time_at_berth_hours]) /1000) The results of the survey as expressed in formula [3] are given in Table 6

45 Table 6 Weighted fuel consumption per type of equipment Equipment Fuel Consumption (kg/GT*1000.hours) Share Auxiliary engines 4.3 20% Oil fired boilers 16.1 77% Inert gas generators 0.7 3% Total 21.1 4.4.2 Linear regression of fuel consumption against ships volumes Time weighted fuel consumption per type of equipment was plotted against the individual ship volumes (expressed as GT). Time weighted fuel consumption per type of equipment was calculated as: formula [4]: [Eqx_fuelatberth_kgperhour] phase I * ([Total_time_at_berth_hours]-2) + 2* Eqx_fuelatberth_kgperhour] phaseII The fuel usage of auxiliary engines during phase I and phase II plotted against ships volumes is shown in Figure 1.

. Figure 1 Fuel usage of auxiliary engines of tankers plotted against ships volumes Figure 1 does not show a strong relationship between fuel usage by auxiliary engines and ships volumes expressed in GT. Possible explanations for this may be the considerable spread in the data and most of the tankers were of a similar volume. The spread in the data are probably due to the differences in the power of the auxiliary engines that are installed on tankers with similar gross tonnage. This can be inferred from the data in Table 2, which indicates that the load factors are quite constant as is the value of the SFOC.

46 SURVEY OF FUEL CONSUMPTION OF SEAGOING TANKERS AT BERTH IN ROTTERDAM Figure 2 does not indicate any significant relationship between the fuel usage of oil-fired boilers and inert gas generators and ships volumes expressed as GT. Nevertheless a regression line through zero was drawn because it is anticipated that the amount of fuel used by oil-fired boilers is related to the amount of fuel pumped. Similarly, a relationship between the fuel used in boilers and ships volume is expected. The two data samples for ships with 160 and 115 thousand GT show a low fuel usage compared to the GT number.

The 160 thousand GT ship had to unload 300 thousand MT of crude oil. Assuming that formula 5 (see paragraph 4.4.3) is applicable, a fuel usage of 1500 kg/hour (Figure 2) corresponds with a discharge rate 1500/0.3= 5000 m3 /hour. This suggests that the ship could have been unloaded within 60 hours. In the questionnaire it was reported that the ship planned to remain at berth for 200 hours, so it would appear that the data for this ship are plausible.

The 115 thousand GT ship had to unload 283 thousand MT of crude oil within 36 hours. Assuming that formula 5 (paragraph 4.4.3) is applicable, a fuel usage of 283000/36*0.3 = 2358 kg/hour was expected. Figure 2 indicates that the ship only used 1000 kg/hour. This implies that during unloading of this ship the number of air changes was limited to approximately two (1000/2358*4 =1.7). It is unclear whether the response in the questionnaire was correct as the ship has more boilers. Perhaps the response represents the fuel usage of only one boiler. 4.4.3 Test of alternatives for activity data Test 1 To check the relationship between the amount of cargo that is pumped (pumping rate) and the fuel usage of oil-fired boilers and inert gas generators, an extra graph was prepared (Figure 3).

The amount of fuel needed for inert gas production was estimated by using the pumping rate as the input variable. Figure 2 Fuel usage of oil-fired boilers and inert gas generators of tankers plotted against ships volumes The fuel usage of oil-fired boilers and inert gas generators during phase I and phase II is displayed in Figure 2.

47 Formula [5]: [FC] = [PR] * [AC [ F1C] Whereby: [FC] = Estimated amount of fuel for inert gas production (kg/hour) [PR] = Pumping rate (m3 /hour) [AC] = Air changes (dimensionless) = 4 [F1C] = Amount of fuel to produce 1 m3 of inert gas = 0.075 (kg) The number of air changes (four) was taken from Annex A (US Navy, 1991), which mentions a value between 3 and 5. The amount of fuel to produce 1 m3 of inert gas was taken from (Hamworthy ND); a fuel usage 0.075 kg fuel/nm3 inert gas is indicated. In Figure 3 three out of the 20 data samples were excluded because these data were considered as outliers.

Although a relationship between the energy used for pumping in oil-fired boilers and the actual physical pumping rate could be expected, the survey results suggest this relationship is weak. Although there are a number of factors that could explain this weak relationship, two specific aspects are considered. Firstly, the number of air changes may vary between 3 and 5 according the reference used (US Navy, 1991). This may have influenced the amount of inert gas that was produced. The second aspect is the back pressure of cargo from the tanks. This may vary considerably due to differences in the levels of oil in the tanks, differences in length of pipelines to the storage tanks and differences in the viscosities of the cargo to be pumped.

This may have influenced the amount of steam that had to be produced by the oil- fired boilers to operate the steam driven pumps. Figure 3 Comparison between calculated amount of fuel for inert gas production and observed fuel consumption in oil-fired boilers (OFB) and inert gas generators (IGG)

48 SURVEY OF FUEL CONSUMPTION OF SEAGOING TANKERS AT BERTH IN ROTTERDAM Test 2 A test was performed to check whether the installed boiler capacity could be used as an alternative for GT in estimating boilers fuel consumption. Of the 20 tankers surveyed, the total boiler capacity was only available for nine tankers. However for three of those nine tankers, the boilers fuel consumption had already been estimated by the installed boiler capacity. This implied that the relationship between boiler capacity and boiler fuel consumption could only be independently tested for six tankers. The result of this test is presented in Figure 4.

Figure 4 Calculated versus observed boiler fuel consumption The fuel consumption of boilers was estimated by taking 30% of the total boiler capacity (expressed as ton steam/hour) and multiplying this figure by 75 kg fuel/ton steam. The rather high value of the correlation coefficient in Figure 4 suggests that the estimation of boiler fuel consumption based on boiler capacity could be a good alternative. However, as the number of values that have been compared is limited, this method of estimating fuel consumption requires further investigation.

.

49 4.5 Recommendations for the calculation of hourly fuel consumption The number of ships and the value of the gross tonnage of the ships in emission inventories will probably remain the most practical input values for the calculating fuel consumption and emissions. 4.5.1 Auxiliary engines No strong relationship was observed in this survey between the gross tonnage and the fuel consumption of auxiliary engines. Nevertheless a weak relationship is discernible in Figure 1. It should also be noted that the survey reported on tankers with similar gross tonnage values, which possibly prevented the illustration of such as relationship.

According to Figure 1 the hourly fuel oil consumption of tanker auxiliary engines can probably be calculated most accurately using a formula which includes intercept and a slope: [FC] = 140 + 1.8 * [GT]/1000 Whereby: [FC] = hourly fuel consumption, (kg/hour) 140 = Intercept (hourly fuel consumption irrespective of GT), (kg/hour) 1.8 = Slope (hourly fuel consumption dependent on GT), (kg/hour) [GT] = Value of (average) gross tonnage 4.5.2 Oil-fired boilers and inert gas generators No relationship was observed in this survey between gross tonnage and the fuel consumption of oil-fired boilers and inert gas generators.

However, a relationship is assumed between the energy used for pumping by oil-fired boilers and the amount of cargo that is physically pumped. Probably the most accurate value is reported in Table 6, which lists a value of 16.8 kg/GT*1000/hour.

4.5.3 Alternative for auxiliary engines To estimate the hourly fuel consumption, assuming the specific details about auxiliary engines are known, a load factor of 60% for the first two engines combined with a specific oil consumption of 0.22 kg/kWh can be assumed. 4.5.4 Alternatives for oil-fired boilers and inert gas generators a. Based on pumping rate To estimate the hourly fuel consumption, assuming the pumping rate of a tanker is known, according to formula [5] the pumping rate (m3 /hour) can be multiplied with 0.3 kg/m3 .

b. Based on steam capacity of oil fired boilers To estimate the hourly fuel consumption, assuming the total steam capacity of the oil-fired boilers is known, 30 percent of the total steam capacity (ton/hour) can be multiplied with 75 kg fuel/ton steam.

50 SURVEY OF FUEL CONSUMPTION OF SEAGOING TANKERS AT BERTH IN ROTTERDAM 5.1 Activity data and emission factors Based on the recommendation for the calculation of fuel consumption in paragraph 4.5, new emission calculations for the port of Rotterdam for ships at berth have been performed. The results of the reference calculation were based on data collected in 2008; this was the last year for which data were directly available. Data for ships at berth in Rotterdam during 2008 are presented in Table 7. 5 Emissions from tankers in the port of Rotterdam Table 7 Activity data of ships at berth in Rotterdam in 2008 Ship type Visits GT (average) Total GT Oil tankers (crude) 1668 53563 8.93E+07 Source: Statistics Netherlands Table 8 Fuel consumption of oil tankers at berth in Rotterdam in 2008, kg MGO HFO Total Auxiliary engines 1,03E+07 1,14E+06 1,14E+07 OFB+IGG 3,92E+07 4,35E+06 4,35E+07 Total 4,95E+07 5,50E+06 5,50E+07 Emission factors were taken from Oonk et al.

(2003). Emission factors of SO2 and PM10 (Duyzer et al., 2006) were adapted in accordance with the lowered sulphur content of fuels of 0.1 percent sulphur for MGO and 1 percent sulphur for all other fuels (Hulskotte et al., 2013).

In the report prepared by Hulskotte et al. (2013), it was advised to assume that 90% of MGO used has an average sulphur content of 0.1 percent and 10% of HFO has an average sulphur content of 1 percent. By combining data from Table 7 with the recommendations for fuel consumption, new annual fuel consumption data for tankers are produced (Table 8). Fuel consumption as presented in Table 8 can be combined with emission factors in Table 9 to calculate emissions. One complicating factor to be considered is that emissions from oil-fired boilers and inert gas generators are passed through a scrubber to remove most of the acid components of exhaust gases (see appendix A, US navy, 1991).

Moreover, part of the inert gas that is generated will not be emitted because it must remain in the cargo tanks to maintain the inert status.

51 Assuming a cargo density of 0.9 ton/m3 and 13,3 m3 of inert gas produced per kg of fuel used in oil-fired boilers and inert gas generators (fuel usage 0.075 kg fuel/nm3 inert gas, Hamworthy ND), it could be calculated that 3.5 m3 of inert gas per m3 of cargo room was produced on average for the 20 tankers in the survey. This number (3.5) is very close to the number of 4 air changes that was proposed in paragraph 4.4.3. With a water pressure of 200 mm to be maintained in the cargo rooms, about (4 - 1.2) / 4*100 = 70 percent of the inert gas will be emitted to the atmosphere. It has been assumed that ultimately all CO2 produced will be emitted to the atmosphere.

As in the EMS-protocol (Hulskotte et al., 2003) for the scrubbers, removal efficiencies of 90% for SO2 and 50% for PM10 have been assumed. Emissions presented in Table 10 are calculated by using Table 8 and Table 9 in combination with the assumptions outlined above.

Table 9 Emission factors for different fuels depending on engine type/machine,(g/kg fuel) Substance MGO1 HFO2 Boiler Auxiliary Engine Boiler Auxiliary Engine VOC 0.76 2.5 0.76 2.5 SO2 2 2 20 20 NOx 3.5 68 4.1 68 CO 2 12 1,6 12 CO2 3173 3173 3173 3173 PM10 0.7 2.1 1.2 2.5 1 Marine Gas Oil (MGO); 2 Heavy Fuel Oil (HFO); Table 10 Emissions of oil tankers at berth in Rotterdam in 2008, ton Substance Auxiliary engines OFB+IGG Total Total 2008 2005 MGO HFO MGO HFO (this work) (Hulskotte et al., 2010) VOC 26 3 21 2 52 67 SO2 21 2 5 6 34 1023 NOx 700 78 96 12 886 1372 CO 124 14 55 5 197 255 CO2 32657 3629 124303 13811 174400 142410 PM10 22 2 10 2 35 97

52 SURVEY OF FUEL CONSUMPTION OF SEAGOING TANKERS AT BERTH IN ROTTERDAM The emission totals based on 2008 data (Table 10) can be compared with the results of the published study based on 2005 data (Hulskotte et al., 2010). There is negligible difference in the activity rates between 2005 and 2008. Emissions of VOC and CO are somewhat lower primarily due to the increased amount of boiler fuel and the new assumption about retention of inert gas in the cargo tanks. With respect to air quality, one of the most important substances is NOx. The main difference in emissions of NOx is partly due to the fuel that is used by auxiliary engines.

According to the last survey 21 percent of fuel used by tankers at berth was used by auxiliary engines as opposed to 37 percent of fuel used by auxiliary engines mentioned in the EMS-protocol (Hulskotte et al., 2003). However, this picture is somewhat distorted in part due to the fact that the total tanker fuel usage at berth reported in this survey is about 20 percent higher, resulting in 20 percent higher CO2 emissions.

In absolute terms fuel used by auxiliary engines reported in this survey is about 30 percent lower compared to the EMS-protocol. The emissions of SO2 are lower because bunker fuels have a maximum sulphur content of 0.1 percent (from 1 January 2010). Emissions of PM10 are lower due to the lower amount of fuel used in auxiliary engines and the lower sulphur content of bunker fuels. 5.2 Conclusions and recommendations Twenty tankers have been surveyed to quantity their fuel consumption in auxiliary engines, boilers and inert gas generators. This report has identified new relationships between the size of the tankers (in GT) and their fuel use per hour of operation.

The data presented here supersedes the data collected by Hulskotte et al., 2013 for tankers. The general recommendation for the calculation of fuel usage from the current survey will provide more accurate results for the preparation of emission inventories.

When detailed data about the auxiliary engines and boilers of individual ships is available, the load factors observed in this survey can be used to calculate fuel usage instead of relying on the gross tonnage of tankers as an activity rate. The pumping rate of tankers may also be used as an alternative to fuel consumption for inert gas production. However, a comparison of alternative methods with the methods proposed in this report is advisable. Groningen Seaports

53 6 References Duyzer, J., Hollander, K., Voogt, M., Verhagen, H., Westrate, H., Hensen, A., Kraai, A., Kos, G., 2007.

Assessment of Emissions of PM and NOx of Seagoing Vessels by Field Measurements. TNO-report 2006-A- R0341/B US Navy, Ship Salvage Manual volume 5 (Pol offloading), 31 January 1991 Hamworthy, Specifications of MOSS Mult-Inert System, HMO 4004 0411/3, ND Hulskotte J.H.J., B. Wester, A.M. Snijder, V. Matthias, International survey of fuel consumption of seagoing ships at berth, TNO 2013 R10472 (Final draft), 12 March 2013 Hulskotte, J. H. J., H. A. C. Denier van der Gon, 2010: Fuel consumption and associated emissions from seagoing ships at berth derived from an on-board survey. Atmos.Environ., 44, 1229-1236.

Hulskotte, J., Bolt, E., Broekhuizen, D., November 2003. EMS-Protocol Combustion Emissions by Seagoing Ships at Berth (in Dutch). Ministry of traffic and transport Mitsubishi Heavy Industries, Specification of MAC-**B series, 2007 Oonk, H., Hulskotte, J., Koch, R., Kuipers, G., Ling van, J., 2003. Emission Factors of Seagoing Ships on the Purpose of Yearly Emission Calculation (in Dutch). TNO-report R 2003/438 version 2 Palsson, C., Bengtsson, N., 2008. OPTIMAR: Benchmarking Strategic Options for European Shipping and for the European Maritime Transport System in the Horizon 2008-2018. Final report, Lloyd's Register/Fairplay Research, Vastra Frolundalondon, Sweden, p.

286.

54 SURVEY OF FUEL CONSUMPTION OF SEAGOING TANKERS AT BERTH IN ROTTERDAM Appendix Inert gas systems

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INTERNATIONAL SURVEY OF FUEL CONSUMPTION OF SEAGOING SHIPS AT BERTH LEAD BENEFICIARY CNSS: Competitive Marine Transport Services and Reduction of Emissions – a North Sea Model www.cnss.no

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