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
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
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
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
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
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
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
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
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
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