Tabell 1.1 viser de ny anbefalte NOx faktorene for den norske innenriksflåten hvor også referanseverdier fra 2006 er inkudert.

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3 2 TABLE OF CONTENTS 1. Norsk sammendrag Summary and conclusions Introduction and background Previous studies and data sources Methodology Data source Data filtering NOx weighting factor versus operation profile NOx factors before and after year NOx factor based on measurement data NOx-factors from EIAPP certificates Recommended emission factors from Comparison with other data sources NOx emission factors by engine age Slow speed Medium speed High speed Ship segment emission factors NOx reduction measures References...23

4 3 1. Norsk sammendrag Denne rapporten gir en oppsummering av tilgjengelig data for etablering av NOx faktor for den norske innenriksflåten. NOx faktorene er oppdatert i forhold til tidligere studier og baserer seg på ombordmålinger av NOx utslipp fra skip som rapporter til NOx fondet. I tillegg til data fra NOx fondet er det blitt brukt NOx faktorer fra EIAPP sertifikater for motorer bygget etter år. Følgende motorkategorier er blitt brukt: Slow speed motorer: rpm <200 Medium speed motorer: 200 rpm < 1000 High speed motorer: 1000 rpm Data har blitt filtrert etter følgende kriterier: 1. NOx verdier lavere enn 40% og høyere enn 140% av NOx faktorene anbefalt i MARINTEK 2006 rapporten er utelatt. 2. NOx fonds databasen mangler byggeår for motor. Byggeår for skipet er brukt som tilnærming for motoralder. 3. Kun data fra skip uten motormodifikasjon eller NOx reduserende tiltak er benyttet for å etablere NOx faktorene. Tabell 1.1 viser de ny anbefalte NOx faktorene for den norske innenriksflåten hvor også referanseverdier fra 2006 er inkudert. Table 1.1 Anbefalte NOx faktorer basert på ombordmålinger av NOx utslipp fra 2009 og referanseverdier fra 2006 NOx-faktor 2009 Kilde: NOx fond, EIAPP sertifikater Motor byggeår NOx faktor: [kg NOx/tonn fuel] Før Etter Slow speed NOx-faktor Antall motorer Stdev 7,94 11,02 Medium speed NOx-faktor Antall motorer Stdev 8,49 6,61 High speed NOx-faktor Antall motorer Stdev 5,73 6,20 MARINTEK, 2006, referanse

5 4 Konklusjon Nye NOx faktorene er etablert og er 10 til 15 % lavere enn det som er presentert i tidligere studier, (MARINTEK, 2006) 2. Summary and conclusions This report summarizes latest available data on NOx factors for Norwegian domestic ships. The NOx factor is updated from previous studies based on onboard measurement reported to the Norwegian NOx fund. In addition NOx factors from EIAPP certificates for engines with building year later than year is presented. The following engine categories are used: Slow speed engine: rpm <200 Medium speed engine: 200 rpm < 1000 High speed engine: 1000 rpm Recommended NOx factors for use in Norwegian marine domestic NOx account calculations from 2009 are: Table 2.1 Recommended NOx emission factors for Norwegian domestic ships, update from 2009 and reference values from NOx factor, 2009 Source: NOx fund, EIAPP certificates Engine building year NOx factor: [kg NOx/tonne fuel] Before After Slow speed engine NOx-factor 78 Number of engines 1057 Stdev 11,02 Medium speed engine NOx-factor 53 Number of engines 114 Stdev 6,61 High speed engine NOx-factor Number of engines Stdev 5, MARINTEK, 2006, reference Conclusion The new NOx emission factors have been established, and are found to be 10 to 15 % lower than the previous factors.

6 5 3. Introduction and background MARINTEK estimated the NOx emission factors from ship engines in the domestic Norwegian fleet in 2006 /1/. These factors were used by Statistics Norway to estimate the NOx emissions from the Norwegian domestic fleet. Norwegian Pollution Control Authority has asked MARINTEK to review and update these factors for ship engines in operation in the period 2006 using available data based on onboard measurement from ships and certificate data from engines produced after. Based on the available data MARINTEK was also asked to investigate the change in NOx factor with engine age, and also to present typical NOx emission factors for engine which have implemented NOx reduction measures as engine modification, SCR or natural gas as fuel. These can be found in chapter 10. This report presents the updated NOx factors for the Norwegian domestic fleet based on measurement data from the NOx fund. 4. Previous studies and data sources In a previous study in 2006, MARINTEK estimated NOx factors based on available sources. Results are shown in Table 4.1. Table 4.1 Recommended NOx emission factors for Norwegian domestic fleet, (MARINTEK 2006 /1/) Engine category Slow Speed < 200 rpm Medium Speed rpm Emission factor kg NOx/ton fuel High Speed > 1000 rpm During the last two years a substantial measurement campaign has been carried out to improve the knowledge of actual NOx emissions from Norwegian domestic shipping. The Norwegian NOx fund /6/ has collected most of the data regarding NOx factors in Norway and made the data available through the NOx-fund database. The NOx factors are used to calculate NOx tax and to investigate the effect of reduction measures funded by the NOx fund. In this study it was therefore decided to use the NOx-fund database as basis for updating the NOx factors. A database containing information of Engine International Air Pollution

7 6 Prevention (EIAPP) emissions certificates provided by DNV, was also used to estimate the NOx factors for engines produced after year. The 2006-study is used as a reference for findings presented in this report. 5. Methodology 5.1 Data source As described above it was decided to use the NOx fund database and a database of EIAPP certified engines to estimate the NOx factor for the Norwegian domestic ships. Every ship with more than 750 kw installed power have to pay the NOx tax. The NOx tax is based on the fuel consumption and NOx factor. The NOx factor used may be a tablet NOx factor based on the engine speed, or a measured NOx factor. The tablet factor is generally higher than the real NOx factor measured. The Norwegian Maritime Directorate (NMD) regulates how the measurements and reporting is done /7/. Measurements are generally to be performed in accordance with NOx technical code, 6.3 Simplified measurement method. Alternatively NMD allows certain exemptions from the NOx technical code, like documented operation profiles and only 75% load on auxiliary engines. 5.2 Data filtering The database may contain errors caused by miss typing or by measurement errors. The data was filtered to remove obvious errors and ships with NOx reduction measures. The following data filters have been used to establish the NOx factors presented in this report: 4. NOx values lower than 40% and higher than 140% of MARINTEK 2006 values from 2006 was excluded. 5. In these databases the engine age is missing, and it was decided to use the ship age as an approximation for engine age. It is assumed that this approximation can be used for ships built after Only data from ships without any engine modifications to reduce NOx emissions and/or NOx reduction measures was included. The upper and lower NOx exclusion limit was decided based on MARINTEK s NOx measuring experience from ships and laboratory engines. The MARINTEK 2006 values were chosen as a reference since it is the existing approximation of NOx factors used by Statistics Norway. These factors are based on international studies and publications. It is assumed that a reasonable fraction of the engines put in operation after 1980 is still in operation without major rebuilds or modifications. The number of rebuilds and

8 7 modifications increases with the engine or ship age, which introduces an uncertainty in the engine age distribution. This uncertainty will not influence the overall NOx factor, but will introduce an uncertainty in the age distributed NOx factors. Due to the low number of NOx reduction measures put in operation to this date, it is not practical to include the NOx reduction measures in the overall NOx factor. The effect of NOx reduction measures is instead given in Table NOx factors presented are independent of the fuel quality. The NOx factors calculated is based on the average fuel composition consumed by the Norwegian domestic fleet. 5.3 NOx weighting factor versus operation profile The IMO weighted NOx factor does not take into account the real operation profile of the ship. When the operation profile differs from the IMO weighting and the NOx emissions varies with the engine speed, there will be a difference in NOx emissions calculated based on the IMO weighted NOx factor and the real emissions. According to the MARINTEK 2006/1/ report the NOx factor has minor variations with engine speed. Difference between operation profile and IMO weighting should therefore be of minor importance.

9 8 6. NOx factors before and after year 6.1 NOx factor based on measurement data Based on available measurement data two set of NOx factors have been established, one for engines built before year and one for engines built after year. These factors give the status of the Norwegian domestic fleet NOx emissions with today s fleet composition. Table 6.1 NOx factor for engines built before and after year. Source NOx fund. Source: NOx fund Engine building year NOx factor: [kg NOx/tonne fuel] Before After Slow speed NOx-factor Number of engines 18 3 Stdev 9,84 6,30 Medium speed NOx-factor Number of engines Stdev 8,49 6,61 High speed NOx-factor Number of engines Stdev 5,73 6,20 The number of slow speed engines in the NOx fond database is too low to establish a NOx factor before and after the year based on measurements. Therefore, EIAPP data should be used for as the best estimate for this engine category after year. For high and medium speed engines, a significant number of measurements are available. The high speed engines have a high reduction in NOx emissions after year resulting in a lower NOx factor after year. The medium speed engines have only a limited NOx reduction after year.

10 9 6.2 NOx-factors from EIAPP certificates For all engines built after year, an EIAPP certificate is issued. Based on EIAPP data from DNV the NOx factor for the various engine categories have been calculated. Table 6.2 NOx factor for engines built after year. Source DNV, EIAPP certificates. Source: EIAPP Engine building year NOx factor: [kg NOx/tonne fuel] After Slow speed NOx-factor 78 Number of engines 1057 Stdev 11,02 Medium speed NOx-factor 55 Number of engines 1912 Stdev 5,20 High speed NOx-factor 46 Number of engines 1181 Stdev 7,20 Comparison of data from the NOx fund and from EIAPP certificate shows some deviation on all engine categories. In general the data from EIAPP certificates show higher NOx factors than the measured data from the NOx fund. This difference may be explained my operational issues, maintenance and restrictions on engine settings and operational profile of each ship during a measurement campaign. MARINTEK experiences during onboard measurements are that it is always difficult to obtain the 100% load point in ordinary operation. Hence, there will be some deviation between onboard measurements and testbed data.

11 Recommended emission factors from 2009 Based on the discussion above the following emission factors are recommended from 2009 for calculation of NOx emissions from the Norwegian domestic fleet: Table 6.3 Recommended NOx emission factors for Norwegian domestic ships, update from 2009 Source: NOx fund, EIAPP certificates Engine building year NOx factor: [kg NOx/tonne fuel] Before After Slow speed NOx-factor Number of engines Stdev 7,94 11,02 Medium speed NOx-factor Number of engines Stdev 8,49 6,61 High speed NOx-factor Number of engines Stdev 5,73 6,20 7. Comparison with other data sources In Table 7.1 the new recommended NOx factors are compared to previous NOx factors by MARINTEK, Lloyd s and ENTEC. The MARINTEK 2006 report contains three scenarios, where the best case fits well to the new NOx factors based on measurements. Table 7.1 Comparison of measured NOx factors with previous factors Slow Speed HFO Medium Speed HFO Medium Speed GO High Speed GO MARINTEK 2009 Before Measured NOx factors After IMO - Base case compliant - Worst case engines /1/ (MARINTEK 2006) - Best case Previous Lloyd s /8/ factors ENTEC /10/ IMO: International Maritime Organization HFO: Heavy fuel oil GO: Gas oil

12 11 The new 2009 recommended NOx factors do not take different fuel quality into account since this information is not available in the NOx fund database. The EMEP Guidebook 1 has published emission factors based on data from EMEP/CORINAIR 2006 which use Lloyds Register (1995) and ENTEC(2002) as their main source for NOx factors. As shown in Table 7.1 the new 2009 recommended NOx factors are lower than previous studies performed by Lloyd s, ENTEC and MARINTEK Although there are differences between previous and the new reported NOx factors, MARINTEK is confident that the new NOx factors is the best description of the Norwegian domestic fleet due to the number of recently performed measurements used to calculate the new NOx factors. The new factors reflects the development in engine technology towards reduced exhaust emissions. 8. NOx emission factors by engine age Marine diesel engines are typically divided into three categories: Slow speed, medium speed and high speed. The slow speed category has a speed range from 0 to 200 rpm and the engines are virtually always two strokes. The medium speed category has a speed range from 200 to 1000 rpm and the high speed category contains all engines with speed above 1000 rpm. Both medium speed and high speed engines are virtually always four stroke engines. The age distribution of the NOx fund database is presented in the following graph. Age distribution for engines in the NOx database Number of Engines Number of engines in the NOx fond database Number of engines w ith NOx factors measured Year Figure Number of ships registered in the NOx fund database, age distribution. 1 Cooperative Programme for Monitoring and Evaluation of the Long-range Transmission of Air Pollutants in Europe (EMEP) of the Convention on Long-range Transboundary Air Pollution provides scientific support to the Convention.

13 12 Ship registered in the NOx database may report a measured NOx factor or they may use a given tablet value based on the engine speed. The pink curve in the graph shows the number of ships registered in the NOx fund database which have reported a measured NOx factor. 8.1 Slow speed The number of measurements carried out on slow speed engines is very limited. The following graph shows the number of measurements on slow speed engines in different age categories. Only 21 slow speed engines have been measured on ships built between 1980 and. Number of NOx emission measurements on slow speed engines Number of measurements Engine building year Figure Number of NOx emission measurements on slow speed engines The lack of NOx factor data on slow speed engines gives a NOx factor by age graph that is of very limited use. Slow speed NOx factor NOx factor [kg Nox/tonn fuel] Engine building year NOx factor slow speed engines Figure NOx factor for slow speed engines based on measurement data, 95% confidence interval bars are added

14 Medium speed The number of measurements is much higher for medium speed engines than for the slow speed engines. A total of 260 engines on ships built between 1980 and have been measured. Number of NOx emission measurements on medium speed engines Number of measurements Engine building year Figure Number of NOx emission measurements on medium speed engines versus ship age Medium speed NOx factor 70 NOx factor [kg Nox/tonn fuel] Engine building year NOx factor medium speed engines Figure NOx factor for medium speed engines based on measurement data, 95% confidence interval bars are added From Figure 8.5 it can be observed that there is quite a high spread in the NOx factor from Date from ships measured later than 1995 show less spread in reported NOx factor.

15 High speed As with medium speed, the high speed category has a high number of measured engines. A total of 335 engines have been measured onboard ships built between 1980 and. Number of NOx emission measurements on high speed engines 140 Number of measurements Engine building year Figure Number of NOx emission measurements on high speed engines versus ship age High speed NOx factor 60 NOx factor [kg Nox/tonn fuel] Engine building year NOx factor high speed engines Figure NOx factor for high speed engines based on measurement data, 95% confidence interval bars are added The high speed engines show a reduction in NOx factor after the year.

16 15 9. Ship segment emission factors In previous report the emission factors for ship segments was calculated base on an engine specific emission factors and engine type distribution data. The engine type distribution data has been evaluated based on available information in the databases used in this report. The following engine distribution among ship categories has been established. This distribution does only contain ships registered in the NOx fund database: Table 9.1 Distribution of engine types within ship groups and emission factor Bulk - Total number of propulsion engines Slow speed Medium speed High speed Number of auxiliary engines Medium speed High speed Number of unknown engines measured Number of auxiliary engines measured Cement carriers - Total number of propulsion engines Slow speed Medium speed High speed Number of auxiliary engines Medium speed High speed Number of unknown engines measured Number of auxiliary engines measured 0 0 1

17 16 Chemical and Product Tankers - Total number of propulsion engines Slow speed Medium speed High speed Number of auxiliary engines Medium speed High speed Number of unknown engines measured Number of auxiliary engines measured Container Vessels - Total number of propulsion engines Slow speed Medium speed High speed Number of auxiliary engines Medium speed High speed Number of unknown engines measured Number of auxiliary engines measured 0 3 0

18 17 Fishing Vessels - Total number of propulsion engines Slow speed Medium speed High speed Number of auxiliary engines Medium speed High speed Number of unknown engines measured Number of auxiliary engines measured General Cargo - Total number of propulsion engines Slow speed Medium speed High speed Number of auxiliary engines Medium speed High speed Number of unknown engines measured Number of auxiliary engines measured Liquefied Gas Tankers (LGT) - Total number of propulsion engines Slow speed Medium speed High speed Number of auxiliary engines Medium speed High speed Number of unknown engines measured Number of auxiliary engines measured 0 0 4

19 18 Offshore Other Vessels - Total number of propulsion engines Slow speed Medium speed High speed Number of auxiliary engines Medium speed High speed Number of unknown engines measured Number of auxiliary engines measured Offshore Supply Vessels - Total number of propulsion engines Slow speed Medium speed High speed Number of auxiliary engines Medium speed High speed Number of unknown engines measured Number of auxiliary engines measured Oil Tankers - Total number of propulsion engines Slow speed Medium speed High speed Number of auxiliary engines Medium speed High speed Number of unknown engines measured Number of auxiliary engines measured 0 0 0

20 19 Shuttle Tankers - Total number of propulsion engines Slow speed Medium speed High speed Number of auxiliary engines Medium speed High speed Number of unknown engines measured Number of auxiliary engines measured Other Service Vessels - Total number of propulsion engines Slow speed Medium speed High speed Number of auxiliary engines Medium speed High speed Number of unknown engines measured Number of auxiliary engines measured Passenger Vessels - Total number of propulsion engines Slow speed Medium speed High speed Number of auxiliary engines Medium speed High speed Number of unknown engines measured Number of auxiliary engines measured

21 20 Reefers - Total number of propulsion engines Slow speed Medium speed High speed Number of auxiliary engines Medium speed High speed Number of unknown engines measured Number of auxiliary engines measured Ro-Ro Cargo - Total number of propulsion engines Slow speed Medium speed High speed Number of auxiliary engines Medium speed High speed Number of unknown engines measured Number of auxiliary engines measured Tug - Total number of propulsion engines Slow speed Medium speed High speed Number of auxiliary engines Medium speed High speed Number of unknown engines measured Number of auxiliary engines measured

22 NOx reduction measures In previous study (MARINTEK, 2006) a NOx reduction factor was proposed for alternative NOx reduction technologies. These factors are still valid with the same argument as in previous study. Emissions of NOx can be reduced by a number of technologies. This can be accounted for in the NOx estimate by multiplying the NOx emission estimate for an engine without NOx reduction with an emission reduction factor, i.e.: NOx = EF * FC * (1-RF) NOx = NOx emission (kg) EF = emission factor (kg NOx /tonne fuel) FC = Fuel consumption (tonnes) RF = reduction factor specific to each NOx reduction technique (-) The effect of most emission reduction techniques is dependent upon the effort made to achieve the reduction e.g. the amount of water injected into the combustion or how far the fuel injection is retarded. The effect may also vary with engine load and hence depend upon operating profile. Finally, emissions will only be reduced when the reduction system is operating, hence the total reduction will depend also on the downtime of the reduction technology. We have thus chosen to calculate the reduction factor as the product from two components: RF = WR * AV WR = weighted reduction factor AV = uptime or availablility of the NOx reduction technology The weighted reduction factor WR expresses the NOx emission reduction at different loads weighted using the same factors as used in emission measurements. This approach generally results in a lower reduction factor than would be the result if reduction at full load alone was considered. For instance, combustion air saturation is, for instance, not effective and turned off at low load. In case of SCR, the temperature of the catalyst may be insufficient for NOx reduction during start up or during extended low-load operation - unless specific measures are made to heat the catalyst. Fuel water emulsion is typically not used at low load to avoid white smoke and possible unstable combustion. This must be considered when comparing the WR factors with data from other sources. The uptime or availability AV factor accounts for the time the NOx reduction measure is not operating while the engine is running. This could be the result of a technical failure or simply lack of water or urea. How often this type of situation occurs depends upon

23 22 system design and quality as well as the priorities of the user. MARINTEK does not have data to accurately estimate the technical downtime of the NOx reduction equipment, however it is prudent to distinguish between systems with inherent reduction like engine rebuild and gas fuel from independent systems like SCR and fuel-water emulsification. A downtime of 5% is chosen for all independent systems as a best guess for the industry average. A number of NOx emission reduction measures that have been installed on Norwegian ships -including fuel water emulsification, direct water injection and SCR - are not in use, predominantly because the extra costs for operation and maintenance are difficult to justify in a competitive marked with no economic incentives for NOx reduction. The uptime factor in Table 10.1 assumes that the NOx measures are in actual use, not simply installed. Table Emission reduction factors for NOx reduction technologies Technology Weighted Reduction (WR) Uptime or availability (AV) Reduction Factor (RF) Engine % 0.23 optimization Fuel water % 0.14 emulsification Direct water % 0.52 injection (DWI) Combustion air % 0.52 saturation (CAS) Humid air motor % 0.52 (HAM) Selective catalytic % 0.76 reduction (SCR) Natural gas fuel % 0.85 Note that these factors are meant to represent the expected industry average NOx reduction, not the technology potential. Only a limited number of ships which have installed NOx reduction technologies have been measured, so statistical data are yet not available to verify the factors above.

24 References /1/ MARINTEK. Report MT28 F06-033, no NOx Emission Factors estimate Rev.2. /2/ DNV. Report no , rev01. Næringslivets NOx fond. NOx Emissions factors 2008 estimates based on reported values. /3/ NOx fund database /4/ MARINTEK NOx database /5/ EIAPP certificate database /6/ NOx fund /7/ Guideline on the NOx tax rev 6, Sjøfarstdirektoratet /8/ Marine Exhaust Emissions Research Programme, Lloyd s Register (1995) /9/ IMO (), Study of Greenhouse Gas Emissions from Ships issue No by Marintek, Det Norske Veritas, Econ Centre for Economic Analysis and Carnegie Mellon University. /10/ European Commission Quantification of emissions from ships associated with ship movements between ports in the European Community Final Report July 2002 Entec UK Limited. /11/ Data retrieved from Marintek s NOx database. /12/ Trozzi, C., Vaccaro, R., Methodologies for estimating air pollutant emissions from ships.techne Report MEET RF98;