1.A.3.c - Railways

Last updated on 30 Aug 2017 16:54 (cf. Authors)

Short description

In category 1.A.3.c - Railways the emissions from German railways are reported.

NFR-Code Name of Category Method AD EF Key Category for (by1)
1.A.3.c Railways T1, T2 NS, M CS, D, M no key category

Germany's railway sector is undergoing a long-term modernisation process, aimed at making electricity the main energy source for rail transports. Use of electricity, instead of diesel fuel, to power locomotives has been continually increased, and electricity now provides 80% of all railway traction power. Railways' power stations for generation of traction current are allocated to the stationary component of the energy sector (1.A.1.a) and are not included in the further description that follows here. In energy input for trains of German Railways (Deutsche Bahn AG), diesel fuel is the only energy source that plays a significant role apart from electric power.

Method

Activity Data

Basically, total inland deliveries of diesel oil are available from the National Energy Balances (NEBs) (AGEB, 2016) [1]. This data is based upon sales data of the Association of the German Petroleum Industry (MWV) [2]. As a recent revision of MWV data on diesel oil sales for the years 2005 to 2009 has not yet been adopted to the respective NEBs, this original MWV data has been used for this five years.

Data on the consumption of biodiesel in railways is provided in the NEBs as well, from 2004 onward. But as the NEBs do not provide a solid time series regarding most recent years, the data used for the inventory is estimated based on the prescribed shares of biodiesel to be added to diesel oil.

Small quantities of solid fuels are used for historical steam engines vehicles operated mostly for tourism and exhibition purposes. Official fuel delivery data are available for lignite, through 2002, and for hard coal, through 2000, from the NEBs. In order to complete these time series, a study was carried out in 2012 by Probst & Consorten. During this study, questionaires were provided to any known operator of historical steam engines in Germany. Here, due to limited data archiving, nearly complete data could only be gained for years as of 2005.
For earlier years, in order to achieve a solid time series, conservative gap filling was applied.

Table 1: Overview of data sources for domestic fuel sales to railway operators
Fuel data source / quality of activity data
Diesel oil 1990-2004: NEB lines 74 and 61: 'Schienenverkehr' / 2005-2009: MWV annual report, table: 'Sektoraler Verbrauch von Dieselkraftstoff' / from 2010: NEB line 61
Biodiesel calculated from official blending rates
Hard coal 1990-1994: NEB lines 74 / 1995-2004: interpolated data / from 2005: original data from studies
Hard coal coke 1990-1997: NEB lines 74 and 61 / 1998-2004: interpolated data / from 2005: original data from studies
Raw lignite from 1990: NEB lines 74 and 61
Lignite briquettes from 1990: NEB lines 74 and 61
Table 2: Annual fuel consumption in German railways, in TJ
1990 1995 2000 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015
Diesel Oil 38,458 31,054 25,410 18,142 17,101 16,730 16,389 14,336 14,626 14,730 13,514 13,771 12,283 11,989
Biodiesel 0 0 0 397 498 747 810 987 949 966 882 798 745 652
Liquids TOTAL 38,458 31,054 25,410 18,539 17,599 17,477 17,199 15,324 15,575 15,696 14,396 14,569 13,028 12,641
Lignite Briquettes 0 0 431 0 0 0 0 0 0 0 0 0 0 0
Raw Lignite 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Hard Coal 576 250 250 255 262 255 300 321 314 345 357 352 341 339
Hard Coal Coke 0 86 1,33 0,79 0,71 0,71 0,71 0,71 0,79 0,75 0,75 0,75 0,75 0,75
Solids TOTAL 576 336 682 256 263 256 301 322 315 346 357 353 342 340

Use of other fuels – such as vegetable oils or gas – in private narrow-gauge railway vehicles has not been included to date and may still be considered negligible.

Emission factors

The (implied) emission factors used here are of very different quality:
For main pollutants, carbon monoxide and particulate matter from the combustion of diesel fuels, annual tier2 IEF computed within the TREMOD model are used , representing the development of German railway fleet, fuel quality and mitigation technologies (ifeu, 2016a) [4].
On the other hand, constant default values from (EMEP/EEA, 2016) [5] are used for all reported PAHs and heavy metals and from (Rentz et al., 2008) [6] regarding PCDD/F.
As no emission factors are available for HCB and PCBs, no such emissions have been calculated yet.

Regarding emissions from solid fuels used in historic steam engines, all emission factors displayed below have been adopted from small-scale stationary combustion.

Table 3: (I)EFs used for 2015 emission estimates
NH3 NMVOC NOx SO2 CO PM2.5 PM10 TSP BC Pb Cd Hg As Cr Cu Ni Se Zn B[a]P B[b]F B[k]F I[…]P ∑PAH 1-4 PCDD/F HCB PCBs
[kg/TJ] [g/TJ] [mg/TJ] [g I-Teq] [mg/TJ]
Diesel oil1 0.542 41.22 8472 0.323 1032 15.32, 4 9.4910 1.215 0.236 0.125 0.0025 1.166 406 1.636 0.236 236 6986 1.1646 8005 1835 2.8467 2.098 NE NE
Hard coal9 4 15 120 650 500 222 250 278 14.210 NE NE NE NE NE
Hard coal coke9 4 0.5 120 500 1,000 154 0.9610 NE NE NE NE NE
Lignite9 4 15 120 500 500 560 630 700 35.8410 NE NE NE NE NE
Lignite briquettes9 4 15 120 120 500 560 630 700 35.8410 NE 34,500 IE in ∑PAH 90,000 30 NE NE

1 due to lack of better information: similar EF are applied for fossil diesel oil and biodiesel
2 annual country-specific value from [3]
3 country-specific value from [3]
4 EF(PM2.5) also applied for PM10 and TSP (assumption: > 99% of TSP from diesel oil combustion consists of PM2.5)
5 tier1 default from [5], chapter: 1.A.3.b i-iv - Road transport: exhaust emissions: tier1 value for diesel vehicles
6 tier1 default from [5], chapter: 1.A.3.c - Railways
7 sum of tier1 default value applied for B[a]P, B[b]F, B[k]F, and I[1,2,3-c,d]P
8 tier1 value derived from [6]
9 EFs derived from stationary combustion
10 EFs calculated via f-BCs as provided in [5]: diesel fuels: 0.56 (Chapter: 1.A.3.c - Railways, Appendix A: tier1), solid fuels: 0.064 (Chapter: 1.A.4 - Small Combustion: Residential combustion (1.A.4.b): Table 3-3, Zhang et al., 2012)

Discussion of emission trends

NFR 1.A.3.c is no key source.

Basically, for all unregulated pollutants, emission trends directly follow the trend in over-all fuel consumption.

Here, as emission factors for solid fuels tend to be much higher than those for diesel oil, emission trends are disproportionately effected by the amount of solid fuels used.
Therefore, for the main pollutants, carbon monoxide, particulate matter and PAHs, emission trends show remarkable jumps especially after 1995 that result from the significantly higher amounts of solid fuels used.

For all fractions of particulate matter, the majority of emissions generally result from diesel fuels combustion. Additional jumps in the over-all trend result from the use of lignite briquettes (1996-2001).
Here, as the EF(BC) are estimated via fractions provided in [5], black carbon emissions follow the corresponding emissions of PM2.5.

Due to fuel-sulphur legislation, the trend of sulphur dioxide emissions follows not only the trend in fuel consumption but also reflects the impact of regulated fuel-qualities.
For the years as of 2005, sulphur emissions from diesel combustion have decreased so strongly, that the over-all trend shows a slight increase again due to the now dominating contribution of sulphur from the use of solid fuels.

Regarding heavy metals, as there are emission factors applied for diesel oil only at the moment, the specific emission trends reflect the trend of diesel oil consumption:

Recalculations

Activity data

Given the revised NEB 2014, both the activity data fo diesel oil and the annual amounts of blended biodiesel were revised accordingly within TREMOD.
Furthermore, the fragmantary data for solid fuels sold to operators of historical steam engines available from the National Energy Balance have been completed based on information from a study carried out throughout 2016, also replacing the former projected data for the years as of 2011. (see description of AD above)

Table 4: Revised fuel consumption data, in TJ
2005 2006 2007 2008 2009 2010 2011 2012 2013 2014
Diesel Oil
Submission 2017 18,142 17,101 16,730 16,389 14,336 14,626 14,730 13,514 13,771 12,283
Submission 2016 18,142 17,101 16,730 16,389 14,336 14,626 14,730 13,514 13,771 13,658
absolute change 0 0 0 0 0 0 0 0 0 -1.375
relative change 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% -10.07%
Biodiesel
Submission 2017 397 498 747 810 987 949 966 882 798 745
Submission 2016 397 498 747 810 987 949 966 882 798 822
absolute change 0 0 0 0 0 0 0 0 0 -77
relative change 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% -9.42%
Hard Coal
Submission 2017 254.89 262.21 254.92 300.32 321.03 314.23 345 357 352 341
Submission 2016 255.00 262.00 255.00 300.00 321.00 314.00 325 325 325 325
absolute change -0.11 0.21 -0.08 0.32 0.03 0.23 20 32 27 16
relative change -0.04% 0.08% -0.03% 0.11% 0.01% 0.07% 6.22% 9.72% 8.36% 5.07%

Emission factors

Due to the routine revision of the TREMOD model [3], tier2 emission factors changed for recent years.

Table 5: Revised (I)EFs 2014 for emissions from diesel fuels, in kg/TJ
NOx NMVOC CO PM
Submission 2017 890 42.8 103.0 15.3
Submission 2016 891 43.3 103.6 15.4
absolute change -1 -0.3 -0.6 -0.1
relative change -0.1% -0.8% -0.5% -0.7%

In addition, EF(BC) have been implemented for the first time based on the BC-fractions provided in [5]:

Table 6: Newly implemented EF(BC), in kg/TJ
Diesel Fuels1 Hard Coal Hard Coal Coke Lignite (Briquettes)
Submission 2017 9.49 14.23 0.96 35.84
Submission 2016 NE NE NE NE

1 annual value for 2015

Furthermore, based on the implementation of BC emissions in the inventory, the EF(PM) for solid fuels were revised based on information from [5]:

Table 7: Newly implemented EF(PM) for raw lignite and lignite briquettes, in kg/TJ
PM2.5 PM10 TSP
Submission 2017 560 630 700
Submission 2016 NE NE 700
Table 8: New and revised tier1 EF(PM) for hard coal, in kg/TJ
PM2.5 PM10 TSP
Submission 2017 250 222 278
Submission 2016 NE NE 700
absolute change -422
relative change -60%
Table 9: New and revised tier1 EF(PM) for hard coal coke, in kg/TJ
PM2.5 PM10 TSP
Submission 2017 15 15 15
Submission 2016 NE NE 700
absolute change -685
relative change -98%

As the revised emission estimates resulting from these revisions cannot be displayed here in detail please see the pollutant specific recalculation tables following chapter 8.1 - Recalculations for information on the impacts on 1990 and 2014 emission estimates.

Uncertainties

Uncertainty estimates for activity data of mobile sources derive from research project FKZ 360 16 023: "Ermittlung der Unsicherheiten der mit den Modellen TREMOD und TREMOD-MM berechneten Luftschadstoffemissionen des landgebundenen Verkehrs in Deutschland" by (ifeu & INFRAS, 2009) [7]. - For detailled information, please refer to the project's final report here (German version only!)

Planned improvements

Besides the scheduled routine revision of TREMOD, no further improvements are planned for the next annual submission.

FAQs

Why are similar EF applied for estimating exhaust heavy metal emissions from both fossil and biofuels?

The EF provided in [5] represent summatory values for (i) the fuel's and (ii) the lubricant's heavy-metal content as well as (iii) engine wear. Here, there might be no heavy metals contained in the biofuels. But since the specific shares of (i), (ii) and (iii) cannot be separated, and since the contributions of lubricant and engine wear might be dominant, the same emission factors are applied to biodiesel.


Bibliography
1. AGEB, 2016: Arbeitsgemeinschaft Energiebilanzen (Hrsg.): Energiebilanz für die Bundesrepublik Deutschland; URL: http://www.ag-energiebilanzen.de/7-0-Bilanzen-1990-2014.html, Köln & Berlin, 2016.
2. MWV, 2016: Mineralölwirtschaftsverband (MWV, Association of the German Petroleum Industry); URL: https://www.mwv.de/publikationen/jahresberichte/, Berlin, 2016.
3. Probst & Consorten, 2012: Recherche des jährlichen Kohleeinsatzes in historischen Schienenfahrzeugen seit 1990 ('Inquiry of annual coal use in historic railway vehicles since 1990') - Study carried out for UBA; FKZ 363 01 392; not yet published
4. ifeu, 2016a: Knörr, W. et al., IFEU - Institut für Energie- und Umweltforschung Heidelberg gGmbH: Fortschreibung des Daten- und Rechenmodells: Energieverbrauch und Schadstoffemissionen des motorisierten Verkehrs in Deutschland 1960-2030, sowie TREMOD, im Auftrag des Umweltbundesamtes, Heidelberg, 2016.
5. EMEP/EEA, 2016: EMEP/EEA air pollutant emission inventory guidebook 2016, Copenhagen, 2016
6. Rentz et al., 2008: Nationaler Durchführungsplan unter dem Stockholmer Abkommen zu persistenten organischen Schadstoffen (POPs), im Auftrag des Umweltbundesamtes, FKZ 205 67 444, UBA Texte | 01/2008, January 2008 - URL: http://www.umweltbundesamt.de/en/publikationen/nationaler-durchfuehrungsplan-unter-stockholmer
7. ifeu & INFRAS, 2009: IFEU – Institut für Energie- und Umweltforschung Heidelberg gGmbH und INFRAS Zürich: Ermittlung der Unsicherheiten der mit den Modellen TREMOD und TREMOD-MM berechneten Luftschadstoffemissionen des landgebundenen Verkehrs in Deutschland, FKZ 360 16 023, Heidelberg & Zürich.
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