This document summarizes research characterizing methane (CH4) isotopic signatures (δ13CH4) from various sources in Germany using mobile measurements. Mobile measurements were conducted using a Picarro cavity ring-down spectrometer and AirCore sampling system. Isotopic signatures were determined for sources including natural gas facilities, coal mines, wastewater treatment plants, landfills, biogas facilities, and dairy farms. The results provide δ13CH4 values that can distinguish between thermogenic and biogenic CH4 sources and are in agreement with other studies.

1. antje.hoheisel@iup.uni-heidelberg.de
Characterisation of δ13
CH4 source signatures from
methane sources in Germany using mobile
measurements
A. Hoheisel, C. Yeman, F. Dinger, H. Eckhardt and M. Schmidt
Institute of Environmental Physics Heidelberg University
September 13, 2018
3rd
ICOS Science Conference, Prague September 13, 2018 1 / 13

2. Motivation
Global Atmospheric CH4 Mole Fraction and δ13
C
HS
GAW
HS
NOAA-ESRL
1980 1990 2000 2010
1800
1700
1600
-47.8
-47.6
-47.4
-47.2
-47.0
Year Year
[CH4](p.p.b.)
δ13
C(Atm)(‰) 1980 1990 2000 2010
(Schaefer et al., 2016)
September 13, 2018 2 / 13

3. Motivation
δ13
CH4 Isotopes
isotope ratio R and δ-notation
13
R =
13CH4
[12CH4 ]
δ =
Rsample
Rstandard
− 1 · 1000
main formation processes of CH4
biogenic −55 to −70 e.g. wetlands, landfills, WWTPs and
ruminants
thermogenic −25 to −45 e.g. main component of natural gas
pyrogenic −13 to −25 e.g. incomplete combustion of organic
matter
September 13, 2018 3 / 13

4. Motivation
CH4 Sources
Berlin
Hamburg
Frankfurt on the Main
Cologne
Stuttgart
Amsterdam
Brussels
Munich
dairy farm in Kleve
deep coal mine in Bottrop
opencast mine Hambach
measuring sites
near Heidelberg
dairy farm in Weinheim
dairy farm in Ladenburg
natural gas storage and
compressorstations
Hähnlein/Gernsheim
natural gas storage
Sandhausen landfill in Sinsheim
WWTP in
Heidelberg
biogas plant in
Heidelberg
Heidelberg
Weinheim
Sinsheim
Mannheim
358 km
22.4 km
measuring sites
near Heidelberg
Berlin
Frankfurt on the Main
Cologne
Stuttgart
Amsterdam
Brussels
Kleve
Bottrop
Weinheim
Ladenburg
Sandhausen
Sinsheim
Heidelberg
Heidelberg
Weinheim
Sinsheim
Mannheim
400 km 20 km
Munich
Hähnlein/Gernsheim
Heidelberg
dairy farm
biogas plant
wastewater
treatment plant
landfill
natural gas storage
and compressor
stations
deep coal mine
measuring sites
September 13, 2018 4 / 13

5. Measurement Setup
Measuring Principle
7
15s mean:
raw:
September 13, 2018 5 / 13

6. Measurement Setup
Mobile Measurement Setup
AirCore
Picarro G2201-i
(Yeman,2015)
September 13, 2018 6 / 13

7. Measurement Setup
Mobile Measurement Setup
filter
air
inlet
three-way
valve
Nafion
dryer
critical orifice
AirCore
needle pump
CRDS
laptop
filter
valve
AirCore
volume: 1.77 l
length: 25 m
diameter: 9.5 mm
flow through instrument
monitoring mode: 0.16 l/min
AirCore measurement: 0.10 l/min
September 13, 2018 7 / 13

8. Measurement Setup
AirCore Measurements
2
3
4
5
6
CH4[ppm]
monitoring mode AirCore measurement
0 2 4 6 8 10 12 14
δ13
CH4[‰]
-65
-50
-55
-45
-60
-40
time [min]
CRDS
Nafion
dryer
AirCore
air
inlet
September 13, 2018 8 / 13

9. Data Analysis
Determination of δ13
CH4 Signature
δ13
CH4 Correction and Calibration
CH4 interference → no effect
CO2 interference → no effect
H2O interference → drying unit
C2H6 interference → corrections
September 13, 2018 9 / 13

10. Data Analysis
Determination of δ13
CH4 Signature
δ13
CH4 Correction and Calibration
H2O interference → drying unit
C2H6 interference → corrections
Fit Method
Miller-Tans Approach
δ13
CH4M · CH4M = CH4B δ13
CH4B − δ13
CH4S + δ13
CH4S · CH4M
York fit
Limitation Factors:
precision of the analyser
number of data points → importance of AirCore
CH4 range
Criterion:
uncertainty of δ13
CH4
lower than 5
September 13, 2018 9 / 13

11. Data Analysis
Limitation Factors
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0 1 2 3 4 5 6 7 8 9 10
CH4 range [ppm]
δ13
CH4[‰]fiterrorof
40
35
30
25
20
15
10
5
0
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0
10
20
30
40
0.0 0.2 0.4 0.6 0.8 1.0
CH4 range [ppm]
●
δ13
CH4[‰]fiterrorof
simulations
measured data}
number of
data points
10
20
40
70
140
210
280
25-280
Criterion:
uncertainty of δ13
CH4
lower than 5
September 13, 2018 10 / 13

12. Data Analysis
δ13
CH4 Signature of CH4 Sources
79 AirCore measurements on 21 days between July 2016 to July 2017
q
q
−70 −65 −60 −55 −50 −45 −40
δ13
CH4 [‰]
natural gas facility Sandhausen
natural gas facility Hähnlein/Gernsheim
bituminous deep coal mine Bottrop
WWTP Heidelberg
landfill Sinsheim (plume)
landfill Sinsheim (on landfill)
biogas plant Heidelberg
dairy farm Ladenburg
dairy farm Kleve
dairy farm Weinheim
q qq q qq
qq q
q qqq q qqq q
q qqq q q
qq qqqq qq
qqq qqq qqqq qqq q
qq q q qq q q
qqq qqqq q
q q
q qq qqqqqq qq
q q
qq
q q
q qq qqqqqq qq
q q
qq
q qqq qq
qqq q qqqq q q
q qq q qq
qq qq
qq
q
q
q
q
qq
q
q
single mobile result
mean mobile result
direct sample result
September 13, 2018 11 / 13

13. Data Analysis
Samples from Natural Gas Distribution Network Heidelberg
δ13
CH4[‰]
−50
−45
−40
−35
−30
sample date
12/2016 03/2017 06/2017 09/2017 12/2017 03/2018 06/2018
winter
(Levin et al., 1999)
summer
(Levin et al., 1999)
−43.1 ± 0.8‰ 12/2016 to 02/2018
−40.3 ± 3.0‰ 1991 to 1996 (Levin et al., 1999)
(Lowry et al., 2001)
-48‰ to -54‰
(Cramer et al., 1998)
North Sea gas
Russian gas
-34 ± 3‰
September 13, 2018 12 / 13

14. Conclusion
Conclusion
development and test of a mobile instrument setup
results of mobile campaigns are in good agreement with direct
samples and values from other studies
advantages:
measurements can be done downwind of emission source
consent of the owner is not necessary
measurements can be done where it is not possible to take direct
samples
September 13, 2018 13 / 13

15. Thank you for your attention.
September 13, 2018 13 / 13