Quantification of methane emissions from offshore oil & gas platforms in the Norwegian Sea

2021 ◽  
Author(s):  
Amy Foulds ◽  
Keyword(s):  
Oil And Gas ◽  
Dispersion Model ◽  
Particle Dispersion ◽  
Atmospheric Methane ◽  
Atmospheric Measurements ◽  
Norwegian Sea ◽  
Ch4 Emissions ◽  
Reported Data ◽  
Offshore Oil ◽  
Global Emissions

<p>Atmospheric methane (CH4) is an extremely potent greenhouse gas, with ever-increasing global emissions expected to have a significant influence on the Earth’s climate. The Oil and Gas sector is considered to be a significant source of CH4 to the atmosphere, estimated to make up approximately 22% of global emissions. Offshore facility emissions are poorly ground-truthed, with their quantification being heavily dependent on “bottom-up” scaling of inventory data. It is therefore important to devise reliable methods for locating these emissions and to pinpoint their sources, as this will aid emission quantification and validation against reported data.</p><p>As part of the United Nations Climate and Clean Air Coalition (UN CCAC) project, this study aims to characterise CH4 emissions from oil and gas infrastructure in the Norwegian Sea. The campaign comprised surveys of selected operational oil and gas platforms in this region and included targeted observations of CH4.  These surveys were conducted by the Facility of Airborne Atmospheric Measurements (FAAM) and Scientific Aviation Mooney research aircrafts in July and August 2019, with a total 14 flights. Fluxes are derived using a mass balance approach and aircraft sampling. The Lagrangian particle dispersion model “FLEXPART” is used to aid the attribution of the observed CH4 emissions to the platform(s). We will present results for derived fluxes and uncertainties for individual facilities in the Norwegian Sea.  These fluxes will be compared with emissions estimates from platform operators, as well as a global, gridded emission inventory.</p>

Modelling of methane emissions from offshore oil platforms in the Norwegian sea

2021 ◽  
Author(s):  
Ignacio Pisso ◽  
Amy Foulds ◽  
Grant Allen
Keyword(s):  
Radiative Forcing ◽  
Oil And Gas ◽  
Lagrangian Model ◽  
Model Parameters ◽  
Positive Contribution ◽  
Atmospheric Methane ◽  
Norwegian Sea ◽  
Oil Platforms ◽  
Offshore Oil Platforms ◽  
Offshore Oil

<p>Methane is a major greenhouse gas that has increased since the pre-industrial era and reducing its emissions is potentially an effective way of mitigating the radiative forcing in the short term. The oil & gas industry has a positive contribution to the global atmospheric methane budget with fugitive emissions from infrastructure installations such as offshore oil platforms. As part of the United Nations Climate and Clean Air Coalition (UN CCAC) objective to quantify global CH4 emissions from oil and gas facilities, a series of aircraft campaigns have been carried out in the Norwegian sea among other areas. We report on the Lagrangian modelling activity of the emissions and transport sensitivities used to support the flux assessment. Source identification has been carried out based on backward modelling and has proved useful to interpret observations form the in situ airborne platforms. In addition, forward modelling of the emission plume in high resolution has been applied to constraining the plume height for mass balance methods assessment. Dependency of the resulting uncertainty of the flux estimates on various factors such as the choice of the meteorology and the of the Lagrangian model parameters is also discussed.</p>

scholarly journals Estimates of sub-national methane emissions from inversion modelling

2018 ◽  
Author(s):  
Sarah Connors ◽  
Alistair J. Manning ◽  
Andrew D. Robinson ◽  
Stuart N. Riddick ◽  
Grant L. Forster ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
High Spatial Resolution ◽  
Dispersion Model ◽  
Methane Emissions ◽  
Particle Dispersion ◽  
Eastern Region ◽  
Atmospheric Methane ◽  
Atmospheric Measurements ◽  
East Anglia ◽  
The Uk

Abstract. Methane is a strong contributor to global climate change, yet our current understanding and quantification of its sources and their variability is incomplete. There is a growing need for comparisons between emission estimates produced using bottom-up inventory approaches and top-down inversion techniques based on atmospheric measurements, especially at higher spatial resolutions. To meet this need, this study presents using an inversion approach based on the Inversion Technique for Emissions Modelling (InTEM) framework and measurements from four sites in East Anglia, United Kingdom. Atmospheric methane concentrations were recorded at 1–2 minute time-steps at each location within the region of interest. These observations, coupled with the UK Met Office's Lagrangian particle dispersion model, NAME (Numerical Atmospheric dispersion Modelling Environment), were used within InTEM2014 to produce methane emission estimates for a 1-year period (June 2013–May 2014) in this eastern region of the UK (~ 100 × 150 km) at high spatial resolution (up to 4 × 4 km). InTEM2014 was able to produce realistic emissions estimates for East Anglia, and highlighted potential areas of difference from the UK National Atmospheric Emissions Inventory (NAEI). As this study was part of the UK Greenhouse gAs Uk and Global Emissions (GAUGE) project, observations were included within a national inversion using all eleven measurement sites across the UK to directly compare emission estimates for the East Anglia Region. Results show similar methane estimates for the East Anglia region. Methane emissions from Norfolk and Suffolk show good agreement with the estimates in NAEI, with differences of ~ 5 %. Larger differences are found for Cambridgeshire where our estimate is 22.5 % lower than that of NAEI. The addition of the EA sites within the national inversion system enabled finer spatial resolution and a decrease in the associated uncertainty for that area. Further development of our approach to include a more robust analysis of the methane concentration in the air entering this region and the uncertainty associated with the resulting emissions would strengthen this inverse method. Nonetheless, our results show there is value in high spatial resolution measurement networks and the resulting inversion emission estimates.

Novel stable isotopic measurements for understanding atmospheric methane

2021 ◽  
Author(s):  
Chris Rennick ◽  
Ed Chung ◽  
Tim Arnold ◽  
Emmal Safi ◽  
Alice Drinkwater ◽  
...  
Keyword(s):  
Inverse Method ◽  
Dispersion Model ◽  
Measurement Techniques ◽  
Ambient Air ◽  
Isotope Ratios ◽  
Reaction Rates ◽  
Particle Dispersion ◽  
Added Value ◽  
Atmospheric Methane ◽  
Air Sample

<p>We demonstrate the possibilities for continuous high precision in situ measurements of δ<sup>13</sup>C(CH<sub>4</sub>) and δ<sup>2</sup>H(CH<sub>4</sub>) for understanding regional CH<sub>4</sub> emissions and explain how advances in nascent measurement techniques looking at ‘clumped’ CH<sub>4</sub> might improve our understanding on the global scale.</p><p>‘Boreas’ is a new fully automated sample-preparation coupled dual laser spectrometer system developed at the National Physical Laboratory, able to make accurate and precise simultaneous measurements of δ<sup>13</sup>C(CH<sub>4</sub>) and δ<sup>2</sup>H(CH<sub>4</sub>) through the measurement of isotopologue ratios of CH<sub>4</sub>. Average daily repeatabilities of <0.08 ‰ for δ<sup>13</sup>C (n=10, 1 SD)  and <1‰ δ<sup>2</sup>H of a compressed ‘background’ air sample (1.9 ppm dry air amount fraction CH<sub>4</sub>) are achieved, making the measurements comparable to bulk isotope ratio mass spectrometry. These measurements are interspersed with air sample measurements from the roof of our building in west London, and we show the possibility to differentiate potential sources of CH<sub>4</sub> under different meteorological conditions.</p><p>We use a particle dispersion model (the Met Office’s NAME) and inverse method to predict the possible impact of the new continuous isotope ratios measurements on quantification of emissions from individual source sectors, should the technique be deployed to a tall tower network of monitoring sites in the UK.</p><p>Finally, our theoretical analysis is extended beyond the most abundant isotopologues of CH<sub>4</sub> to look at how analysis of the clumped isotopes might be able to impact our understanding of interannual variability in the global CH<sub>4</sub> burden. We incorporate measurements from emission sources and information on reaction rates into a global box model (with an inverse method) to show the added value of strategic ∆CH<sub>2</sub>D<sub>2</sub> and ∆<sup>13</sup>CH<sub>3</sub>D ambient air measurements relative to bulk isotope ratios alone.</p>

Using atmospheric in-situ measurements of 13CH4 to investigate methane emissions in Western Canada

2021 ◽  
Author(s):  
Felix Vogel ◽  
Sebastien Ars ◽  
Karlis Muehlenbachs ◽  
Gabriela Gonzalez Arismendi ◽  
Doug Worthy
Keyword(s):  
Fossil Fuels ◽  
Oil And Gas ◽  
Dispersion Model ◽  
Methane Emissions ◽  
Isotopic Signature ◽  
Atmospheric Measurements ◽  
Hysplit Model ◽  
Contour Maps ◽  
The Government ◽  
Government Of Canada

<p>The climate change impact of methane is significant and the recent increase in its atmospheric concentrations raises great concerns. Across Canada, methane emissions are unevenly distributed with a large part attributed to the Western Canadian Sedimentary Basin (WCSB), which is the fourth largest reserve of fossil fuels in the world. The WCSB extends from northeastern British Columbia to southwestern Manitoba, encompassing Alberta and southern Saskatchewan. The extraction of  hydrocarbons mostly takes place in the provinces of Alberta and Saskatchewan and is a large source of methane.</p><p>According to recent international agreements, the Government of Canada has committed to reducing methane emissions by 40 to 45% by 2025 based on 2012 levels. However, a recent study using atmospheric measurements of methane concentrations in the region showed that methane emissions from the oil and gas sector might be nearly twice that reported in Canada’s National Inventory (Chan et al., 2020). More investigations are required to better understand the discrepancy between these two estimates.</p><p>In this study, we use atmospheric observations of δ<sup>13</sup>C measured successively at three locations across the WCSB between 2016 and 2020 to help identify the influence of different types of methane sources across the provinces of Alberta and Saskatchewan. We compare our atmospheric measurements with compilations and isotope contour maps of fugitive methane from energy facilities across the basin. Combining these measurements with trajectories computed with the HYSPLIT model developed by NOAA, we show a gradient in the methane isotopic signature across Alberta: methane being more depleted in southwestern Saskatchewan than northwestern Alberta. We also used the HYSPLIT5-STILT dispersion model to derive footprints during our measurements and estimate methane contributions of these two provinces using an optimization based on the isotopic measurements.</p><p> </p><p>Chan et al. 2020: </p>

scholarly journals Estimating regional-scale methane flux and budgets using CARVE aircraft measurements over Alaska

2018 ◽  
Vol 18 (1) ◽  
pp. 185-202 ◽  
Author(s):  
Sean Hartery ◽  
Róisín Commane ◽  
Jakob Lindaas ◽  
Colm Sweeney ◽  
John Henderson ◽  
...  
Keyword(s):  
Soil Temperature ◽  
Dispersion Model ◽  
Linear Regression Analysis ◽  
Regional Scale ◽  
Methane Flux ◽  
Particle Dispersion ◽  
Environmental Drivers ◽  
Study Region ◽  
Ch4 Emissions ◽  
Soil Temperature And Moisture

Abstract. Methane (CH4) is the second most important greenhouse gas but its emissions from northern regions are still poorly constrained. In this study, we analyze a subset of in situ CH4 aircraft observations made over Alaska during the growing seasons of 2012–2014 as part of the Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE). Net surface CH4 fluxes are estimated using a Lagrangian particle dispersion model which quantitatively links surface emissions from Alaska and the western Yukon with observations of enhanced CH4 in the mixed layer. We estimate that between May and September, net CH4 emissions from the region of interest were 2.2 ± 0.5 Tg, 1.9 ± 0.4 Tg, and 2.3 ± 0.6 Tg of CH4 for 2012, 2013, and 2014, respectively. If emissions are only attributed to two biogenic eco-regions within our domain, then tundra regions were the predominant source, accounting for over half of the overall budget despite only representing 18 % of the total surface area. Boreal regions, which cover a large part of the study region, accounted for the remainder of the emissions. Simple multiple linear regression analysis revealed that, overall, CH4 fluxes were largely driven by soil temperature and elevation. In regions specifically dominated by wetlands, soil temperature and moisture at 10 cm depth were important explanatory variables while in regions that were not wetlands, soil temperature and moisture at 40 cm depth were more important, suggesting deeper methanogenesis in drier soils. Although similar environmental drivers have been found in the past to control CH4 emissions at local scales, this study shows that they can be used to generate a statistical model to estimate the regional-scale net CH4 budget.

scholarly journals Novel approaches to improve estimates of short-lived halocarbon emissions during summer from the Southern Ocean using airborne observations

2019 ◽  
Vol 19 (22) ◽  
pp. 14071-14090
Author(s):  
Elizabeth Asher ◽  
Rebecca S. Hornbrook ◽  
Britton B. Stephens ◽  
Doug Kinnison ◽  
Eric J. Morgan ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Sea Ice ◽  
Dispersion Model ◽  
Particle Dispersion ◽  
Marine Phytoplankton ◽  
Shortwave Radiation ◽  
Atmospheric Measurements ◽  
Chl A ◽  
Novel Approaches ◽  
Model Measurement

Abstract. Fluxes of halogenated volatile organic compounds (VOCs) over the Southern Ocean remain poorly understood, and few atmospheric measurements exist to constrain modeled emissions of these compounds. We present observations of CHBr3, CH2Br2, CH3I, CHClBr2, CHBrCl2, and CH3Br during the O2∕N2 Ratio and CO2 Airborne Southern Ocean (ORCAS) study and the second Atmospheric Tomography mission (ATom-2) in January and February of 2016 and 2017. Good model–measurement correlations were obtained between these observations and simulations from the Community Earth System Model (CESM) atmospheric component with chemistry (CAM-Chem) for CHBr3, CH2Br2, CH3I, and CHClBr2 but all showed significant differences in model : measurement ratios. The model : measurement comparison for CH3Br was satisfactory and for CHBrCl2 the low levels present precluded us from making a complete assessment. Thereafter, we demonstrate two novel approaches to estimate halogenated VOC fluxes; the first approach takes advantage of the robust relationships that were found between airborne observations of O2 and CHBr3, CH2Br2, and CHClBr2. We use these linear regressions with O2 and modeled O2 distributions to infer a biological flux of halogenated VOCs. The second approach uses the Stochastic Time-Inverted Lagrangian Transport (STILT) particle dispersion model to explore the relationships between observed mixing ratios and the product of the upstream surface influence of sea ice, chl a, absorption due to detritus, and downward shortwave radiation at the surface, which in turn relate to various regional hypothesized sources of halogenated VOCs such as marine phytoplankton, phytoplankton in sea-ice brines, and decomposing organic matter in surface seawater. These relationships can help evaluate the likelihood of particular halogenated VOC sources and in the case of statistically significant correlations, such as was found for CH3I, may be used to derive an estimated flux field. Our results are consistent with a biogenic regional source of CHBr3 and both nonbiological and biological sources of CH3I over these regions.

scholarly journals The variability of methane, nitrous oxide and sulfur hexafluoride in Northeast India

2013 ◽  
Vol 13 (6) ◽  
pp. 17053-17085
Author(s):  
A. L. Ganesan ◽  
A. Chatterjee ◽  
R. G. Prinn ◽  
C. M. Harth ◽  
P. K. Salameh ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Large Scale ◽  
Sulfur Hexafluoride ◽  
Asian Summer Monsoon ◽  
Dispersion Model ◽  
Particle Dispersion ◽  
South Asian Summer Monsoon ◽  
Atmospheric Measurements ◽  
Large Variability ◽  
Ch4 And N2o

Abstract. High-frequency atmospheric measurements of methane (CH4), nitrous oxide (N2O) and sulfur hexafluoride (SF6) from Darjeeling, India are presented from December 2011 (CH4)/March 2012 (N2O and SF6) through February 2013. These measurements were made on a gas chromatograph equipped with a flame ionization detector and electron capture detector and were calibrated on the Tohoku University, the Scripps Institution of Oceanography (SIO)-98 and SIO-2005 scales for CH4, N2O and SF6, respectively. The observations show large variability and frequent pollution events in CH4 and N2O mole fractions, suggesting significant sources in the regions sampled by Darjeeling throughout the year. In contrast, SF6 mole fractions show little variability and only occasional pollution episodes, likely due to weak sources in the region. Simulations using the Numerical Atmospheric dispersion Modelling Environment (NAME) particle dispersion model suggest that many of the enhancements in the three gases result from the transport of pollutants from the densely populated Indo-Gangetic plains of India to Darjeeling. The meteorology of the region varies considerably throughout the year from Himalayan flows in the winter to the strong South Asian summer monsoon. The model is consistent in simulating a diurnal cycle in CH4 and N2O mole fractions that is present during the winter but absent in the summer and suggests that the signals measured at Darjeeling are dominated by large scale (~100 km) flows rather than local (<10 km) flows.

scholarly journals The variability of methane, nitrous oxide and sulfur hexafluoride in Northeast India

2013 ◽  
Vol 13 (21) ◽  
pp. 10633-10644 ◽  
Author(s):  
A. L. Ganesan ◽  
A. Chatterjee ◽  
R. G. Prinn ◽  
C. M. Harth ◽  
P. K. Salameh ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Large Scale ◽  
Sulfur Hexafluoride ◽  
Asian Summer Monsoon ◽  
Dispersion Model ◽  
Particle Dispersion ◽  
South Asian Summer Monsoon ◽  
Atmospheric Measurements ◽  
Large Variability ◽  
Ch4 And N2o

Abstract. High-frequency atmospheric measurements of methane (CH4), nitrous oxide (N2O) and sulfur hexafluoride (SF6) from Darjeeling, India are presented from December 2011 (CH4)/March 2012 (N2O and SF6) through February 2013. These measurements were made on a gas chromatograph equipped with a flame ionization detector and electron capture detector, and were calibrated on the Tohoku University, the Scripps Institution of Oceanography (SIO)-98 and SIO-2005 scales for CH4, N2O and SF6, respectively. The observations show large variability and frequent pollution events in CH4 and N2O mole fractions, suggesting significant sources in the regions sampled by Darjeeling throughout the year. By contrast, SF6 mole fractions show little variability and only occasional pollution episodes, likely due to weak sources in the region. Simulations using the Numerical Atmospheric dispersion Modelling Environment (NAME) particle dispersion model suggest that many of the enhancements in the three gases result from the transport of pollutants from the densely populated Indo-Gangetic Plains of India to Darjeeling. The meteorology of the region varies considerably throughout the year from Himalayan flows in the winter to the strong south Asian summer monsoon. The model is consistent in simulating a diurnal cycle in CH4 and N2O mole fractions that is present during the winter but absent in the summer and suggests that the signals measured at Darjeeling are dominated by large-scale (~100 km) flows rather than local (<10 km) flows.

Sign in / Sign up

Export Citation Format

Share Document