Assessment Of Methane Emissions Research Articles

GIS-Based Assessment of Methane Emission from Livestock in India

GIS-Based Assessment of Methane Emission from Livestock in India

Assessment of methane emissions from the U.S. oil and gas supply chain

Methane emissions from the U.S. oil and natural gas supply chain were estimated by using ground-based, facility-scale measurements and validated with aircraft observations in areas accounting for ~30% of U.S. gas production. When scaled up nationally, our facility-based estimate of 2015 supply chain emissions is 13 ± 2 teragrams per year, equivalent to 2.3% of gross U.S. gas production. This value is ~60% higher than the U.S. Environmental Protection Agency inventory estimate, likely because existing inventory methods miss emissions released during abnormal operating conditions. Methane emissions of this magnitude, per unit of natural gas consumed, produce radiative forcing over a 20-year time horizon comparable to the CO2 from natural gas combustion. Substantial emission reductions are feasible through rapid detection of the root causes of high emissions and deployment of less failure-prone systems.

Nam Theun 2 Reservoir four years after commissioning: significance of drawdown methane emissions and other pathways

Hydro-reservoirs are recognized as potentially significant emitters of methane at the global scale. However, there are still large uncertainties in estimating such emissions at this scale due to the lack of comprehensive measurements of methane emissions in a wide range of climatic zones, for hydro-reservoirs with variable characteristics, and including all emissions pathways. This study presents an assessment of methane emissions for the 2013 year, that is four years after commissioning, for the Nam Theun 2 hydro-system, a 489 km² subtropical reservoir with a large drawdown area. All of the major pathways have been computed here, i.e., ebullition, diffusion, degassing, emissions from the drawdown area, and diffusion from downstream, and included in an emission budget. Emissions from the upstream area strongly dominate when compared to the downstream ones, a feature quite specific to the Nam Theun 2 reservoir. The drawdown area and the emissions by diffusion downstream represented a small contribution to the total emissions. About half of the methane is emitted during the four months of the warm dry season (from mid-February to Mid-June). Total methane emissions in NT2 have decreased from 35.6±2.6 Gg(CH4 ) year-1 in 2010 to 24.5±1.5 Gg(CH4 ) year-1 in 2013 though this difference was not found to be quite statistically significant.

Development of a mobile tracer correlation method for assessment of air emissions from landfills and other area sources

A standardized version of a mobile tracer correlation measurement method was developed and used for assessment of methane emissions from 15 landfills in 56 field deployments from 2009 to 2013. Using cavity ring-down spectroscopy and acetylene tracer gas, this method has potential implementation and cost advantages over other mobile tracer correlation approaches. The field deployment, data acquisition and analysis procedures, and a range of use conditions are discussed. To test real-world method application, the field studies were conducted by engineering technician-level personnel under randomly-encountered daytime atmospheric conditions. A total of 1876 mobile tracer correlation measurement transects were attempted over 131 field sampling days. Of these, 1366 transect (73%) were successfully completed and passed basic data acceptance criteria as valid measurement attempts. Invalid data were caused primarily by equipment failures, transect execution errors, or poor plume transport conditions. Valid transects were further analyzed using signal-to-noise ratio, plume correlation, and emission rate difference method quality indicators described here. Encountered scenarios that can result in high emission measurement uncertainty or bias are discussed in term of these indicators. Reasonable values for the acceptance levels of the method quality indicators that help protect against method errors and reduce measurement noise are discussed. The application of a default indicator set to the valid data yield 456 transects (33%) that pass data acceptance criteria. Transects that fail were associated with insufficient advected plume transport, poor correlation between the tracer and source plumes, and potential emissions pooling conditions.

Assessment of Methane Emissions from Oil and Gas Production Pads using Mobile Measurements

A new mobile methane emissions inspection approach, Other Test Method (OTM) 33A, was used to quantify short-term emission rates from 210 oil and gas production pads during eight two-week field studies in Texas, Colorado, and Wyoming from 2010 to 2013. Emission rates were log-normally distributed with geometric means and 95% confidence intervals (CIs) of 0.33 (0.23, 0.48), 0.14 (0.11, 0.19), and 0.59 (0.47, 0.74) g/s in the Barnett, Denver-Julesburg, and Pinedale basins, respectively. This study focused on sites with emission rates above 0.01 g/s and included short-term (i.e., condensate tank flashing) and maintenance-related emissions. The results fell within the upper ranges of the distributions observed in recent onsite direct measurement studies. Considering data across all basins, a multivariate linear regression was used to assess the relationship of methane emissions to well age, gas production, and hydrocarbon liquids (oil or condensate) production. Methane emissions were positively correlated with gas production, but only approximately 10% of the variation in emission rates was explained by variation in production levels. The weak correlation between emission and production rates may indicate that maintenance-related stochastic variables and design of production and control equipment are factors determining emissions.

Assessment of Methane (CH4) Emissions from Rice Paddy and Crop Residues Burning in 2011 with the IPCC Guideline Methodology

Rice cultivation in the paddy field and the burning of crop residues have been identified as the important sources of methane emission in agricultural sector. This study aimed at assessment of the methane emission from croplands in the year of 2011 with the IPCC guideline methodology. Methane from rice cultivation was emitted 6,813 <TEX>$CO_2$</TEX>-eq Gg in 2011. According to the water management, methane emission amounts by continuously flooded and intermittently flooded were 1,499 and 5,314 <TEX>$CO_2$</TEX>-eq Gg, respectively. Methane emission by crop residues burning was highest in red pepper and followed by rice straw, pulses and barely in 2011. Methane emission by field burning was very little compared with rice cultivation.

Assessment of methane emission and oxidation at Air Hitam Landfill site cover soil in wet tropical climate

Methane (CH₄) emissions and oxidation were measured at the Air Hitam sanitary landfill in Malaysia and were modeled using the Intergovernmental Panel on Climate Change waste model to estimate the CH₄ generation rate constant, k. The emissions were measured at several locations using a fabricated static flux chamber. A combination of gas concentrations in soil profiles and surface CH₄ and carbon dioxide (CO₂) emissions at four monitoring locations were used to estimate the CH₄ oxidation capacity. The temporal variations in CH₄ and CO₂ emissions were also investigated in this study. Geospatial means using point kriging and inverse distance weight (IDW), as well as arithmetic and geometric means, were used to estimate total CH₄ emissions. The point kriging, IDW, and arithmetic means were almost identical and were two times higher than the geometric mean. The CH₄ emission geospatial means estimated using the kriging and IDW methods were 30.81 and 30.49 gm(−2) day(−1), respectively. The total CH₄ emissions from the studied area were 53.8 kg day(−1). The mean of the CH₄ oxidation capacity was 27.5 %. The estimated value of k is 0.138 year(−1). Special consideration must be given to the CH₄ oxidation in the wet tropical climate for enhancing CH₄ emission reduction.

Using GIS to Assess the Contribution of Farming Activities towards Climate Change in the State of Mississippi

The study uses primary data, descriptive statistics, Geographic Information Systems (GIS) and correlation analysis to analyze the contributions of farming activities to climate change in Mississippi between 1992 through 2002. This involved the assessment of methane emissions from rice cultivation in the state of Mississippi as well as the relationship between the levels of methane gas concentration and other variables associated with rice production. In highlighting the extent to which rice production activities fuel climate change, the results of the study not only showed greenhouse gas emission related rice production activities to be on the rise, but there is a relationship between methane emissions and rice farming. The GIS analysis also points to a visible concentration of rice production activities associated with methane emissions in the major counties of Bolivia, Sunflower and Washington along the Northwest portion of the state. While this raises the threats of climate change predictors in the area. To remedy the problems, the paper suggests five future lines of actions from the need for education to the promotion of emission trading.

00/01079 Assessment of methane emission in underground mining exploitation in Vietnam

00/01079 Assessment of methane emission in underground mining exploitation in Vietnam

Contribution of remote sensing techniques to the assessment of methane emission from large tropical reservoirs

Abstract The objective of this paper is to exemplify the use of remote sensing to assess methane emissions from reservoirs. Man‐made reservoirs seem to behave as flood plain environments that are known to make a significant contribution to tropospheric methane (CH4). Methane emissions from the flood plain, however, are variable: open water environments produce lower fluxes than those covered by floating aquatic vegetation. TM/Landsat images were used to identify aquatic habitats resulting from the construction of the three largest reservoirs in the Amazon region: Tucurui, Balbina and Samuel. These habitats are: open water, floating aquatic vegetation, and transition zone. The area covered by each of these environments was computed for each of the reservoirs. Data on the methane emission for these various environments were not available. Published data were then used to compute their likely contribution to the methane flux, assuming that the reservoir's environments were similar to those on which the data ...

Review and assessment of methane emissions from wetlands

The number of emission measurements of methane (CH 4) to the atmosphere has increased greatly in recent years, as recognition of its atmospheric chemical and radiative importance becomes widespread. In this report, we review progress on estimating and understanding both the magnitude of, and controls on, emissions of CH 4 from natural wetlands. We also calculate global wetland CH 4 emissions using this extensive flux data base and the wetland areas compiled and published by Matthews and Fung (1987). Tropical regions (20° N-30° S) were calculated to release 66 TgCH 4/yr, 60% of the total wetland emission of 109 Tg/yr. Flux data from tropical wetlands, reported only within the last four years, are currently restricted in geographic coverage. Additional data from other regions will be required to confirm these calculated large emissions. Although emissions from subtropical and temperate wetlands (45° N-20° N and 30° S-50° S) were relatively low at 5 Tg/yr, the process-oriented focus of most of the research in this region suggests that work at these latitudes may serve as models to examine controls and possible uncertainties in estimating fluxes. These types of efforts are frequently not possible in more remote, globally significant wetlands. Northern wetlands (north of 45° N) were calculated to release a total of 38 TgCH 4/yr (34% of total flux); 34 Tg/yr from wet soils and 4 Tg/yr from relatively dry tundra. These latitudes have been the focus of recent intensive research. Significant differences between the relatively large flux data bases accumulated in the two primary measurement areas, northern Minnesota and the Hudson Bay Lowlands of Canada, indicate that extrapolation from one wetland region to another may be subject to considerable error. Global emissions were also compared to fluxes calculated using the wetland areas published by Aselmann and Crutzen (1989) in an effort to assess uncertainties due to wetland area estimates. Further refinement of wetland CH 4 emissions awaits flux measurements from large areas currently lacking data, particularly in the tropics and the Siberian Lowlands, more realistic assessments of seasonal active periods, and accurate, up-to-date habitat classification and measurement.