Fugitive Emissions Research Articles

Quantification of fugitive emissions from an oil sands tailings pond by eddy covariance

Oil sands tailings ponds are sources of greenhouse gasses (GHG) and air pollutants. The flux chamber technique, typically used to measure emissions from tailings ponds, samples a small area for a short duration, which may not account for the spatial and temporal variability of emissions from oil sands tailings ponds. The eddy covariance (EC) technique, with large spatial coverage and better temporal resolution, is a promising method to improve the accuracy of emission flux quantification. A field campaign was conducted to measure emissions from an oil sands tailings pond in Alberta using an EC system. Average CH4 and CO2 emission fluxes were 4.56 × 10−2 g/(m2-d) and 3.59 g/(m2-d), respectively. Diurnal and daily variations of CH4 and CO2 emission fluxes were strong with relative standard deviations of 97–158%. Nighttime (18:30 to 8:00, inclusive) CH4 average emission flux (6.55 × 10−2 g/(m2-d)) was 2.8 times daytime (8:30 to 18:00, inclusive) CH4 flux (2.32 × 10−2 g/(m2-d)) while nighttime CO2 average emission flux (2.97 g/(m2-d)) was 0.7 times daytime CO2 emission flux (4.29 g/(m2-d)). Pearson correlation test results suggest that short-term (i.e., days to weeks) variations of CH4 and CO2 emission fluxes measured in this study were not strongly (but can be weakly) correlated with meteorological variables or the 90% cumulative flux contour distance. The CH4 and CO2 emission fluxes determined in this study were of the same order of magnitude as those from a previous study that used the EC technique at the same tailings pond. CO2 fluxes in this study were similar while CH4 fluxes in this study were more than an order of magnitude lower than fluxes based on flux chamber measurements conducted by a 3rd party at the same location and in the same month and year. Continuous, real-time, and long-term monitoring of tailings ponds emissions is necessary to reduce uncertainty and improve representativeness and accuracy of emission flux quantification.

Proposal of a method for evaluating odour emissions from refinery storage tanks

Oil refineries are one of the greatest type of industrial plant which can lead to emission of VOC and sulphur compounds. Such emissions often originate a problem of odour pollution in the human settlements located around the refinery. In many cases, odour nuisances lead the local authorities to intervene, sometimes by closing the whole plant. Odour emissions in refineries typically arise from the operating process: the aim of this work is to propose a method for the evaluation of the Odour Emission Rates from the different sources of a refinery. More in detail, the proposed method aims to quantify the Odour Emission Rate from the fugitive emissions relevant to storage tanks, whose evaluation is very complex due to the difficulty of determining both a representative odour concentration and an emitted air flow representative of this kind of sources. This method first quantifies the mass emission from the tanks, by means of the software US EPA TANKS 4.09, and after the so called “Hydrocarbon Odour Emission Capacity”, associated with different hydrocarbons mixtures. By coupling this information, it is finally possible to give an estimate of the Odour Emission Rate deriving from a storage tank and use it in an atmospheric dispersion model.

Fugitive Methane and Odour Emission Characterization at a Composting Plant using Remote Sensing Measurements

<p>Gaseous emissions of biowaste treatment facilities have several adverse effects. In Germany, a law to collect biological waste separately was introduced in January 2015. Since then there is a discussion about greenhouse gases which could be emitted in a significant rate and exceed the positive aspects. Default factors for methane and nitrous oxide from biological treatments given by the Intergovernmental Panel on Climate Change (IPPC) suggests that fugitive emissions even from composting processes should not be neglected. The research work presents an innovative method to quantify fugitive methane and odour emissions at a composting plant. The proposed method uses a combination of a remote sensing measurements and the application of a backwards Lagrangian stochastic (bLs) based micrometeorological dispersion modelling. The remote sensing technology is based on the absorption of infrared light with a wavelength sensitive to the substance to be determined. With the downwind measured methane concentration deducted by the upwind measured background concentration and the known wind conditions, a gas dispersion is simulated back in time to estimate the gas emission rate of a plant. Using the methane emissions as a tracer for dispersion characteristics in the atmosphere it is even possible to estimate a more accurate odour emission rate from passive sources at composting plants.</p>

Improving air quality model predictions of organic species using measurement-derived organic gaseous and particle emissions in a petrochemical-dominated region

Abstract. This study assesses the impact of revised volatile organic compound (VOC) and organic aerosol (OA) emissions estimates in the GEM-MACH (Global Environmental Multiscale–Modelling Air Quality and CHemistry) chemical transport model (CTM) on air quality model predictions of organic species for the Athabasca oil sands (OS) region in Northern Alberta, Canada. The first emissions data set that was evaluated (base-case run) makes use of regulatory-reported VOC and particulate matter emissions data for the large oil sands mining facilities. The second emissions data set (sensitivity run) uses total facility emissions and speciation profiles derived from box-flight aircraft observations around specific facilities. Large increases in some VOC and OA emissions in the revised-emissions data set for four large oil sands mining facilities and decreases for others were found to improve the modeled VOC and OA concentration maxima in facility plumes, as shown with the 99th percentile statistic and illustrated by case studies. The results show that the VOC emission speciation profile from each oil sand facility is unique and different from standard petrochemical-refinery emission speciation profiles used for other regions in North America. A significant increase in the correlation coefficient is reported for the long-chain alkane predictions against observations when using the revised emissions based on aircraft observations. For some facilities, larger long-chain alkane emissions resulted in higher secondary organic aerosol (SOA) production, which improved OA predictions in those plumes. Overall, the use of the revised-emissions data resulted in an improvement of the model mean OA bias; however, a decrease in the OA correlation coefficient and a remaining negative bias suggests the need for further improvements to model OA emissions and formation processes. The weight of evidence suggests that the top-down emission estimation technique helps to better constrain the fugitive organic emissions in the oil sands region, which are a challenge to estimate given the size and complexity of the oil sands operations and the number of steps in the process chain from bitumen extraction to refined oil product. This work shows that the top-down emissions estimation technique may help to constrain bottom-up emission inventories in other industrial regions of the world with large sources of VOCs and OA.

Using multi-site data to apportion PM-bound metal(loid)s: Impact of a manganese alloy plant in an urban area

The identification and quantification of the PM emission sources influencing a specific area is vital to better assess the potential health effects related to the PM exposure of the local population. In this work, a multi-site PM10 sampling campaign was performed in seven sites located in the southern part of the Santander Bay (northern Spain), an urban area characterized by the proximity of some metal(loid) industrial sources (mainly a manganese alloy plant). The total content of V, Mn, Fe, Ni, Cu, Zn, As, Mo, Cd, Sb and Pb was determined by ICP-MS. This multi-site dataset was evaluated by positive matrix factorization (PMF) in order to identify the main anthropogenic metal(loid) sources impacting the studied area, and to quantify their contribution to the measured metal(loid) levels. The attribution of the sources was done by comparing the factor profiles obtained by the PMF analysis with representative profiles from known metal(loid) sources in the area, included in both the European database SPECIEUROPE (V2.0) and the US database EPA-SPECIATE (V4.5) or calculated from literature data. In addition, conditional bivariate probability functions (CBPF)s were used to assist in the identification of the sources. Four metal(loid) sources were identified: Fugitive and point source emissions from the manganese alloy plant (49.9% and 9.9%, respectively), non-exhaust traffic emissions (38.3%) and a minor source of mixed origin (1.8%). The PMF analysis was able to make a clear separation between two different sources from the manganese alloy plant, which represented almost 60% of the total measured metal(loid) levels, >80% of these emissions being assigned to fugitive emissions. These results will be useful for the assessment of the health risk associated with PM10-bound metal(loid) exposure and for the design of efficient abatement strategies in areas impacted by similar industries.

Life cycle greenhouse gas emissions and freshwater consumption of liquefied Marcellus shale gas used for international power generation

The recent growth in U.S. natural gas reserves has led to interest in exporting liquefied natural gas (LNG) to countries in Asia, Europe and Latin America. Here, we estimate the life cycle greenhouse gas (GHG) emissions and life cycle freshwater consumption associated with exporting Marcellus shale gas as LNG for power generation in different import markets. The well-to-wire analysis relies on operations data for gas production, processing, transmission, and regasification, while also accounting for the latest measurements of fugitive CH4 emissions from U.S. natural gas activities. To estimate GHG emissions from a typical U.S. liquefaction facility, we use a bottom-up process model that can evaluate the impact of gas composition, technology choices for gas treatment and on-site power generation on overall facility GHG emissions. For LNG exports to Mumbai, India for power generation in a combined cycle power plant with 50% efficiency, the base case life cycle GHG emissions, freshwater consumption, and CH4 emissions as fraction of gross gas production are estimated to be 473 kg CO2eq/MWh (80% confidence interval: 452–503 kg CO2eq/MWh), 243 gal/MWh (80% CI: 200–300 gal/MWh) and 1.2% (80% CI: 0.81–1.79%), respectively. Among all destinations considered, typical life cycle GHG emissions range from 459 kg CO2eq/MWh to 473 kg CO2eq/MWh, with GHG emissions from liquefaction, shipping and regasification contributing 7–10% of life cycle GHG emissions.

Techno-economic and environmental assessments of storing woodchips and pellets for bioenergy applications

Storage is the critical operation within the biomass supply chain to reduce feedstock supply risks and to manage smooth year-around operations of a biorefinery or a bioenergy plant. This paper analyzed the economic and environmental impacts of four different biomass storage systems for woodchips (Outdoor-open, Outdoor-tarped, Indoor, and Silo) and two systems for pellets (Indoor and Silo). Storage cost includes the costs for handling (including ventilation in case of silo storage), infrastructure investment, and dry matter loss (DML) for each system. The estimation of total greenhouse gas (GHG) emissions includes the fugitive emissions from storage piles and emissions due to electricity and fuel consumption for each system. Among four storage systems, the outdoor-tarped ($15.0 ODMT−1, ODMT: Oven Dry Metric Ton) and silo ($5.8 ODMT−1) storage were the least-cost options for woodchips and pellets respectively. However, silo-storage could be the most promising option for storing woodchips ($5.8 ODMT−1) and pellets ($2.3 ODMT−1), if it is used for short-term (two months) and frequently (at least six times) in a year. The total GHG emissions for six-month storage were 2.8–11.8 kgCO2e ODMT−1 for woodchips and 8.6–42.0 kgCO2e ODMT−1 for pellets. During Outdoor-open storage, the lower heating value of woodchips could drop to 37% due to increased dry-matter loss (DML) and moisture content. The initial moisture content, bulk density, DML, and resource required during handling were the most sensitive parameters influenced the storage performances of both woodchips and pellets. This study has demonstrated that a combination of different storage options along the supply chain could reduce the total biomass storage cost for a biorefinery or power plant.

Ozone Generation Potential and Highly Contributing Substances of NMOCs from Landfill Working Face

Non-methane organic compounds (NMOCs) are major ozone precursors in atmospheric photochemical reactions. The working face of a landfill is a significant source of fugitive NMOC emissions. In order to control tropospheric ozone pollution, it is necessary to minimize NMOCs, and this requires identification of contributing substances. In this study, gas samples were collected from the working face of a landfill and analyzed. Their ozone formation potential was calculated using the propylene-equivalent concentration method and the maximum incremental reactivity method. In total, 36 kinds of substances met the standard for detection frequency and concentration. The average annual concentration of NMOCs was about 10000 μg·m-3, with total concentration greatest in summer. Concentrations of materials were as follows:oxygenated compounds > sulfur compounds > halogenated hydrocarbons > benzene series > hydrocarbons. Based on the results of the two calculation methods, ethanol, m-xylene, propylene, ethyl acetate, and n-pentane were found to be significant ozone formation contributors across the whole year. The pattern for spring was similar. Contributors to high ozone formation were ethanol, 1-butene, toluene, cyclohexane, and styrene in summer and spring, while ethanol contributed very significantly in winter. The propylene-equivalent concentration method was found to be more suitable for estimating ozone formation potential from the working face.

Removal of acetone from air emissions by biotrickling filters: providing solutions from laboratory to full-scale

A full-scale biotrickling filter (BTF) treating acetone air emissions of wood-coating activities showed difficulties to achieve outlet concentrations lower than 125 mg C m−3, especially for high inlet concentrations and oscillating emissions. To solve this problem, a laboratory investigation on acetone removal was carried out simulating typical industrial conditions: discontinuous and variable inlet concentrations and intermittent spraying. The results were evaluated in terms of removal efficiency and outlet gas emission pattern. Industrial emissions and operational protocols were simulated: inlet load up to 70 g C m−3 h−1 during 2 cycles of 4 h per day and intermittent trickling of 15 min per hour. The outlet gas stream of the pollutant was affected by intermittent spraying, causing a fugitive emission of pollutant. Complete removal efficiency was obtained during non-spraying. Average removal efficiencies higher than 85% were obtained, showing the feasibility of BTF to treat acetone. The outlet gas stream showed a clear dependence on the pH of the trickling liquid, decreasing the removal at pH < 5.5. Thus, a proper control of alkalinity, with regular NaHCO3 addition, was required for successful operation. The laboratory findings were fruitfully transferred to the industry, and the removal of acetone by full-scale BTF was improved.

E&amp;P Notes (September 2018)

E&amp;P Notes (September 2018)

Air quality assessment and modelling of pollutants emission from a major cement plant complex in Nigeria

Cement manufacturing contributes to the elevation of air pollutants in the atmosphere and thus impact on the nearby communities. This study assessed air quality in a major Cement Plant in Ibese Ogun State, Nigeria, through an ambient air quality monitoring and air emission dispersion modelling. Particulate Matter (PM) and gaseous pollutants were measured using portable samplers and AERMOD View was used for the emission dispersion modelling. Combustion products including SO 2 , NO, NO 2 , CO and VOCs were the gaseous pollutants detected along the complex fenceline and in the receptor environments. Pollutants measurements were undertaken at 23 locations within the fence line and receptor locations. The daily SO 2 and NO 2 Federal Ministry of Environment - Nigeria (FMEnv) limits were exceeded in ten (10) and five (5) locations along the fenceline, respectively. Particulates were detected in all the locations along the fenceline and in the communities. The cumulative gaseous pollutants resulting from simultaneous operations of all the identified plant air emission point sources are 0.01–276.13% of their respective 24-h limits along the fenceline, with 1-h SO 2 within the threshold limit at all fenceline locations, but 1-h NO X exceeds the threshold limit at all locations 16–21 times. The 24-h CO and VOCs are within their limits at all fenceline locations; however the 24-h SO 2 and NO X are breaching the limits at some locations 30–34 times (0.34–0.39% of the investigation period) and 44–87 times, respectively. Daily and Annual averaging concentrations of PM 10 was 14.32–31.54% and 4.90–52.60% of their respective limits. Process facilities are the major point sources of atmospheric emissions identified in the factory. Several fugitive emission sources were also identified during the field work. Comprehensive evaluation of the fugitive emission sources should be carried out in the cement plant for immediate attention. • Pollutants measurements were undertaken at 23 locations around a Nigerian major cement plant complex. • AERMOD View was used to model the impact of the cement plant activities on the receptor environment. • The daily SO 2 and NO 2 FMEnv - Nigeria and the World Bank’s limits were exceeded in 10 locations. • Process facilities are the major point sources of atmospheric emissions identified in the factory.

Life cycle assessment of passively aerated composting in gas-permeable bags of olive mill waste

In Italy, composting olive mill waste has become a common practice, since it mitigates the environmental problems associated with spreading the waste on land. Compost can be used to prepare growth media for plant nursery cultivation as a substitute for peat, a non-renewable resource whose extraction has long raised environmental concerns. Here, we investigate two common composting procedures—open windrow and static-pile in gas-permeable bags—and compare them to evaluate their environmental impact. We perform a cradle-to-grave life cycle assessment (LCA) in accordance with ISO 14040 and 14044. The LCA considers carbon storage in the soil after 100 years, fugitive greenhouse gas (GHG) emissions, and the impacts avoided by substituting for peat. We use cumulative energy demand, global warming potential (GWP), acidification potential, and eutrophication potential indicators in a contribution analysis and explore how the re-use of olive pits for energy production and reduction of commercial fertilizers improves the environmental balance. We also present a scenario analysis that indicates how parameter fluctuations affect the results. Our study shows that peat’s impacts can be significantly reduced from 1162.3 to 96.3 kg CO2-eq/Mg for open windrow compost or 43.1 kg CO2-eq/Mg for static-pile compost in gas-permeable bags. For static-pile composting, the lack of volatile organic compound and ammonia emissions and the detection of oxygen concentrations above 12% vol. suggest fully aerobic conditions. Fugitive greenhouse gas emissions were the most important contributions to the GWP. In the contribution analysis for static-pile composting, the avoidance of compost spreading and the carbon storage effect (due to compost usage) contributed 54% of the overall impacts to GWP and between 21 and 45% to the other indicators. This LCA study illustrates how horticulturists can improve their resource management practices by recycling olive mill waste materials. Proper management of composting unit aeration can reduce fugitive GHG emissions.

Fugitive Emissions and Health Implications of Plancha-Type Stoves.

Plancha-type stoves have been widely disseminated in Mexico and Central America, but the contribution of fugitive emissions from these stoves to indoor air concentrations has been poorly quantified. In this study, fugitive emissions were measured for four plancha-type cookstoves most disseminated in Mexico (Patsari, ONIL, Ecostufa, and Mera-Mera). In controlled testing, fugitive emissions from plancha-type chimney stoves ( n = 15 for each stove) were on average 5 ± 3% for PM2.5 and 1 ± 1% for CO, much lower than defaults in WHO Guidelines (25 ± 10%). Using a Monte Carlo single zone model with locally measured parameters, average kitchen concentrations resulting from fugitive emissions were 15 ± 9 μg/m3 for PM2.5 and 0.06 ± 0.04 mg/m3 for CO. On the basis of these models, plancha-type stoves meet benchmarks for WHO Air Quality Guidelines (AQG) Interim Target I for PM2.5 and the 24 h AQG for CO, respectively, with on average 97% of homes meeting the guideline for PM2.5. Similarly, all four plancha-type stoves were ISO IWA Tier 4 for indoor emissions of CO and Tier 3 for indoor emissions of PM2.5. Three-dimensional computational fluid dynamics (CFD) analysis was used to estimate neighborhood pollution impacts of upstream chimney emissions. When chimney emissions were included as background concentrations combined with indoor contributions from fugitive emissions, plancha-type stoves would still meet the WHO AQG Annual Interim Target I for PM2.5 and the 24 h AQG for CO for the scenario modeled in this study.

Improving spatial resolution of soil fugitive dust emission inventory using RS-GIS technology: An application case in Tianjin, China

Soil fugitive dust (SFD) contributes significantly to ambient particulate matter (PM) in Northern China. In this study, an improved method is developed to establish a high spatial resolution SFD emission inventory through the use of remote sensing (RS)-geographical information system (GIS) technology based on the wind erosion equation (WEQ). The purpose of the application of RS is to obtain vegetation coverage data, which can be achieved through the supervised classification of land use and retrieval of vegetation coverage. Vegetation coverage was then converted to vegetative cover factor by adopting the approach given in this study. Given that the excellent spatial data analysis and the calculation function of the GIS, the high-spatial-resolution vegetative cover factor, soil texture, control efficiency, and other parameters could be multilayer nested and calculated. The SFD emission inventory is eventually obtained, with the highest spatial resolution of 30 m. As an application case, the SFD emission inventory of Tianjin city in 2013 was established with an activity level of 6383 sq. km. bare land, and 27.14 kt, 14.39 kt, 6.240 kt emitted TSP, PM10, PM2.5, respectively. Moreover, the Calpuff model was used to simulate the contributions of SFD to ambient springtime PM10 and compare the predicted PM10 to observation data to explore the feasibility of this method. This study could be a reference for the establishment of a high spatial resolution SFD emission inventory in dust dominated regions, providing information that will meet the requirement of air quality models and support the efforts of government to reduce particulate matter pollution.

Leak prediction through porous compressed packing rings: A comparison study

The Prediction of leak rate is a significant challenge in the design of bolted flange joints and valves. With the increase of the strict regulations on fugitive emissions appropriate leakage-based standard design procedures are required. Fluid flow through porous media is a very attractive theory that can be used to predict leak rates through gaskets and compression packings. Valves that are the major source of fugitive emissions in the category of pressurized equipment use compression packings and seals the design of which is not covered by a standard design procedure.In this study, three different models; capillary, concentric cylinders, and modified Darcy's models, are used to characterize the sealing behavior of graphite-based compression packing rings. Based on data from several experimental tests, the ability of each model to predict accurate leak rates is evaluated. The comparison between the predicted and the measured leak rates is conducted for different molecular size gasses and a wide range of gland stresses and gas pressures.

Estimates of exceedances of critical loads for acidifying deposition in Alberta and Saskatchewan

Abstract. Estimates of potential harmful effects on ecosystems in the Canadian provinces of Alberta and Saskatchewan due to acidifying deposition were calculated, using a 1-year simulation of a high-resolution implementation of the Global Environmental Multiscale-Modelling Air-quality and Chemistry (GEM-MACH) model, and estimates of aquatic and terrestrial ecosystem critical loads. The model simulation was evaluated against two different sources of deposition data: total deposition in precipitation and total deposition to snowpack in the vicinity of the Athabasca oil sands. The model captured much of the variability of observed ions in wet deposition in precipitation (observed versus model sulfur, nitrogen and base cation R2 values of 0.90, 0.76 and 0.72, respectively), while being biased high for sulfur deposition, and low for nitrogen and base cations (slopes 2.2, 0.89 and 0.40, respectively). Aircraft-based estimates of fugitive dust emissions, shown to be a factor of 10 higher than reported to national emissions inventories (Zhang et al., 2018), were used to estimate the impact of increased levels of fugitive dust on model results. Model comparisons to open snowpack observations were shown to be biased high, but in reasonable agreement for sulfur deposition when observations were corrected to account for throughfall in needleleaf forests. The model–observation relationships for precipitation deposition data, along with the expected effects of increased (unreported) base cation emissions, were used to provide a simple observation-based correction to model deposition fields. Base cation deposition was estimated using published observations of base cation fractions in surface-collected particles (Wang et al., 2015).Both original and observation-corrected model estimates of sulfur, nitrogen, and base cation deposition were used in conjunction with critical load data created using the NEG-ECP (2001) and CLRTAP (2017) methods for calculating critical loads, using variations on the Simple Mass Balance model for terrestrial ecosystems, and the Steady State Water Chemistry and First-order Acidity Balance models for aquatic ecosystems. Potential ecosystem damage was predicted within each of the regions represented by the ecosystem critical load datasets used here, using a combination of 2011 and 2013 emissions inventories. The spatial extent of the regions in exceedance of critical loads varied between 1 × 104 and 3.3 × 105 km2, for the more conservative observation-corrected estimates of deposition, with the variation dependent on the ecosystem and critical load calculation methodology. The larger estimates (for aquatic ecosystems) represent a substantial fraction of the area of the provinces examined.Base cation deposition was shown to be sufficiently high in the region to have a neutralizing effect on acidifying deposition, and the use of the aircraft and precipitation observation-based corrections to base cation deposition resulted in reasonable agreement with snowpack data collected in the oil sands area. However, critical load exceedances calculated using both observations and observation-corrected deposition suggest that the neutralization effect is limited in spatial extent, decreasing rapidly with distance from emissions sources, due to the rapid deposition of emitted primary dust particles as a function of their size. We strongly recommend the use of observation-based correction of model-simulated deposition in estimating critical load exceedances, in future work.

Inhibition of fine particles fugitive emission from the open-pit lignite mines by polymer aqueous solutions

To reduce the fugitive emission of fine particles from the open-pit lignite mines, a dust suppressant was proposed by applying a blend of 0.7% water-soluble polymer (guar gum) and 0.1% nonionic surfactant (Triton X-100) in this paper. The characteristics of the polymer protection film formed on the lignite sample's surface, as well as the wetting performances of surfactants on lignite were investigated, and the simulated dust suppression experiments aimed for the inhibition of lignite fine particles were also carried out. The results showed that the polymer molecules could adhere to the lignite fine particles through the solid-bridge force to form a polymer protective film, and the solid-bridge force between the lignite particles and polymer molecules was a type of chemical force. GG solution showed excellent solidified and anti rain erosion properties. The surface tension and contact angle of GG solution were obviously reduced with adding surfactant, and Triton X-100 with a mass concentration of 0.1% was chosen as the wetting component of the lignite dust suppressant. Besides, the lignite dust suppressant showed superior removal performances on lignite fine particles, and could effectively reduced the fugitive emission of fine particles in windy weather. When the air flow speed was in the range of 5–15 m/s, the dust suppression efficiency on lignite fine particles was above 98%.

Can power to methane systems be sustainable and can they improve the carbon intensity of renewable methane when used to upgrade biogas produced from grass and slurry?

The recast of the renewable energy directive (RED recast) considers power to gas (P2G) an advanced transport biofuel if a 70% greenhouse gas savings as opposed to the fossil fuel displaced is achieved. Power to methane systems can store electricity as gas and the system can be optimised in sourcing CO2 from biogas to upgrade biogas to biomethane. The crucial question in this work is whether P2G systems can be sustainable and if they can improve the sustainability of biomethane systems using traditional upgrading systems. This work evaluates a comparative lifecycle assessment of grass and slurry (50:50 wet weight equivalent to 80:20 volatile solid weight) biomethane using P2G and/or amine scrubbing as an upgrading method. The sustainability of P2G upgrading systems is heavily dependent on the carbon intensity of the source of electricity. Using a 41% decarbonised electricity mix the sustainability was reduced using P2G and would not be deemed sustainable under criterion set by the RED recast. Maintaining a maximum of 2% fugitive CH4 emissions, using 74% slurry (wet weight) in a grass slurry feedstock, allowing for 0.6 t carbon sequestration per hectare per annum in grasslands and using an electricity mix with 85% renewable electricity the whole system including P2G upgrading could satisfy the GHG savings of 70%. However, the traditional system employing amine scrubbing had higher levels of sustainability.

Integrating Greenhouse gases (GHG) assessment for low carbon economy path: Live case study of Indian national oil company

Abstract Physical, Regulatory and Brand value risks due to climate change challenges are foreseen by businesses globally. This paper is oriented towards these challenges and prepared a comprehensive Greenhouse gases (GHG) footprint plan and identification of mitigation opportunities for ONGC, a fortune 500 and national oil company of India. Internationally recognized standards and guidelines like Greenhouse Gas Protocol, ISO-14064, and American Petroleum Institute compendium have been referred for quantifying carbon emissions in nearly real 400 + operation control facilities. The GHG inventory is based on Operational Control approach to identify the boundary for which emissions are to be quantified and two significant scopes of emissions viz Direct Emissions and Indirect Emissions are identified and quantified. The quantification concluded that GHG emission footprint for the year 2016–17 is in the range of 9 million tons of CO2equivalent. GHG emissions mainly account due to stationary combustion, fugitive emissions and wastewater treatment, which share the around 56% of total emissions. Another 24–26% of emissions are contributed due to flaring, processes by glycol dehydrator, acid gas removal units, and by electricity purchased from the grid. As a result, it has been found that ONGC emits 187 kg CO2e emissions per tonne throughput and also compared with its global peer organizations. At the organization level, “Key Industrial Sites” have been identified as contributing higher GHG emissions and accordingly key “hot-spots,” a list of 15 GHG mitigation opportunities have been proposed in the paper. Two GHG mitigation initiatives based on solar energy and bioenergy application undertaken at ONGC has also been briefed on case studies.

The methane time bomb

During much of the upper Cenozoic, the accumulation of organic matter in Polar Regions, as well as in bogs in tropical and subtropical zones, has created large reservoirs of methane, the most potent common greenhouse gas, vulnerable to release upon a rise in temperature. Global warming, driving a mean rise of 3 to 8 °C in the Arctic early during 2015- 2018, is leading toward the release of billions of tons of methane into the atmosphere, from permafrost, lakes, shallow seas and sediments. This release threatens to melt large parts of the polar ice caps, leading to meters to tens of meters of sea level rise. Global warming is a major factor leading to the disappearance of species throughout the planet at a rate two orders of magnitude faster than they would have without human interference. Compounding this effect is extensive drilling for coal seam gas, perforating the crust in several parts of the world and releasing commercial and fugitive emissions of methane into the atmosphere. The triggering of methane release induced by anthropogenic transfer of carbon to the atmosphere is leading to a major shift in state of the terrestrial atmosphere and habitats.