Assessment Of Methane Emissions Research Articles

457 Prediction of methane emissions using rumination time and milk mid-infrared spectral data via artificial neural networks

Abstract Cattle methane emissions (ME) account for approximately 6% of global anthropogenic greenhouse gas emissions. Given the challenges in measuring ME directly from individual animals, there is a need for the development of novel indirect methods. Rumination time (RT) and milk mid-infrared spectral data (MIR) show promise for the indirect assessment of ME in dairy cows. Both traits have been used as indicators of reproduction, production, and gas emission traits. Methodologies combining the use of MIR and machine learning algorithms such as artificial neural networks (ANN) for the prediction of ME have been successful; however, the inclusion of RT has not been assessed. This study aimed to evaluate the impact of RT on milk MIR-based models using ANN for the prediction of ME. One-week averages for RT, ME, and MIR from first-lactation Canadian Holstein cows (n = 412) were calculated. Six data sets were evaluated using a multilayer perceptron ANN. All sets included age at calving, season of calving and days in milk as model factors, but varied in using milk MIR data points (1,060 or 235) and including or not including RT. The ANN architecture consisted of one input layer, one hidden layer with one or more neurons, and one output layer. Results showed that sets using both RT and milk MIR data achieved correlations from 0.5 to 0.6 between predicted and observed ME. Notably, the inclusion of RT did not improve the performance of the models. Predictions may be improved through the use of larger data sets, the use of daily records, and inclusion of data across herds and lactations. Optimizing parameters of the ANN could also improve predictions. Further research is needed to fully assess the potential of RT as a predictor of ME in dairy cows.

Fluxes, Mechanisms, Influencing Factors, and Bibliometric Analysis of Tree Stem Methane Emissions: A Review

Methane (CH4) emissions exert large effects on the global climate. Tree stems are vital sources of emissions in ecosystem CH4 budgets. This paper reviewed the number of publications, journals, authors, keywords, research hotspots, and challenges. A total of 990 articles from 2006 to 2022 were collected based on the Web of Science database. The intellectual base was analyzed using CiteSpace 6.3.1 and VOSviewer 1.6.20 softwares. The results illustrated a growing trend in the study of tree stem methane emissions. The United States was the most research-active country; however, the most active institution was the Chinese Academy of Sciences in China. The research on stem methane emission by Vincent Gauci, Katerina Machacova, Zhi-Ping Wang, Kazuhiko Terazawa, Kristofer R. Covey, and Sunitha R. Pangala has had a significant impact. Current research indicates that stem CH4 emissions significantly vary among different tree species and are influenced by leaf type, forest type, tree height, whether the trees are alive or dead, and other environmental conditions (such as soil water content, air temperature, CO2 fluxes, and specific density). Soil CH4 fluxes and production by methanogens in heartwood were the primary sources of tree stem methane. Some pectin or cellulose from trees may also be converted into methane. Moreover, methane can be produced and released during the decomposition of deadwood by basidiomycetes. Furthermore, there are some trends and challenges for the future: (1) distinguishing and quantifying emissions from various sources; (2) accurately assessing the impact of floods on methane emissions is crucial, as the water level is the main factor affecting CH4 emissions; and (3) addressing the limited understanding of the microbial mechanisms of methane production in different tree species and investigating how microbial communities affect the production and emission of methane is vital. These advances will contribute to the accurate assessment of methane emissions from global ecosystems.

Comparative assessment of methane emissions from the manure of Mexican Creole Hairless Pigs and Commercial Pigs fed the same diet

AbstractPig production contributes significantly to the high environmental footprint of the livestock sector. Therefore, in this framework, a transition toward more sustainable production is essential. Local natural livestock resources, such as Mexican Creole Hairless Pigs, provide a good opportunity to achieve sustainable pig production. In the present study, a first approximation to compare the carbon emissions of Mexican Creole Hairless Pig manure from Commercial Pig manure is presented. Under the same feeding and housing conditions, the specific methane emissions of both Mexican Creole Hairless Pigs and Commercial Pigs manure were determined experimentally at room temperature. In addition, specific methane production kinetics was modeled using the Gompertz equation to estimate the specific methane production rate. The methane emission factors for Mexican Creole Hairless Pig manure (0.33 ± 0.02 kg[CO2‐eq]/LU per day) were half those of Commercial Pig manure (0.7 ± 0.04 kg[CO2‐eq]/LU per day), and biochemical manure analysis suggested that Mexican Creole Hairless Pigs had better digestibility of the diet. In general, due to physiological factors such as food intake rate and gut microbiota development, which could influence the fat and fiber digestibility of Creole genotypes, pig genotype should be included as an additional factor to estimate greenhouse gas emissions from pig manure. The production of Mexican Creole Hairless Pigs in an extensive local system is therefore an attractive option for developing new sustainable markets.

Assessment of methane emissions from oil, gas and coal sectors across inventories and atmospheric inversions

Emissions from fossil fuel exploitation are a leading contributor to global anthropogenic methane emissions, but are highly uncertain. The lack of reliable estimates hinders monitoring of the progress on pledges towards methane reductions. Here we analyze methane emissions from exploitation of coal, oil and gas for major producing nations across a suite of bottom-up inventories and global inversions. Larger disagreement in emissions exists for the oil/gas sector across the inventories compared to coal, arising mostly from disparate data sources for emission factors. Moreover, emissions reported to the United Nations Framework Convention on Climate Change are lower than other bottom-up and inversion estimates, with many countries lacking reporting in the past decades. Finally, comparison with previous global inversions, revealed a strong influence of the prior inventory on the inferred sub-sectoral emissions magnitude. This study highlights the need to improve consensus on the methodological inputs among the bottom-up inventories in order to obtain more consistent inverse modelling results at the sub-sectoral level.

Empirical assessment of methane emissions, socioeconomic factors, and infant mortality in Europe

AbstractThe 2030 United Nations Sustainable Development Goals (SDG) Target 3.9 aims to “reduce the number of deaths and illnesses from hazardous chemicals and air, water and soil pollution and contamination.” Methane belongs to the class of greenhouse gases and it is a harmful ambient atmospheric pollutant with adverse effects on human health. Hence, this paper aligns with SDG 3 and 11 to analyze the impact of methane emissions on infant mortality rate in Europe. Using an unbalanced panel data on 53 European countries from 1990 to 2018, we probe if the impact differs by union membership. Consistent findings from static and dynamic panel data techniques reveal that: methane emissions exhibit mortality‐inducing properties on the full sample, European Union (EU) and non‐EU countries by 0.041%, 0.037%, and 0.047%, respectively; EU countries show lower mortality rates relative to non‐EU countries by −0.164%; and mortality rate is persistent. Additional sensitivity checks by including nitrous oxide as a regressor indicates that it picks up the mortality effects of methane emissions due to collinearity (in the static analysis) but the aggravating impact of methane is upheld in the dynamic model. Likewise, the results are sustained when we control for outliers by excluding Russia (the largest emitter in Europe) and robustness checks using under‐5 mortality rate uphold the mortality‐increasing effect of methane emissions. Based on our empirical investigations, adequate policy recommendations are provided to help in stemming the harmful effects of methane emissions on the environment such that it reduces its adverse effect on infant mortality rate in Europe. These outcomes enrich the health economics and child health literature, and policy recommendations are discussed.

Assessment of methane emissions from pressure regulation stations in China

Pressure regulation stations are responsible for transporting natural gas downstream and are an indispensable part of the gas supply chain. In recent years, countries and enterprises have attached increasing importance to methane emission accounting. However, methane emissions from pressure regulation stations are still not comprehensively understood and accounted for. In this study, methane emissions from 21 pressure regulation stations under normal conditions were quantified using the Environmental Protection Agency's (EPA's) “Other Test Method 33 A” (OTM 33 A) in three regions of China: the eastern, northern, and central regions of China. The results showed that the emission rate from pressure regulation stations generally lied in the order of 10−1-10−3 kg/h, whereas the measured methane emission rate (MMER) with 95% confidence interval (95%CI) was 0.671 (0.066, 3.040) (kg/h), which was determined from the bootstrapping measurements from all pressure regulation stations. The MMER (95%CI) values were 0.051 (0.026, 0.102) for East China, 2.263 (0.095, 8.317) for North China, and 0.004 (0.003, 0.005) (kg/h) for Central China, showing a relatively obvious skewed distribution. Overall, MMER had a diminutive correlation with gas throughput and pipeline pressure. In contrast, the degree of correlation of pipeline pressure was higher than that of gas throughput.

Comparative Assessment of Methane Emissions from Onshore LNG Facilities Measured Using Differential Absorption Lidar.

This study provides results from measurements of methane emissions from three onshore LNG liquefaction facilities and two regasification facilities across different regions using the Differential Absorption Lidar (DIAL) technique. The measurement approach was to quantify, at each facility, emissions from the key functional elements (FEs), defined as spatially separable areas related to different identified processes. The DIAL technique enabled quantification of emissions at the FE level, allowing emission factors (EFs) to be determined for each FE using activity data. The comprehensive data set presented here should not be used for annualization, however shows the potential of what could be achieved with a larger sample size in terms of potential methane reduction and improving inventory accuracy. Among the benefits in obtaining data with this level of granularity is the possibility to compare the emissions of similar FEs on different plants including FEs present in both liquefaction and regasification facilities. Emissions from noncontinuous sources and superemitters can also be identified and quantified enabling more accurate inventory reporting and targeted maintenance and repair. Site throughput during the measurement periods was used to characterize total site EF; on average the methane losses were 0.018% and 0.070% of throughput at the regasification and liquefaction facilities, respectively.

An assessment of methane emission from the CNG cylinder testing stations in Delhi and its implication for global warming.

Methane is an important greenhouse gas, which constitutes minimum 90% of automotive grade compressed natural gas (CNG) used in India. The use of CNG as automotive fuel has been implemented in almost all major tier I to tier III cities of the country. Delhi, the capital city of India, has world largest CNG-fuelled public transport system. The cylinders fitted to the CNG-fuelled vehicles are required to be subjected to hydrostatic stretch test every 3years at Government of India approved CNG cylinder testing stations, as mandated under Rule 35 of Gas Cylinders Rules, 2016. During the testing of cylinders, CNG present in the cylinders are discharged in the atmosphere at the degassing point of CNG testing stations. This study estimates annual methane emissions from the CNG cylinder testing stations of Delhi. The annual average methane emission from the CNG cylinder testing stations of Delhi was found to be 30.8 tons during the year 2019. The uncertainties in the emission estimate are also identified and discussed.

Methane emissions from agricultural ponds are underestimated in national greenhouse gas inventories

Agricultural ponds have some of the highest methane emissions per area among freshwater systems, and these anthropogenic emissions should be included in national greenhouse gas inventories. Here we deliver a continental-scale assessment of methane emissions from agricultural ponds in the United States and Australia. We source maps of agricultural ponds, compile a meta-analysis for their emissions and use published data to correct for temperature and the relative contributions of two methane fluxes (diffusion and ebullition). In the United States, 2.56 million agricultural ponds cover 420.9 kha and emit about 95.8 kt year−1 of methane. In Australia, 1.76 million agricultural ponds cover 291.2 kha and emit about 75.1 kt year−1 of methane. Despite large uncertainties, our findings suggest that small water bodies emit twice as much methane than is currently accounted for in national inventories. Managing these systems can reduce these emissions while benefiting productivity, ecosystem services, and biodiversity.

Assessment of Methane Emission and the Factors That Influence It, from Three Rice Varieties Commonly Cultivated in the State of Puducherry

India being the world’s second largest cultivator of paddy, it is very important that the extent of the resulting methane emissions is estimated, and steps are taken to minimize these emissions. Peninsular India is a prime rice-producing region; however, no significant information is available on the contribution of this region to methane emissions, nor are there available studies that show the effect of cultivars, growth seasons, soil characteristics, etc., on methane emissions. As one of the attempts to cover this knowledge gap, emissions of methane from paddy fields, situated in four villages of Puducherry, India, involving three rice cultivars, three soil types and two growth seasons have been studied. All the fields had a continuously flooded pattern of irrigation with water supplied at a rate of 11,500–20,000 m3/ha. Whereas the cultivars ADT 39 and ADT 45 generated the highest methane flux during their reproductive phase, with lesser emission during the vegetative phase and much less during maturity, CO 45 exhibited copious methane emissions during the vegetative phase, with several orders of magnitude lesser emission during the reproductive and the maturity phases. These trends were independent of the location of the field and soil type, though the absolute and the relative values of the emissions varied from location to location. Irrespective of the cultivar, the quantities of methane emission increased linearly with soil temperature across the day but decreased exponentially as soil pH increased beyond 7.

Assessment of methane emissions from a California landfill using concurrent experimental, inventory, and modeling approaches

Methane flux and emissions were obtained at a California landfill concurrently using field measurements, inventory analyses, and modeling. Measured fluxes ranged from −3.7 to 828 g/m2-day and generally decreased from daily to intermediate to final covers. Soil covers with high-plasticity clay had the lowest fluxes. Whole-site emissions ranged from 406 to 47,414 tonnes/year (11,368 to 1,327,592 tonnes CO2-eq./year), and were dominated by intermediate covers with high relative surface area. Emissions estimates from flux chamber tests and California Landfill Methane Inventory Model (CALMIM) with oxidation were similar and low, whereas emissions from aerial measurements and CALMIM without oxidation were similar and high. The inventory analyses provided intermediate emissions and a new Gaussian plume model based on ground cavity ring-down spectrometer measurements provided the highest emissions. The assumptions used and the inherent strengths and limitations of the different approaches resulted in the flux and emissions differences. With varied attributes (experimental/modeling; flux/emissions; whole-site/cover-specific, top-down/bottom-up), the approaches provide envelopes of methane emissions and can be used selectively for the two main purposes of landfill methane emissions analysis: to mechanistically determine the factors that control/limit surface emissions and to provide data for atmospheric methane analysis. To reduce emissions, progression from temporary to permanent cover areas can be accelerated and covers with coarser materials can be amended with plastic fines.

Life cycle environmental impact assessment of methane emissions from the biowaste management strategy of the United Kingdom: Towards net zero emissions

Waste-related methane (CH4) emissions could account for 31% of total UK CH4 emissions. Waste management strategies in the UK have recently changed as more waste is diverted from landfills to anaerobic digesters (AD) and composting facilities, which can be significant sources of CH4. In this study, we combined mobile CH4 emissions data from waste treatment facilities to perform a life cycle assessment of current biowaste treatment and potential future mitigation, including AD, in-vessel composting, incineration, and landfilling scenarios. We found that diverting biowaste from landfill to AD is an effective strategy, but it is not enough to eliminate emissions. The fugitive CH4 emissions from anaerobic digesters have a significant impact on the environmental sustainability of waste management strategies, with upgrading the biogas into biomethane being the best option for climate change mitigation, in the case where natural gas is replaced. A change in the biowaste strategy can also reduce CH4 emissions from the waste sub-sector analysed, from 58.2 to 30.3 kilotonnes per year, an emissions saving of approximately 52%. However, with these technologies, net-zero emissions is challenging unless the absolute minimum emissions from the treatment technologies is consistently achieved. Therefore, we strongly recommend a focus on mitigating CH4 emissions from AD to achieve the goal of net-zero waste management.

Quantification and assessment of methane emissions from offshore oil and gas facilities on the Norwegian continental shelf

Abstract. The oil and gas (O&G) sector is a significant source of methane (CH4) emissions. Quantifying these emissions remains challenging, with many studies highlighting discrepancies between measurements and inventory-based estimates. In this study, we present CH4 emission fluxes from 21 offshore O&G facilities collected in 10 O&G fields over two regions of the Norwegian continental shelf in 2019. Emissions of CH4 derived from measurements during 13 aircraft surveys were found to range from 2.6 to 1200 t yr−1 (with a mean of 211 t yr−1 across all 21 facilities). Comparing this with aggregated operator-reported facility emissions for 2019, we found excellent agreement (within 1σ uncertainty), with mean aircraft-measured fluxes only 16 % lower than those reported by operators. We also compared aircraft-derived fluxes with facility fluxes extracted from a global gridded fossil fuel CH4 emission inventory compiled for 2016. We found that the measured emissions were 42 % larger than the inventory for the area covered by this study, for the 21 facilities surveyed (in aggregate). We interpret this large discrepancy not to reflect a systematic error in the operator-reported emissions, which agree with measurements, but rather the representativity of the global inventory due to the methodology used to construct it and the fact that the inventory was compiled for 2016 (and thus not representative of emissions in 2019). This highlights the need for timely and up-to-date inventories for use in research and policy. The variable nature of CH4 emissions from individual facilities requires knowledge of facility operational status during measurements for data to be useful in prioritising targeted emission mitigation solutions. Future surveys of individual facilities would benefit from knowledge of facility operational status over time. Field-specific aggregated emissions (and uncertainty statistics), as presented here for the Norwegian Sea, can be meaningfully estimated from intensive aircraft surveys. However, field-specific estimates cannot be reliably extrapolated to other production fields without their own tailored surveys, which would need to capture a range of facility designs, oil and gas production volumes, and facility ages. For year-on-year comparison to annually updated inventories and regulatory emission reporting, analogous annual surveys would be needed for meaningful top-down validation. In summary, this study demonstrates the importance and accuracy of detailed, facility-level emission accounting and reporting by operators and the use of airborne measurement approaches to validate bottom-up accounting.

Evaluating urban methane emissions from space using TROPOMI methane and carbon monoxide observations

Anthropogenic methane emissions from urban centers are important and addressable, yet remain poorly characterized, and the representativeness of studies from individual cities is unknown. A satellite-based approach provides a pathway to tackle this challenge on a national or global scale. Here we present a space-based method that uses the simultaneous, daily observation of methane and carbon monoxide from the TROPOMI satellite to estimate urban methane emissions. We assess and validate the method and demonstrate that using these simultaneous observations enables robust assessment of methane emissions from urban centers without relying on atmospheric transport models. Initial assessments with this approach in eight United States cities suggest emission inventory underestimates previously discovered in older East Coast cities are more broadly representative, with aggregated emissions totaling 1.47 (0.56, 3.19, 95% confidence interval) Tg CH4/year, compared to the Environmental Protection Agency estimate of 0.52 Tg CH4/year. We show this data driven approach provides a pathway to study urban methane emissions across the globe and track how emissions respond if urban mitigation measures are implemented by investigating three additional megacities outside the United States.

Methods for instrumental assessment of methane emission in reservoirs

Reservoirs are a significant source of methane in the atmosphere. Different estimations of the total methane emission from reservoirs vary greatly. In order to more accurately estimation of the methane emission from reservoirs, it is necessary to investigate the spatiotemporal variability of CH4 fluxes. To study this variability, detailed instrumental measurements of methane fluxes over a long period are required. Such measurements have been carried out for 6 years at the Mozhaisk Reservoir. These measurements showed that the determining factor of the spatiotemporal methane fluxes variability is the meteorological situation and the water level regime. These factors form the stratification of the water column. The highest values of methane flux into the atmosphere are observed in the middle part of the reservoir. The temporal variation of the methane flux is characterized by a general pattern for all years when the measurements were carried out. The methane flux increases during the summer period and reaches the highest values before the beginning of the autumn mixing stage. Also, high flux values observed during periods of storm events that cause mixing of the water column.

Methods of detecting and measuring fugitive methane emissions from elements of the gas transmission infrastructure – the results of GERG project Detection and Measurement of Fugitive Emissions of Natural Gas from the Transmission Systems

The article presents the results of the project carried out by GAZ-SYSTEM in cooperation with 5 other European gas Transmission System Operators (TSO) – ENAGAS, Fluxys, Gasunie, Snam and GRTgaz. The objective of the project was to investigate and identify the most useful devices for detecting and measuring methane emissions from infrastructure components typical for the TSO. The market analysis showed that methane detectors utilizing different principles of operation are available, but there are much fewer devices for measuring emission rates. 5 devices were selected for tests: 3 exclusively for detection based on the D-1 (semiconductor sensor), D-2 (infrared optical gas detection system), D-3(laser technology) principle of operation, and 2 devices that also enable emissions measurement – P-1 (ultrasound imaging) and P-2 (quantitative optical gas imaging). Laboratory tests were carried out in March 2020 at the Enagás’ Metrological & Innovation Center (M&I); according to the approved program, methane leaks were generated from deliberately unsealed valves, flanges, threaded and open-ended pipe connections. Field tests were carried out at the measuring gas station near the M&I. The main purpose of the research was to verify the accuracy of the selected measuring instruments. It was carried out at different flowrate and various methane concentrations in the gas escaping from the components. Ease of use of the devices, their speed and range of operation were assessed. The results showed both the advantages and limitations of each device, and they clearly indicated that the assessment of methane emissions from gas transmission infrastructure components requires the use of at least two different devices. The results indicate that sniffer devices, characterized by the fact that the probe must be placed in the vicinity of the source of emission, give results similar to the FID Detector, most commonly used in Leak Detection and Repair (LDAR) programs, but can be used in a wider range of methane concentrations. D-3 has a fast response time and a wide measuring range, but their unit of measurement i.e. ppm-m prevents the conversion of the results into methane concentration without additional measurements of the distance between the leak and the device. The P-1 and P-2 allow to measure the emissions in real time, while the measurement errors for both devices are comparable, ranging from about 70% to 100%.

Assessment of methane emission and evaluation of energy potential from the municipal solid waste landfills

ABSTRACT The assessment of energy potential from the elimination of MSW disposed off in landfills has never been estimated in Algeria, while it can make a significant contribution to the municipal institutions. It will help design waste to energy (WTE) measures and facilities aimed at having energy potential and minimizing GHG emissions into atmosphere. In this work, the emission of GHG was estimated for three landfills and an open dumpsite of the city of Oran using different models: IPCC default model (DM), IPCC first order decay (FOD) 2006, LandGem V3.02 model and Modified Triangular Method (MTM). The potential for electric power generation was also estimated during the production of electrical energy each year (kWh/year) from the methane emitted since the landfills opened up to 2018. The total production of methane by the four sites was calculated from 1986 to 2018 and estimated as follows: 904.81 Gg (1,261,938,633 m3) according to the IPCC-DM model, 472,85Gg (659,483,960 m3) by IPCC-FOD, 474.91Gg (669,330,543 m3) by LandGem and 289.93 Gg by MTM. The total potential for the four sites since their opening was estimated at 2214.81GWh by IPCC-FOD, 1921.98 GWh by LandGem and 1111.64 GWh by MTM. The paper finds that the 560 million kg of municipal solid waste generated daily in Oran city can produce about 200 GWh every year, representing 15% of Oran’s total electricity demand in 2018.The results of this work are promising and predict a significant potential of the energy by MSW.

Airborne Assessment of Methane Emissions from Offshore Platforms in the U.S. Gulf of Mexico.

Methane (CH4) emissions from oil and gas activities are large and poorly quantified, with onshore studies showing systematic inventory underestimates. We present aircraft measurements of CH4 emissions from offshore oil and gas platforms collected over the U.S. Gulf of Mexico in January 2018. Flights sampled individual facilities as well as regions of 5-70 facilities. We combine facility-level samples, production data, and inventory estimates to generate an aerial measurement-based inventory of CH4 emissions for the U.S. Gulf of Mexico. We compare our inventory and the Environmental Protection Agency Greenhouse Gas Inventory (GHGI) with regional airborne estimates. The new inventory and regional airborne estimates are consistent with the GHGI in deep water but appear higher for shallow water. For the full U.S. Gulf of Mexico our inventory estimates total emissions of 0.53 Tg CH4/yr [0.40-0.71 Tg CH4/yr, 95% CI] and corresponds to a loss rate of 2.9% [2.2-3.8%] of natural gas production. Our estimate is a factor of 2 higher than the GHGI updated with 2018 platform counts. We attribute this disagreement to incomplete platform counts and emission factors that both underestimate emissions for shallow water platforms and do not account for disproportionately high emissions from large shallow water facilities.

Оценка эмиссии метана водохранилищами России

The assessment of methane emission from the surface of reservoirs in the Russian Federation has been undertaken on the basis of methane emission characteristics from reservoirs’ database, supplemented with measurements made by the authors. We classified the field observations data taking into account the main factors determining the intensity of methanogenesis and its emission from the surface of water bodies. We propose the value of the water exchange coefficient characterizing the flow of water bodies, which determines the possibility of occurrence of oxygen-free conditions in them as the main factor. Further division takes into account the geographical position of the reservoir, trophic status of the reservoir and the average depth. When calculating the average specific flow of methane for the groups allocated on the climatic basis we excluded the emission data from reservoirs within urban areas. Taking into account the proposed values of the averaged methane flux, its emission from the surface of the Russian reservoirs is estimated at 0.53 Tg CH4/year.

Assessment of methane emissions and energy recovery potential from the municipal solid waste landfills of Delhi, India

Rising rate of MSW generation and unscientific disposal in the open dumping sites are responsible for emission of high concentrations of methane in developing countries. IPCC Default method (DM), First-order decay (FOD) and LandGEM were used to estimate methane emissions from the unengineered landfill sites of Delhi-Okhla, Bhalswa and Ghazipur between 1984 and 2015. During the period, the total CH4 emissions was found to be 1288.99, 311.18, 779.32 Gg from the 3 landfill sites of Delhi as predicted by DM, FOD and LandGEM respectively. The energy generation potential from methane for the year 2015 was found to vary from 4.16 × 108 to 9.86 × 108 MJ for Ghazipur, 2.08 × 108 to 4.06 × 108 MJ for Okhla and 3.42 × 108 to 8.11 × 108 MJ for Bhalswa. Efficient utilization of methane from the landfills as an energy source can be a sustainable waste management option.