Suchergebnisse

Enteric methane (CH) production from cattle contributes to global greenhouse gas emissions. Measurement of enteric CH is complex, expensive, and impractical at large scales; therefore, models are commonly used to predict CH production. However, building robust prediction models requires extensive data from animals under different management systems worldwide. The objectives of this study were to (1) collate a global database of enteric CH production from individual lactating dairy cattle; (2) determine the availability of key variables for predicting enteric CH production (g/day per cow), yield [g/kg dry matter intake (DMI)], and intensity (g/kg energy corrected milk) and their respective relationships; (3) develop intercontinental and regional models and cross-validate their performance; and (4) assess the trade-off between availability of on-farm inputs and CH prediction accuracy. The intercontinental database covered Europe (EU), the United States (US), and Australia (AU). A sequential approach was taken by incrementally adding key variables to develop models with increasing complexity. Methane emissions were predicted by fitting linear mixed models. Within model categories, an intercontinental model with the most available independent variables performed best with root mean square prediction error (RMSPE) as a percentage of mean observed value of 16.6%, 14.7%, and 19.8% for intercontinental, EU, and United States regions, respectively. Less complex models requiring only DMI had predictive ability comparable to complex models. Enteric CH production, yield, and intensity prediction models developed on an intercontinental basis had similar performance across regions, however, intercepts and slopes were different with implications for prediction. Revised CH emission conversion factors for specific regions are required to improve CH production estimates in national inventories. In conclusion, information on DMI is required for good prediction, and other factors such as dietary neutral detergent fiber (NDF) concentration, improve the prediction. For enteric CH yield and intensity prediction, information on milk yield and composition is required for better estimation. ; This study is part of the Joint Programming Initiative on Agriculture, Food Security and Climate Change (FACCE‐JPI)'s "GLOBAL NETWORK" project and the "Feeding and Nutrition Network" (http://animalscience.psu.edu/fnn) of the Livestock Research Group within the Global Research Alliance for Agricultural Greenhouse Gases (www.globalresearchalliance.org). Authors gratefully acknowledge funding for this project from: USDA National Institute of Food and Agriculture Grant no. 2014‐67003‐21979) University of California, Davis Sesnon Endowed Chair Program, USDA, and Austin Eugene Lyons Fellowship (University of California, Davis); Funding from USDA National Institute of Food and Agriculture Federal Appropriations under Project PEN 04539 and Accession number 1000803, DSM Nutritional Products (Basel, Switzerland), Pennsylvania Soybean Board (Harrisburg, PA, USA), Northeast Sustainable Agriculture Research and Education (Burlington, VT, USA), and PMI Nutritional Additives (Shoreview, MN, USA); the Ministry of Economic Affairs (the Netherlands; project BO‐20‐007‐006; Global Research Alliance on Agricultural Greenhouse Gases), the Product Board Animal Feed (Zoetermeer, the Netherlands) and the Dutch Dairy Board (Zoetermeer, the Netherlands); USDA National Institute of Food and Agriculture (Hatch Multistate NC‐1042 Project Number NH00616‐R; Project Accession Number 1001855) and the New Hampshire Agricultural Experiment Station (Durham, NH); French National Research Agency through the FACCE‐JPI program (ANR‐13‐JFAC‐0003‐01), Agricultural GHG Research Initiative for Ireland (AGRI‐I), Academy of Finland (No. 281337), Helsinki, Finland; Swiss Federal Office of Agriculture, Berne, Switzerland; the Department for Environment, Food and Rural Affairs (Defra; UK); Defra, the Scottish Government, DARD, and the Welsh Government as part of the UK's Agricultural GHG Research Platform projects (www.ghgplatform.org.uk); INIA (Spain, project MIT01‐GLOBALNET‐EEZ); German Federal Ministry of Food and Agriculture (BMBL) through the Federal Office for Agriculture and Food (BLE); Swedish Infrastructure for Ecosystem Science (SITES) at Röbäcksdalen Research Station; Comisión Nacional de Investigación Científica y Tecnológica, Fondo Nacional de Desarrollo Científico y Tecnológico (Grant Nos. 11110410 and 1151355) and Fondo Regional de Tecnología Agropecuaria (FTG/RF‐1028‐RG); European Commission through SMEthane (FP7‐SME‐262270). The authors are thankful to all colleagues who contributed data to the GLOBAL NETWORK project and especially thank Luis Moraes, Ranga Appuhamy, Henk van Lingen, James Fadel, and Roberto Sainz for their support on data analysis. All authors read and approved the final manuscript. The authors declare that they have no competing interests. ; Peer Reviewed

Enteric methane (CH4 ) production from cattle contributes to global greenhouse gas emissions. Measurement of enteric CH4 is complex, expensive, and impractical at large scales; therefore, models are commonly used to predict CH4 production. However, building robust prediction models requires extensive data from animals under different management systems worldwide. The objectives of this study were to (1) collate a global database of enteric CH4 production from individual lactating dairy cattle; (2) determine the availability of key variables for predicting enteric CH4 production (g/day per cow), yield [g/kg dry matter intake (DMI)], and intensity (g/kg energy corrected milk) and their respective relationships; (3) develop intercontinental and regional models and cross-validate their performance; and (4) assess the trade-off between availability of on-farm inputs and CH4 prediction accuracy. The intercontinental database covered Europe (EU), the United States (US), and Australia (AU). A sequential approach was taken by incrementally adding key variables to develop models with increasing complexity. Methane emissions were predicted by fitting linear mixed models. Within model categories, an intercontinental model with the most available independent variables performed best with root mean square prediction error (RMSPE) as a percentage of mean observed value of 16.6%, 14.7%, and 19.8% for intercontinental, EU, and United States regions, respectively. Less complex models requiring only DMI had predictive ability comparable to complex models. Enteric CH4 production, yield, and intensity prediction models developed on an intercontinental basis had similar performance across regions, however, intercepts and slopes were different with implications for prediction. Revised CH4 emission conversion factors for specific regions are required to improve CH4 production estimates in national inventories. In conclusion, information on DMI is required for good prediction, and other factors such as dietary neutral detergent fiber (NDF) concentration, improve the prediction. For enteric CH4 yield and intensity prediction, information on milk yield and composition is required for better estimation.

Measuring and mitigating methane (CH4) emissions from livestock is of increasing political and economic importance. Potentially, the most sustainable way of reducing CH4 emission from ruminants is through the estimation of genomic breeding values to facilitate genetic selection. Enteric CH4 emissions are difficult and expensive to measure, thus genomic prediction could provide significant, long term economic benefits. Implementation will require global collaboration to define a suitable measure and many thousands of records to ensure valid and accurate evaluations. A number of approaches for individual measures on a large scale have been recently proposed including fixed and portable respiratory chambers, SF6 tracer gas, laser detector systems and sniffers or spot samples at milking. Some studies have also shown promising results in predicting individual animal CH4 emission from mid infra-red milk spectra data. It is currently unclear, however, how well measures between these approaches correlate. Comparison and validation of these novel phenotypes presents a huge task over the coming years. A crucial first step is to define a trait phenotype and measuring protocols to create a robust resource for the global sharing and comparison of data, and further, to measure correlations with production traits. Proposed phenotypes could be measures of "total methane emissions", measured in grams CH4 per day, or "methane yield" measured in grams CH4 per kg dry matter intake (DMI) when DMI is available as a phenotype, or "methane intensity" measured in grams CH4 per kg of produced human edible protein. Here, we describe how two recently established entities; an ICAR Working Group and the EU COST-Action network METHAGENE are working in close collaboration to successfully address these major challenges together with the Animal Selection Genetics and Genomics Network (ASGGN) of the Livestock Research Group of the Global Research Alliance (GRA) on agricultural greenhouse gases. ; Peer reviewed

The Global Methane Pledge to reduce emissions by at least 30 per cent by 2030, was signed by more than 100 countries at the COP26 Conference in November 2021. Reducing methane emissions from fossil fuel sources by up to 75 per cent by 2030 has been identified as an essential contribution to reducing the rate of global temperature increase. The EU Methane Strategy proposed the establishment of a methane intensity standard for domestically produced and imported fossil fuels, with an initial focus on emissions from natural gas and LNG imports, however no such standard is included in the 2021 legislative proposals. Of the six major pipeline gas and LNG suppliers to Europe, Norway has progressed MRV and reduced emissions to a much greater extent than other major exporters to Europe. The complexity of the US LNG export supply chain, with huge numbers of production locations and multiple pipelines and processing plants contrasts with the relative simplicity of the Qatari supply chain. In the case of Russia, the focus is on Gazprom's long transmission pipelines, while Algerian and Nigerian companies are only just beginning to address these issues. European buyers will need to establish supply chain emission values with exporting companies, and possibly also with governments. Asian importers will need to agree similar values with their LNG suppliers. The SGE and GIIGNL methodologies, published in late 2021, combined with the study of Cheniere's 2018 cargos and its commitment to provide individual cargo emission tags from 2022, are important milestones in the creation of frameworks for establishing LNG supply chain emission values. By contrast, `carbon-neutral' LNG cargos lack MRV ransparency and therefore environmental credibility. Transparent MRV of emissions has become a non-negotiable requirement for the international gas community. A lack of this information undermines claims that natural gas can play a significant ongoing role in the low carbon energy transition. The longer it takes to establish such documentation, the more likely it is that countries will adopt alternative energy options.

The paper presents the results of field measurements of methane fluxes into the atmosphere from thermokarst lakes located on the Russian Federation territory on the three key sites: foothills of the Polar Urals, coast of the Kara Sea and the northwestern part of the Yamal Peninsula. A total of 13 lakes were studied and about 500 methane fluxes were measured by the floating chamber method. The results showed most of the fluxes does not exceed 8 mg CH4 m–2 h–1. For more significant values, a statistically significant correlation with the wind speed was revealed, which largely determines the intensity of gas exchange on the "water-atmosphere" boundary. The exceptions are measurements in zone of lake methane seeps. For most lakes, the greatest scatter of measured fluxes was observed in the shallow part. The diurnal dynamics of methane fluxes was approximated by a sinusoidal function. For the lakes presented in the work, the range of emission assessment is 0.23–775.38 g CH4 h–1. Obtained results are important material for estimating regional methane emission from the surface of thermokarst lakes in the tundra zone.

This work is devoted to studies of the shallow methane seepages temporal variability in the coastal area of
Laspi Bay and high-frequency monitoring of the hydrological parameters daily dynamics in this area. The
paper presents results obtained during the summer months of 2016, 2018-2021, and early February 2023.
Using the passive acoustic method, it is shown that the intensity and periodicity of bubble gas emission by
individual point sources can vary during the day and from season to season. It was obtained that a decreased
content of dissolved oxygen and its saturation is observed above the active site of the seepages as compared
to the distant (background) site. Moments of sharp decrease in oxygen content not accompanied by changes
in temperature and other hydrological parameters were noted.

Morgan Bazilian, Greg Clough and Simon LomaxThe Biden administration's pause on liquefied natural gas (LNG) export approvals has been a political lightning rod ever since it was announced in late January. U.S. Energy Secretary Jennifer Granholm recently promised the pause will be over in a matter of months, once federal officials have completed a review of the climate, environmental and economic impacts of LNG exports.But House Speaker Mike Johnson has signaled that Republicans in Congress will demand the immediate lifting of the pause in exchange for congressional approval of foreign aid for Ukraine in its war with Russia. Likewise, Texas and 15 other states filed a federal lawsuit last month seeking to end the pause. Time will tell if these political and legal challenges succeed or fail. But if the U.S. Department of Energy (DOE) does manage to complete its review, what's the likely outcome?The following five data points offer some critical clues.$1.50This was the daily price for 1,000 cubic feet – or 1 million British thermal units – of natural gas on Feb. 20, which was "the lowest price in inflation-adjusted dollars since at least 1997," according to the U.S. Energy Information Administration. Some critics of LNG exports have raised fears of higher domestic energy prices. While there was a spike in natural gas prices in 2022, as Europe quickly ramped up consumption of U.S. LNG in response to the Russia-Ukraine war, those prices have quickly returned to pre-war levels and below.50%This is the increase in methane emissions when Russian natural gas is used instead of U.S. natural gas, according to the International Energy Agency (IEA) 2023 methane tracker.For some other gas exporting nations, the jump in methane emissions is much higher. Algeria's methane emissions per unit of gas produced is roughly double that of the U.S. Turkmenistan's is 550% higher, according to IEA data.If anything, these figures may understate the difference in methane intensities between nations.That's because the operation of the U.S. oil and natural gas industry is much more transparent and subject to more stringent reporting requirements than its counterparts in Russia, Algeria, Turkmenistan and other energy exporting countries.4%This is an estimated methane leakage rate that would make LNG and pipeline gas no better for the climate than coal. Natural gas, which is mostly made of methane, emits roughly half as much carbon dioxide as coal when used as a fuel for generating electricity. But when methane escapes during the production and transportation of natural gas, it erodes this climate benefit, because methane traps much more heat than carbon dioxide on a pound-for-pound basis.To be sure, no single data point can capture the full complexity of the global energy system. Not all natural gas is produced in the same way and the same can be said for coal.Natural gas also has uses outside the energy sector – such as a feedstock for making agricultural fertilizer – which further limits the usefulness of comparisons with coal. 2.3%This is a frequently quoted estimate for the average methane intensity of U.S. natural gas production, referenced in the White House Methane Action Plan of November 2022.It is based on 2015 data, which is now almost 10 years old. Therefore, it does not reflect almost a decade of increasingly stringent regulations on methane emissions, introduced by state and federal environmental agencies.In addition, over the past decade, new technologies have been developed to closely monitor oil and gas operations for methane leaks, including ground-level sensors, drone flights, aerial surveys and satellite imagery.Those technologies are being used today to set aggressive public and private sector targets for reducing the methane intensity of natural gas to much, much lower levels. At the federal level, a newly finalized regulation from the U.S. Environmental Protection Agency is projected to reduce oil and gas industry methane emissions by 80% between now and the end of this decade.0.2%This is the new methane intensity benchmark for U.S. natural gas production that is currently being implemented by the Biden administration. It is also emerging as a new global standard.For example, the European Union has proposed the same 0.2% benchmark for the production phase – also known as upstream operations – for LNG and pipeline gas imports. During last year's climate talks, almost 50 of the world's largest oil and gas companies also committed to achieving the 0.2% upstream methane intensity benchmark by 2030.Meanwhile, in Asia, major LNG importers Japan and South Korea have also launched their own initiative to drive down methane emissions from the natural gas they buy from the U.S. and other suppliers.In practical terms, these developments mean that U.S. LNG will have to comply with stringent domestic and international methane controls in the coming years.Taken together, these five data points may explain some earlier comments from the DOE just a few days after the pause and review process was announced by the Biden White House in January."It will be robust analysis," DOE assistant secretary Brad Crabtree said. "I actually believe that it will serve the industry well in terms of responding to criticism, whether it's about domestic prices in the United States or climate implications of our exports."To be sure, political or legal influences may intervene before the DOE's review process is complete.But as things currently stand, the data is moving in the direction of lifting the pause and restarting the LNG permitting process with an updated set of parameters for assessing individual projects on their merits.Morgan Bazilian is the director of the Payne Institute for Public Policy at the Colorado School of Mines. Greg Clough is the institute's deputy director. Simon Lomax is a policy and outreach advisor to the institute.

Morgan Bazilian, Greg Clough and Simon LomaxThe Biden administration's pause on liquefied natural gas (LNG) export approvals has been a political lightning rod ever since it was announced in late January. U.S. Energy Secretary Jennifer Granholm recently promised the pause will be over in a matter of months, once federal officials have completed a review of the climate, environmental and economic impacts of LNG exports.But House Speaker Mike Johnson has signaled that Republicans in Congress will demand the immediate lifting of the pause in exchange for congressional approval of foreign aid for Ukraine in its war with Russia. Likewise, Texas and 15 other states filed a federal lawsuit last month seeking to end the pause. Time will tell if these political and legal challenges succeed or fail. But if the U.S. Department of Energy (DOE) does manage to complete its review, what's the likely outcome?The following five data points offer some critical clues.$1.50This was the daily price for 1,000 cubic feet – or 1 million British thermal units – of natural gas on Feb. 20, which was "the lowest price in inflation-adjusted dollars since at least 1997," according to the U.S. Energy Information Administration. Some critics of LNG exports have raised fears of higher domestic energy prices. While there was a spike in natural gas prices in 2022, as Europe quickly ramped up consumption of U.S. LNG in response to the Russia-Ukraine war, those prices have quickly returned to pre-war levels and below.50%This is the increase in methane emissions when Russian natural gas is used instead of U.S. natural gas, according to the International Energy Agency (IEA) 2023 methane tracker.For some other gas exporting nations, the jump in methane emissions is much higher. Algeria's methane emissions per unit of gas produced is roughly double that of the U.S. Turkmenistan's is 550% higher, according to IEA data.If anything, these figures may understate the difference in methane intensities between nations.That's because the operation of the U.S. oil and natural gas industry is much more transparent and subject to more stringent reporting requirements than its counterparts in Russia, Algeria, Turkmenistan and other energy exporting countries.4%This is an estimated methane leakage rate that would make LNG and pipeline gas no better for the climate than coal. Natural gas, which is mostly made of methane, emits roughly half as much carbon dioxide as coal when used as a fuel for generating electricity. But when methane escapes during the production and transportation of natural gas, it erodes this climate benefit, because methane traps much more heat than carbon dioxide on a pound-for-pound basis.To be sure, no single data point can capture the full complexity of the global energy system. Not all natural gas is produced in the same way and the same can be said for coal.Natural gas also has uses outside the energy sector – such as a feedstock for making agricultural fertilizer – which further limits the usefulness of comparisons with coal. 2.3%This is a frequently quoted estimate for the average methane intensity of U.S. natural gas production, referenced in the White House Methane Action Plan of November 2022.It is based on 2015 data, which is now almost 10 years old. Therefore, it does not reflect almost a decade of increasingly stringent regulations on methane emissions, introduced by state and federal environmental agencies.In addition, over the past decade, new technologies have been developed to closely monitor oil and gas operations for methane leaks, including ground-level sensors, drone flights, aerial surveys and satellite imagery.Those technologies are being used today to set aggressive public and private sector targets for reducing the methane intensity of natural gas to much, much lower levels. At the federal level, a newly finalized regulation from the U.S. Environmental Protection Agency is projected to reduce oil and gas industry methane emissions by 80% between now and the end of this decade.0.2%This is the new methane intensity benchmark for U.S. natural gas production that is currently being implemented by the Biden administration. It is also emerging as a new global standard.For example, the European Union has proposed the same 0.2% benchmark for the production phase – also known as upstream operations – for LNG and pipeline gas imports. During last year's climate talks, almost 50 of the world's largest oil and gas companies also committed to achieving the 0.2% upstream methane intensity benchmark by 2030.Meanwhile, in Asia, major LNG importers Japan and South Korea have also launched their own initiative to drive down methane emissions from the natural gas they buy from the U.S. and other suppliers.In practical terms, these developments mean that U.S. LNG will have to comply with stringent domestic and international methane controls in the coming years.Taken together, these five data points may explain some earlier comments from the DOE just a few days after the pause and review process was announced by the Biden White House in January."It will be robust analysis," DOE assistant secretary Brad Crabtree said. "I actually believe that it will serve the industry well in terms of responding to criticism, whether it's about domestic prices in the United States or climate implications of our exports."To be sure, political or legal influences may intervene before the DOE's review process is complete.But as things currently stand, the data is moving in the direction of lifting the pause and restarting the LNG permitting process with an updated set of parameters for assessing individual projects on their merits.Morgan Bazilian is the director of the Payne Institute for Public Policy at the Colorado School of Mines. Greg Clough is the institute's deputy director. Simon Lomax is a policy and outreach advisor to the institute.

For countries with limited access to conventional hydrocarbon gases, methane hydrates have emerged as a potential energy source. In view of the European Union's requirements to reduce the energy intensity of technological processes and increase energy security, it appears promising to accumulate natural gas and biomethane in the form of hydrate structures and release them if necessary. Storing gas in this form in an energy-efficient manner creates interest in developing and innovating technologies in this area. Hydrates that form in gas pipelines are generated by a more or less random process and are an undesirable phenomenon in gas transportation. In our case, the process implemented in the proposed experimental device is a controlled process, which can generate hydrates in orders of magnitude shorter times compared to the classical methods of generating natural gas hydrates in autoclaves by saturating water only. The recirculation of gas-saturated water has been shown to be the most significant factor in reducing the energy consumption of natural gas hydrate generation. Not only is the energy intensity of generation reduced, but also its generation time. In this paper, a circuit diagram for an experimental device for natural gas hydrate generation is shown with complete description, principle of operation, and measurement methodology. The natural gas hydrate formation process is analyzed using a mathematical model that correlates well with the measured hydrate formation times. Hydrates may become a current challenge in the future and, once verified, may find applications in various fields of technology or industry.