Effects of hydrogen blending on methane emissions in natural gas distribution and end-use piping

Methane emissions along biomethane and biogas supply chains are underestimated

Methane is a potent greenhouse gas, contributing significantly to global warming and climate change. Methane emissions from natural gas systems have gained increasing attention due to their environmental and economic implications. The detection and quantification of methane leaks and emissions are crucial for minimizing their impact on the environment and ensuring the safety and efficiency of natural gas infrastructure. In recent years, advancements in sensor technology have provided new opportunities for accurate and cost-effective methane leak detection and quantification. This paper aims to provide an overview of the current state-of-the-art in methane leak detection and quantification using sensors, focusing on the types of sensors, sensing principles, and applications. A particular focus is given to sensors that can be installed on mobile robots and drones. Traditional methods for methane leaks detection and quantification have limitations in terms of spatial and temporal resolution, cost, and accessibility. Robots equipped with gas and methane leak detection sensors have emerged as promising solutions to address these challenges. This work contributes to the development of more effective strategies for reducing methane emissions and mitigating climate change. In particular, this paper explores the adoption of advanced sensors - such as Tunable Diode Laser Absorption Spectroscopy (TDLAS) sensors and optical gas imaging (OGI) cameras - and their integration into robots. We discuss the advantages of using these platforms for methane detection, including their ability to access hard-to-reach areas, real-time data acquisition, and high spatial and temporal resolution. Furthermore, we present an application in which we integrated methane and gas leak detectors on the payload of a legged robot, and we introduce a testing architecture for assessing the quality of standalone and mobile sensors for methane detection and quantification. This manuscript is structured as follows. First, we review the state-of-the-art on sensors for methane leaks detection and quantification. We deepen the discussion by reviewing the most relevant robotic solutions integrating gas and methane leak sensors, highlighting their advantages and limitations. Therefore, we present our current work on integrating a methane leak detection sensor on a legged robot. We introduce also our current activities and architecture for testing OGI cameras. We conclude the paper by showing the opportunities that our solutions can bring, and by highlighting challenges and limitations of current sensing technologies to overcome.

We present the results of analysis of the state of greenhouse gas emissions in the oil and gas industry according to data of the last National Inventory Reports. It was shown that industry is a great source of methane leakage, responsible for 44% of total country's methane emissions in 2017. Carbon dioxide emissions from the industry make a marginal contribution to total country's carbon dioxide emissions, responsible for only 3% in 2017. It was established that the main priority for oil and gas industry is the reduction of methane emissions from natural gas activities, which is typical for gas industries in other countries. The experience of national and international programs and initiatives aimed at reducing methane emissions from oil and gas operations were used for forming the lists of measures and technologies advisable for introduction in Ukraine, concerning the hydrocarbons exploration, development, and production as well as their preparation to transportation, activities for the natural gas transportation and its underground storage, activities for the natural gas distribution and its consumption by the residential and commercial sectors. The necessity to solve in Ukraine the problem of monitoring of methane emissions and leakages in the oil and gas sector, which requires the improvement and standardization of their quantification, reporting, and verification, is mentioned separately, but this problem is not completely solved in any country of the world, which is connected with certain peculiarities of emissions sources. The article provides a comparative analysis of the results of cost calculations for the services of main pipeline transportation of natural gas with replacing existing gas-turbine gas pumping units by new gas-turbine or electric drive units. We present the external conditions for development of the oil and gas industry, for which overall estimates of greenhouse gas emissions by 2040 are calculated for two formed scenarios – with and without measures for emission reduction.

Achieving the Paris Agreement 1.5 C target requires a reversal of the growing atmospheric concentrations of methane, which is about 80 times more potent than CO 2 on a 20-year timescale. The Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report stated that methane is underregulated, but little is known about the effectiveness of existing methane policies. In this review, we systematically examine existing methane policies across the energy, waste, and agriculture sectors. We find that currently only about 13% of methane emissions are covered by methane mitigation policies. Moreover, the effectiveness of these policies is far from clear, mainly because methane emissions are largely calculated using potentially unrepresentative estimates instead of direct measurements. Coverage and stringency are two major blind spots in global methane policies. These findings suggest that significant and underexplored mitigation opportunities exist, but unlocking them requires policymakers to identify a consistent approach for accurate quantification of methane emission sources alongside greater policy stringency. ll

Många berättar om de ekonomiska vinster de gjort på börsen under senaste åren, och hur lätt pengarna rullat in på deras konton. Med en liten inblick i finansmarknaden och genom att titta på A-ekonomi då och då så blir i stort sett alla aktieaffärer lyckade. Vi hör dock sällan någon berätta om folks dåliga aktieaffärer. Börsen verkar med andra ord vara en guldgruva för dem som investerar där. Med hjälp av dyra aktierekommendationer kan man göra ännu större vinster enligt en rad olika fondkommissionär. Betting är en trend som aldrig tycks ta slut. Även där påpekar spelbolagen hur lätt det är att ta hem vinster, bara man har lite kunskap blir man en vinnare. Och vem vill inte bli det? Syftet med denna uppsats är att reda ut nämnda påstående. Är det så lätt som visa försöker påvisa att öka sina likvida medel med hjälp av en smärre aktiekunskap? Denna studie försöker visa hur det egentligen ligger till i denna fråga. Vem vinner när kunskap ställs mot slump i spel- och aktievärlden? I denna uppsats vill vi undersöka likheterna av slumpens betydelse vid kortsiktiga placeringar i aktier och spel på multibet. Med hjälp av Random Walk-teorin vill vi se om det finns likheter mellan att köpa aktier på börsen och att spela på multibet. För att få en bredare kunskap inom detta ämne så har vi byggt upp en teoridel i denna uppsats som tar upp elementära och relevanta grundstenar inom dessa ämnen. Det dyker upp en rad olika frågetecken under resans gång, men dessa försöker vi besvara så gott det går ännu längre fram i uppsatsen. De slutsatser vi kommit fram till med hjälp av vår undersökning är att slumpen har en stor betydelse på aktie- respektive spelmarknaden. Men däremot tror vi inte att den tekniska och fundamentala analysen ska förkastas, den kan i viss mån vara till hjälp.

Iron oxide is the most important electron acceptor in paddy fields. We aimed to suppress the methane emission from paddy fields over the long term by single application of iron materials. A revolving furnace slag (RFS; 245 g Fe kg-1) and a spent disposable portable body warmer (PBW; 550 g Fe kg-1) were used as iron materials. Samples of a soil with a low iron level (18.5 g Fe kg-1), hearafter referred to as “a low-iron soil” and of a soil with a high iron level (28.5 g Fe kg-1), hearafter referred to as “an iron-rich soil,” were put into 3 L pots. At the beginning of the experiment, RFS was applied to the pots at the rate of 20 and 40 t ha-1, while PBW was applied at the rate of 10 t ha-1 only, and in the control both were not applied. Methane and nitrous oxide emissions from the potted soils with rice plants were measured by the closed chamber method in 2001 and 2002. When RFS was applied at the rates of 20 and 40 t ha-1 to the low-iron soil, the total methane emission during the cultivation period significantly decreased by 25–50% without a loss of grain yield. Applied iron materials clearly acted as electron acceptors, based on the increase in the amount of ferrous iron in soil. However, the suppressive effect was not evident in the iron-rich soil treated with RFS or PBW. On the other hand, nitrous oxide emission increased by 30–95%. As a whole, when the total methane and nitrous oxide emissions in the low-iron soil were converted to total greenhouse gas emissions expressed as CO2- C equivalents in line with the global warming potential, the total greenhouse gas emissions decreased by about 50% due to the application of RFS.

<p>The worldwide operating petroleum industry is considered as one of the major contributors to global anthropogenic methane emissions. However, not only absolute numbers of methane emissions from oil and natural gas production and distribution vary greatly in different global inventories, also the relative contribution of the oil and the gas sector is under discussion. In different studies, the majority of methane emissions are assigned either to natural gas or to the oil sector. For the climate emission origins are of course irrelevant, however, for the climate budget of natural gas usage it is important to know which emissions are attributable to natural gas and what number is related to oil production with its associated natural gas.</p><p>Here we use the Federal Institute of Geosciences and Natural Resources’ (BGR) worldwide database on natural oil and gas production and consumption, dating back to 1900, and compare it to global bottom-up methane emission inventories. We will present and discuss several regression approaches that fit the global data reasonably well. In addition, methane emissions of country groups are compared to natural oil and gas production and consumption data. This study finds that the emission factors that relate to gas production released during oil and gas extraction likely vary over the time and across different production areas in the world.</p>

Rapidly reducing urban methane (CH4) emissions is a critical component of strategies aimed at limiting climate change. Individual source measurements provide the details necessary to develop actionable mitigation strategies and are highly complementary to mobile surveys and other top-down methods. Here, we perform 615 individual source measurements in Montréal, Canada, to quantify CH4 emissions from historic landfills, manholes, and fugitive emissions from natural gas (NG) distribution systems. We find that in 2020, historic landfills produced 901 (452 to 1541, 95% c.i.) tons of CH4, manholes emitted 786 (32 to 2602, 95% c.i.) tons of CH4, and NG distribution systems emitted 451 (176-843, 95% c.i.) tons of CH4, placing them all within the top four CH4 sources in Montréal. Methane emissions from both historic landfills and manholes are not accounted for in any greenhouse gas inventory. We find that geochemistry alone cannot positively identify source subcategories (e.g., type of manhole or NG infrastructure) in almost all cases, although C2/C1 ratios can distinguish NG distribution sources from biogenic sources (historic landfills and manholes). Using our individual source measurement data, we show that historic landfills have the greatest potential for CH4 reductions but the highest mitigation costs, unless we target the highest emitting landfills. In contrast, CH4 emissions from manholes can be reduced at low costs, but reduction methods are commercially unavailable. For NG distribution, methods such as increasing repair rates for high-emitting industrial meters can greatly reduce mitigation costs and emissions. Overall, our results highlight the role of individual source measurements in developing actionable CH4 mitigation strategies to meet municipal, regional, and national climate action plans.

To date, estimation of greenhouse gas (GHG) emissions from the natural gas (NG) value chain have focused on upstream (production) and midstream (gathering, transmission, and storage) operations. In this study, we estimate methane emissions from an important downstream consumer of NG, the ammonia fertilizer industry, which commonly uses NG as a feedstock and a fuel for the production of ammonia and other upgraded products. Using a Google Street View (GSV) car equipped with a high-precision methane analyzer, we adopted a mobile sensing approach to measure methane mixing ratios along public roads that are downwind of the ammonia fertilizer plants. Useful data were collected from six plants, which represent >25% of the total number of U.S NG-based ammonia fertilizer plants, and use >20% of the total NG consumption by this industry. Based on the measured data, a source characterization model was applied to estimate the methane emission rates from the upwind plants. Assuming that the estimates are representative of emissions during normal operations of a plant, we calculated the NG loss rate (i.e. the ratio between NG emission rate and NG throughput). If the sampled plants are representative of the U.S. ammonia fertilizer industry, the industrial-averaged NG loss rate (± standard deviation) is estimated to be 0.34% (±0.20%), and the total methane emissions (± standard deviation) from this industry are estimated to be 29 (±18) Gigagram per year (Gg CH4/yr) in 2015–2016. This is significantly higher than the reported methane emissions of 0.2 Gg CH4/yr from the U.S. EPA’s Facility Level Information on Greenhouse Gas Tools (FLIGHT). This study begins to fill an important knowledge gap in quantifying methane emissions along the NG value chain, and demonstrates the capability of mobile sensing for characterizing airborne emissions.

Numerical evaluation of internal combustion spark ignition engines performance fuelled with hydrogen – Natural gas blends

Three considerations for modeling natural gas system methane emissions in life cycle assessment

The concentration of surface air methane (CH4) measured in parts per million by volume (ppmv) near the soil/atmosphere interface should, in theory, have a positive correlation with surface methane emissions fluxes, measured in grams per square meter per day (gm−2d−1). Some researchers suggest that CH4 flux can be reasonably inferred from simple measurements of CH4 concentrations near the landfill surface. Ground-based and drone-based surface emissions monitoring (SEMs) were performed at several municipal solid waste landfills as tracer correlation method (TCM) testing was being used to measure total methane emissions from the same landfills. The TCM data and SEM data were used to establish a new simple correlation to convert surface methane concentrations in ppmv to localized surface methane emission flux in gm−2d−1. The SEM data obtained from ten ground and drone monitoring campaigns were log-transformed and geospatially treated using inverse distance weighting to the power of 2 to predict methane surface concentrations in the entire footprint of the SEM measurements area. The developed new correlation equation was then used to convert every predicted surface methane concentration to an emissions flux. The total estimate of surface emissions from the entire landfill was obtained by integrating the predicted fluxes over the area of the footprint of the SEM measurement area. The use of the new developed correlation resulted in higher total emissions estimates than other correlations reported in the literature and should be considered more conservative. Not including other factors, the proposed approach provides estimate of total methane emissions with a coefficient of variation of 20%. This study introduces a novel approach that utilizes a developed correlation between surface methane concentrations and surface emissions fluxes to estimate total methane emissions from municipal solid waste landfills or from a specified area. This study provides an additional use of the quarterly SEM data. Implications: The proposed approach provides an occasion for additional use of the easily obtainable quarterly SEMs data that can be performed by most landfills. The SEMs data are the most abundant landfill methane concentrations data. This approach gives them more benefit for the user. It is intended to convert ambient air concentrations to some estimates of surface emissions that can help landfill owners with decision making such as remediation activities or adjustments of their gas collection a systems.

Measuring methane emissions during the installation of residential and commercial natural gas meters in China

Methane cracking as a bridge technology to the hydrogen economy

The conversion of water and carbon dioxide into useful products such as synthetic natural gas using renewably supplied electrical energy can offer several advantages for stabilizing the electric grid and increasing the security of energy supply chains. In addition to providing increased grid operational flexibility for dealing with intermittent renewable electrical energy supplies, infrastructure changes such as hydrogen pipelines could conceivably be avoided in situations where natural gas pipelines and CO2 sources coincide. The natural gas distribution infrastructure is well developed in many countries, enabling the fuel to be transported long distances and easily delivered throughout cities. Using the existing pipeline to transport renewably generated synthetic natural gas (SNG) can further enhance the value of the product via offering grid services such as load leveling. While the price of natural gas is near record lows in the United States, many other countries are working to develop SNG as an alternative fuel for transportation and residential/commercial heating markets, especially in Europe and for island nations. This study presents pathway studies of low- and high-temperature electrolysis integrated with an SNG plant design and evaluates their performance for producing SNG by reacting renewably generated hydrogen with carbon dioxide. The carbon dioxide feedstock is assumed to be captured and scrubbed from either an existing coal fired power plant at the city-gate or from sequestered CO2, where the SNG plant is co-located. In the first pathway, water is split using either low-temperature alkaline or proton exchange membrane technology. In a second path, the co-electrolysis of steam and CO2 is done in-situ using high temperature (600°C) solid oxide cell technology. Historically, methanation has been a common practice for eliminating carbon monoxide and carbon dioxide in various chemical processes such as ammonia production and natural gas purification; for these processes, only small amounts (1-3% molar basis) of carbon oxides need to be converted to methane. A “bulk” methanation process is unique due to the high concentration of carbon oxides and hydrogen. In addition, the carbon dioxide is the only carbon source, and the reaction characteristics of carbon dioxide are much different than carbon monoxide. In process paths involving low-temperature electrolyzers, a methanation plant is required. In this study, thermodynamic and kinetic considerations of the methanation reaction are explored to model and simulate a system of reactors for the conversion of hydrogen and carbon dioxide to SNG. Multiple reactor stages are used to increase temperature control of the reactor and drain water to promote the forward direction of the methanation reaction. Heat recuperation and recovery using organic Rankine cycle units for electricity generation utilizes the heat produced from the methanation reaction. Bulk recycle is used to increase the overall reactant conversion while allowing a satisfactorily high methane content SNG product. A hydrogen membrane separates hydrogen for recycle to increase the Wobbe index of the product SNG by increasing the methane content to nearly 93% by volume. In both pathways, the product SNG has a minimum Wobbe index of 47.5 MJ/m3 which is acceptable for natural gas pipeline transport and end-use appliances in existing infrastructures. The overall plant efficiencies of both pathways are compared as well as the expected price of the product SNG using the H2A tool.