Natural Gas Infrastructure Research Articles

Assessing urban methane emissions using column-observing portable Fourier transform infrared (FTIR) spectrometers and a novel Bayesian inversion framework

Abstract. Cities represent a large and concentrated portion of global greenhouse gas emissions, including methane. Quantifying methane emissions from urban areas is difficult, and inventories made using bottom-up accounting methods often differ greatly from top-down estimates generated from atmospheric observations. Emissions from leaks in natural gas infrastructure are difficult to predict and are therefore poorly constrained in bottom-up inventories. Natural gas infrastructure leaks and emissions from end uses can be spread throughout the city, and this diffuse source can represent a significant fraction of a city's total emissions. We investigated diffuse methane emissions of the city of Indianapolis, USA, during a field campaign in May 2016. A network of five portable solar-tracking Fourier transform infrared (FTIR) spectrometers was deployed throughout the city. These instruments measure the mole fraction of methane in a total column of air, giving them sensitivity to larger areas of the city than in situ sensors at the surface. We present an innovative inversion method to link these total column concentrations to surface fluxes. This method combines a Lagrangian transport model with a Bayesian inversion framework to estimate surface emissions and their uncertainties, together with determining the concentrations of methane in the air flowing into the city. Variations exceeding 10 ppb were observed in the inflowing air on a typical day, which is somewhat larger than the enhancements due to urban emissions (<5 ppb downwind of the city). We found diffuse methane emissions of 73(±22) mol s−1, which is about 50 % of the urban total and 68 % higher than estimated from bottom-up methods, although it is somewhat smaller than estimates from studies using tower and aircraft observations. The measurement and model techniques developed here address many of the challenges present when quantifying urban greenhouse gas emissions and will help in the design of future measurement schemes in other cities.

Analysis of the optimal spatial distribution of natural gas under ‘transition from coal to gas’ in China

China has been attempting to realise green sustainable economic development. Thus, China has proposed and begun to implement the ‘switching from coal to gas’ policy to realise the energy structure transition but neglected to consider seasonal natural gas demand fluctuations, gas supply shortages, the backward gas transportation and storage infrastructure. This paper constructs a model of China’s natural gas distribution system by incorporating these four factors: ① supply factors including domestic natural gas fields, liquid natural gas receiving stations, internationally piped gas sources, ② demand factors including domestic regional demands, ③ real natural gas transportation pipeline systems in the country, and ④ the pricing mechanism of natural gas. Optimal spatial natural gas distribution with maximum social welfare under the three conditions are simulated, respectively: the ① fixed price system, ② market pricing mechanism, and ③ seasonal fluctuations. The simulation results indicate substantial changes would occur in China’s natural gas system during the switch from coal to gas, and the natural gas infrastructure requires further improvement. This paper also provides references for the natural gas storage facility location selection in China.

Aspects of Hydrogen and Biomethane Introduction in Natural Gas Infrastructure and Equipment

The injection of green hydrogen and biomethane is currently seen as the next step towards the decarbonization of the gas sector in several countries. However, the introduction of these gases in existent infrastructure has energetic, material and operational implications that should be carefully looked at. With regard to a fully blown green gas grid, transport and distribution will require adaptations. Furthermore, the adequate performance of end-use equipment connected to the grid must be accounted for. In this paper, a technical analysis of the energetic, material and operational aspects of hydrogen and biomethane introduction in natural gas infrastructure is performed. Impacts on gas transmission and distribution are evaluated and an interchangeability analysis, supported by one-dimensional Cantera simulations, is conducted. Existing gas infrastructure seems to be generally fit for the introduction of hydrogen and biomethane. Hydrogen content up to 20% by volume appears to be possible to accommodate in current infrastructure with only minor technical modifications. However, at the Distribution System Operator (DSO) level, the introduction of gas quality tracking systems will be required due to the distributed injection nature of hydrogen and biomethane. The different tolerances for hydrogen blending of consumers, depending on end-use equipment, may be critical during the transition period to a 100% green gas grid as there is a risk of pushing consumers off the grid.

The Uncertain World of Natural Gas Infrastructure

A very interesting combination of court decisions came out in June, regarding natural gas infrastructure, its justification and the rights of its developers. One court decision would make it more difficult to prove the need for a natural gas pipeline. The other decision would make it easier for a pipeline with a Federal Energy Regulatory Commission (FERC) certificate to condemn rights‐of‐way, even across state land when the state does not support the build‐out of natural gas pipelines. In other words, one decision is restrictive for new pipeline infrastructure, while the other decision is supportive. The dueling decisions impact two significant issues regarding the authorization of new natural gas infrastructure development; (1) whether firm contracts are sufficient to prove supply need, and (2) how broad the right of eminent domain conferred by a FERC certificate can be.

Design Optimization of a Thermally Integrated Solid Oxide Fuel Cell with Triple Effect Absorption Chiller

To reduce emissions and energy use in data centers, a novel integration between a solid-oxide fuel cell (SOFC) and a triple-effect absorption chiller (AC) is proposed to meet both the electrical and cooling requirements of server computers. An installation of SOFC units at a data center can operate using natural gas infrastructure that today supplies natural gas or directed renewable fuel and which can increasingly introduce biogas, renewable hydrogen, and/or synthetic fuels in the future. In fact, SOFC systems have already been employed to produce primary power for data centers[i]with high fuel-to-electricity conversion efficiencies and these efficiencies can be further improved by integration with AC waste heat recovery technology. Utilizing the waste heat in the exhaust stream of the SOFC, a triple-effect AC system, using aqueous lithium bromide as a working fluid, can produce the required cooling for the servers and eliminate the requirement for a backup mechanical cooling system. A 200 kW SOFC system is selected for row-level discretization of power production and is coupled to an equivalent 200 kW AC system to provide the necessary cooling. An additional benefit of this discretized installation is the inherent reliability of the distributed power and cooling generation with limited failure domain. Using this system and an n+1 installation strategy, it is possible to eliminate the requirement for backup power systems as well.A numerical simulation investigates the design of the integrated 200 kW SOFC and AC system. The 200 kW SOFC is optimized to produce the required electricity at conversion efficiencies up to 60%[ii], while still producing enough thermal energy to run the 200 kW triple-effect AC system. The numerical simulation indicates that a 200 kW SOFC can produce anywhere from 80 – 130 kW of useful heat in the exhaust, as shown in Figure 1. The AC system is optimized to harness this thermal energy from the SOFC exhaust to meet the cooling demand of the servers and can operate at a coefficient of performance (COP) of up to 1.89. A control strategy for the integrated system is developed based on the power demand of the servers and the ambient conditions of the data center to provide the required power and cooling.Additionally, the numerical study addresses the multiple possible cooling configurations that could be adopted by a data center. Liquid cooled servers utilize higher temperature cooling medium, which allows the AC system to operate at a higher COP. The improvement in AC efficiency when cooling to a higher temperature is explored to further improve the chilling capacity.In conjunction with the numerical simulation, an experimental system has been constructed to demonstrate the efficacy of an integrated SOFC and AC system for data center applications. The experimental system consists of a single server rack, a 12-kW array of SOFC systems for power, and an 18-kW single-effect absorption chiller for cooling. The experimental setup is shown in Figure 2. The server computers are operated at a simulated computational load, which exercises the SOFC array and absorption chiller, testing the system’s ability to produce power and chilling. The experimental system has demonstrated the ability to operate at a COP of up to 0.77 with SOFC exhaust gasses at 235°C, producing 12.5 kW of chilling, equivalent to 47% of the cooling demand of the server rack at full capacity.The experimental system is also used to validate the thermo-physical models used in the numerical simulations. This includes the desorber physics at elevated temperatures created by the utilization of fuel cell exhaust heat, which is much hotter than typical AC heat sources. Additionally, by altering the control strategy of the AC system, it is possible to explore elevated cooling temperatures in the evaporator and absorber, pursuing improved COPs that are possible in a liquid-cooled server configuration.Finally, the financial viability of a large-scale installation of such a system is addressed. The high capital costs associated with SOFC and triple-effect AC systems typically hinder the implementation of such systems. However, our results demonstrate that the integrated system is competitive on a levelized cost basis mainly because of primary energy savings (up to 34% compared to a conventional data center) and ability to displace the installation of backup electrical and chilling systems. [i] eBay turns on first fuel cell powered data centre, has Bloom tech. (2013). Fuel Cells Bulletin, 2013(10), 3–4. https://doi.org/10.1016/s1464-2859(13)70341-9 [ii] Williams, M. C., Vora, S. D., & Jesionowski, G. (2020). Worldwide Status of Solid Oxide Fuel Cell Technology. ECS Transactions, 96(1), 1–10. https://doi.org/10.1149/09601.0001ecst Figure 1

Development of Sustainable Infrastructure in Eastern Indonesia

The condition of limited infrastructure in Indonesia positions that current infrastructure is very important to be built immediately to support development in various fields so that economic, trade, industrial and other social activities run more smoothly and develop, so that the dynamics of society in all corners of the country will increase. The cost of producing electricity in Eastern Indonesia, such as Sulawesi, Papua, Maluku and Nusa Tenggara is currently 2 to 5 times the cost of producing electricity in Java, Bali and Sumatra. One of the ways that should be intensified is by building a small-scale Liquid Natural Gas (LNG) infrastructure concept that aims to meet the needs of gas consumers who do not receive gas pipelines or who require small volumes of gas, for example small capacity power plants, especially those in islands in Eastern Indonesia. In this archipelago, it is impossible for all regions to be connected by pipelines that cross the oceans, because of course it requires very large funds. The application of small-scale LNG technology is the right solution for LNG supply in Eastern Indonesia. If the energy infrastructure is available, the quality of human resources must also be improved so that they become human resources who are always active and always adapt to developments.

Analytics in Extracting Intelligence from IoT-Based Sensors in Transportation, Healthcare and Natural Gas Detection

Networking of sensors and the development of sensor systems have become routine technological endeavors. The advent of Internet-of-Things (IoT) technologies has enabled an expanding matrix of applications for integration of specialized sensor systems. The focus on innovation is now on driving costs down, while increasing performance. Additive manufacturing techniques and topological improvements are key drivers of innovation for sensors.As sensors and sensor systems transform their capabilities from (strictly) data generation and gathering, the focus now shifts on how to increase the utility of the sensor and sensor system.SensorComm defines the utility of a sensor as its ability to provide intelligence. Intelligence comes from the collection of data. Through data-analytics, information can be extracted. The final step of interpreting the information is through the generation of intelligence. Off-the-shelf tools are available that include machine learning, artificial intelligence, and even toolboxes in platforms like MATLAB, all of which have changed the way we obtain information. The next step is obtaining the intelligence.SensorComm has applied this methodology of intelligence extraction in three areas: 1) transportation 2) healthcare and now 3) natural gas monitoring/detection.In transportation, we will describe how intelligence is obtained from SensorComm’s IoT-based mobile pollution monitoring system. Installed at the tailpipe, Wi-NOx™ captures the real-time pollution footprint of vehicles. The system extracts, analyzes and transforms NOx emissions data into real-time information providing transportation managers with business intelligence that leads to operational efficiencies and measurable savings. Wi-NOx™ is the cornerstone of a global pollution mitigation strategy that enables fuel savings, emissions reduction, vehicle optimization and extended asset life (to responsibly delay significant infrastructure investments like electrification).The Wi-NOx™ system was developed to monitor emissions from vehicles. Recently, we have modified it to remotely monitor patients in healthcare applications, and now, to monitor natural gas for oil & gas applications.In healthcare, Sensorcomm has developed a wrist-worn temperature monitoring system for COVID-19 detection using the Data-Centric Care™ model. Data-Centric Care™ focuses on data to provide the necessary intelligence to correctly assess the situation. The system uses (near) continuous temperature monitoring of individuals to identify at-risk persons who may or may not be symptomatic (for COVID-19 and beyond). The system uses a smart wearable device (wrist-worn) that monitors temperature as a trigger for second-tier screening from which a corresponding response is implemented (e.g. return to daily activity, isolate, elevated care). The continuous monitoring allows for the development of individualized thresholds (average temperature and fever threshold) rather than using population thresholds. The system identifies at-risk individuals (people with anomalies in their daily temperature profiles) for additional screening, prior to entering a facility.The most recent development at SensorComm is the partnership with the Center for Micro-Engineered Materials at the University of New Mexico, who is developing mixed-potential methane sensors using additive manufacturing. Mitigating environmental effects and financial costs of methane leaks requires a robust, widely deployable, low-cost sensing technology to provide continuous monitoring of natural gas infrastructure. Since methane emissions originate from multiple sources (agricultural or wetlands sites), sensors need to distinguish between natural gas or one of these other sources. Strategies for gathering the data, extracting the information and providing intelligence will be discussed.This talk will discuss the different techniques utilized in the data analytics and will provide key examples of how intelligence is extracted in the various applications.This material is based upon work supported by the U.S. Department of Energy, National Energy Technology Office program under Award Number DE-FOA-0031864, and partially by the National Science Foundation under Grant No. 1632498. Figure 1

Approaches to cost-effective near-net zero energy new homes with time-of-use value of energy and battery storage

Abstract California requires all new residential buildings to meet near-net zero energy building (near-NZEB) targets in its building energy efficiency standards (Title 24) starting January 2020. For the first time, rooftop solar PV is required in new homes under three stories tall. While individual technologies are available for energy efficiency and renewable energy, significant challenges exist for scaling up NZEB homes across the State of California. This study presents a novel and holistic modeling and cost-effective analysis of new single-family homes in California to inform the design of cost-effective near-NZEB homes, as well as to guide future updates of Title 24. California's NZEB homes are defined using the time dependent valuation methodology to evaluate their cost-effectiveness. A comprehensive set of energy efficiency measures, solar PV, and battery storage are considered in the modeling and analysis as well as different net-metering policies for rooftop PV compensation rates for exported power. The BEopt tool with the EnergyPlus simulation engine is used to model and optimize, based on cost, the building designs for all-electric and mixed-fuel single-family homes across all 16 California climate zones. Results show that optimal designs of near-NZEB single-family homes have lower lifecycle costs for both all-electric and mixed-fuel cases in all California climate zones than the 2020 baseline code-compliant homes. Cost-optimal designed all-electric homes are comparable in lifecycle costs to mixed-fuel homes in most climate zones in part because no natural gas infrastructure is needed. For battery storage, electricity rates with a greater degree of time-dependence will improve cost-effectiveness of near-NZEB or full NZEB homes. These findings provide technical and investment insights into the scale up of cost-effective near-NZEB home design in California. The methodology and models can be adopted for other U.S. states or international cities to inform policy making and design of near-net zero energy residential buildings.

Understanding gas prices: an overview of regulations and components affecting the Indonesian natural gas prices

Natural gas is the primary commodity of Indonesia’s energy supply and an important policy issue. Domestic gas demand is dominated by the industrial, power sector, and fertilizer. Over the past five years, Indonesia’s natural gas prices have increased significantly, which will undoubtedly affect the consumers. We summarized and analyzed policy, literature, and interviews with stakeholders to find the main factors of gas prices. This study concluded that the government has a more dominant role in determining gas prices. The increase in gas prices was mainly influenced by the upstream project’s economics, the tariff for transmission, and managing natural gas infrastructure. The application of indexation with ICP and the escalation price also contributed to the high price. The Government needs to consider gas price adjustments carefully because these commodities have a multiplier effect and affect industry competitiveness.

Challenges and prospects of developing city gas to reduce imported LPG in Indonesia

Indonesia has natural gas potential that can be developed through the city gas program. Although the city gas program has been designed since 2009, its effectiveness in addressing the critical LPG issues is still insignificant. The achievement of the city gas development target in 2019 has only reached 12% of the government’s target of 4.7 million SR (house connections) in 2025. We conducted content analysis and in-depth studies on several legal products and literature related to opportunities and challenges in the city gas development. We found that the main problem was the limited investment from both the government budget and the corporate budget. Challenges of city gas development are low project economics, delays in upstream natural gas projects and natural gas infrastructure development, and low customer satisfaction. Meanwhile, obstacles to city gas development are the length of the licensing process, social problems, unclear KPBU (Community - Business Entity Cooperation) scheme, and undefined handling of LPG subsidy (3 Kg). This finding is expected to be taken into consideration in the formulation of a more effective and massive city gas development strategy in the future.

Hydrogen and the Transition from Gas Networks to a New Energy Carrier Paradigm

Portugal has developed a national roadmap for hydrogen deployment as a key element of the Portuguese energy transition towards carbon neutrality, with a major contribution towards the electrification of society, generating synergies between the electric and gas systems. Considering the government goals for hydrogen injection within natural gas infrastructures for 2025 and 2030, as long as the indicative trajectories for 2040 and 2050, the authors used the natural gas forecast of the security of supply official report in order to obtain the hydrogen demand and power plant capacity, evaluating the system effort to meet public policy goals. Several alternative scenarios were developed for sensitive analysis, in order to assess the different strategies of hydrogen deployment, considering production from an electrolyzer. Regarding the current Portuguese situation and every scenario outcome, the authors stated that major efforts must be undertaken in order to develop full-scale hydrogen projects in order to meet the national goals.

Integration of Excess Renewable Energy with Natural Gas Infrastructure for the Production of Hydrogen and Chemicals

Power to gas (PtG) capitalizes on the free or low-cost power made available during frequent mismatches between power demand and power supply by converting water into hydrogen and oxygen via electrolysis. Current PtG projects vent the oxygen to the atmosphere and utilize the hydrogen for myriad purposes. Although oxygen has relatively little value when compared to hydrogen on a mass basis, the value of oxygen produced via electrolysis is significant compared to the value of the hydrogen due to the composition of water. This work presents a systematic methodology for designing a PtG project which co-utilizes hydrogen and oxygen to manufacture hydrogen and chemicals via integration with the natural gas infrastructure. A case study is developed and solved to demonstrate the applicability of the proposed methodology. The results of the case study show that significant value may be added by utilizing oxygen and the natural gas infrastructure.

Urban Emissions of Nitrogen Oxides, Carbon Monoxide, and Methane Determined from Ground-Based Measurements in Philadelphia

Nitrogen oxides (NOX) and methane impact air quality through the promotion of ozone formation, and methane is also a strong greenhouse gas. Despite the importance of these pollutants, emissions in urban areas are poorly quantified. We present measurements of NOX, CH4, CO, and CO2 made at Drexel University in Philadelphia along with NOX and CO observations at two roadside monitors. Because CO2 concentrations in the winter result almost entirely from combustion with negligible influence from photosynthesis and respiration, we are able to infer fleet-averaged fuel-based emission factors (EFs) for NOX and CO, similar in some ways to how EFs are determined from tunnel studies. Comparison of the inferred NOX and CO fuel-based EF to the National Emissions Inventory (NEI) suggests errors in NEI emissions of either NOX, CO, or both. From the measurements of CH4 and CO2, which are not emitted by the same sources, we infer the ratio of CH4 emissions (from leaks in the natural gas infrastructure) to CO2 emissions (from fossil fuel combustion) in Philadelphia. Comparison of the CH4/CO2 emission ratios to emission inventories from the Environmental Protection Agency suggests underestimates in CH4 emissions by almost a factor of 4. These results demonstrate the need for the addition of long-term observations of CH4 and CO2 to existing monitoring networks in urban areas to better constrain emissions and complement existing measurements of NOX and CO.

Liquefied Natural Gas Infrastructure and Prospects for the Use of LNG in the Baltic States and Finland

Abstract In the early 2010s, only 23 countries had access to the liquefied natural gas (hereinafter – LNG). Import terminals, despite attractive short-term economics, took long time to build, and rigid supply contracts made truly global use of LNG rather complicated. Concerns about geo-political risks also stunted demand growth from existing supply sources, even when new LNG export routes and sources became available. Current natural gas market is very different, both in terms of market participants and accessibility and diversity of services. In 2019, the number of LNG importing countries reached 43. Rising competition among suppliers and increasing liquidity of markets themselves created favourable conditions to diversify contract duration, size, and flexibility. In addition, development of floating storage and regasification unit (hereinafter – FSRU) technology provided LNG suppliers with a quick response option to sudden demand fluctuations in regional and local natural gas markets [1]. Moreover, LNG is one of the major options not only for bringing the natural gas to regions where its pipeline supply infrastructure is historically absent, limited or underdeveloped, but also for diversification of the natural gas supply routes and sources in regions with sufficient state of pipeline delivery possibilities. And it concerns smaller natural gas markets, like the Baltic States and Finland as well. Accordingly, prospects for use of LNG there in both mid and long-term perspective must be carefully evaluated, especially in regards to emerging bunkering business in the Baltic Sea aquatory and energy transition in Finland, replacing coal base-load generation with other, more sustainable and environmentally friendly alternatives.

The Eastern Baltic LNG Terminal as a Prospect to Improve Security of Regional Gas Supply

One of the crucial issues in Europe at the moment is securing reliable gas supply. Achieving security of gas supply implies diversifying gas sources, while having enough supply, transportation, and storage capacity to meet demand peaks and supply interruptions. In 2013, the Baltic States still remain disintegrated from the rest of Europe in one crucial way: their natural gas infrastructure isolates them into “energy islands”. The Eastern Baltic Sea European Union (EU) member states of Finland, Estonia, Latvia and Lithuania are the only ones which remain isolated from the present integrated EU natural gas transmission system. The gas demand in these isolated member states is approximately ten billion cubic meters (bm3) of natural gas per year. The third energy package of EU proposes a new series of measures to promote competition and create a single European energy market. Estonia, Latvia, Lithuania and Finland now for the first time have a chance to secure their energy independence by connecting their natural gas systems with those of their European allies and evolving them into market-based trading systems. Liquefied natural gas (LNG) is an important energy source that contributes to energy security and diversity, therefore a concept of a regional LNG terminal has been proposed. In this paper the authors give an overview of the current situation and present possible future scenarios with the development of Eastern Baltic regional LNG terminal. 2013 is a crucial time as in September the decision will be made regarding weather the regional LNG terminal will be chosen as a project of common interest in the trans-European energy networks.

Price-region bids in electricity markets

Current bid formats in pool-based electricity markets are ill-equipped to accommodate the broad range of non-conventional sources of flexibility, such as demand response and interconnected heating, natural gas and water infrastructure networks. To address this issue, this paper introduces the novel price-region bid format to be used in both forward electricity markets and financial right auctions. We show that price-region bids are able to accommodate a broad range of techno-economic characteristics, including complex spatial and temporal couplings, and facilitate market access to non-conventional flexibility providers. We then show that this new bid format is compatible with existing market structures, and satisfies desirable market properties under common assumptions. Three numerical studies are provided: two motivating examples based on a district heating utility and a cascaded hydro power plant, and a case study based on an integrated power and heat system. These studies illustrate the inability of existing bid formats to accommodate flexible resources, and show how price-region bids overcome this shortcoming.

Experience and Enlightenment of Japan’s Emergency Power Supply Guarantee Mechanism

Japan is a country prone to natural disasters such as earthquakes, tsunamis, and typhoons. Electricity is the key material basis for production, life and emergency management, so the reliability and stability of its supply is an important content of Japan’s disaster protection. In recent years, people have paid more and more attention to maintaining a normal and independent life even after the power and natural gas infrastructure has stopped. Therefore, the concept and practice of emergency power supply have been circulated and widely implemented in Japan for a long time. This paper summarizes the concepts, legal standards, development history, main methods, work of power grid companies, development trends, etc. of emergency power supply in Japan, and provides relevant experience and inspiration for the development of emergency power supply in China.

Development of Natural Gas Infrastructure to Enhance National Energy Security in Indonesia

The current use of energy in Indonesia highly still depends on fossil-derived energy. Thus, policies to reduce the use of fossil energy towards the use of new and renewable energy (NRE), which is more environmentally friendly, receive great concern. The government encourages the use of low-carbon technology following up the Paris Agreement to reduce greenhouse gas (GHG) emissions by 29% (without assistance) and by 41% (with international assistance) under Business as Usual (BAU) by 2030. However, accelerating the utilization of renewable energy still faces some obstacles because the economic price of NRE is still more expensive than that of fossil energy. The most likely transition policy is to substitute the use of oil and fuel to natural gas through improving natural gas infrastructure. This transition is following the Sustainable Development Goal (SDG) which guides the achievement of global goals until 2030, namely to ensure access to affordable, reliable, sustainable, and modern energy for all. The development of natural gas infrastructure is currently in an early stage (point to point scheme) and is expected to develop into a hub and spoke scheme towards multiple networks. The more developed infrastructure will further enhance national energy security in the long run.

Noise and landscape features influence habitat use of mammalian herbivores in a natural gas field.

Anthropogenic noise is a complex disturbance known to elicit a variety of responses in wild animals. Most studies examining the effects of noise on wildlife focus on vocal species, although theory suggests that the acoustic environment influences non-vocal species as well. Common mammalian prey species, like mule deer and hares and rabbits (members of the family Leporidae), rely on acoustic cues for information regarding predation, but the impacts of noise on their behaviour has received little attention. We paired acoustic recorders with camera traps to explore how average daily levels of anthropogenic noise from natural gas activity impacted occupancy and detection of mammalian herbivores in an energy field in the production phase of development. We consider the effects of noise in the context of several physical landscape variables associated with natural gas infrastructure that are known to influence habitat use patterns in mule deer. Our results suggest that mule deer detection probability was influenced by the interaction between physical landscape features and anthropogenic noise, with noise strongly reducing habitat use. In contrast, leporid habitat use was not related to noise but was influenced by landscape features. Notably, mule deer showed a stronger predicted negative response to roads with high noise exposure. This study highlights the complex interactions of anthropogenic disturbance and wildlife distribution and presents important evidence that the effects of anthropogenic noise should be considered in research focused on non-vocal specialist species and management plans for mule deer and other large ungulates.

Impact of hydrogen injection on thermophysical properties and measurement reliability in natural gas networks

In the context of the European decarbonization strategy, hydrogen is a key energy carrier in the medium to long term. The main advantages deriving from a greater penetration of hydrogen into the energy mix consist in its intrinsic characteristics of flexibility and integrability with alternative technologies for the production and consumption of energy. In particular, hydrogen allows to: i) decarbonise end uses, since it is a zero-emission energy carrier and can be produced with processes characterized by the absence of greenhouse gases emissions (e.g. water electrolysis); ii) help to balancing electricity grid supporting the integration of non-programmable renewable energy sources; iii) exploit the natural gas transmission and distribution networks as storage systems in overproduction periods. However, the hydrogen injection into the natural gas infrastructures directly influences thermophysical properties of the gas mixture itself, such as density, calorific value, Wobbe index, speed of sound, etc [1]. The change of the thermophysical properties of gaseous mixture, in turn, directly affects the end use service in terms of efficiency and safety as well as the metrological performance and reliability of the volume and gas quality measurement systems. In this paper, the authors present the results of a study about the impact of hydrogen injection on the properties of the natural gas mixture. In detail, the changes of the thermodynamic properties of the gaseous mixtures with different hydrogen content have been analysed. Moreover, the theoretical effects of the aforementioned variations on the accuracy of the compressibility factor measurement have been also assessed.