Showing papers on "Natural gas published in 2022"

On the climate impacts of blue hydrogen production

Abstract: Natural gas based hydrogen production with carbon capture and storage is referred to as blue hydrogen. If substantial amounts of CO2 from natural gas reforming are captured and permanently stored, such hydrogen could be a low-carbon energy carrier. However, recent research raises questions about the effective climate impacts of blue hydrogen from a life cycle perspective. Our analysis sheds light on the relevant issues and provides a balanced perspective on the impacts on climate change associated with blue hydrogen. We show that such impacts may indeed vary over large ranges and depend on only a few key parameters: the methane emission rate of the natural gas supply chain, the CO2 removal rate at the hydrogen production plant, and the global warming metric applied. State-of-the-art reforming with high CO2 capture rates combined with natural gas supply featuring low methane emissions does indeed allow for substantial reduction of greenhouse gas emissions compared to both conventional natural gas reforming and direct combustion of natural gas. Under such conditions, blue hydrogen is compatible with low-carbon economies and exhibits climate change impacts at the upper end of the range of those caused by hydrogen production from renewable-based electricity. However, neither current blue nor green hydrogen production pathways render fully “net-zero” hydrogen without additional CO2 removal.

Hydrate Deposition Model and Flow Assurance Technology in Gas-Dominant Pipeline Transportation Systems: A Review

Abstract: With the exploration and development of natural gas gradually extended to the deep sea, low-temperature and high-pressure environmental conditions and long-distance transportation make flow assurance engineers have to consider the impact of the formation and blockage of natural gas hydrates on the flow stability in the pipeline. Therefore, an inadequate understanding of the hydrate formation and plugging mechanism in a gas-rich (gas-dominant) system has become a serious obstacle to the prediction of hydrate formation and implementation of blocking prevention and control strategies. To this end, this review has conducted a comprehensive review of recent experimental investigations into hydrate formation and blockage in gas-rich systems in flow loop devices, and the physical models to characterize the clogging mechanism of hydrates established by previous scholars were summarized. In addition, the three flow patterns of the gas-rich system were divided, and the hydrate deposition mechanism corresponding to each flow pattern and the prediction model of the deposition layer thickness was summarized. Eventually, the natural gas hydrate mitigation and prophylaxis and restrain strategies used in the process of deep-sea natural gas transportation were summarized, including advantages and disadvantages of natural gas dehydration, changing the gas flow rate, and adding chemical inhibitors. The advantages and feasibility of an under-inhibited system and changing the gas flow rate for the management and prevention of hydrate blockage were emphasized. The conclusion can improve the safety index of natural gas development and transportation operations and reduce the output loss of natural gas energy and economic loss of hydrate anti-blocking.

An integrated future approach for the energy security of Pakistan: Replacement of fossil fuels with syngas for better environment and socio-economic development

Abstract: Energy security necessitates the continuous availability of sufficient supply in different forms at economical prices. Energy security is a priority for states like Pakistan since it is a prerequisite for socioeconomic development. Pakistan's electricity demand is gradually increasing, and the country is being challenged with significant natural gas supply-demand deficit. Thar fossil fuel reserves, mostly coal reserves will play a critical role in meeting energy needs for decades. This study aimed to provide framework for tapping indigenous alternate energy resources to address growing natural gas crisis in Pakistan for sustainable energy security. This study may aid in understanding the value of oil, energy protection, and natural gas scarcity in Pakistan, the impact of gas shortages on energy security, syngas as a natural gas substitute, syngas production through coal gasification technology, coal gasification as a high-performance low-emission solution, and syngas applications for long-term energy security.

Methane and NOx Emissions from Natural Gas Stoves, Cooktops, and Ovens in Residential Homes.

Abstract: Natural gas stoves in >40 million U.S. residences release methane (CH4)─a potent greenhouse gas─through post-meter leaks and incomplete combustion. We quantified methane released in 53 homes during all phases of stove use: steady-state-off (appliance not in use), steady-state-on (during combustion), and transitory periods of ignition and extinguishment. We estimated that natural gas stoves emit 0.8-1.3% of the gas they use as unburned methane and that total U.S. stove emissions are 28.1 [95% confidence interval: 18.5, 41.2] Gg CH4 year-1. More than three-quarters of methane emissions we measured originated during steady-state-off. Using a 20-year timeframe for methane, annual methane emissions from all gas stoves in U.S. homes have a climate impact comparable to the annual carbon dioxide emissions of 500 000 cars. In addition to methane emissions, co-emitted health-damaging air pollutants such as nitrogen oxides (NOx) are released into home air and can trigger respiratory diseases. In 32 homes, we measured NOx (NO and NO2) emissions and found them to be linearly related to the amount of natural gas burned (r2 = 0.76; p ≪ 0.01). Emissions averaged 21.7 [20.5, 22.9] ng NOx J-1, comprised of 7.8 [7.1, 8.4] ng NO2 J-1 and 14.0 [12.8, 15.1] ng NO J-1. Our data suggest that families who don't use their range hoods or who have poor ventilation can surpass the 1-h national standard of NO2 (100 ppb) within a few minutes of stove usage, particularly in smaller kitchens.

An optimized nonlinear grey Bernoulli prediction model and its application in natural gas production

Abstract: Natural gas, an efficient, eco-friendly and clean green energy, has become one of the important energy structures of various countries in the world, accurately predicting the production of natural gas can help the national energy agency solve “gas shortage” problem. To accurately predict natural gas production in China, this paper establishes an optimized grey system model with weighted fractional accumulation generation operation (abbreviated as WFNGBM(1,1,N)). The proposed model has all the advantages of the GMP(1,1,N) model, NGBM(1,1) model and weighted fractional accumulation generation operation, which makes it have excellent prediction performance. Moreover, five outstanding intelligent optimization algorithms (whale optimization algorithm, marine predators algorithm, grasshopper optimization algorithm, equilibrium optimization algorithm and arithmetic optimization algorithm) are used to solve the hyperparameters of the WFNGBM(1,1,N) model. It is found that the WFNGBM(1,1,N) model has the characteristics of convertibility and small sample modeling, which indicates that it is a small sample prediction model with strong compatibility. After confirming the feasibility of the proposed model compared with its competing models by using natural gas production in Germany, Italy and Canada as examples, the proposed model is used to study China’s natural gas production. The results show that this model is very suitable for predicting and analyzing natural gas production in China. Based on this, the WFNGBM(1,1,N) model is used to estimate China’s natural gas production in the next three years, and some reasonable suggestions are given according to the development trend of natural gas production.

Quantifying Regional Methane Emissions in the New Mexico Permian Basin with a Comprehensive Aerial Survey.

Abstract: Limiting emissions of climate-warming methane from oil and gas (O&G) is a major opportunity for short-term climate benefits. We deploy a basin-wide airborne survey of O&G extraction and transportation activities in the New Mexico Permian Basin, spanning 35 923 km2, 26 292 active wells, and over 15 000 km of natural gas pipelines using an independently validated hyperspectral methane point source detection and quantification system. The airborne survey repeatedly visited over 90% of the active wells in the survey region throughout October 2018 to January 2020, totaling approximately 98 000 well site visits. We estimate total O&G methane emissions in this area at 194 (+72/-68, 95% CI) metric tonnes per hour (t/h), or 9.4% (+3.5%/-3.3%) of gross gas production. 50% of observed emissions come from large emission sources with persistence-averaged emission rates over 308 kg/h. The fact that a large sample size is required to characterize the heavy tail of the distribution emphasizes the importance of capturing low-probability, high-consequence events through basin-wide surveys when estimating regional O&G methane emissions.

A tactical scheduling framework for wind farm‐integrated multi‐energy systems to take part in natural gas and wholesale electricity markets as a price setter

Abstract: Correspondence Sajad Najafi Ravadanegh, Resilient Smart Grids Research Lab, Electrical Engineering Department, Azarbaijan Shahid Madani University, Tabriz, Iran. Email: s.najafi@azaruniv.ac.ir Abstract The wind integrated multi-energy systems (MES) have gained significant momentum in recent years on account of their self-sufficiency and attractive clean attributes. This study puts forward a bi-level multi-follower optimization framework to study the tactical response of a wind integrated MES in the wholesale electricity market (WEM) and the natural gas market (NGM) as a price setter. At the upper level, the MES endeavors to minimize the overall operational costs by giving the best offer/bid in WEM/NGM, and by utilizing thermal energy storage (TES), compressed air energy storage (CAES), and natural gas storage (NGS). When the MES submits offers/bids in WEM and NGM, the NGM and WEM operators, as individual followers, clear their respective markets to maximize public welfare and announce the ultimate market-clearing price (MCP). Additionally, risk-averse and riskseeker information gap decision theory (IGDT) have been deployed to provide various decision-making options for MES operators considering wind underproduction and overproduction scenarios. Standard 6-node natural gas network (NGN) and 6-bus transmission system (TS) have been deployed to model WEM and NGM, respectively. The results testify to the capabilities of the MES in influencing the decisions of WEM and NGM.

Fully coupled modeling of two-phase fluid flow and geomechanics in ultra-deep natural gas reservoirs

Abstract: Efficiently and accurately understanding the fluid flow behavior in ultra-deep natural gas reservoirs is very challenging due to the complex geological environment and the intricate gas properties at high pressure. In this study, a fully coupled fluid flow and geomechanical model was developed to simulate complex production phenomena in ultra-deep natural gas reservoirs. Stress-dependent porosity and permeability models were applied, and then the governing equations of the model were incorporated into COMSOL Multiphysics. Furthermore, the model was verified by the reservoir depletion from the Keshen gas field in China, and the effects of reservoir properties and geomechanics on gas production were discussed. The results showed that the reservoir pressure and water saturation exhibited a significant funnel-shaped decline during the reservoir depletion. The higher relative permeability of the gas phase results in more methane gas production, thereby reducing the average pore pressure and gas saturation near the wellhead. When considering geomechanical effects, the production behavior significantly changes. The predictive value of gas production was higher when the reservoir rock deformation was ignored. The gas production exhibited strong positive correlations with reservoir porosity, fracture permeability, elastic modulus, and Poisson's ratio. Larger porosity, elastic modulus, and Poisson's ratio resulted in smaller deformation, while a smaller fracture permeability leads to larger deformation in ultra-deep natural gas reservoirs.

Hydrogen Blending in Gas Pipeline Networks—A Review

Abstract: Replacing fossil fuels with non-carbon fuels is an important step towards reaching the ultimate goal of carbon neutrality. Instead of moving directly from the current natural gas energy systems to pure hydrogen, an incremental blending of hydrogen with natural gas could provide a seamless transition and minimize disruptions in power and heating source distribution to the public. Academic institutions, industry, and governments globally, are supporting research, development and deployment of hydrogen blending projects such as HyDeploy, GRHYD, THyGA, HyBlend, and others which are all seeking to develop efficient pathways to meet the carbon reduction goal in coming decades. There is an understanding that successful commercialization of hydrogen blending requires both scientific advances and favorable techno-economic analysis. Ongoing studies are focused on understanding how the properties of methane-hydrogen mixtures such as density, viscosity, phase interactions, and energy densities impact large-scale transportation via pipeline networks and end-use applications such as in modified engines, oven burners, boilers, stoves, and fuel cells. The advantages of hydrogen as a non-carbon energy carrier need to be balanced with safety concerns of blended gas during transport, such as overpressure and leakage in pipelines. While studies on the short-term hydrogen embrittlement effect have shown essentially no degradation in the metal tensile strength of pipelines, the long-term hydrogen embrittlement effect on pipelines is still the focus of research in other studies. Furthermore, pressure reduction is one of the drawbacks that hydrogen blending brings to the cost dynamics of blended gas transport. Hence, techno-economic models are also being developed to understand the energy transportation efficiency and to estimate the true cost of delivery of hydrogen blended natural gas as we move to decarbonize our energy systems. This review captures key large-scale efforts around the world that are designed to increase the confidence for a global transition to methane-hydrogen gas blends as a precursor to the adoption of a hydrogen economy by 2050.