Energy Vector Research Articles

Hydrogen adsorption on fcc metal surfaces towards the rational design of electrode materials

The successful large-scale implementation of hydrogen as an energy vector requires high performance electrodes and catalysts made of abundant materials. Rational materials design strategies are the most efficient means of reaching this goal. Here we present a study on the adsorption of H-atoms onto fcc transition metal surfaces and propose descriptors for the rational design of electrodes and catalysts by means of correlations between fundamental properties of the materials and among other properties, their experimentally measured performance as hydrogen evolution electrodes (HEE). A large set of quantum mechanical modelling data at the DFT level was produced, covering the adsorption of H-atoms onto the most stable surfaces (100), (110) and (111) of: Ag, Au, Co, Cu, Ir, Ni, Pd, Pt and Rh. For each material and surface, a coverage dependent set of minimum energy structures was produced and chemical potentials for adsorption of H-atoms were obtained. Averaging procedures are here proposed to approach modelling to the experiments. Several correlations between the computed data and experimentally measured quantities are done to validate our methodology: surface plane dependent adsorption energies, chemical potentials and experimentally determined surface energies and work functions. We search for descriptors of catalytic activity by testing correlations between the DFT data obtained from our averaging procedures and experimental data on HEE performance. Our methodology allows us to obtain linear correlations between the adsorption energy of H-atoms and the exchange current density (i0) in a HEE, avoiding the volcano-like plots. We show that the chemical potential has limitations as a descriptor of i0 because it reaches an early plateau in terms of i0. Simple quantities obtained from database data such as the first stage electronegativity (χ) as devised by Mulliken has a strong linear correlation i0. With a quantity we denominate modified second-stage electronegativity (χ2m) we can reproduce the typical volcano plot in a correlation with i0. A theoretical and conceptual framework is presented. It shows that both χ and χ2m, that depend on the first ionization potential, second ionization potential and electron affinity of the elements can be used as descriptors in rational design of electrodes or of catalysts for hydrogen systems.

Technical–Economic Analysis of Renewable Hydrogen Production from Solar Photovoltaic and Hydro Synergy in a Pilot Plant in Brazil

Renewable hydrogen obtained from renewable energy sources, especially when produced through water electrolysis, is gaining attention as a promising energy vector to deal with the challenges of climate change and the intermittent nature of renewable energy sources. In this context, this work analyzes a pilot plant that uses this technology, installed in the Itumbiara Hydropower Plant located between the states of Goiás and Minas Gerais, Brazil, from technical and economic perspectives. The plant utilizes an alkaline electrolyzer synergistically powered by solar photovoltaic and hydro sources. Cost data for 2019, when the equipment was purchased, and 2020–2023, when the plant began continuous operation, are considered. The economic analysis includes annualized capital, maintenance, and variable costs, which determines the levelized cost of hydrogen (LCOH). The results obtained for the pilot plant’s LCOH were USD 13.00 per kilogram of H2, with an efficiency loss of 2.65% for the two-year period. Sensitivity analysis identified the capacity factor (CF) as the main determinant of the LCOH. Even though the analysis specifically applies to the Itumbiara Hydropower Plant, the CF can be extrapolated to larger plants as it directly influences hydrogen production regardless of plant size or capacity.

Improvement in Efficiency of Four Stroke Petrol Engine Blend with Butanol Using Hydrogen Supplementation

Hydrogen is seen as one of energy vector of the next century. Hydrogen, as a renewable energy source provides a potential form sustainable development particular in transportation sector. The hydrogen driven engine reduces both local as well as global emission. Hydrogen gas is in brown color and form of un-separated hydrogen and oxygen generated by the electrolysis process of water by a unique electrode design. Hydrogen gas was used as a supplementary fuel in a petrol engine with few modifications and without need of storage tanks. As hydrogen, Butanol is also used as fuel in engine. Blending of small proportion of petrol and butanol can be used in petrol engine without modification of engine. Using of butanol with petrol improve performance of engine. As hydrogen gas is used as a supplementary and butanol is blend with petrol, it will enhance the combustion characteristics of petrol engine and improve performance. In this project we are going to analyze the performance characteristics of petrol engine with butanol blends using HHO kit. Key Words: Hydrogen, Four stroke petrol engine, Butanol

Prospects of green hydrogen production in the Philippines from solar photovoltaic and wind resources: A techno-economic analysis for the present and 2030

As global temperatures continue to rise, reducing greenhouse gas emissions is more important than ever – demanding an urgent transition to renewable energy systems. In this study, the potential for green hydrogen production from solar and wind sources in the Philippines is explored. Renewable energy systems can yield higher decarbonization by producing green hydrogen, potentially an ‘energy vector’ for industrial, power, and transportation applications, thereby representing a promising solution for the nation's energy transition. This study explores the competitiveness of green hydrogen production in the Philippines through a comprehensive techno-economic analysis to predict the levelized cost of hydrogen (LCOH) derived from solar- and wind-powered electrolysis. The 2030 projections explore three scenarios, each representing varying research and development intensities resulting in different electrolyzer costs. The resulting LCOH values underscore the need for economic policy interventions to slash hydrogen costs to a competitive level. The present and near-future costs and attributes of electrolysis technologies still fall short compared to fossil fuel-based pathways. Furthermore, sensitivity and uncertainty analyses are conducted to investigate subsidy and policy requirements, and random changes to costs. The findings of this work provide a comprehensive understanding of the potential fluctuations and challenges in the economic landscape in the Philippines.

Microwave absorption properties of Co/C and Ni/C composite nanofibers prepared by electrospinning

Abstract Carbon nanofibers with Co, Ni nanoparticle were synthesized by a two-step process involving electrospinning and heat treatment. Their phase composition, microstructure, elemental composition and electromagnetic characteristics were characterized using x-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and vector network analyzer (VNA). The microwave absorption performance of these carbon nanofibers was also studied. The results indicate that these composite nanofibers are intact and consist of amorphous carbon and face-centered cubic structured magnetic metals. The resultant metal nanoparticles are uniformly dispersed along carbon-based nanofibers which enhance the synergistic and interfacial effects between magnetic loss and dielectric loss. When the thicknesses of the absorbers are 1.5 mm, the absorption bandwidths (RL ≤ −10 dB) are approximately 4 GHz and 2.5 GHz for the Co/C, Ni/C composite nanofibers, respectively, which are obviously superior to pure carbon nanofibers. Co/C composite nanofibers exhibit a wider absorption band range and stronger microwave absorption intensity compared to Ni/C composite nanofibers, attributed to their excellent electromagnetic impedance matching and attenuation characteristics. This indicates that the Co/C composite nanofibers are promising candidates for novel microwave absorbing materials.

Spin-dependent Goos-Hänchen shift for electron in single-layered semiconductor microstructure modulated by Rashba spin–orbit coupling

We theoretically investigate Goos-Hänchen effect for electron in single-layered semiconductor microstructure (SLSM) modulated by Rashba spin–orbit coupling (SOC). Due to the SOC effect, GH displacement is obviously dependent on spins, which allows electron spins to be separated in space dimension and results in spin polarization of electrons in semiconductors. Spin polarization ratio is associated with incident energy, incident direction and in-plane wave vector, e.g., it reaches maximum at resonance, but no spin polarization effect appears at normal incidence. In particular, both magnitude and sign of spin polarization ratio are controlled by external electric field or semiconductor-layer thickness, therefore, a manipulable spatial electron-spin splitter is obtained for semiconductor spintronics device applications.

Understanding the thermodynamic effects of chemically reactive working fluids in the Stirling heat pump

Within the realm of sustainable heating technologies, this study examines the performance of a Stirling heat pump employing chemically reactive working fluids in contrast to conventional inert counterparts. Reactive working fluids are energy vectors that enable the conversion of not only thermal but also chemical energy within the heat pump. The investigation spans a wide range of theoretical reactive gaseous mixtures, leveraging the ideal gas mixture thermodynamic model. Each fluid is characterized by an equilibrated chemical reaction, denoted as A2(g)⇄2A(g), and distinguished by a set of reaction coordinates: the standard entropy change of reaction and standard enthalpy change of reaction. The chemical reaction evolution and thermodynamic properties are observed in each transformation, and the overall coefficient of performance (COP) of the system is evaluated and benchmarked against that of comparable inert working fluids. It is observed that the exothermic reaction during isothermal compression significantly increases the thermal energy supplied to the heat sink, as well as the thermal energy density per unit maximum volume, by up to 269 %, compared to an inert gas system. However, for the majority of reactive fluids studied, chemical reactions introduce irreversibility in the internal regenerator due to heat transfer across a finite temperature difference, contrary to the case of inert working fluids, penalizing the COP. Consequently, a reduction of up to 28 % in the COP is observed. Nevertheless, there exists a range of reactive fluids, characterized by reversible heat exchange in the internal regenerator, offering increased thermal energy transfer to the heat sink without compromising the COP.

Green Hydrogen in Focus: A Review of Production Technologies, Policy Impact, and Market Developments

This paper navigates the critical role of hydrogen in catalyzing a sustainable energy transformation. This review delves into hydrogen production methodologies, spotlighting green and blue hydrogen as pivotal for future energy systems because of their potential to significantly reduce greenhouse gas emissions. Through a comprehensive literature review and a bibliometric analysis, this study underscores the importance of technological advancements, policy support, and market incentives in promoting hydrogen as a key energy vector. It also explores the necessity of expanding renewable energy sources and international cooperation to secure a sustainable, low-carbon future. The analysis highlights the importance of scalable and cost-effective hydrogen production methods, such as solar-thermochemical and photo-electrochemical processes, and addresses the challenges posed by resource availability and geopolitical factors in establishing a hydrogen economy. This paper serves as a guide for policy and innovation toward achieving global sustainability goals, illustrating the essential role of hydrogen in the energy transition.

Metal-Organic Framework-Based Electrodes for Efficient CO2 Electroreduction to Formate at High Current Densities (up to 1 A cm−2)

Achieving efficient CO2 electroreduction for production of valuable chemicals requires affordable, stable, and non-toxic catalysts. One of the most studied and promising products of CO2 reduction is formic acid/formate. The latter species is receiving increased attention as an energy vector [1] or energy storage media (e.g., in CO2 redox flow batteries [2]). At present, the practical application of CO2 reduction to formate still faces challenges due to the lack of electrocatalysts capable of operating at high current densities (> 200 mA cm−2) with low degradation over long-duration operation [3].Traditional metallic catalysts like Bi, Sn, In or Pb when scaled in flow cells typically suffer from low faradaic efficiencies (< 70%) at current densities ≥ 200 mA cm-2, coupled with inadequate durability [4]. Metal-organic frameworks (MOFs) present promising and thus far largely unexplored attributes as electrocatalysts for CO2 reduction, including high atom utilization during catalysis due to their porous crystal structure and tunable pore size distribution [5,6]. However, they also face challenges related to high overpotentials and complex synthesis methods [7].This study elucidates the efficacy of a Bi metal-organic framework (Bi-MOF) synthesized through a rapid and facile method. The Bi-MOF obtained by our proprietary novel method [8], exhibits exceptional catalytic performance. Notably, it demonstrates outstanding faradaic efficiencies towards formate (FEHCOO - = 95–100%) at current densities up to 1 A cm−2 in a gas diffusion electrode, at low catalyst loading (0.5 mg cm−2).Moreover, Bi-MOF displays extended stability, operating continuously for over 20 hours at an industrially relevant current density (200 mA cm−2) and without electrolyte (1.5 M KOH) replenishment. In a flow reactor with 10 cm2 electrode geometric area, a 100% FEHCOO - was obtained during 2-hour electrolysis at 100 mA cm−2 across a broad pH range (8–14). The electrochemical testing of the Bi-MOF was supplemented by surface and structural characterizations to correlate the activity with structural features. This analysis unveiled the role of the organic framework and the reason why Bi-MOF surpasses other Bi-based catalysts, including commercial Bi2O2CO3, Bi2O3, and metallic Bi, in selectivity (FE), cell potential, and durability.These findings hold promise for further scale-up of CO2 reduction to formate using the cost-effective and easily prepared Bi-MOF catalyst.[1] Bienen, F., Kopljar, D., Löwe, A., Aßmann, P., Stoll, M., Rößner, P., Wagner, N., Friedrich, A., & Klemm, E. (2019). Utilizing Formate as an Energy Carrier by Coupling CO2 Electrolysis with Fuel Cell Devices. Chemie Ingenieur Technik, 91(6), 872-882.[2] Hosseini-Benhangi, P., Gyenge, C., & Gyenge, E. (2021). The carbon dioxide redox flow battery: Bifunctional CO2 reduction/formate oxidation electrocatalysis on binary and ternary catalysts. Journal of Power Sources, 495, 229752.[3] Masel, R. I., Liu, Z., Yang, H., Kaczur, J. J., Carrillo, D., Ren, S., Salvatore, D., & Berlinguette, C. P. (2021). An industrial perspective on catalysts for low-temperature CO2 electrolysis. Nature Nanotechnology, 16(2), 118-128.[4] Zou, J., Liang, G., Lee, C., & Wallace, G. G. (2023). Progress and perspectives for electrochemical CO2 reduction to formate. Materials Today Energy, 38, 101433.[5] Mazari, S. A., Hossain, N., Basirun, W. J., Mubarak, N. M., Abro, R., Sabzoi, N., & Shah, A. (2021). An overview of catalytic conversion of CO2 into fuels and chemicals using metal organic frameworks. Process Safety and Environmental Protection, 149, 67-92.[6] Xie, W., Mulina, O. M., O., A., & He, L. (2023). Metal–Organic Frameworks for Electrocatalytic CO2 Reduction into Formic Acid. Catalysts, 13(7), 1109.[7] Köppen, M., Dhakshinamoorthy, A., Inge, A.K., Cheung, O., Ångström, J., Mayer, P. and Stock, N. (2018), Synthesis, Transformation, Catalysis, and Gas Sorption Investigations on the Bismuth Metal–Organic Framework CAU-17. Eur. J. Inorg. Chem., 2018: 3496-3503.[8] Selva-Ochoa, A.G., Habibzadeh F., Gyenge E.L. (2023). Manuscript in preparation. Department of Chemical & Biological Engineering, UBC.

Ammonia Decomposition By Microwave Plasma Discharges

The global discourse focuses on future energy vectors, with hydrogen emerging as a robust candidate owing to its established industrial applications. However, a current challenge lies in storing and transporting hydrogen-based fuels. This research focuses on advancing efficient and environmentally friendly techniques for large-scale hydrogen production, leveraging its widespread industrial presence. Ammonia, identified as a promising energy vector, offers advantages in storage and transport over hydrogen. It capitalizes on existing global infrastructures, with approximately 20 million metric tons traded annually, contributing to a total production of 150 million tons annually. If many works focus on producing ammonia by electrical discharges [1], only a few are devoted to ammonia cracking and generally concentrate on catalysis [2]. In this study, we propose an investigation into the decomposition of ammonia by applying microwave (MW) plasma. Utilizing a MW cavity that confines an electromagnetic field excited at 2.45 GHz, we induce electrodeless plasma within a fused silica tube where pure ammonia (NH3) gas flow. At first, the plasma discharge was characterized with Fourier Transform Infrared Spectroscopy (FTIR). This preliminary part of the study exhibited that, for fixed input power (300 W) and fixed working pressure (100 mbar), NH3 decomposition decreased with a flow rate ranging from 0.4 to 2.4 SLM. It also showed that for fixed input power (300 W) and fixed flow rate (2.4 SLM), the NH3 dissociation increased with pressure ranging from 40 to 140 mbar. These experiments exhibited the predominant role of the residence time of ammonia but also reactive species in plasma. To further understand the NH3 cracking mechanisms, we performed optical emission spectroscopy (OES). This technique allowed us to determine the various light-emitting species produced during NH3 dissociation in the discharge and their physical parameters, such as temperatures and relative densities, as a function of different experimental parameters. We study the influence of gas flow rate ranging from 1 to 15 SLM, input power and near-atmospheric pressure on NH3 cracking and hydrogen (H2) recombination mechanisms. Gas chromatography (GC) was employed to measure the dissociation yield of NH3 and assess the efficiency of the H2 production process. In parallel, we synthesize iron (Fe) and nickel (Ni) nanoparticles through a plasma solution process. Both metals are abundant and inexpensive; hence, they are good candidates as catalysts for potential industrial applications. In the experimental setup, a pair of tungsten electrodes, connected by a high-voltage cathode, was submerged in an aqueous solution containing Fe and Ni chlorides. One electrode was the high-voltage cathode, while the other was the grounded anode. Pulsed discharges were generated to produce Fe and Ni compounds. The resulting Fe-Ni nanoparticles (NPs) were characterized by transmission electron microscopy (TEM) to determine their shape, size and composition, which depends on the concentrations of the metal chlorides in the electrolyte solution. Those NPs were then coated on silica tubes inserted in the MW reactor at various positions to establish their influence on the NH3 decomposition and H2 recombination processes. The primary goal of this study is to compare the dissociation of NH3 with and without catalysts, aiming to achieve optimal results for H2 production. This study investigates the impact of experimental parameters on ammonia cracking efficiency within a microwave plasma combined with catalysis. We compare these factors with ruthenium-catalyzed and non-catalyzed thermal processes, recognized as leading methods for ammonia cracking. The goal is to gain insights into the mechanisms of ammonia decomposition in microwave plasmas and evaluate the efficiency of our proposed methodology relative to established thermal processes, contributing to the advancement of sustainable and optimized ammonia cracking practices and decarbonated hydrogen production. Acknowledgements The authors would like to thank the Department of Physics, College of Science, Jazan University, Jazan 45142, Saudi Arabia, for the financial support to M. Awaji and SAKOWIN for the financial support to L. Pentecoste.

(Invited) Cost Reduction Strategies in Low Temperature Water Electrolysis with Improved Catalytic Activity

Proton exchange membrane water electrolysis (PEMWE) technology is especially advantageous for green H2 production as a clean energy vector. During the water electrolysis process, the oxygen evolution reaction (OER) requires a large amount of iridium (2-3 mgIr cm−2) as catalyst. This material is scarce and expensive, representing a major bottleneck for large-scale deployment of electrolyzers. Recently, Retuerto et al. have synthesized different Ir double perovskites (Sr2CaIrO6) with the Ir atoms in a high oxidation state (Ir6+/5+) 1 and their catalytic activity was extensively investigated. Specifically, a Ca-based double perovskite (Sr2CaIrO6) has showed the highest OER activity similar to those of Ir or Ir oxides-based catalysts while being stable for the OER in half cell measurements. We report the development of a membrane electrode assembly taking advantage of the high activity of the Sr2CaIrO6 catalyst that has only 0.2 mgIr cm−2, around 10 times lower compared to what it is used in the anodes of commercial PEMWE, showing superior performance and stability. The morphology/structure of the developed anode and Sr2CaIrO6 catalyst, before and after operation in PEMWE, were extensively characterized by X-ray diffraction (XRD, high-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and X-ray absorption near edge structure (XANES). We discuss in this contribution how the finding of this work can provide a strategy to lower the Ir content in commercial PEMWE.Anion exchange membrane water electrolysis (AEMWE) combines the advantages of proton exchange membrane water electrolysis (PEMWE), i.e., high current density while maintaining high efficiency and fast dynamic response with the advantages of alkaline water electrolysis (AWE), i.e., low-cost materials. However, AEMWE technology is still depends on a supporting electrolyte and its durability is low. In this regard, the German Aerospace Center (DLR) is developing novel approaches and cell components. Raney-nickel electrodes were developed via vacuum plasma spraying, reaching performance and stability comparable to SoA MW size PEMWE. The electrodes were further refined, switching to lower cost atmospheric plasma spraying while maintaining high performance. Studying the effect of supporting electrolyte concentration it was found, that lowering the ohmic resistance is by far the largest challenge for high performance AEMWE, especially at low KOH concentrations and electrode kinetics are less impactful. Moreover, a 17% efficiency uplift was achieved by applying a carefully tuned, thermally sprayed, nickel-based macro porous layer (MPL) onto a traditional mesh porous transport layer. Both ohmic and mass transport resistances were found to be lowered by the MPL. FIB-SEM and µCT analysis revealed an ideal structure, i.e., 30-40% porosity, almost exclusively open pores, and a broad pore size distribution2. In a fundamental study3, the mechanism of the OER activity was investigated as well as the effect of trace amounts of iron in Ni(OH)2. X-ray diffraction (XRD) and Thermogravimetric analysis (TGA) TGA analysis lead to the conclusion, that iron stabilized the α-Ni(OH)2which is the most active. CV analysis showed that an important redox switching step is also accelerated by Fe-doping. M. Retuerto, L. Pascual, J. Torrero, M. A. Salam, Á. Tolosana-Moranchel, D. Gianolio, P. Ferrer, P. Kayser, V. Wilke, S. Stiber, V. Celorrio, M. Mokthar, A. S. Gago, K. A. Friedrich, M. A. Peña, J. A. Alonso, D. G. Sanchez, S. Rojas, Highly Active and Stable OER Electrocatalysts Derived from Sr2MIrO6 for Proton Exchange Membrane Water Electrolyzers. Nat. Commun. 2022, 13, 7935. Razmjooei, F.; Morawietz, T.; Taghizadeh, E.; Hadjixenophontos, E.; Mues, L.; Gerle, M.; Wood, B. D.; Harms, C.; Gago, A. S.; Ansar, S. A.; Friedrich, K. A., Increasing the performance of an anion-exchange membrane electrolyzer operating in pure water with a nickel-based microporous layer. Joule 2021, 5 (7), 1776-1799. Wang, L.; Saveleva, V. A.; Eslamibidgoli, M. J.; Antipin, D.; Bouillet, C.; Biswas, I.; Gago, A. S.; Hosseiny, S. S.; Gazdzicki, P.; Eikerling, M. H.; Savinova, E. R.; Friedrich, K. A., Deciphering the Exceptional Performance of NiFe Hydroxide for the Oxygen Evolution Reaction in an Anion Exchange Membrane Electrolyzer. ACS Applied Energy Materials 2022, 5 (2), 2221-2230.

Hybrid CFD/techno-economic assessments of carbon capturing combustion system integrated with PEM electrolyzer for efficient hydrogen production

The issue of global warming is a significant challenge in the field of environmental science, resulting primarily from the burning of fossil fuels and the subsequent increase in greenhouse gas (GHG) emissions, thus emphasizing the importance of utilizing renewable energy vectors, carbon capture technology, oxy-fuel combustion, and carbon-free fuels like hydrogen to mitigate these negative effects. In this study, the possibility of utilizing low-calorific value biogas in a gas turbine (GT) combustor under various combustion conditions is numerically simulated, and techno-economic analysis of energy systems coupled with the GT combustor is conducted. Herein, two distinct energy systems utilizing different combustion modes for H2 production via PEM electrolyzer have been designed and examined. This investigation focuses on the impact of various influencing factors in oxy-fuel combustion mode, such as the equivalence ratio and the O2 content in the two types of oxidizers, on the rate of hydrogen production, power generation, energy/exergy efficiencies, and the economic index of the proposed energy system. Additionally, a suitable system for large-scale operation is identified among the presented systems. The findings of the study demonstrate that the energy system based on the O2/CO2 combustion mode exhibits a higher rate of hydrogen production compared to the O2/H2O combustion mode and particularly, within the equivalence ratio range of 0.55≤ϕ ≤ 0.85, the hydrogen production rate in the O2/CO2 combustion mode decreases from 5.16 kg/h to 3.72 kg/h.

Green Hydrogen from Hydroelectric Energy: Assessing the Potential at the Abanico Power Plant in Morona Santiago Province

A key strategy for optimizing the utilization of clean energy sources involves integrating energy vectors to effectively manage surplus power generated from renewable sources. This study specifically delves into the assessment of a hydrogen (H₂) generation project utilizing energy generated by the Hidroabanico power plant. Over a span of 13 years, the average monthly energy production was meticulously scrutinized, with a determination that 20% of this energy would be allocated for H₂ production. The operational framework of the prototype plant, which relies on Proton Exchange Membrane (PEM) electrolyser technology, is comprehensively elucidated. This system boasts an annual energy capacity capable of reaching 62,439 MWh (20% of total production), culminating in the production of 1,123 Tn of H₂. However, it is noteworthy that this quantity remains relatively limited compared to analyses conducted utilizing alternative technologies.

Observational constrained Weyl type [formula omitted] gravity cosmological model and the dynamical system analysis

Using the cosmological date sets, the cosmological parameters are constrained in this paper, with well known phantom behavioural Hubble parameter. To understand the dynamics of the Weyl type f(Q,T) gravity, functional form of f(Q,T) has been introduced, where Q and T respectively represents the nonmetricity scalar that depends on the Weyl vector (Q=−6w2) and trace of energy–momentum tensor. Using the constrained values of the parameters, the other geometrical parameters are analysed and the accelerating behaviour has been shown. The dynamical parameters and energy conditions are also analysed. Further to get the complete evolutionary behaviour of the Universe, the dynamical system analysis has been performed.

Study of salt free-diffusion by 1D transport numerical simulations and shadowgraph experiments

Applying the Nernst-Planck formalism of 1D diffusive flux equations for ionic species of salts dissolved in water, Pitzer formalism for activity coefficients and PHREEQC software for species diffusion coefficients, with ionic strength-dependence coefficients optimized, we obtained expressions for apparent diffusion coefficients of sodium chloride, calcium chloride, and sodium sulphate, prevalent in deep aquifers. PHREEQC 1D transport simulations of free-diffusion experiments yielded temporal evolution of the concentration and gradient vertical profiles. The dynamics of concentrations non-equilibrium fluctuations during the free-diffusion experiments have been recorded by shadowgraphy. Thanks to the calculated gradient profiles the thickness of the sample has been integrated in the analysis equations of the structure functions. From the earliest stages of the diffusion process we measured the diffusion coefficients for the three salts, in very good agreement with reference measurements, validating the technique and method of analysis for studying free-diffusion in reservoirs targeted for CO2 and energy vectors storage.

Decarbonizing hydrogen supply chain via electrifying endothermic processes

Chemical/manufacturing industries are significant source of CO2 emissions. Despite the ongoing development of renewable pathways, there remains a substantial gap in enabling these resources for industrial applications while enhancing the thermal efficiency. Hydrogen has been proposed as a useful energy vector, however, its large-scale storage/transportation is still a challenge. Alternatively, ammonia has been proposed as a hydrogen carrier, since it is more readily transported and stored. But the hydrogen recovery from ammonia requires a high endothermic heat and may cause significant emissions when the traditionally fossil-fuel-based heating is used. In this work, we describe the electrified reactor configurations that can enable the integration of renewable powers with the manufacturing processes to provide the endothermic heat. In particular, we demonstrate the technical feasibility of the proposed reactor configurations for ammonia decomposition, enabling the storage and transportation of hydrogen while decarbonizing its production and retaining the mechanical/process integrity through a programmed heating.

Technology Focus: Decarbonization (July 2024)

While significant progress has been made in carbon abatement, evidenced in literature produced over the past year, particularly within the realm of carbon capture and storage (CCS), I’d like to invite your attention to three key topics in this discussion. First, despite more than 3 decades of intense focus on emissions issues, highlighted since the 1980s and formalized with the establishment of the United Nations Framework Convention on Climate Change in 1992, global emissions have only increased instead of going down. It’s imperative to question the efficacy, premises, practicality, and overlooked hurdles of current approaches. Paper SPE 214950, summarized here, sheds light on some of these challenges. It emphasizes that implementing costly carbon-abatement methods in a world marked by sharp regional economic disparities with wealth concentrated in a few countries could worsen economic inequalities by making access to energy even less equitable. Additionally, paper SPE 215050 (included in the list for further reading) underscores the priority of energy security over carbon reduction, citing recent evidence from leading proponent nations of climate action resorting to the use of coal. Failing to address energy security and economic disparity, though these are not the only obstacles, could hinder progress toward societal carbon-reduction goals. My second topic for your kind attention is the progress made on the CCS front, on which an overwhelming number of papers (approximately 75% of those reviewed) were presented at SPE conferences last year. An ongoing challenge with CCS, particularly in deep saline aquifers, is the prolonged period required for injected CO2 to chemically react and solidify for permanent storage. Paper SPE 215352, summarized here, introduces a different perspective based on the author’s exposure to another industry: proposing the coinjection of CaCl2 to expedite the permanent storage of CO2, potentially addressing this issue. The third topic that you will find interesting is developments on the hydrogen front, aimed at replacing direct use of fossil fuels as energy vectors. The cost of producing green hydrogen is expected to come down with advancement of technology, at least in some geographical areas, as the second paper shortlisted for further reading, paper IPTC 23652, suggests. One promising application involves using excess solar power during the day to convert hydrogen and store it underground for use when sunlight is unavailable. This could green the so-called peaker plants. While the approach of underground hydrogen storage (UHS) undoubtedly has the advantage of storing large amounts of energy, it may still struggle to compete with utility-scale battery storage in terms of the associated round-trip energy efficiency. There are many technoeconomic challenges to be solved in the hydrogen-based energy approach, including in the UHS context, before it can be used at a significant scale. Despite some previous experience with controlled and small-scale application of UHS, much remains to be learned about its safety and economics. The risks include leakage hazards, underground chemical reactions, loss from residual trapping, and contamination, among others. However, papers like IPTC 23943, one summarized here, along with the third one selected for further reading, paper SPE 215489, underline the necessity and the strides being made by the engineering community in overcoming these technological challenges. Recommended additional reading at OnePetro: www.onepetro.org. SPE 215050 Energy Transition or Energy Advancement! by Sami A. Alnuaim, King Fahd University of Petroleum and Minerals, et al. IPTC 23652 Sun-Powered Green Hydrogen—A Comparative Analysis From the Kingdoms of Morocco and Saudi Arabia by Waldemar Szemat-Vielma, SLB, et al. SPE 215489 Role of Hydrogen Storage for UK Energy Resilience for Net Zero by S.K. Kimpton, DNV, et al.

State-of-the-art review on hydrogen's production, storage, and potential as a future transportation fuel.

Global energy consumption is expected to reach 911 BTU by the end of 2050 as a result of rapid urbanization and industrialization. Hydrogen is increasingly recognized as a clean and reliable energy vector for decarbonization and defossilization across various sectors. Projections indicate a significant rise in global demand for hydrogen, underscoring the need for sustainable production, efficient storage, and utilization. In this state-of-the-art review, we explore hydrogen production methods, compare their environmental impacts through life cycle analysis, delve into geological storage options, and discuss hydrogen's potential as a future transportation fuel. Combining electrolysis to make hydrogen and storing it in porous underground materials like salt caverns and geological reservoirs looks like a good way to balance out the variable supply of renewable energy and meet the demand at peak times. Hydrogen is a key component of our sustainable economy, and this article gives a broad overview of the process from production to consumption, touching on technical, economic, and environmental concerns along the way. We have made an attempt in this paper to compile different methods for the production of hydrogen and its storage, the challenges faced by current methods in the manufacturing of hydrogen gas, and the role of hydrogen in the future. This review paper will serve as a very good reference for hydrogen system engineering applications. The paper concludes with some suggestions for future research to help improve the technological efficiency of certain production methods, all with the goal of scaling up the hydrogen economy.

Application of the Pythagorean Theorem as a Quick Solution in Solving Relativistic Momentum Problems

The Pythagorean theorem is a fundamental concept in mathematics that is often used to solve various geometric problems. In physics studies, especially in relativistic momentum analysis, the application of this theorem can be a fast and effective solution. This article explores the application of the Pythagorean theorem in the context of relativistic momentum, where the speed and energy of objects approach the speed of light. By exploiting the quadratic relationship between the components of the relativistic momentum and energy vectors, the Pythagorean theorem allows for simpler and more efficient calculations. This research identifies the relationship between the Pythagorean theorem equation and the relativistic momentum equation through several steps. The first step involves calculating the Pythagorean theorem equation. The second step is to calculate Einstein's special relativity equations. The final step is to analyze the relationship between the two equations. In this case, the relativistic and Pythagorean momentum equations have similarities and one of the formulas can be used.

Ship base vibration reduction design technology based on visualization of power flow and discrete optimization

The ship base is a structure that connects the equipment to the hull and may play a role in restraining and isolating the dynamic load. Adding damping on the base to improve the vibration isolation performance is an important measure to control ship vibration. In this research, the energy transfer route and vector cloud of the ship base were analyzed employing the power flow theory, and then the placement of the particle damper was determined. Through the discrete optimization of different particle parameters including the particle material, diameter and filling rate, the best vibration reduction effect was acquired. The simulation and experiment results show that the particle damping has obvious damping effect, and the steel particle has better damping effect than the lead particle and the aluminum particle. The change of particle filling rate influences the vibration characteristics, and the best effect is achieved when the filling rate is 82%. The vibration reduction performance relies strongly on particle diameters, and they all exert obvious vibration suppression effect at the peak acceleration admittance. The proposed discrete optimization strategy effectively saves experiment cost, and the presented particle damper may be traded as an optional scheme in vibration reduce treatment of ship base.