Saudi Arabia

Feeding IC engines with hydrogen‐rich syngas as an admixture to hydrocarbon fuels can decrease pollutant emissions particularly NOx. It offers a potential technique for low‐environmen‐ tal impact hydrocarbon fuel use in automotive applications. However hydrogen‐rich reformate gas (syngas) production via fuel reforming still needs more research and optimization. In this paper we describe the effect of a plasma torch assembly design on syngas yield and composition during plasma‐assisted reforming of gasoline. Additionally erosion resistance of the cathode‐emitting ma‐ terial under the conditions of gasoline reforming was studied using hafnium metal and lanthanated tungsten alloy. The gasoline reforming was performed with a noncatalytic nonthermal low‐current plasma system in the conditions of partial oxidation in an air and steam mixture. To find the most efficient plasma torch assembly configuration in terms of hydrogen production yield four types of anode design were tested i.e. two types of the swirl ring and two cathode materials while varying the inlet air and fuel flow rates. The experimental results showed that hydrogen was the highest proportion of the produced syngas. The smooth funnel shape anode design in Ring 1 at air/fuel flow rates of 24/4 27/4.5 and 30/5 g/min respectively was more effective than the edged funnel shape. Lanthanated tungsten alloy displayed higher erosion resistance than hafnium metal.

As countries around the world rally behind net zero targets hydrogen is increasingly seen as a missing piece of the energy transformation puzzle to decarbonise harder-to-abate sectors. The possible pathway on which hydrogen might evolve still involves many uncertainties. With the growing momentum to establish a global hydrogen market comes the need for a deeper understanding of its broader effects including geopolitical aspects. IRENA has carried out an in-depth analysis of the geopolitics of hydrogen as part of the work of the Collaborative Framework on the Geopolitics of Energy Transformation (CF-GET). The report builds on IRENA’s substantial body of work in hydrogen and benefits from a wide range of expert input in the fields of energy and geopolitics.

This report considers whether and how hydrogen may disrupt future energy systems reflecting on many of the key themes discussed in the Global Commission’s report A New World – The Geopolitics of the Energy Transformation. The analysis offers insights into how countries and stakeholders can navigate the uncertainties and shape the development of hydrogen markets and outlines policy considerations to help mitigate the geopolitical risks and capitalise on opportunities. Some of the key findings of the report include:

• Hydrogen is part of a much bigger energy transition picture and its development and deployment strategies should not be considered in isolation.
• Setting the right priorities for hydrogen use will be essential for its rapid scale-up and long-term contribution to decarbonisation efforts.
• The 2020s could become the era of a big race for technology leadership as costs are likely to fall sharply with learning and scaling-up of needed infrastructure. Equipment manufacturing offers an opportunity to capture value in the coming years and decades.
• Hydrogen trade and investment flows will spawn new patterns of interdependence and bring shifts in bilateral relations.
• Countries with an abundance of low-cost renewable power could become producers of green hydrogen with commensurate geoeconomic and geopolitical consequences.
• Hydrogen could be an attractive avenue for fossil fuel exporters to help diversify their economies and develop new export industries.
• Supporting the advancement of renewable energy and green hydrogen in developing countries is critical for decarbonising the energy system and can contribute to global equity and stability.
• International co-operation will be necessary to devise a transparent hydrogen market with coherent standards and norms that contribute to climate change efforts meaningfully.

Hydrogen (H2) as a cleaner fuel has been suggested as a viable method of achieving the decarbonization objectives and meeting increasing global energy demand. However successful implementation of a full-scale hydrogen economy requires large-scale hydrogen storage (as hydrogen is highly compressible). A potential solution to this challenge is injecting hydrogen into geologic formations from where it can be withdrawn again at later stages for utilization purposes. The geostorage capacity of a porous formation is a function of its wetting characteristics which strongly influence residual saturations fluid flow rate of injection rate of withdrawal and containment security. However literature severely lacks information on hydrogen wettability in realistic geological and caprock formations which contain organic matter (due to the prevailing reducing atmosphere). We therefore measured advancing (θa) and receding (θr) contact angles of mica substrates at various representative thermo-physical conditions (pressures 0.1-25 MPa temperatures 308–343 K and stearic acid concentrations of 10−9 - 10−2 mol/L). The mica exhibited an increasing tendency to become weakly water-wet at higher temperatures lower pressures and very low stearic acid concentration. However it turned intermediate-wet at higher pressures lower temperatures and increasing stearic acid concentrations. The study suggests that the structural H2 trapping capacities in geological formations and sealing potentials of caprock highly depend on the specific thermo-physical condition. Thus this novel data provides a significant advancement in literature and will aid in the implementation of hydrogen geo-storage at an industrial scale.

The virtual energy storage system (VESS) is one of the emerging novel concepts among current energy storage systems (ESSs) due to the high effectiveness and reliability. In fact VESS could store surplus energy and inject the energy during the shortages at high power with larger capacities compared to the conventional ESSs in smart grids. This study investigates the optimal operation of a multi-carrier VESS including batteries thermal energy storage (TES) systems power to hydrogen (P2H) and hydrogen to power (H2P) technologies in hydrogen storage systems (HSS) and electric vehicles (EVs) in dynamic ESS. Further demand response program (DRP) for electrical and thermal loads has been considered as a tool of VESS due to the similar behavior of physical ESS. In the market three participants have considered such as electrical thermal and hydrogen markets. In addition the price uncertainties were calculated by means of scenarios as in stochastic programming while the optimization process and the operational constraints were considered to calculate the operational costs in different ESSs. However congestion in the power systems is often occurred due to the extreme load increments. Hence this study proposes a bi-level formulation system where independent system operators (ISO) manage the congestion in the upper level while VESS operators deal with the financial goals in the lower level. Moreover four case studies have considered to observe the effectiveness of each storage system and the simulation was modeled in the IEEE 33-bus system with CPLEX in GAMS.

Hydrogen future depends on large-scale storage which can be provided by geological formations (such as caverns aquifers and depleted oil and gas reservoirs) to handle demand and supply changes a typical hysteresis of most renewable energy sources. Amongst them depleted natural gas reservoirs are the most cost-effective and secure solutions due to their wide geographic distribution proven surface facilities and less ambiguous site evaluation. They also require less cushion gas as the native residual gases serve as a buffer for pressure maintenance during storage. However there is a lack of thorough understanding of this technology. This work aims to provide a comprehensive insight and technical outlook into hydrogen storage in depleted gas reservoirs. It briefly discusses the operating and potential facilities case studies and the thermophysical and petrophysical properties of storage and withdrawal capacity gas immobilization and efficient gas containment. Furthermore a comparative approach to hydrogen methane and carbon dioxide with respect to well integrity during gas storage has been highlighted. A summary of the key findings challenges and prospects has also been reported. Based on the review hydrodynamics geochemical and microbial factors are the subsurface’s principal promoters of hydrogen losses. The injection strategy reservoir features quality and operational parameters significantly impact gas storage in depleted reservoirs. Future works (experimental and simulation) were recommended to focus on the hydrodynamics and geomechanics aspects related to migration mixing and dispersion for improved recovery. Overall this review provides a streamlined insight into hydrogen storage in depleted gas reservoirs.

The combination of catalytic decomposition of ammonia and in situ separation of hydrogen holds great promise for the use of ammonia as a clean energy carrier. However finding the optimal catalyst – membrane pair and operation conditions have proved challenging. Here we demonstrate that cobalt-based catalysts for ammonia decomposition can be efficiently 2 used together with a Pd-Au based membrane to produce high purity hydrogen at elevated pressure. Compared to a conventional packed bed reactor the membrane reactor offers several operational advantages that result in energetic and economic benefits. The robustness and durability of the combined system has been demonstrated for more than 1000 h on stream yielding a very pure hydrogen stream (>99.97 % H2) and recovery (>90 %). When considering the required hydrogen compression for storage/utilization and environmental issues the combined system offers the additional advantage of production of hydrogen at moderate pressures along with full ammonia conversion. Altogether our results demonstrate the possibility of deploying high pressure (350 bar) hydrogen generators from ammonia with H2 efficiencies of circa 75% without any external energy input and/or derived CO2 emissions.

The continuous rise of global carbon emissions demands the utilization of fossil fuels in a sustainable way. Owing to various forms of emissions our environment conditions might be affected necessitating more focus of scientists and researchers to upgrade oil processing to more efficient manner. Gasification is a potential technology that can convert fossil fuels to produce clean and environmentally friendly hydrogen fuel in an economical manner. Therefore this study analyzed and examined it critically. In this study two different routes for the production of high-purity hydrogen from vacuum residue while minimizing the carbon emissions were proposed. The first route (Case I) studied the gasification of heavy vacuum residue (VR) in series with dry methane reforming (DMR). The second route studied the gasification of VR in parallel integration with DMR (Case II). After investigating both processes a brief comparison was made between the two routes of hydrogen production in terms of their CO2 emissions energy efficiency energy consumption and environmental and economic impacts. In this study the two vacuum-residue-to-hydrogen (VRTH) processes were simulated using Aspen Plus for a hydrogen production capacity of 50 t/h with 99.9 wt.% purity. The results showed that Case II offered a process energy efficiency of 57.8% which was slightly higher than that of Case I. The unit cost of the hydrogen product for Case II was USD 15.95 per metric ton of hydrogen which was almost 9% lower than that of Case I. In terms of the environmental analysis both cases had comparably low carbon emissions of around 8.3 kg of CO2/kg of hydrogen produced; with such high purity the hydrogen could be used for production of other products further downstream or for industrial applications.

Green Hydrogen Microgrid System has been selected as a source of clean and renewable alternative energy because it is undergoing a global revolution and has been identified as a source of clean energy that may aid the country in achieving net-zero emissions in the coming years. The study proposes an innovative Microgrid Renewable hybrid system to achieve these targets. The proposed hybrid renewable energy system combines a photovoltaic generator (PVG) a fuel cell (FC) a supercapacitor (SC) and a home vehicle power supply (V2H) to provide energy for a predefined demand. The proposed architecture is connected to the grid and is highly dependent on solar energy during peak periods. During the night or shading period it uses FC as a backup power source. The SC assists the FC with high charge power. SC performs this way during load transients or quick load changes. A multi-agent system (MAS) was used to build a real energy management system (RT-HEMS) for intelligent coordination between components (MAS). The scheduling algorithm reduces energy consumption by managing the required automation devices without the need for additional network power. It will meet household energy requirements regardless of weather conditions including bright cloudy or rainy conditions. Implementation and discussion of the RT-HEMS ensures that the GHS is functioning properly and that the charge request is satisfied.

Fuel cell hybrid electric vehicles (FCEVs) are mainly electrified by the fuel cell (FC) system. As a supplementary power source a battery or supercapacitor (SC) is employed (besides the FC) to enhance the power response due to the slow dynamics of the FC. Indeed the performance of the hybrid power system mainly depends on the required power distribution manner among the sources which is managed by the energy management strategy (EMS). This paper considers an FCEV based on the proton exchange membrane FC (PEMFC)/battery/SC. The energy management strategy is designed to ensure optimum power distribution between the sources considering hydrogen consumption. Its main objective is to meet the electric motor’s required power with economic hydrogen consumption and better electrical efficiency. The proposed EMS combines the external energy maximization strategy (EEMS) and the bald eagle search algorithm (BES). Simulation tests for the Extra-Urban Driving Cycle (EUDC) and New European Driving Cycle (NEDC) profiles were performed. The test is supposed to be performed in typical conditions t = 25 ◦C on a flat road without no wind effect. In addition this strategy was compared with the state machine control strategy classic PI and equivalent consumption minimization strategy. In terms of optimization the proposed approach was compared with the original EEMS particle swarm optimization (PSO)-based EEMS and equilibrium optimizer (EO)-based EEMS. The results confirm the ability of the proposed strategy to reduce fuel consumption and enhance system efficiency. This strategy provides 26.36% for NEDC and 11.35% for EUDC fuel-saving and efficiency enhancement by 6.74% for NEDC and 36.19% for EUDC.

The demand for clean and sustainable energy solutions is escalating as the global population grows and economies develop. Fossil fuels which currently dominate the energy sector contribute to greenhouse gas emissions and environmental degradation. In response to these challenges hydrogen storage technologies have emerged as a promising avenue for achieving energy sustainability. This review provides an overview of recent advancements in hydrogen storage materials and technologies emphasizing the importance of efficient storage for maximizing hydrogen’s potential. The review highlights physical storage methods such as compressed hydrogen (reaching pressures of up to 70 MPa) and material-based approaches utilizing metal hydrides and carboncontaining substances. It also explores design considerations computational chemistry high-throughput screening and machine-learning techniques employed in developing efficient hydrogen storage materials. This comprehensive analysis showcases the potential of hydrogen storage in addressing energy demands reducing greenhouse gas emissions and driving clean energy innovation.

Steam natural gas reforming is the preferred technique presently used to produce hydrogen. Proposed in 1932 the technique is very well established but still subjected to perfections. Herein first the improvements being sought in catalysts and processes are reviewed and then the advantage of replacing the energy supply from burning fuels with concentrated solar energy is discussed. It is especially this advance that may drastically reduce the economic and environmental cost of hydrogen production. Steam reforming can be easily integrated into concentrated solar with thermal storage for continuous hydrogen production.

This paper investigates the performance of hydrogen-fueled spark-ignited single-cylinder Cooperative Fuel Research using experimental and numerical approaches. This study examines the effect of the air–fuel ratio on engine performance emissions and knock behaviour across different compression ratios. The results indicate that λ significantly affects both engine performance and emissions with a λ value of 2 yielding the highest efficiency and lowest emissions for all the tested compression ratios. Combustion analysis reveals normal combustion at λ ≥ 2 while knocking combustion occurs at λ < 2 irrespective of the tested compression ratios. The Livenwood–Wu integral approach was evaluated to assess the likelihood of end-gas autoignition based on fuel reactivity demonstrating that both normal and knocking combustion possibilities are consistent with experimental investigations. Combustion analysis at the ignition timing for maximum brake torque conditions demonstrates knock-free stable combustion up to λ = 3 with increased end-gas autoignition at lower λ values. To achieve knock-free combustion at those low λs the spark timings are significantly retarded to after top dead center crank angle position. Engine-out NOx emissions consistently increase in trend with a decrease in the air–fuel ratio of up to λ = 3 after which a distinct variation in NOx is observed with an increase in the compression ratio.

DFT calculations at B3LYP/6-31g(dp) with the D3 version of Grimme’s dispersion are performed to investigate the application of TM-encapsulated Mg12O12 nano-cages (TM= Mn Fe and Co) as a hydrogen storage material. The molecular dynamic (MD) calculations are utilized to examine the stability of the considered structures. TD-DFT method reveals that the TM-encapsulation converts the Mg12O12 from an ultraviolet into a visible optical active material. The adsorption energy values indicate that the Mn and Fe atoms encapsulation enhances the adsorption of H2 molecules on the Mg12O12 nano-cage. The pristine Mg12O12 and CoMg12O12 do not meet the requirements for hydrogen storage materials while the MnMg12O12 and FeMg12O12 obey the requirements. MnMg12O12 and FeMg12O12 can carry up to twelve and nine H2 molecules respectively. The hydrogen adsorption causes a redshift for the λmax value of the UV-Vis. spectra of the MnMg12O12 and FeMg12O12 nano-cages. The thermodynamic calculations show that the hydrogen storage reaction for MnMg12O12 nano-cage is a spontaneous reaction while for FeMg12O12 nano-cage is not spontaneous. The results suggested that the MnMg12O12 nano-cage may be a promising material for hydrogen storage applications.

Hypothesis: Hydrogen geo-storage is considered as an option for large scale hydrogen storage in a full-scale hydrogen economy. Among different types of subsurface formations coal seams look to be one of the best suitable options as coal’s micro/nano pore structure can adsorb a huge amount of gas (e.g. hydrogen) which can be withdrawn again once needed. However literature lacks fundamental data regarding H2 diffusion in coal. Experiments: In this study we measured H2 adsorption rate in an Australian anthracite coal sample at isothermal conditions for four different temperatures (20 C 30 C 45 C and 60 C) at equilibrium pressure 13 bar and calculated H2 diffusion coefficient (DH2 ) at each temperature. CO2 adsorption rates were measured for the same sample at similar temperatures and equilibrium pressure for comparison. Findings: Results show that H2 adsorption rate and consequently DH2 increases by temperature. DH2 values are one order of magnitude larger than the equivalent DCO2 values for the whole studied temperature range 20–60 C. DH2 / DCO2 also shows an increasing trend versus temperature. CO2 adsorption capacity at equilibrium pressure is about 5 times higher than that of H2 in all studied temperatures. Both H2 and CO2 adsorption capacities at equilibrium pressure slightly decrease as temperature rises.

Hydrogen (H2 ) is currently a highly attractive fuel for internal combustion engines (ICEs) owing to the prospects of potentially near-zero emissions. However the production emissions and cost of H2 fuel necessitate substantial improvements in ICE thermal efficiency. This work aims to investigate a potential implementation of H2 combustion in a highly efficient double compression-expansion engine (DCEE). DICI nonpremixed H2 combustion mode is used for its superior characteristics as concluded in previous studies. The analysis is performed using a 1D GT-Power software package where different variants of the DICI H2 and diesel combustion cycles obtained experimentally and numerically (3D CFD) are imposed in the combustion cylinder of the DCEE. The results show that the low jet momentum free jet mixing dominated variants of the DICI H2 combustion concept are preferred owing to the lower heat transfer losses and relaxed requirements on the fuel injection system. Insulation of the expander and removal of the intercooling improve the engine efficiency by 1.3 and 0.5 %-points respectively but the latter leads to elevated temperatures in the high-pressure tank which makes the selection of its materials harder but allows the use of cheaper oxidation catalysts. The results also show that the DCEE performance is insensitive to combustion cylinder temperatures making it potentially suitable for other high-octane fuels such as methane methanol ammonia etc. Finally a brake thermal efficiency of 56 % is achieved with H2 combustion around 1 %-point higher than with diesel. Further efficiency improvements are also possible with a fully optimized H2 combustion system.

An existing diesel engine was fitted with a common rail direct injection (CRDi) facility to inject fuel at higher pressure in CRDi mode. In the current work rotating blades were incorporated in the piston cavity to enhance turbulence. Pilot fuels used are diesel and biodiesel of Ceiba pentandra oil (BCPO) with hydrogen supply during the suction stroke. Performance evaluation and emission tests for CRDi mode were carried out under different loading conditions. In the first part of the work maximum possible hydrogen substitution without knocking was reported at an injection timing of 15◦ before top dead center (bTDC). In the second part of the work fuel injection pressure (IP) was varied with maximum hydrogen fuel substitution. Then in the third part of the work exhaust gas recirculation (EGR) was varied to study the nitrogen oxides (NOx) generated. At 900 bar HC emissions in the CRDi engine were reduced by 18.5% and CO emissions were reduced by 17% relative to the CI mode. NOx emissions from the CRDi engine were decreased by 28% relative to the CI engine mode. At 20% EGR lowered the BTE by 14.2% and reduced hydrocarbons nitrogen oxide and carbon monoxide by 6.3% 30.5% and 9% respectively compared to the CI mode of operation.

A general rise in environmental and anthropogenically induced greenhouse gas emissions has resulted from worldwide population growth and a growing appetite for clean energy industrial outputs and consumer utilization. Furthermore well-established advanced and emerging countries are seeking fossil fuel and petroleum resources to support their aviation electric utilities industrial sectors and consumer processing essentials. There is an increasing tendency to overcome these challenging concerns and achieve the Paris Agreement’s priorities as emerging technological advances in clean energy technologies progress. Hydrogen is expected to be implemented in various production applications as a fundamental fuel in future energy carrier materials development and manufacturing processes. This paper summarizes recent developments and hydrogen technologies in fuel refining hydrocarbon processing materials manufacturing pharmaceuticals aircraft construction electronics and other hydrogen applications. It also highlights the existing industrialization scenario and describes prospective innovations including theoretical scientific advancements green raw materials production potential exploration and renewable resource integration. Moreover this article further discusses some socioeconomic implications of hydrogen as a green resource.

At present the energy shortage and environmental pollution are the burning global issues. For centuries fossil fuels have been used to meet worldwide energy demand. However thousands of tons of greenhouse gases are released into the atmosphere when fossil fuels are burned contributing to global warming. Therefore green energy must replace fossil fuels and hydrogen is a prime choice. Photocatalytic water splitting (PWS) under solar irradiation could address energy and environmental problems. In the past decade solar photocatalysts have been used to manufacture sustainable fuels. Scientists are working to synthesize a reliable affordable and light-efficient photocatalyst. Developing efficient photocatalysts for water redox reactions in suspension is a key to solar energy conversion. Semiconductor nanoparticles can be used as photocatalysts to accelerate redox reactions to generate chemical fuel or electricity. Carbon materials are substantial photocatalysts for total WS under solar irradiation due to their high activity high stability low cost easy production and structural diversity. Carbon-based materials such as graphene graphene oxide graphitic carbon nitride fullerenes carbon nanotubes and carbon quantum dots can be used as semiconductors photosensitizers cocatalysts and support materials. This review comprehensively explains how carbon-based composite materials function as photocatalytic semiconductors for hydrogen production the water-splitting mechanism and the chemistry of redox reactions. Also how heteroatom doping defects and surface functionalities etc. can influence the efficiency of carbon photocatalysts in H2 production. The challenges faced in the PWS process and future prospects are briefly discussed.

The issue of depleting fossil fuels has emphasized the use of renewable energy. Multigeneration systems fueled by renewables such as geothermal biomass solar etc. have proven to be cutting-edge technologies for the production of different valuable by-products. This study proposes a multigeneration system using a geothermal source of energy. The main outputs include power space heating cooling fresh and hot water dry air and hydrogen. The system includes a regenerative Rankine cycle a double effect absorption cycle and a double flash desalination cycle. A significant amount of electrical power hydrogen and fresh water is generated which can be used for commercial or domestic purposes. The power output is 103 MW. The thermal efficiency is 24.42% while energetic and exergetic efficiencies are 54.22% and 38.96% respectively. The COPen is found to be 1.836 and the COPex is found to be 1.678. The hydrogen and fresh water are produced at a rate of 0.1266 kg/s and 37.6 kg/s respectively.

About 95% of the hydrogen presently produced is from natural gas and coal and the remaining 5% is generated as a by-product from the production of chlorine through electrolysis1 . In the hydrogen economy (Crabtree et al. 2004; Penner 2006; Marbán and Valdés-Solís 2007) hydrogen is produced entirely from renewable energy. The easiest approach to advance renewable energy production is through solar photovoltaic and electrolysis a pathway of high technology readiness level (TRL) suffering however from two downfalls. First of all electricity is already an energy carrier and transformation with a penalty into another energy carrier hydrogen is in principle flawed. The second problem is that the efficiency of commercial solar panels is relatively low. The cadmium telluride (CdTe) thin-film solar cells have a solar energy conversion efficiency of 17%. Production of hydrogen using the current best processes for water electrolysis has an efficiency of ∼70%. As here explained the concentrated solar energy may be used to produce hydrogen using thermochemical water-splitting cycles at much global higher efficiency (fuel energy to incident sun energy). This research and development (R&D) effort is therefore undertaken to increase the TRL of this approach as a viable and economical option.

Hydrogen as a suitable and clean energy carrier has been long considered a primary fuel or in combination with other conventional fuels such as gasoline and diesel. Since the density of hydrogen is very low in port fuel-injection configuration the engine’s volumetric efficiency reduces due to the replacement of hydrogen by intake air. Therefore hydrogen direct in-cylinder injection (injection after the intake valve closes) can be a suitable solution for hydrogen utilization in spark ignition (SI) engines. In this study the effects of hydrogen direct injection with different hydrogen energy shares (HES) on the performance and emissions characteristics of a gasoline port-injection SI engine are investigated based on reactive computational fluid dynamics. Three different injection timings of hydrogen together with five different HES are applied at low and full load on a hydrogen– gasoline dual-fuel SI engine. The results show that retarded hydrogen injection timing increases the concentration of hydrogen near the spark plug resulting in areas with higher average temperatures which led to NOX emission deterioration at −120 Crank angle degree After Top Dead Center (CAD aTDC) start of injection (SOI) compared to the other modes. At −120 CAD aTDC SOI for 50% HES the amount of NOX was 26% higher than −140 CAD aTDC SOI. In the meanwhile an advanced hydrogen injection timing formed a homogeneous mixture of hydrogen which decreased the HC and soot concentration so that −140 CAD aTDC SOI implied the lowest amount of HC and soot. Moreover with the increase in the amount of HES the concentrations of CO CO2 and soot were reduced. Having the HES by 50% at −140 CAD aTDC SOI the concentrations of particulate matter (PM) CO and CO2 were reduced by 96.3% 90% and 46% respectively. However due to more complete combustion and an elevated combustion average temperature the amount of NOX emission increased drastically.

The solar to hydrogen (STH) efficiency of photovoltaic-electrolysis (PV-E) setups is a key parameter to lower the cost of green hydrogen produced. Commercial c-Si solar cells have neared saturation with respect to their efficiency which warrants the need to look at alternative technologies. In this work we report a concentrator photovoltaic-electrolysis (CPV-E) setup with a STH efficiency of 28% at 41 suns (without the use of Fresnel lenses) the highest reported efficiency using an alkaline system to date. Using this as a base case we carried out a detailed techno-economic (TEA) analysis which showed that despite the high cost associated with CPV cells the levelized cost of hydrogen (LCOH) is at $5.9 kg1 close to that from c-Si solar farms ($4.9 kg1 ) primarily due to the high STH efficiency. We also report sensitivity analysis of factors affecting both CPV and alkaline electrolyser systems such as the CPV module efficiency and installed capacity electrolyser stack lifetime operating current density and working hours. Our results indicate that in a scenario where the installed capacity of CPV technology matches that of silicon and with an electrolyser operating current density of 0.7 A cm2 the LCOH from CPV electrolysis systems can be.

In this work we are interested in examining the strain rate effect on the mechanical behavior of Ni–Ti superelastic wires after hydrogen charging and ageing for 24 h. Specimens underwent 50 cycles of loading-unloading reaching an imposed deformation of 7.6%. During loading strain rates from 10⁻⁴ s⁻¹ to 10⁻² s⁻¹ were achieved. With a strain rate of 10⁻² s⁻¹ the specimens were charged by hydrogen for 6 h and aged for one day showed a superelastic behavior marked by an increase in the residual deformation as a function of the number of cycles. In contrast after a few number of cycles with a strain rate of 10⁻⁴ s⁻¹ the Ni-Ti alloy archwire specimens fractured in a brittle manner during the martensite transformation stage. The thermal desorption analysis showed that for immersed specimens the desorption peak of hydrogen appeared at 320 °C. However after annealing the charged specimens by hydrogen at 400 °C for 1 h an embrittlement took place at the last cycles for the lower strain rates of 10⁻⁴ s⁻¹. The present study suggests that the embrittlement can be due to the development of an internal stress in the subsurface of the parent phase during hydrogen charging and due to the creation of cracks and local zones of plasticity after desorption.

Hydrogen has received tremendous global attention as an energy carrier and an energy storage system. Hydrogen carrier introduces a power to hydrogen (P2H) and power to hydrogen to power (P2H2P) facility to store the excess energy in renewable energy storage systems with the facts of large-scale storage capacity transportability and multiple utilities. This work examines the techno-economic feasibility of hybrid solar photovoltaic (PV)/hydrogen/fuel cell-powered cellular base stations for developing green mobile communication to decrease environmental degradation and mitigate fossil-fuel crises. Extensive simulation is carried out using a hybrid optimization model for electric renewables (HOMER) optimization tool to evaluate the optimal size energy production total production cost per unit energy production cost and emission of carbon footprints subject to different relevant system parameters. In addition the throughput and energy efficiency performance of the wireless network is critically evaluated with the help of MATLAB-based Monte-Carlo simulations taking multipath fading system bandwidth transmission power and inter-cell interference (ICI) into consideration. Results show that a more stable and reliable green solution for the telecommunications sector will be the macro cellular basis stations driven by the recommended hybrid supply system. The hybrid supply system has around 17% surplus electricity and 48.1 h backup capacity that increases the system reliability by maintaining a better quality of service (QoS). To end the outcomes of the suggested system are compared with the other supply scheme and the previously published research work for justifying the validity of the proposed system.

A technical–economic assessment was carried out in this study to determine the possibilities for wind and solar power generation in Afghanistan’s Helmand province. The results showed that most of the province has a solar irradiance of over 400 W/m2 and also showed that wind and solar power generated in the province can be up to twice as cheap as the official price of renewable power in Afghanistan. The most suitable site for solar and hydrogen production was found to be Laškar Gah where solar and hydrogen can be produced at a cost of 0.066 $/kWh and 2.1496 $/kg-H ¯ 2 respectively. In terms of wind power production and hydrogen production from wind the most suitable site was Sang¯ın where wind power and hydrogen could be produced at costs of 0.057 $/kWh and 1.4527 $/kg-H2 respectively. Despite the high potential of wind and solar energy in the Helmand province the most suitable place in this region to produce hydrogen from wind/solar energy was evaluated from technical economic and environmental perspectives with the Multi-Criteria DecisionMaking (MCDM) method. The Stepwise Weight Assessment Ratio Analysis (SWARA) method was used for weighting criteria and the Weighted Aggregated Sum Product Assessment (WASPAS) method was used to prioritize locations. The results show that Sang¯ın is the most suitable place for the construction of a wind hydrogen power plant and Laškar Gah is the most suitable place for the ¯ construction of a solar hydrogen power plant.

The present study investigates a process for the selective production of hydrogen from the catalytic decomposition of formic acid in the presence of iridium and iridium–palladium nanoparticles under various conditions. It was found that a loading of 1 wt.% of 2% palladium in the presence of 1% iridium over activated charcoal led to a 43% conversion of formic acid to hydrogen at room temperature after 4 h. Increasing the temperature to 60 °C led to further decomposition and an improvement in conversion yield to 63%. Dilution of formic acid from 0.5 to 0.2 M improved the decomposition reaching conversion to 81%. The reported process could potentially be used in commercial applications.

Hydrogen (H₂) is a promising renewable energy source that can replace fossil fuels since it can solve several environmental and economic issues. However the widespread usage of H₂ is constrained by its storage and safety issues. Many researchers consider solid materials with an excellent capacity for H₂ storage and generation as the solution for most H₂-related issues. Among solid materials ammonia borane (abbreviated hereafter as AB) is considered one of the best hydrogen storage materials due to its extraordinary H₂ content and small density. However the process must be conducted in the presence of efficient catalysts to obtain a reasonable amount of generated H₂. Electrospun nanofibrous catalysts are a new class of efficient catalysts that involves the usage of polymers. Here a comprehensive review of the ceramic-supported electrospun NF catalysts for AB hydrolysis is presented with a special focus on catalytic and photolytic performance and preparation steps. Photocatalytic AB hydrolysis was discussed in detail due to its importance and promising results. AB photocatalytic hydrolysis mechanisms under light were also explained. Electrospun catalysts show excellent activity for AB hydrolysis with good recyclability. Kinetics studies show that the AB hydrolysis reaction is independent of AB concentration and the first-order reaction of NF catalysts.

Observing the growing energy demand of modern societies many countries have recognized energy security as a looming problem and renewable energies as a solution to this issue. Renewable hydrogen production is an excellent method for the storage and transfer of energy generated by intermittent renewable sources such as wind and solar so that they can be used at a place and time of our choosing. In this study the suitability of 15 cities in Fars province Iran for renewable hydrogen production was investigated and compared by the use of multiple multi-criteria decision-making methods including ARAS SAW CODAS and TOPSIS. The obtained rankings were aggregated by rank averaging Borda method and Copeland method. Finally the partially ordered set ranking technique was used to reach a general consensus about the ranking. The criteria that affect hydrogen production were found to be solar energy potential wind energy potential population air temperature natural disasters altitude relative humidity land cost skilled labor infrastructure topographic condition and distance from main roads. These criteria were weighted using the best–worst method (BWM) based on the data collected by a questionnaire. Solar energy potential was estimated using the Angstrom model. Wind energy potential was estimated by using the Weibull distribution function for each month independently. The results of the multi-criteria decision-making methods showed Izadkhast to be the most suitable location for renewable hydrogen production in the studied area.

In recent times renewable energy systems (RESs) such as Photovoltaic (PV) and wind turbine (WT) are being employed to produce hydrogen. This paper aims to compare the efficiency and performance of PV and WT as sources of RESs to power polymer electrolyte membrane electrolyzer (PEMEL) under different conditions. The study assessed the input/ output power of PV and WT the efficiency of the MPPT controller the calculation of the green hydrogen production rate and the efficiency of each system separately. The study analyzed variable irradiance from 600 to 1000 W/m2 for a PV system and a fixed temperature of 25˚C while for the WT system it considered variable wind speed from 10 to 14 m/s and zero fixed pitch angle. The study demonstrated that the applied controllers were effective fast low computational and highly accurate. The obtained results showed that WT produces twice the PEMEL capacity while the PV system is designed to be equal to the PEMEL capacity. The study serves as a reference for designing PV or WT to feed an electrolyzer. The MATLAB program validated the proposed configurations with their control schemes.

Replacement of fossil fuels with clean hydrogen has been recognized as the most feasible approach of implementing CO2-free hydrogen economy globally. However large-scale storage of hydrogen is a critical component of hydrogen economy value chain because hydrogen is the lightest molecule and has moderately low volumetric energy content. To achieve successful storage of buoyant hydrogen at the subsurface and convenient withdrawal during the period of critical energy demand the integrity of the underground storage rock and overlying seal (caprock) must be assured. Presently there is paucity of information on hydrogen wettability of shale and the interfacial properties of H2/brine system. In this research contact angles of shale/H2/brine system and hydrogen/brine interfacial tension (IFT) were measured using Krüss drop shape analyzer (DSA 100) at 50 ◦C and varying pressure (14.7–1000 psi). A modified form of sessile drop approach was used for the contact angles measurement whereas the H2- brine IFT was measured through the pendant drop method. H2-brine IFT values decreased slightly with increasing pressure ranging between 63.68◦ at 14.7 psia and 51.29◦ at 1000 psia. The Eagle-ford shale with moderate total organic carbon (TOC) of 3.83% attained fully hydrogen-wet (contact angle of 99.9◦ ) and intermediate-wet condition (contact angle of 89.7◦ ) at 14.7 psi and 200 psi respectively. Likewise the Wolf-camp shale with low TOC (0.30%) attained weakly water-wet conditions with contact angles of 58.8◦ and 62.9◦ at 14.7 psi and 200 psi respectively. The maximum height of hydrogen that can be securely trapped by the Wolf-camp shale was approximately 325 meters whereas the value was merely 100 meters for the Eagle-ford shale. Results of this study will aid in assessment of hydrogen storage capacity of organic-rich shale (adsorption trapping) as well as evaluation of the sealing potentials of low TOC shale (caprock) during underground hydrogen storage.

Photocatalysts lead vitally to water purifications and decarbonise environment each by wastewater treatment and hydrogen (H2 ) production as a renewable energy source from waterphotolysis. This work deals with the photocatalytic degradation of ciprofloxacin (CIP) and H2 production by novel silver-nanoparticle (AgNPs) based ternary-nanocomposites of thiolated reducegraphene oxide graphitic carbon nitride (AgNPs-S-rGO2%@g-C3N4 ) material. Herein the optimised balanced ratio of thiolated reduce-graphene oxide in prepared ternary-nanocomposites played matchlessly to enhance activity by increasing the charge carriers’ movements via slowing down charge-recombination ratios. Reduced graphene oxide (rGO) >2 wt.% or < 10 nm. Therefore AgNPs-S-rGO2%@g-C3N4 has 3772.5 µmolg−1 h −1 H2 production which is 6.43-fold higher than g-C3N4 having cyclic stability of 96% even after four consecutive cycles. The proposed mechanism for AgNPs-S-rGO2%@g-C3N4 revealed that the photo-excited electrons in the conduction-band of g-C3N4 react with the adhered water moieties to generate H2 .

The paper discusses some of the requirements drivers and resulting technological paths for manufacturers to develop hydrogen combustion engines for use in two types of market application – onroad heavy- and light-duty. One of the main requirements is legislative certainty and this has now been afforded – at least in the major market of Europe – by the European Union’s recent adoption into law of tailpipe emissions limits specifically designed to encourage the uptake of hydrogen engines in heavy-duty vehicles giving manufacturers the confidence they need to invest in productionized solutions to offer to customers. It then discusses combustion systems and boosting systems for the two market types emphasizing that heavy-duty vehicles need best efficiency throughout their operating map while light-duty ones since they are rarely operated at full load will mainly primarily need efficiency in the part-load region. This difference will likely cause a divergence in solutions with heavy-duty engines running very lean everywhere and light-duty ones likely operating at the stoichiometric air-fuel ratio at least for most of the map. The impacts of the strategies on engine systems and vehicle integration are discussed. It is postulated that due to reasons of preignition avoidance and efficiency hydrogen engines will rapidly adopt direct injection and that the long-term heavy-duty types will migrate towards the typical current spark-ignition-type cylinder head architecture where tumble rather than swirl will ultimately be needed for air motion in the cylinder for these reasons. They may also adopt active pre-chamber technology to ignite extremely lean mixtures for maximum efficiency and minimum emissions of oxides of nitrogen. It is suggested that light-duty engines will evolve less from their current gasoline architectural norm since they already contain all of the necessary fundamentals for hydrogen combustion. However since partload efficiency will be important some new strategies may become desirable. Developing dual-fuel light-duty engines could accelerate their uptake as the heavy-duty market simultaneously accelerates the creation of the fuel supply infrastructure. The likely technological evolution suggests that variable valve trains and specifically cam profile switching technology would be extremely useful for all types of hydrogen engine especially since they are readily available in different gasoline engines now. New operating strategies afforded by variable valve trains would benefit both heavy- and light-duty engines and these strategies will become more sophisticated. There will therefore likely be a convergence of technologies for the two markets albeit with some key differences maintained due to their vehicle applications and their differing operation in the field.

The global push for clean hydrogen production has identified nuclear energy particularly high-temperature gas-cooled reactors (HTGRs) as a promising solution due to their ability to provide high-temperature heat. This study conducted a techno-economic analysis of hydrogen production in Saudi Arabia using the pebble bed modular reactor (HTRPM) focusing on two methods: high-temperature steam electrolysis (HTSE) and the sulfur– iodine (SI) thermochemical cycle. The Hydrogen Economic Evaluation Program (HEEP) was used to assess the economic viability of both methods considering key production factors such as the discount rate nuclear power plant (NPP) capital cost and hydrogen plant efficiency. The results show that the SI cycle achieves a lower levelized cost of hydrogen (LCOH) at USD 1.22/kg H2 compared to HTSE at USD 1.47/kg H2 primarily due to higher thermal efficiency. Nonetheless HTSE offers simpler system integration. Sensitivity analysis reveals that variations in the discount rate and NPP capital costs significantly impact both production methods while hydrogen plant efficiency is crucial in determining overall economics. The findings contribute to the broader discourse on sustainable hydrogen production technologies by highlighting the potential of nuclear-driven methods to meet global decarbonization goals. The paper concludes that the HTR-PM offers a viable pathway for large-scale hydrogen production in Saudi Arabia aligning with the Vision 2030 objectives.

The conversion of solar to chemical energy is one of the central processes considered in the emerging renewable energy economy. Hydrogen production from water splitting over particulate semiconductor catalysts has often been proposed as a simple and a cost-effective method for largescale production. In this review we summarize the basic concepts of the overall water splitting (in the absence of sacrificial agents) using particulate photocatalysts with a focus on their synthetic methods and the role of the so-called “co-catalysts”. Then a focus is then given on improving light absorption in which the Z-scheme concept and the overall system efficiency are discussed. A section on reactor design and cost of the overall technology is given where the possibility of the different technologies to be deployed at a commercial scale and the considerable challenges ahead are discussed. To date the highest reported efficiency of any of these systems is at least one order of magnitude lower than that deserving consideration for practical applications.

Rapid industrialization is consuming too much energy and non-renewable energy resources are currently supplying the world’s majority of energy requirements. As a result the global energy mix is being pushed towards renewable and sustainable energy sources by the world’s future energy plan and climate change. Thus hydrogen has been suggested as a potential energy source for sustainable development. Currently the production of hydrogen from fossil fuels is dominant in the world and its utilization is increasing daily. As discussed in the paper a large amount of hydrogen is used in rocket engines oil refining ammonia production and many other processes. This paper also analyzes the environmental impacts of hydrogen utilization in various applications such as iron and steel production rocket engines ammonia production and hydrogenation. It is predicted that all of our fossil fuels will run out soon if we continue to consume them at our current pace of consumption. Hydrogen is only ecologically friendly when it is produced from renewable energy. Therefore a transition towards hydrogen production from renewable energy resources such as solar geothermal and wind is necessary. However many things need to be achieved before we can transition from a fossil-fuel-driven economy to one based on renewable energy

The global issue of climate change caused by humans and its inextricable linkage to our present and future energy demand presents the biggest challenge facing our globe. Hydrogen has been introduced as a new renewable energy resource. It is envisaged to be a crucial vector in the vast low-carbon transition to mitigate climate change minimize oil reliance reinforce energy security solve the intermittency of renewable energy resources and ameliorate energy performance in the transportation sector by using it in energy storage energy generation and transport sectors. Many technologies have been developed to generate hydrogen. The current paper presents a review of the current and developing technologies to produce hydrogen from fossil fuels and alternative resources like water and biomass. The results showed that reformation and gasification are the most mature and used technologies. However the weaknesses of these technologies include high energy consumption and high carbon emissions. Thermochemical water splitting biohydrogen and photo-electrolysis are long-term and clean technologies but they require more technical development and cost reduction to implement reformation technologies efficiently and on a large scale. A combination of water electrolysis with renewable energy resources is an ecofriendly method. Since hydrogen is viewed as a considerable game-changer for future fuels this paper also highlights the challenges facing hydrogen generation. Moreover an economic analysis of the technologies used to generate hydrogen is carried out in this study.

Hydrogen is a new promising energy source. Three operating parameters including inlet gas flow rate pH and impeller speed mainly determine the biohydrogen production from membrane bioreactor. The work aims to boost biohydrogen production by determining the optimal values of the control parameters. The proposed methodology contains two parts: modeling and parameter estimation. A robust ANIFS model to simulate a membrane bioreactor has been constructed for the modeling stage. Compared with RMS thanks to ANFIS the RMSE decreased from 2.89 using ANOVA to 0.0183 using ANFIS. Capturing the proper correlation between the inputs and output of the membrane bioreactor process system encourages the constructed ANFIS model to predict the output performance exactly. Then the optimal operating parameters were identified using the honey badger algorithm. During the optimization process inlet gas flow rate pH and impeller speed are used as decision variables whereas the biohydrogen production is the objective function required to be maximum. The integration between ANFIS and HBA boosted the hydrogen production yield from 23.8 L to 25.52 L increasing by 7.22%.

This study assesses the competitiveness of producing green hydrogen (H2) in Saudi Arabia and Germany using a power-to-carrier (P2X) model in PLEXOS for 2030 and beyond. The target amount of H2 to be produced serves as the only exogenous input allowing the model which runs on an hourly temporal resolution to endogenously optimize the electrolyzer technology (alkaline proton exchange membrane or solid oxide electrolyzer cell) the capacity of the electrolyzer to be built and the optimal carbon-free energy mix. Results suggest the overall investment needs in Saudi Arabia are approximately 25% lower than those for wind-based hydrogen production in Germany with the best-case scenario to produce 0.213 Mt of green H2 costing a net present value of $6.20 billion in Saudi Arabia compared to $8.11 billion in Germany. The findings indicate that alkaline electrolyzers dominate the production process favored for their low cost despite the higher efficiencies of other electrolyzer types. Moreover the model opts to dump excess energy rather than construct battery storage. Based on 16 scenarios the study determines a levelized cost of hydrogen of 2.34–3.08 $/kg for Saudi Arabia compared with 3.06–3.69 $/kg in Germany. Subsequently a detailed sensitivity analysis considers various discount rates for both countries. It is concluded that even when considering shipment costs from Saudi Arabia to Germany (~1 $/kg) green H2 can still be competitively delivered from Saudi Arabia to Germany.

The most challenging aspect of developing a green hydrogen economy is long-distance oceanic transportation. Hydrogen liquefaction is a transportation alternative. However the cost and energy consumption for liquefaction is currently prohibitively high creating a major barrier to hydrogen supply chains. This paper proposes using solid nitrogen or oxygen as a medium for recycling cold energy across the hydrogen liquefaction supply chain. When a liquid hydrogen (LH2) carrier reaches its destination the regasification process of the hydrogen produces solid nitrogen or oxygen. The solid nitrogen or oxygen is then transported in the LH2 carrier back to the hydrogen liquefaction facility and used to reduce the energy consumption cooling gaseous hydrogen. As a result the energy required to liquefy hydrogen can be reduced by 25.4% using N2 and 27.3% using O2. Solid air hydrogen liquefaction (SAHL) can be the missing link for implementing a global hydrogen economy.

High-temperature proton exchange membranes (HT-PEMs) for fuel cells are considered transformative technologies for efficient energy conversion particularly in hydrogen-based transportation owing to their ability to deliver high power density and operational efficiency in harsh environments. However several critical challenges limit their broader adoption notably the limited durability and high costs associated with core components such as membranes and electrocatalysts under elevated temperature conditions. This review systematically addresses these challenges by examining the role of engineered nanomaterials in overcoming performance and stability limitations. The potential of nanomaterials to improve catalytic activity proton conductivity and thermal stability is discussed in detail emphasizing their impact on the optimization of catalyst layer composition including catalysts binders phosphoric acid electrolytes and additives. Recent advancements in nanostructured assemblies and 3D morphologies are explored to enhance fuel cell efficiency through synergistic interactions of these components. Additionally ongoing issues such as catalyst degradation long-term stability and resistance to high-temperature operation are critically analyzed. This manuscript offers a comprehensive overview of current HT-PEMs research and proposes future material design strategies that could bridge the gap between laboratory prototypes and large-scale industrial applications.

This study comprehensively analyzes an integrated renewable energy system complementing offshore wind turbines (OWT) and floating solar photovoltaic (FPV) technology designed for producing electric power and green hydrogen. The research explores the technical feasibility techno-economic performance and optimal sizing of the system components. The system integrates OWT farms FPV arrays water electrolyzer and hydrogen storage tank to minimize the levelized cost of energy (LCOE) loss of power supply probability (LPSP) and excess energy. A novel optimization approach Dung Beetle Optimization (DBO) algorithm is utilized and compared with the Grey Wolf Optimizer (GWO) for performance validation. To ensure the robustness of the proposed DBO algorithm it is thoroughly tested on two system configurations: a standalone OWT hydrogen production system and a hybrid FPV/OWT hydrogen production system. The results showed that the DBO algorithm outperforms the GWO algorithm in terms of system efficiency cost-effectiveness and reliability. The optimization findings reveal that the FPV/OWT hybrid system optimized with the DBO algorithm leads to a more cost-effective configuration with the OWT component contributing 45.96% of the total costs. Moreover the optimized FPV/OWT system achieves a lower levelized cost of energy (LCOE) of 0.5797 $/kWh compared to 0.8190 $/kWh for the standalone OWT system. Furthermore the hybrid FPV/OWT system maintains a levelized cost of hydrogen (COH) of 1.205 $/kg making it a competitive option for large-scale hydrogen production. Conclusively the findings demonstrate the technical feasibility and economic viability of the designated hybrid system for sustainable off-grid rural electrification and hydrogen production offering a robust solution to meet future energy demands.

In the twenty-first century global energy consumption is rapidly increasing particularly in emerging nations hastening the depletion of fossil fuel reserves and emphasizing the vital need for sustainable and renewable energy sources. This study aims to analyze hybrid renewable energy systems (HRESs) that use solid waste to generate power focusing on difficulties linked to intermittent renewable sources using a techno-economic framework. Employing the HOMER Pro software prefeasibility analysis is performed to meet the energy needs of an Indian community. System architecture optimization depends on factors like minimizing net present cost (NPC) achieving the lowest cost of energy (COE) and maximizing renewable source utilization. This study evaluates the technical economic and environmental feasibility of a hybrid renewable energy system (HRES) comprising a 400-kW solar photovoltaic (PV) array a 100-kW wind turbine (WT) a 100-kW electrolyzer 918 number of 12V batteries a 200-kW converter a 200-kW reformer and a 15-kg hydrogen tank (H-tank). This optimal configuration has the lowest NPC of $26.8 million and COE of $4.32 per kilowatt-hour and a Renewable Fraction (RF) of 100%. It can provide a dependable power supply and satisfy 94% of the daily onsite load demand which is 1080 kilowatt-hours per day. The required electricity is sourced to load demand entirely from renewable energy at the given location. Additionally the study highlights the benefits of HRES in solid waste management considering technological advancements and regulatory frameworks. Furthermore sensitivity analysis is conducted to measure economic factors that influence HRES accounting for fluctuations in load demand project lifespan diesel fuel costs and interest rates. Installing an HRES custom-made to the local environmental conditions would provide a long-lasting reliable and cost-effective energy source. The results show that the optimal HRES system performs well and is a viable option for sustainable electrification in rural communities.

Alternative fuel opportunities can satisfy energy security and reduce carbon emissions. In this regard the hydrogen fuel is derived from the source of environmental pollutants like sewage and algae wastewater through hydrothermal gasification technique using a KOH catalyst with varied gasification process parameters of duration and temperature of 6–30 min and 500-800 ◦C. The novelty of the work is to identify the optimum gasification process parameter for obtaining the maximum hydrogen yield using a KOH catalyst as an alternative fuel for agricultural engine applications. Influences of gasification processing time and temperature on H2 selectivity Carbon gasification efficiency (CE) Lower heating value (LHV) Hydrogen yield potential (HYP) and gasification efficiency (GE) were studied. Its results showed that the gasifier operated at 800 ◦C for 30 min offering maximum hydrogen yield (26 mol/kg) and gasification efficiency (58 %). The synthesized H2 was an alternative fuel blended with diesel fuel/TiO2 nanoparticles. It was experimentally studied using an internal combustion engine. Influences of H2 on engine perfor mance like brake-specific fuel consumption brake thermal efficiency and emission performances were measured and compared with diesel fuel. The results showed that DH20T has the least (420g/kWh) brake-specific fuel consumption (BSFC) and superior brake thermal efficiency of about 25.2 %. The emission results revealed that the DH20T blend showed the NOX value increased by almost 10.97 % compared to diesel fuel whereas the CO UHC and smoke values reduced by roughly 31.25 28.34 and 42.35 %. The optimum fuel blend (DH20T) result is rec ommended for agricultural engine applications.

Conventional hydrogen production processes which often involve fossil raw materials emit significant amounts of carbon dioxide into the atmosphere. This study critically evaluates the feasibility of using sugarcane biomass as an energy source to produce green hydrogen. In the 2023/2024 harvest Brazil the world’s largest sugarcane producer processed approximately 713.2 million metric tons of sugarcane. This yielded 45.68 million metric tons of sugar and 29.69 billion liters of first-generation ethanol equivalent to approximately 0.0416 liters of ethanol per kilogram of sugarcane. A systematic literature review was conducted using Scopus and Clarivate Analytics Web of Science resulting in the assessment of 335 articles. The study has identified seven potential biohydrogen production methods including two direct approaches from second-generation ethanol and five from integrated bioenergy systems. Experimental data indicate that second-generation ethanol can yield 594 MJ per metric ton of biomass with additional energy recovery from lignin combustion (1705 MJ per metric ton). Moreover advances in electrocatalytic reforming and plasma-driven hydrogen production have demonstrated high conversion efficiencies addressing key technical barriers. The results highlight Brazil’s strategic potential to integrate biohydrogen production within its existing bioenergy infrastructure. By leveraging sugarcane biomass for green hydrogen the country can contribute significantly to the global transition to sustainable energy while enhancing its energy security.

Developing clean and renewable energy instead of the ones related to hydrocarbon resources has been known as one of the different ways to guarantee reduced greenhouse gas emissions. Geothermal systems and native hydrogen exploration could represent an opportunity to diversify the global energy matrix and lower carbon-related emissions. All of these natural energy sources require a well to be drilled for its access and/or extractions similar to the petroleum industry. The main focuses of this technical–scientific contribution and research are (i) to evaluate the global energy matrix; (ii) to show the context over the years and future perspectives on geothermal systems and natural hydrogen exploration; and (iii) to present and analyze the importance of developing technologies on drilling process optimization aiming at accessing these natural energy resources. In 2022 the global energy matrix was composed mainly of nonrenewable sources such as oil natural gas and coal where the combustion of fossil fuels produced approximately 37.15 billion tons of CO2 in the same year. In 2023 USD 1740 billion was invested globally in renewable energy to reduce CO2 emissions and combat greenhouse gas emissions. In this context currently about 353 geothermal power units are in operation worldwide with a capacity of 16335 MW. In addition globally there are 35 geothermal power units under pre-construction (project phase) 93 already being constructed and recently 45 announced. Concerning hydrogen the industry announced 680 large-scale project proposals valued at USD 240 billion in direct investment by 2030. In Brazil the energy company Petroleo Brasileiro SA (Petrobras Rio de Janeiro Brazil) will invest in the coming years nearly USD 4 million in research involving natural hydrogen generation and since the exploration and access to natural energy resources (oil and gas natural hydrogen and geothermal systems among others) are achieved through the drilling of wells this document presents a technical–scientific contextualization of social interest.

This review thoroughly examines the potential of water ultrasonication (US) for producing hydrogen. First it discusses ultrasonication reactor designs and techniques for measuring ultrasonication power and optimizing energy. Then it explores the results of hydrogen production via ultrasonication experiments focusing on the impact of processing factors such as ultrasonication frequency acoustic intensity dissolved gases pH temperature and static pressure on the process. Additionally it examines advanced ultrasonication techniques such as US/photolysis US/catalysis and US/photocatalysis emphasizing how these techniques could increase hydrogen production. Lastly to progress the efficacy and scalability of hydrogen generation through ultrasonication the review identifies existing challenges proposes solutions and suggests areas for future research.

This study examined the effects of adding hydrogen to flammable liquid fuel droplets on emissions. It was found that an optimal mixing ratio with hydrogen can reduce the amount of NO in the reaction zone which is the area where the primary combustion reactions occur. N-pentane is burnt in air enriched with different amounts of hydrogen and the effects of the amount of hydrogen in the air on the combustion and emission parameters are investigated numerically. The combustion is modelled with the PDF/mixture fraction and standard twoequation turbulence models and thermal NO models are used for this modelling. The determination of the optimum H2 blending ratio is evaluated after the estimation results. It is evident that the addition of H2 led to an increase in spray flame temperatures. As a result the addition of H2 increases the combustion performance of n-pentane. The emissions evaluation results show that a blending ratio of 20% H2 reduces CO emissions at the combustion’s reaction zone and also results in a decrease in the mixture fraction. There is an increase in NO emissions due to the increase in spray flame temperatures. Combustion under air conditions containing 20% H2 by volume resulted in the highest temperature levels reaching 2130 K while the reduced NO levels decreased to approximately 11.3%. The thermal NO model when combined with the combustion model provides a sufficient level of agreement with the experimental data.

The Kingdom of Saudi Arabia has rich renewable energy resources specifically wind and solar in addition to geothermal beside massive natural gas reserves. This paper investigates the potential of both green and blue hydrogen production for five selected cities in Saudi Arabia. To accomplish the said objective a techno-economic model is formulated. Four renewable energy scenarios are evaluated for a total of 1.9 GW installed capacity to reveal the best scenario of Green Hydrogen Production (GHP) in each city. Also Blue Hydrogen Production (BHP) is investigated for three cases of Steam Methane Reforming (SMR) with different percentages of carbon capture. The economic analysis for both GHP and BHP is performed by calculating the Levelized Cost of Hydrogen (LCOH) and cash flow. The LCOH for GHP range for all cities ($3.27/kg -$12.17/kg)) with the lowest LCOH is found for NEOM city (50% PV and 50% wind) ($3.27/kg). LCOH for BHP are $0.534/kg $0.647/kg and $0.897/kg for SMR wo CCS/U SMR 55% CCS/U and SMR 90% CCS/U respectively.

Industrial sectors pivotal for the economic prosperity of nations rely heavily on affordable reliable and environmentally friendly energy sources. Industries like iron and steel oil refineries and coal-fired power plants while instrumental to national economies are also the most significant contributors to waste gases that contain substantial volumes of carbon monoxide (CO). CO can be converted to a highly efficient and carbon free fuel hydrogen (H2) through a well-known water gas shift reaction. However the untapped potential of H2 from waste industrial streams is yet to be explored. This is the first article that investigates the potential of H2 production from industrial waste gases. The available resource (i.e. CO) and its H2 production potential are estimated. The article also provides insights into the principal challenges and potential avenues for long-term adoption. The results showed that 249.14 MTPY of CO are available to produce 17.44 MTPY of H2 annually. This suggests a significant potential for H2 production from waste gases to revolutionize industrial waste management and contribute significantly towards Sustainable Development Goals 7 9 and 13ensuring access to affordable reliable sustainable and modern energy for all and taking decisive climate action respectively.

Optimal design and performance analysis of renewable energy system to serve the cruise ship main and auxiliary power in Stockholm Sweden is presented in this paper. The goal is to integrate renewable energy systems in small and large ships for greener and sustainable marine transport. The power load for the cruise ship was determined and modeling and simulation analysis was used to investigate the daily and annual performance of the power system architectures including the efficiency and capacity factors of the energy conversion systems. The total electrical power generated from the solar PV PEM fuel cell and Diesel generator; the cost of electricity; and the greenhouse gas and particulate matter PM emissions were determined. The proposed renewable energy system offers a good penetration of renewable energy system (13.83%) and greenhouse gas and particulate emissions reduction (9.84% emissions reduction compared to baseline system using Diesel engines). The integration of renewable and clean power systems such as solar PV and PEM fuel cell (high electrical efficiency) is very attractive solution for onboard ship power generation. They are economically viable (reduce the cost of Diesel fuel) cleaner than the conventional gas turbine and internal combustion engines and reduce the dependency on fossil fuel.