Saudi Arabia

Solutions that simulate hydrometallurgical base metal process streams with high nickel (Ni) and minor platinum (Pt) concentrations were used to create Pt/Ni nanoparticles on TiO₂ nanotube surfaces. For this electrochemical deposition – redox replacement (EDRR) was used that also allowed to control the nanoparticle size density and Pt/Ni content of the deposited nanoparticles. The Pt/Ni nanoparticle decorated titanium dioxide nanotubes (TiO₂ nanotubes) become strongly activated for photocatalytic hydrogen (H₂) evolution. Moreover EDRR facilitates nanoparticle formation without the need for any additional chemicals and is more effective than electrodeposition alone. Actually a 10000-time enrichment level of Pt took place on the TiO₂ surface when compared to Pt content in the solution with the EDRR method. The results show that hydrometallurgical streams offer great potential as an alternative raw material source for industrial catalyst production when coupled with redox replacement electrochemistry.

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.

Without remorse fossil fuels have made a huge contribution to global development in all of its forms. However the recent scientific outlooks are currently shifting as more research is targeted towards promoting a carbon-free economy in addition to the use of electric power from renewable sources. While renewable energy sources may be a solution to the anthropogenic greenhouse gas (GHG) emissions from fossil fuel they are yet season-dependent faced with major atmospheric drawbacks which when combined with annually varying but steady energy demand results in renewable energy excesses or deficits. Therefore it is essential to devise a long-term storage medium to balance their intermittent demand and supply. Hydrogen (H2) as an energy vector has been suggested as a viable method of achieving the objectives of meeting the increasing global energy demand. However successful implementation of a full-scale H2 economy requires large-scale H2 storage (as H2 is highly compressible). As such storage of H2 in geological formations has been considered as a potential solution where it can be withdrawn again at the larger stage for utilization. Thus in this review we focus on the potential use of geological formations for large-scale underground hydrogen storage (UHS) where both conventional and non-conventional UHS options were examined in depth. Also insights into some of the probable sites and the related examined criteria for selection were highlighted. The hydrodynamics of UHS influencing factors (including solid fluid and solid–fluid interactions) are summarized exclusively. In addition the economics and reaction perspectives inherent to UHS have been examined. The findings of this study show that UHS like other storage systems is still in its infancy. Further research and development are needed to address the significant hurdles and research gaps found particularly in replaceable influencing parameters. As a result this study is a valuable resource for UHS researchers.

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.

Natural gas pipelines have attracted increasing attention in the energy industry thanks to the current demand for green energy and the advantages of pipeline transportation. A novel deep learning method is proposed in this paper using a coupled network structure incorporating the thermodynamics-informed neural network and the compressor Boolean neural network to incorporate both functions of pipeline transportation safety check and energy supply predictions. The deep learning model is uniformed for the coupled network structure and the prediction efficiency and accuracy are validated by a number of numerical tests simulating various engineering scenarios including hydrogen gas pipelines. The trained model can provide dispatchers with suggestions about the number of phases existing during the transportation as an index showing safety while the effects of operation temperature pressure and compositional purity are investigated to suggest the optimized productions.

An increase in human activities and population growth have significantly increased the world’s energy demands. The major source of energy for the world today is from fossil fuels which are polluting and degrading the environment due to the emission of greenhouse gases. Hydrogen is an identified efficient energy carrier and can be obtained through renewable and non-renewable sources. An overview of renewable sources of hydrogen production which focuses on water splitting (electrolysis thermolysis and photolysis) and biomass (biological and thermochemical) mechanisms is presented in this study. The limitations associated with these mechanisms are discussed. The study also looks at some critical factors that hinders the scaling up of the hydrogen economy globally. Key among these factors are issues relating to the absence of a value chain for clean hydrogen storage and transportation of hydrogen high cost of production lack of international standards and risks in investment. The study ends with some future research recommendations for researchers to help enhance the technical efficiencies of some production mechanisms and policy direction to governments to reduce investment risks in the sector to scale the hydrogen economy up.

An energy system centred on renewable energy can help resolve many of Africa’s social economic health and environmental challenges. A profound energy transition is not only feasible it is essential for a climate-safe future in which sustainable development prerogatives are met. Renewables are key to overcoming energy poverty providing needed energy services without damaging human health or ecosystems and enabling a transformation of economies in support of development and industrialisation.

Africa is extraordinarily diverse and no single approach will advance its energy future. But efforts must be made to build modern resilient and sustainable energy systems across the continent to avoid trapping economies and societies in increasingly obsolete energy systems that burden them with stranded assets and limited economic prospects.

This report from the International Renewable Energy Agency (IRENA) sets out the opportunities at hand while also acknowledging the challenges Africa faces. It lays out a pathway to a renewables-based energy system and shows that the transition promises substantial gains in GDP employment and human welfare in each region of the continent.

Among the findings:

A large part of Africa has so far been left out of the energy transition:

• Only 2% of global investments in renewable energy in the last two decades were made in Africa with significant regional disparities
• Less than 3% of global renewables jobs are in Africa
• In Sub-Saharan Africa electrification rate was static at 46% in 2019 with 906 million people still lacking access to clean cooking fuels and technologies

But the continent has enormous potential:

• Africa has vast resource potential in wind solar hydro and geothermal energy and falling costs are increasingly bringing renewables within reach
• Central and Southern Africa have abundant mineral resources essential to the production of electric batteries wind turbines and other low-carbon technologies

The last decade has seen progress:

• Renewable energy deployment has grown in the last decade with more than 26 GW of renewables-based generation capacity added. The largest additions were in solar energy
• Average annual investments in renewable energy grew ten-fold from less than USD 0.5 billion in the 2000-2009 period to USD 5 billion in 2010-2020
• Distributed renewable energy solutions including stand-alone systems and mini-grids are playing a steadily growing role in expanding electricity access in off-grid areas and strengthening supply in already connected areas

Despite the difficult shift away from carbon-intensive energy sources the energy transition – when accompanied by an appropriate policy basket – holds huge promise for Africa:

• The energy transition under IRENA’s 1.5°C Scenario pathway predicts 6.4% higher GDP 3.5% higher economy-wide jobs and a 25.4% higher welfare index than that realised under current plans on average up to 2050
• Jobs created in the renewable energy transition will outweigh those lost by moving away from traditional energy. Every million U.S. dollars invested in renewables between 2020 – 2050 would create at least 26 job-years; for every million invested in energy efficiency at least 22 job-years would be created annually; for energy flexibility the figure is 18

For these benefits to materialise the following will be required:

• A comprehensive policy package that combines the pursuit of climate and environmental goals; economic development and jobs creation; and social equity and welfare for society as a whole
• Strong institutions international co-operation (including South- South co-operation) and considerable co-ordination at the regional level

The present work addresses the modelling control and simulation of a microgrid integrated wind power system with Doubly Fed Induction Generator (DFIG) using a hybrid energy storage system. In order to improve the quality of the waveforms (voltages and currents) supplied to the grid instead of a two level-inverter the rotor of the DFIG is supplied using a three-level inverter. A new adaptive algorithm based on combined Direct Reactive Power Control (DRPC) and fuzzy logic controls techniques is applied to the proposed topology. In this work two topologies are proposed. In the first one the active power injected into the grid is smoothened by using an economical hybrid battery and supercapacitor energy storage system. However in the second one the excess wind energy is used to produce and store the hydrogen and then a solid oxide fuel cell system (SOFC) is utilized to regenerate electricity by using the stored hydrogen when there is not enough wind energy. To avoid overcharging deep discharging of batteries to mitigate fluctuations due to wind speed variations and to fulfil the requirement of the load profile a power management algorithm is implemented. This algorithm ensures smooth output power in the first topology and service continuity in the second. The modelling and simulation results are presented and analysed using Matlab/Simulin.

A rigorous heterogeneous mathematical model is used to simulate a cascade of multi-stage fixed bed membrane reactors (MSFBMR) with inter-stage heating and fresh sweep gas for the decomposition of ammonia to produce high purity hydrogen suitable for the PEM fuel cells. Different reactor configurations are compared. The comparison between a single fixed bed reactor (FBR) and a single fixed bed membrane reactor (FBMR) shows that the FBMR is superior to the FBR and gives 60.48% ammonia conversion higher than the FBR. However 20.91% exit ammonia conversion obtained by the FBMR is considered to be poor. The FBMR is limited by the kinetics at low temperatures. The numerical results show that the MSFBMR of four beds achieve 100.0% ammonia conversion. It was found that the membrane plays the prime role in the displacement of the thermodynamic equilibrium. The results also show that a linear relationship exists between the number of beds and the feed temperature and a correlation has been developed. A critical point for an effective hydrogen permeation zone has been identified. It is observed that the diffusion limitation is confined to a slim region at the entrance of the reactor. It is also observed that the heat load assumes a maximum inflection point and explanations offered. The results show that the multi-stage configuration has a promising potential to be applied successfully on-site for ultra-clean hydrogen production.

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.

Power ultrasonic (> 100 kHz) splits water into free radicals and hydrogen. As a result water sonochemistry is considered as an alternative clean and fossil-fuel-free hydrogen production technique. In this research work the impact of rare gases (Xe Ar and He) on the sonochemical production of hydrogen as well as the population of active bubbles has been investigated computationally for various sonicated frequencies (213-515 kHz) and intensities (1-2 W/cm²). It has been found that both the H2 yielding and the bubble population size for H2 yielding are in the order Xe>Ar>He whatever the imposed sonolytic parameters (i.e. frequency and power). These findings were principally ascribed to the thermal conductivity of the saturating gases which is in the reverse order (He>Ar>Xe). Besides the difference between Ar and Xe is condensed in comparison with the He gas. For wave frequencies larger than 213 kHz however all saturating gases (Xe Ar and He) behave identically with the influence of thermal conductivity of these gases on the optimal radius muted. At 213 kHz however this impact is plainly visible (Ropt (Ar and Xe)>Ropt (He)). As per the results obtained helium's inefficiency as a saturating gas for hydrogen production is verified but xenon's maximal efficacy is reached when water is saturated with it. These results support the fewer experimental data reported in this emerging branch of sonochemistry while the discussed results in the present (i.e. noble gases effect on sono-hydrogen production) are treated for the first time consequently our work is considered as a guideline for increasing the efficacy of hydrogen production in a sonochemical reactor.

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.

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.

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

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.

Promoting green hydrogen has emerged as a pivotal discourse in the contemporary energy landscape driven by pressing environmental concerns and the quest for sustainable energy solutions. This paper delves into the multifaceted domain of C-Suite issues about green hydrogen encompassing both technological advancements and policy considerations. The question of whether green hydrogen is poised to become the focal point of the upcoming energy race is explored through an extensive analysis of its potential as a clean and versatile energy carrier. The transition from conventional fossil fuels to green hydrogen is considered a fundamental shift in energy paradigms with far-reaching implications for global energy markets. The paper provides a comprehensive overview of state-of-the-art green hydrogen technologies including fuel cells photocatalysts photo electrocatalysts and hydrogen panels. In tandem with technological advancements the role of policy and strategy in fostering the development of green hydrogen energy assumes paramount significance. The paper elucidates the critical interplay between government policies market dynamics and corporate strategies in shaping the green hydrogen landscape. It delves into policy mechanisms such as subsidies carbon pricing and renewable energy mandates shedding light on their potential to incentivize the production and adoption of green hydrogen. This paper offers a nuanced exploration of C-Suite issues surrounding green hydrogen painting a comprehensive picture of the technological and policy considerations that underpin its emergence as a transformative energy source. As the global community grapples with the imperatives of climate change mitigation and the pursuit of sustainable energy solutions understanding these issues becomes imperative for executives policymakers and stakeholders alike.

Background: Sustainable development requires access to afordable reliable and efcient energy to lift billions of people out of poverty and improve their standard of living. The development of new and renewable forms of energy that emit less CO2 may not materialize quickly enough or at a price point that allows people to attain the standard of living they desire and deserve. As a result a parallel path to sustainability must be developed that uses both renewable and clean carbon-based methods. Hybrid microgrids are promoted to solve various electrical and energy-related issues that incorporate renewable energy sources such as photovoltaics wind diesel generation or a combination of these sources. Utilizing microgrids in electric power generation has several benefts including clean energy increased grid stability and reduced congestion. Despite these advantages microgrids are not frequently deployed because of economic concerns. To address these fnancial concerns it is necessary to explore the ideal confguration of micro-grids based on the quantity quality and availability of sustainable energy sources used to install the microgrid and the optimal design of microgrid components. These considerations are refected in net present value and levelized energy cost. Methods: HOMER was used to simulate numerous system confgurations and select the most feasible solution according to the net present value levelizied cost of energy and hydrogen operating cost and renewable fraction. HOMER performed a repeated algorithm process to determine the most feasible system configuration and parameters with the least economic costs and highest benefits to achieve a practically feasible system configuration. Results: This article aimed to construct a cost-effective microgrid system for Saudi Arabia’s Yanbu city using five configurations using excess energy to generate hydrogen. The obtained results indicate that the optimal configuration for the specified area is a hybrid photovoltaic/wind/battery/generator/fuel cell/hydrogen electrolyzer microgrid with a net present value and levelized energy cost of $10.6 billion and $0.15/kWh. Conclusion: With solar photovoltaic and wind generation costs declining building electrolyzers in locations with excellent renewable resource conditions such as Saudi Arabia could become a low-cost hydrogen supply option even when accounting for the transmission and distribution costs of transporting hydrogen from renewable resource locations to end-users. The optimum confguration can generate up to 32132 tons of hydrogen per year (tH2/year) and 380824 tons per year of CO2 emissions can be avoided.

This research work is the novel state-of-the-art technology performed on multi-cylinder SI engine fueled compressed natural gas emulsified fuel and hydrogen as dual fuel. This work predicts the overall features of performance combustion and exhaust emissions of individual fuels based on AVL Boost simulation technology. Three types of alternative fuels have been compared and analyzed. The results show that hydrogen produces 20% more brake power than CNG and 25% more power than micro-emulsion fuel at 1500 r/min which further increases the brake power of hydrogen CNG and micro-emulsions in the range of 25% 20% and 15% at higher engine speeds of 2500–4000 r/min respectively. In addition the brake-specific fuel consumption is the lowest for 100% hydrogen followed by CNG 100% and then micro-emulsions at 1500 r/min. At 2500– 5000 r/min there is a significant drop in brake-specific fuel consumption due to a lean mixture at higher engine speeds. The CO HC and NOx emissions significantly improve for hydrogen CNG and micro-emulsion fuel. Hydrogen fuel shows zero CO and HC emissions and is the main objective of this research to produce 0% carbon-based emissions with a slight increase in NOx emissions and CNG shows 30% lower CO emissions than micro-emulsions and 21.5% less hydrocarbon emissions than micro-emulsion fuel at stoichiometric air/fuel ratio.

Several research works have investigated the direct supply of renewable electricity to electrolysis particularly from photovoltaic (PV) and wind generator (WG) systems. Hydrogen (H2 ) production based on solar energy is considered to be the newest solution for sustainable energy. Different technologies based on solar energy which allow hydrogen production are presented to study their benefits and inconveniences. The technology of water decomposition based on renewable energy sources to produce hydrogen can be achieved by different processes (photochemical systems; photocatalysis systems photo-electrolysis systems bio-photolysis systems thermolysis systems thermochemical cycles steam electrolysis hybrid processes and concentrated solar energy systems). A comparison of the different methods for hydrogen production based on PV and WG systems was given in this study. A comparative study of different types of electrolyzers was also presented and discussed. Finally an economic assessment of green hydrogen production is given. The hydrogen production cost depends on several factors such as renewable energy sources electrolysis type weather conditions installation cost and the productivity of hydrogen per day. PV/H2 and wind/H2 systems are both suitable in remote and arid areas. Minimum maintenance is required and a power cycle is not needed to produce electricity. The concentrated CSP/H2 system needs a power cycle. The hydrogen production cost is higher if using wind/H2 rather than PV/H2 . The green energy sources are useful for multiple applications such as hydrogen production cooling systems heating and water desalination.

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 .

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.

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.

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.

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.

Hydrogen (H2) internal combustion engines may represent cost-effective and quick solution to the issue of the road transport decarbonization. A major factor limiting their competitiveness relative to fuel cells (FC) is the lower efficiency. The present work aims to demonstrate the feasibility of a H2 engine with FC-like 60%+ brake thermal efficiency (BTE) levels using a double compression-expansion engine (DCEE) concept combined with a high pressure direct injection (HPDI) nonpremixed H2 combustion. Experimentally validated 3D CFD simulations are combined with 1D GT-Power simulations to make the predictions. Several modifications to the system design and operating conditions are systematically implemented and their effects are investigated. Addition of a catalytic burner in the combustor exhaust insulation of the expander dehumidification of the EGR and removal of the intercooling yielded 1.5 1.3 0.8 and 0.5%-point BTE improvements respectively. Raising the peak pressure to 300 bar via a larger compressor further improved the BTE by 1.8%-points but should be accompanied with a higher injector-cylinder differential pressure. The λ of ~1.4 gave the optimum tradeoff between the mechanical and combustion efficiencies. A peak BTE of 60.3% is reported with H2DCEE which is ~5%-points higher than the best diesel-fueled DCEE alternative.