Saudi Arabia

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 As such storage of H2 in geological formations has been considered as a potential solution where it can be withdrawn again at the larger stage for utilization.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.

Urgent action is needed to accelerate the pace of the global energy transition and the decarbonisation of the global economy. International shipping is a key sector of the economy as much as 90% of worldwide trade is transacted via ocean going vessels. The sector is also one of the most challenging to decarbonise.

In this context A Pathway to Decarbonise the Shipping Sector by 2050 by the International Renewable Energy Agency (IRENA) analyses the technology readiness of the renewable fuels suitable for international shipping. This report also explores the options and actions needed to progress towards a decarbonised maritime shipping sector by 2050 and seeks to identify a realistic mitigation pathway to reach the climate goal of limiting global temperature rise to 1.5°C and bringing CO2 emissions closer to net zero by mid-century.

Key messages:

• The sector’s decarbonisation strategy must involve a combination of energy efficiency and renewable fuels. Starting now the active adoption of energy efficiency measures will be critical to reduce energy demand and thus CO2 emissions in the immediate term.
• In the short term advanced biofuels will play a key role in the reduction of CO2 emissions. In the medium and long-term green hydrogen-based fuels are set to be the backbone for the sector’s decarbonisation.
• Renewable e-ammonia will play a pivotal role; where 183 million tonnes of renewable ammonia for international shipping alone will be needed by 2050 - a comparable amount to today’s ammonia global production.
• While renewable fuels production costs are currently high in the next decades renewable fuels will become cost competitive and can shield the shipping sector from the volatility that characterises the fossil fuels market.
• Taking early action is vital. Sector decarbonisation can be accelerated and ambition raised beyond the climate goals by fostering investment in the production of renewable fuels. Stakeholders need to develop broader business models and establish strategic partnerships involving energy-intensive industries as well as power suppliers and the petrochemical sector.

IRENA’s report shows that with the right plans and sufficient support the decarbonisation of the international shipping sector is viable.

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.

This work reports on H2 fuel generation from sewage water using Cu/CuO nanoporous (NP) electrodes. This is a novel concept for converting contaminated water into H2 fuel. The preparation of Cu/CuO NP was achieved using a simple thermal combustion process of Cu metallic foil at 550 ◦C for 1 h. The Cu/CuO surface consists of island-like structures with an inter-distance of 100 nm. Each island has a highly porous surface with a pore diameter of about 250 nm. X-ray diffraction (XRD) confirmed the formation of monoclinic Cu/CuO NP material with a crystallite size of 89 nm. The prepared Cu/CuO photoelectrode was applied for H2 generation from sewage water achieving an incident to photon conversion efficiency (IPCE) of 14.6%. Further the effects of light intensity and wavelength on the photoelectrode performance were assessed. The current density (Jph) value increased from 2.17 to 4.7 mA·cm−2 upon raising the light power density from 50 to 100 mW·cm−2 . Moreover the enthalpy (∆H*) and entropy (∆S*) values of Cu/CuO electrode were determined as 9.519 KJ mol−1 and 180.4 JK−1 ·mol−1 respectively. The results obtained in the present study are very promising for solving the problem of energy in far regions by converting sewage water to H2 fuel.

The use of hybrid renewable energy systems (HRES) has become the best option for supplying electricity to sites remote from the central power system because of its sustainability environmental friendliness and its low cost of energy compared to many conventional sources such as diesel generators. Due to the intermittent nature of renewable energy resources there is a need however for an energy storage system (ESS) to store the surplus energy and feed the energy deficit. Most renewable sources used battery storage systems (BSS) a green hydrogen storage system (GHSS) and a diesel generator as a backup for these sources. Batteries are very expensive and have a very short lifetime and GHSS have a very expensive initial cost and many security issues. In this paper a system consisting of wind turbines and a photovoltaic (PV) array with a pumped hydro energy storage (PHES) system as the main energy storage to replace the expensive and short lifetime batteries is proposed. The proposed system is built to feed a remote area called Dumah Aljandal in the north of Saudi Arabia. A smart grid is used via a novel demand response strategy (DRS) with a dynamic tariff to reduce the size of the components and it reduces the cost of energy compared to a flat tariff. The use of the PHES with smart DRS reduced the cost of energy by 34.2% and 41.1% compared to the use of BSS and GHSS as an ESS respectively. Moreover the use of 100% green energy sources will avoid the emission of an estimated 2.5 million tons of greenhouse gases every year. The proposed system will use a novel optimization algorithm called the gradually reduced particles of particle swarm optimization (GRP-PSO) algorithm to enhance the exploration and exploitation during the searching iterations. The GRP-PSO reduces the convergence time to 58% compared to the average convergence time of 10 optimization algorithms used for comparison. A sensitivity analysis study is introduced in this paper in which the effect of ±20% change in wind speed and solar irradiance are selected and the system showed a low effect of these resources on the Levelized cost of energy of the HRES. These outstanding results proved the superiority of using a pumped-storage system with a dynamic tariff demand response strategy compared to the other energy storage systems with flat-rate tariffs.

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.

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.

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.

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.

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.

Hydrogen is acknowledged as a potential and appealing energy carrier for decarbonizing the sectors that contribute to global warming such as power generation industries and transportation. Many people are interested in employing low-carbon sources of energy to produce hydrogen by using water electrolysis. Additionally the intermittency of renewable energy supplies such as wind and solar makes electricity generation less predictable potentially leading to power network incompatibilities. Hence hydrogen generation and storage can offer a solution by enhancing system flexibility. Hydrogen saved as compressed gas could be turned back into energy or utilized as a feedstock for manufacturing building heating and automobile fuel. This work identified many hydrogen production strategies storage methods and energy management strategies in the hybrid microgrid (HMG). This paper discusses a case study of a HMG system that uses hydrogen as one of the main energy sources together with a solar panel and wind turbine (WT). The bidirectional AC-DC converter (BAC) is designed for HMGs to maintain power and voltage balance between the DC and AC grids. This study offers a control approach based on an analysis of the BAC’s main circuit that not only accomplishes the function of bidirectional power conversion but also facilitates smooth renewable energy integration. While implementing the hydrogen-based HMG the developed control technique reduces the reactive power in linear and non-linear (NL) loads by 90.3% and 89.4%.

Hydrogen is a promising future fuel to enable the transition of transportation sector toward carbon neutrality. The direct utilization of H2 in internal combustion engines (ICEs) faces three major challenges: high NOx emissions severe pressure rise rates and pre-ignition at mid to high loads. In this study the potential of H2 combustion in a truck-size engine operated in spark ignition (SI) and pre-chamber (PC) mode was investigated. To mitigate the high pressure rise rate with the SI configuration the effects of three primary parameters on the engine combustion performance and NOx emissions were evaluated including the compression ratio (CR) the air–fuel ratio and the spark timing. In the simulations the severity of the pressure rise was evaluated based on the maximum pressure rise rate (MPRR). Lower compression ratios were assessed as a means to mitigate the auto-ignition while enabling a wider range of engine operation. The study showed that by lowering CR from 16.5:1 to 12.5:1 an indicated thermal efficiency of 47.5% can be achieved at 9.4 bar indicated mean effective pressure (IMEP) conditions. Aiming to restrain the auto-ignition while maintaining good efficiency growth in λ was examined under different CRs. The simulated data suggested that higher CRs require a higher λ and due to practical limitations of the boosting system λ at 4.0 was set as the limit. At a fixed spark timing using a CR of 13.5 combined with λ at 3.33 resulted in an indicated thermal efficiency of 48.6%. It was found that under such lean conditions the exhaust losses were high. Thus advancing the spark time was assessed as a possible solution. The results demonstrated the advantages of advancing the spark time where an indicated thermal efficiency exceeding 50% was achieved while maintaining a very low NOx level. Finally the optimized case in the SI mode was used to investigate the effect of using the PC. For the current design of the PC the results indicated that even though the mixture is lean the flame speed of H2 is sufficiently high to burn the lean charge without using a PC. In addition the PC design used in the current work induced a high MPRR inside the PC and MC leading to an increased tendency to engine knock. The operation with PC also increased the heat transfer losses in the MC leading to lower thermal efficiency compared to the SI mode. Consequently the PC combustion mode needs further optimizations to be employed in hydrogen engine applications.

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.

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 demand for fossil fuels is rising rapidly leading to increased greenhouse gas emissions. Hydrogen has emerged as a promising clean energy alternative that could help meet future demands way sustainably especially if produced using renewable methods. For hydrogen to meaningfully contribute to energy transitions it needs more integration into sectors like transportation buildings and power that currently have minimal hydrogen usage. This requires developing extensive cross-sector hydrogen infrastructure. This review examines hydrogen combustion as a fuel by exploring and comparing production techniques enriching ammonia with hydrogen as a CO2-free option and hydrogen applications in engines. Additionally a techno-economic environmental risk analysis is discussed. Results showed steam methane reforming is the most established and cost-effective production method at $1.3–1.5/kg H2 and 70–85% efficiency but generates CO2. Biomass gasification costs $1.25–2.20/kg H2 and pyrolysis $1.77–2.05/kg H2 offering renewable options. However bio-photolysis currently has high costs of $1.42–2.13/kg H2 due to low conversion rates requiring large reactors. Blending H2/NH3 could enable carbon-free combustion aiding carbon neutrality pursuits but minimizing resultant NOx is crucial. Hydrogen’s wide uses from transportation to power underline its potential as a transformational energy carrier.

This study provides H2 gas as a renewable energy source from sewage water splitting reaction using a PMT/Au photocathode. So this study has a dual benefit for hydrogen generation; at the same time it removes the contaminations of sewage water. The preparation of the PMT is carried out through the polymerization process from an acid medium. Then the Au sputter was carried out using the sputter device under different times (1 and 2 min) for PMT/Au-1 min and PMT/Au-2min respectively. The complete analyses confirm the chemical structure such as XRD FTIR HNMR SEM and Vis-UV optical analyses. The prepared electrode PMT/Au is used for the hydrogen generation reaction using Na2S2O3 or sewage water as an electrolyte. The PMT crystalline size is 15 nm. The incident photon to current efficiency (IPCE) efficiency increases from 2.3 to 3.6% (at 390 nm) and the number of H2 moles increases from 8.4 to 33.1 mmol h−1 cm−2 for using Na2S2O3 and sewage water as electrolyte respectively. Moreover all the thermodynamic parameters such as activation energy (Ea) enthalpy (∆H*) and entropy (∆S*) were calculated; additionally a simple mechanism is mentioned for the water-splitting reaction.

This paper reviews recent optimization models for hydrogen supply chains and production. Optimization is a central component of systematic methodologies to support hydrogen expansion. Hydrogen production is expected to evolve in the coming years to help replace fossil fuels; these high expectations arise from the potential to produce low-carbon hydrogen via electrolysis using electricity generated by renewable sources. However hydrogen is currently mainly used in refinery and industrial operations; therefore physical infrastructures for transmission distribution integration with other energy systems and efficient hydrogen production processes are lacking. Given the potential of hydrogen the greenfield state of infrastructures and the variability of renewable sources systematic methodologies are needed to reach competitive hydrogen prices and design hydrogen supply chains. Future research topics are identified: 1) improved hydrogen demand projections 2) integrated sector modeling 3) improving temporal and spatial resolutions 4) accounting for climate change 5) new methods to address sophisticated models.

For the first time we quantify cost footprint and reliability implications of deploying hydrogen-based generation in off-grid electric vehicle charging stations (CS) using an optimization model coupled with a geographic information system (GIS) analysis for the city of Riyadh Saudi Arabia. We also account for the challenges associated with wind energy deployment as a candidate generation technology within city centers. The analysis was restricted to carbon-free technologies: photovoltaics (PV) wind battery and hydrogen fuel-cells. At current prevailing technology costs hydrogen can reduce the required footprint of off-grid CSs by 25% at a small incremental cost increase without impacting the charging reliability. By 2030 however hydrogen will simultaneously provide the footprint and cost advantages. If we allow as little as 5% of the annual load to be unmet the required footprint of the CS decreases by 60%. The levelized cost of energy values for the CS by 2030 can range between 0.13 and 0.20 $/kWh depending on learning-curve assumptions. The footprints calculated are then mapped to five land parcel categories in Riyadh: gas station hospital mall school and university. Incorporating hydrogen in CS design increases the number of parcels that could accommodate CSs by 15e45% via reducing the required PV array (i.e. footprint).

This paper presents an experimental prototype of hydrogen fuel cells suitable for training engineering students. The presented system is designed to teach students the V-I characteristics of the fuel cells and how to record the V-I characteristics curve in the case of a single or multiple fuel cells. The prototype contains a compact electrolyzer to produce hydrogen and oxygen to the fuel cell. The fuel cell generates electricity to supply power to various types of loads. The paper also illustrates how to calculate the efficiency of fuel cells in series and parallel modes of operation. In the series mode of operation it is mathematically proven that the efficiency is higher at lower currents. Still the fuel cell operating area is required where the power is the highest. According to experimental results the efficiency in the case of series connection is approximately 25% while in parallel operation mode the efficiency is about 50%. Thus a parallel connection is recommended in the high current applications because the efficiency is higher than the one resulted from series connection. As explained later in the study plan several other experiments can be performed using this educational kit.

The use of green hydrogen as a fuel source for marine applications has the potential to significantly reduce the carbon footprint of the industry. The development of a sustainable and cost-effective method for producing green hydrogen has gained a lot of attention. Water electrolysis is the best and most environmentally friendly method for producing green hydrogen-based renewable energy. Therefore identifying the ideal operating parameters of the water electrolysis process is critical to hydrogen production. Three controlling factors must be appropriately identified to boost hydrogen generation namely electrolysis time (min) electric voltage (V) and catalyst amount (µg). The proposed methodology contains the following two phases: modeling and optimization. Initially a robust model of the water electrolysis process in terms of controlling factors was established using an adaptive neuro-fuzzy inference system (ANFIS) based on the experimental dataset. After that a modern pelican optimization algorithm (POA) was employed to identify the ideal parameters of electrolysis duration electric voltage and catalyst amount to enhance hydrogen production. Compared to the measured datasets and response surface methodology (RSM) the integration of ANFIS and POA improved the generated hydrogen by around 1.3% and 1.7% respectively. Overall this study highlights the potential of ANFIS modeling and optimal parameter identification in optimizing the performance of solar-powered water electrocatalysis systems for green hydrogen production in marine applications. This research could pave the way for the more widespread adoption of this technology in the marine industry which would help to reduce the industry’s carbon footprint and promote sustainability.

The growth of population gross domestic product (GDP) and urbanization have led to an increase in greenhouse gas (GHG) emissions in the Kingdom of Saudi Arabia (KSA). The leading GHG-emitting sectors are electricity generation road transportation cement chemicals refinery iron and steel. However the KSA is working to lead the global energy sustainability campaign to reach net zero GHG emissions by 2060. In addition the country is working to establish a framework for the circular carbon economy (CCE) in which hydrogen acts as a transversal facilitator. To cut down on greenhouse gas emissions the Kingdom is also building several facilities such as the NEOM green hydrogen project. The main objective of the article is to critically review the current GHG emission dynamics of the KSA including major GHG emission driving forces and prominent emission sectors. Then the role of hydrogen in GHG emission reduction will be explored. Finally the researchers and decision makers will find the helpful discussions and recommendations in deciding on appropriate mitigation measures and technologies.

One of the many barriers to decarbonization and decentralization of the energy sector in developing countries is the economic uncertainty. As such this study scrutinizes economics of three grid-independent hybrid renewable-based systems proposed to co-generate electricity and heat for a small-scale load. Accordingly the under-study systems are simulated and optimized with the aid of HOMER Pro software. Here a 20-year average value of discount and inflation rates is deemed a benchmark case. The techno-economic-environmental and reliability results suggest a standalone solar/wind/electrolyzer/hydrogen-based fuel cell integrated with a hydrogen-based boiler system is the best alternative. Moreover to ascertain the impact of economic uncertainty on optimal unit sizing of the nominated model the fluctuations of the nominal discount rate and inflation respectively constitute within the range of 15–20% and 10–26%. The findings of economic uncertainty analysis imply that total net present cost (TNPC) fluctuates around the benchmark value symmetrically between $478704 and $814905. Levelized energy cost varies from an amount 69% less than the benchmark value up to two-fold of that. Furthermore photovoltaic (PV) optimal size starts from a value 23% less than the benchmark case and rises up to 55% more. The corresponding figures for wind turbine (WT) are respectively 21% and 29%. Eventually several practical policies are introduced to cope with economic uncertainty.

Overview of advances in the technology of solid state hydrogen storage methods applying different kinds of novel materials is provided. Metallic and intermetallic hydrides complex chemical hydride nanostructured carbon materials metal-doped carbon nanotubes metal-organic frameworks (MOFs) metal-doped metal organic frameworks covalent organic frameworks (COFs) and clathrates solid state hydrogen storage techniques are discussed. The studies on their hydrogen storage properties are in progress towards positive direction. Nevertheless it is believed that these novel materials will offer far-reaching solutions to the onboard hydrogen storage problems in near future. The review begins with the deficiencies of current energy economy and discusses the various aspects of implementation of hydrogen energy based economy.

Of all the available resources given to mankind the sunlight is perhaps the most abundant renewable energy resource providing more than enough energy on earth to satisfy all the needs of humanity for several hundred years. Therefore it is transient and sporadic that poses issues with how the energy can be harvested and processed when the sun does not shine. Scientists assume that electro/photoelectrochemical devices used for water splitting into hydrogen and oxygen may have one solution to solve this hindrance. Water electrolysis-generated hydrogen is an optimal energy carrier to store these forms of energy on scalable levels because the energy density is high and no air pollution or toxic gas is released into the environment after combustion. However in order to adopt these devices for readily use they have to be low-cost for manufacturing and operation. It is thus crucial to develop electrocatalysts for water splitting based on low-cost and land-rich elements. In this review I will summarize current advances in the synthesis of low-cost earth-abundant electrocatalysts for overall water splitting with a particular focus on how to be linked with photoelectrocatalytic water splitting devices. The major obstacles that persist in designing these devices. The potential future developments in the production of efficient electrocatalysts for water electrolysis are also described.

Hydrogen is an economical source of clean energy that has been utilized by industry for decades. In recent years demand for hydrogen has risen significantly. Hydrogen sources include water electrolysis hydrocarbon steam reforming and fossil fuels which emit hazardous greenhouse gases and therefore have a negative impact on global warming. The increasing worldwide population has created much pressure on natural fuels with a growing gap between demand for renewable energy and its insufficient supply. As a result the environment has suffered from alarming increases in pollution levels. Biohydrogen is a sustainable energy form and a preferable substitute for fossil fuel. Anaerobic fermentation photo fermentation microbial and enzymatic photolysis or combinations of such techniques are new approaches for producing biohydrogen. For cost-effective biohydrogen production the substrate should be cheap and renewable. Substrates including algal biomass agriculture residue and wastewaters are readily available. Moreover substrates rich in starch and cellulose such as plant stalks or agricultural waste or food industry waste such as cheese whey are reported to support dark- and photo-fermentation. However their direct utilization as a substrate is not recommended due to their complex nature. Therefore they must be pretreated before use to release fermentable sugars. Various pretreatment technologies have been established and are still being developed. This article focuses on pretreatment techniques for biohydrogen production and discusses their efficiency and suitability including hybrid-treatment technology