Saudi Arabia

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.

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.

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.

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.

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.

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.

Hydrogen energy has a significant potential in mitigating the intermittency of renewable energy generation by converting the excess of renewable energy into hydrogen through many technologies. Also hydrogen is expected to be used as an energy carrier that contribute to the global decarbonization in transportation industrial and building sectors. Many technologies have been developed to store hydrogen energy. Hydrogen can be stored to be used when needed and thus synchronize generation and consumption. The current paper presents a review on the different technologies used to store hydrogen. The storage capacity advantages drawbacks and development stages of various hydrogen storage technologies were presented and compared.

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.

While Afghanistan’s power sector is almost completely dependent on fossil fuels it still cannot meet the rising power demand of this country. Deploying a combination of renewable energy systems with hydrogen production as the excess energy storage mechanism could be a sustainable long-term approach for addressing some of the energy problems of Afghanistan. Since Badakhshan is known to have a higher average wind speed than any other Afghan province in this study a technical economic and carbon footprint assessment was performed to investigate the potential for wind power and hydrogen production in this province. Wind data of four stations in Badakhshan were used for technical assessment for three heights of 10 30 and 40 m using the Weibull probability distribution function. This technical assessment was expanded by estimating the energy pattern factor probability of wind speeds greater than 5 m/s wind power density annual power output and annual hydrogen output. This was followed by an economic assessment which involved computing the Leveled Cost Of Energy (LCOE) the Leveled Cost Of Hydrogen (LCOH) and the payback period and finally an carbon footprint assessment which involved estimating the consequent CO2 reduction in two scenarios. The assessments were performed for 22 turbines manufactured by reputable companies with capacities ranging from 600 kW to 2.3 MW. The results showed that the entire Badakhshan province and especially Qal’eh-ye Panjeh and Fayazabad have excellent potentials in terms of wind energy that can be harvested for wind power and hydrogen production. Also wind power generation in this province will be highly cost-effective as the produced electricity will cost about one-third of the price of electricity supplied by the government. For better evaluation the GIS maps of wind power and hydrogen outputs were prepared using the IDW method. These maps showed that the eastern and northeastern parts of Badakhshan province have higher wind power-hydrogen production potentials. The results of ranking the stations with SWARA-EDAS hybrid MCDM methods showed that Qal’eh-ye Panjeh station was the best location to produce hydrogen from wind energy.

The commercialization of hydrogen as a fuel faces severe technological economic and environmental challenges. As a method to overcome these challenges microalgal biohydrogen production has become the subject of growing research interest. Microalgal biohydrogen can be produced through different metabolic routes the economic considerations of which are largely missing from recent reviews. Thus this review briefly explains the techniques and economics associated with enhancing microalgae-based biohydrogen production. The cost of producing biohydrogen has been estimated to be between $10 GJ-1 and $20 GJ−1 which is not competitive with gasoline ($0.33 GJ−1 ). Even though direct biophotolysis has a sunlight conversion efficiency of over 80% its productivity is sensitive to oxygen and sunlight availability. While the electrochemical processes produce the highest biohydrogen (>90%) fermentation and photobiological processes are more environmentally sustainable. Studies have revealed that the cost of producing biohydrogen is quite high ranging between $2.13 kg−1 and 7.24 kg−1 via direct biophotolysis $1.42kg−1 through indirect biophotolysis and between $7.54 kg−1 and 7.61 kg−1 via fermentation. Therefore low-cost hydrogen production technologies need to be developed to ensure long-term sustainability which requires the optimization of critical experimental parameters microalgal metabolic engineering and genetic modification.