Qatar

Low carbon hydrogen can be an excellent source of clean energy which can combat global climate change and poor air quality. Hydrogen based economy can be a great opportunity for a country like Qatar to decarbonize its multiple sectors including transportation shipping global energy markets and industrial sectors. However there are still some barriers to the realization of a hydrogen-based economy which includes large scale hydrogen production cost infrastructure investments bulk storage transport & distribution safety consideration and matching supply-demand uncertainties. This paper highlights how the aforementioned challenges can be handled strategically through a multi-sector industrial-urban symbiosis for the hydrogen supply chain implementation. Such symbiosis can enhance the mutual relationship between diverse industries and urban planning by exploring varied scopes of multi-purpose hydrogen usage (i.e. clean energy source as a safer carrier industrial feedstock and intermittent products vehicle and shipping fuel and international energy trading etc.) both in local and international markets. It enables individual entities and businesses to participate in the physical exchange of materials by-products energy and water with strategic advantages for all participants. Besides waste/by-product exchanges several different kinds of synergies are also possible such as the sharing of resources and shared facilities. The diversified economic base regional proximity and the facilitation of rules strategies and policies may be the key drivers that support the creation of a multi-sector hydrogen supply chain in Qatar.

This work presents a comparative novel evaluation of two distinct fuels methanol and hydrogen production and power generation routes via fuel cells. The first route includes the methanol production from direct partial oxidation of methane to methanol where the methanol is condensed stored and sent to a direct methanol fuel cell. The second route is hydrogen production from solar methane cracking (named as turquoise hydrogen) where heat is supplied from concentrated solar power and hydrogen is stored and directed to a hydrogen fuel cell. This study aims to provide insights into these fuel's production conditions storage methods energy and exergy efficiencies. The proposed system is simulated using the Engineering Equation Solver software and a thermodynamic analysis of the entire system including all the equipment and process streams is performed. The methanol and hydrogen route's overall energy and exergy efficiencies are 39.75% 38.35% 35.84% and 34.58% respectively. The highest exergy destruction rate of 1605 kW is observed for the partial oxidation of methane to methanol. The methanol and hydrogen routes generate 32.087 MWh and 11.582 MWh of electricity for 16-hour of fuel cell operation respectively. Sensitivity analysis has been performed to observe the effects of different parameters such as operating temperature and mass flow rate of fuels on the electricity production and energy efficiencies of the systems.

Hydrogen has attracted growing research interest due to its exceptionally high energy per mass content and being a clean energy carrier unlike the widely used hydrocarbon fuels. With the possibility of long-term energy storage and re-electrification hydrogen promises to promote the effective utilization of renewable and sustainable energy resources. Clean hydrogen can be produced through a renewable-powered water electrolysis process. Although alkaline water electrolysis is currently the mature and commercially available electrolysis technology for hydrogen production it has several shortcomings that hinder its integration with intermittent and fluctuating renewable energy sources. The proton exchange membrane water electrolysis (PEMWE) technology has been developed to offer high voltage efficiencies at high current densities. Besides PEMWE cells are characterized by a fast system response to fluctuating renewable power enabling operations at broader partial power load ranges while consistently delivering high-purity hydrogen with low ohmic losses. Recently much effort has been devoted to improving the efficiency performance durability and economy of PEMWE cells. The research activities in this context include investigations of different cell component materials protective coatings and material characterizations as well as the synthesis and analysis of new electrocatalysts for enhanced electrochemical activity and stability with minimized use of noble metals. Further many modeling studies have been reported to analyze cell performance considering cell electrochemistry overvoltage and thermodynamics. Thus it is imperative to review and compile recent research studies covering multiple aspects of PEMWE cells in one literature to present advancements and limitations of this field. This article offers a comprehensive review of the state-of-the-art of PEMWE cells. It compiles recent research on each PEMWE cell component and discusses how the characteristics of these components affect the overall cell performance. In addition the electrochemical activity and stability of various catalyst materials are reviewed. Further the thermodynamics and electrochemistry of electrolytic water splitting are described and inherent cell overvoltage are elucidated. The available literature on PEMWE cell modeling aimed at analyzing the performance of PEMWE cells is compiled. Overall this article provides the advancements in cell components materials electrocatalysts and modeling research for PEMWE to promote the effective utilization of renewable but intermittent and fluctuating energy in the pursuit of a seamless transition to clean energy.

The coupling of photovoltaics (PVs) and PEM water electrolyzers (PEMWE) is a promising method for generating hydrogen from a renewable energy source. While direct coupling is feasible the variability of solar radiation presents challenges in efcient sizing. This study proposes an innovative energy management strategy that ensures a stable hydrogen production rate even with fuctuating solar irradiation. By integrating battery-assisted hydrogen production this approach allows for decentralized grid-independent renewable energy systems mitigating instability from PV intermittency. The system utilizes electrochemical storage to absorb excess energy during periods of low or very high irradiation which falls outside the electrolyzer’s optimal power input range. This stored energy then supports the PV system ensuring the electrolyzer operates near its nominal capacity and optimizing its lifetime. The system achieves an efciency of 7.78 to 8.81% at low current density region and 6.6% at high current density in converting solar energy into hydrogen.

Green hydrogen a critical element in the shift towards sustainable energy is traditionally produced by electrolysis powered by solar photovoltaic (PV) systems. This research explores the potential of underexploited photovoltaic thermal (PV-T) systems for efficient green hydrogen generation. This paper compares this advanced technology performance and economic viability against conventional PV setups. This paper uses TRNSYS simulation software to analyze two distinct solar-based hydrogen production configurations – PV and PV-T – across diverse climatic conditions in Doha Tunis and Stuttgart. The paper’s findings indicate that PV-T significantly outperforms PV in hydrogen generation across diverse climates (Doha Tunis Stuttgart). For instance in Doha PV-T systems increase hydrogen output by 78% in Tunis by 59% and in Stuttgart by 25%. An economic assessment reveals PV panels as the most cost-effective option with hydrogen production costs ranging from $4.92/kg to $9.66/kg across the studied locations. For PV-T collectors the hydrogen cost range from $6.66/kg to $16.80/kg across the studied locations. Nevertheless this research highlights the potential of PV-T technology to enhance the efficiency and economic viability of green hydrogen production. These findings offer valuable insights for policymakers investors and researchers pursuing more efficient solutions for sustainable energy.

The growing demand for clean energy and sustainable industrial processes has driven interest in integrated energy systems that optimize resource utilization while minimizing environmental impacts. This study presents the simulation and environmental sustainability assessment of an integrated process combining liquefied natural gas (LNG) Allam–Fetvedt cycle solid oxide electrolysis’ system and methanol synthesis to produce clean energy. The proposed system enhances overall efficiency and sustainability by utilizing the Allam–Fetvedt cycle to generate power while capturing CO2 which is then used in the manufacture of syngas and hydrogen by the electrolysis of water and CO2. Syngas is subsequently transformed into methanol a viable alternative fuel characterized by lowcarbon emissions. A comprehensive process simulation is conducted to evaluate energy efficiency material flows and system performance. The sustainability assessment focuses on environmental impact indicators including carbon footprint reduction energy efficiency improvements and resource optimization. The results demonstrate that the integrated system significantly reduces CO2 emissions while maximizing energy recovery making it a promising approach for decarbonized energy production. In this study the integrated process including the ASU power cycle electrolyzers methanol production units and LNG unit results in carbon emissions of 0.29 kg CO2 per kg of LNG produced which is very close to the literature-reported lower limit even though it also has methanol production. On the other hand when the identical process is assessed solely for methanol production (without the LNG unit) it attains net-zero carbon emissions. Despite the incorporation of high-energy electrolyzer systems the overall energy demand of the proposed integrated process remains comparable to that of existing conventional technologies with high emission outputs.

This paper presents a comprehensive thermo-economic analysis of a novel Power-to-X (P2X) polygeneration system designed for the production of hydrogen ammonia and methanol with near-zero CO2 emissions. The system integrates an air separation unit (ASU) a direct oxy-combustor (DOC) powered by natural gas combined with a supercritical carbon dioxide (sCO2) power cycle water electrolyzer (WE) a Haber-Bosch process (HBP) and a methanol production unit (MPU). The system is investigated in four configurations: ASU + DOC-sCO2 (S1) ASU + DOC-sCO2 + WE (S2) ASU + DOC-sCO2 + WE + HBP (S3) and ASU + DOC-sCO2 + WE + HBP + MPU (S4) each contributing to improve energy efficiency and reduced emissions. Simulation results show that the overall system efficiency reaches 56 % improving from 45 % to 56 % across different configurations. The system’s levelized cost of hydrogen (LCOH) decreases significantly from $1.70/kg to $0.80/kg and the levelized cost of electricity (LCOE) decreases from 4.30 ¢/kWh to 3.30 ¢/kWh. CO2 emissions are reduced from 200 gCO2/ MWe to 145 gCO2/MWe with the CO2 reduction rate improving from 89 % to 94 %. These results demonstrate the economic viability and environmental sustainability of the proposed P2X system paving the way for industrial decarbonization and large-scale deployment in future energy infrastructures.

Hydrogen transportation through a new pipeline poses significant economic barriers and blending hydrogen into existing natural gas pipelines offers promising alternative. However hydrogen’s low energy density and potential material compatibility challenges necessitate modifications to existing infrastructure. This study conducts a comprehensive thermo-economic analysis of natural gas and hydrogen mixtures with and without gaseous inhibitors evaluating the impact on thermophysical properties (Wobbe index density viscosity energy density higher and lower heating values) compression power economic feasibility and storage volume requirement. A pipeline transmission model was developed in Aspen HYSYS to assess these properties considering major and minor infrastructure modifications. The findings suggest that the addition of 5% carbon monoxide and 2% ethylene as gaseous inhibitors in maintaining desired properties ensuring compatibility with existing infrastructure and operational processes. The findings also indicate that blending 30% hydrogen increases storage volume by 30–55% while reducing higher and lower heating values by 20–25%. However the addition of 5% carbon monoxide and 2% ethylene improves the pipeline performance and reduces the carbon emissions by 23–26% supporting the transition to low-carbon energy systems. The results suggest that hydrogen blending is viable under specific infrastructure modifications providing critical insights for optimizing pipeline repurposing for sustainable hydrogen transportation.

Hydrogen (H2) yields from various gasification and hydrothermal processes demonstrate significant variability depending on feedstock catalysts and process parameters. This systematic review explores hydrogen production through hydrochar-based gasification technologies focusing on the unique properties of hydrochar derived from biomass. Known for its ability to enhance syngas production especially hydrogen hydrochar’s porous structure high surface area and active catalytic sites significantly improve syngas quality and hydrogen yield. Studies show that supercritical water gasification (SCWG) of almond shells with hydrochars yielded up to 11.63 mmol/g while catalytic subcritical and SCWG of waste tires reached 19.7 mmol/g. Hydrothermal carbonization (HTC) coupled with gasification yields as high as 76.7 g H2/kg biochar for sewage sludge hydrochar with processes like anaerobic digestion and HTC producing 1278 mL/g from hemp hurd hydrochar. Key aspects such as the catalytic influence of hydrochar the role of additives and co-catalysts and optimization of gasification parameters including temperature pressure and equivalence ratios are explored. The review also delves into hydrochar preparation advancements such as alkali and alkaline earth metals (AAEMs) incorporation and highlights hydrochar’s role in reducing tar formation enhancing H2/CO ratios and stabilizing syngas heating value.

Minimizing carbon dioxide emissions is crucial due to the generation of energy from fossil fuels. The significance of carbon capture and storage (CCS) technology which is highly successful in mitigating carbon emissions has increased. On the other hand hydrogen is an important energy carrier for storing and transporting energy and technologies that rely on hydrogen have become increasingly promising as the world moves toward a more environmentally friendly approach. Nevertheless the integration of CCS technologies into power production processes is a significant challenge requiring the enhancement of the combined power generation–CCS process. In recent years there has been a growing interest in process intensification (PI) which aims to create smaller cleaner and more energy efficient processes. The goal of this research is to demonstrate the process intensification potential and to model and simulate a hybrid integrated–intensified adsorptive-membrane reactor process for simultaneous carbon capture and hydrogen production. A comprehensive multi-scale multi-phase dynamic computational fluid dynamics (CFD)-based process model is constructed which quantifies the various underlying complex physicochemical phenomena occurring at the pellet and reactor levels. Model simulations are then performed to investigate the impact of dimensionless variables on overall system performance and gain a better understanding of this cyclic reaction/separation process. The results indicate that the hybrid system shows a steady-state cyclic behavior to ensure flexible operating time. A sustainability evaluation was conducted to illustrate the sustainability improvement in the proposed process compared to the traditional design. The results indicate that the integrated–intensified adsorptive-membrane reactor technology enhances sustainability by 35% to 138% for the chosen 21 indicators. The average enhancement in sustainability is almost 57% signifying that the sustainability evaluation reveals significant benefits of the integrated–intensified adsorptive-membrane reactor process compared to HTSR + LTSR.