TECHNICAL PROGRAMME | Energy Fuels and Molecules – Future Pathways
Hydrogen (Green and Blue); Ammonia; Methanol
Forum 14 | Digital Poster Plaza 3
28
April
12:30
14:30
UTC+3
This forum will explore the evolving landscape of hydrogen production, focusing on green (renewable) and blue (low-carbon) hydrogen technologies. It will delve into the role of ammonia and methanol as hydrogen carriers and their applications in energy storage, transportation, and industrial processes. The session will also cover the latest advancements in production methods, infrastructure development, and the integration of these fuels into existing energy systems. Participants will gain insights into the economic, environmental, and technological aspects of these key components in the transition to a lower carbon energy future.
This study designs a renewable energy-powered hydrogen production via water electrolysis and low-temperature/low-pressure ammonia synthesis process using Aspen Plus simulation software, providing technical support for the construction and operation of a 10,000-ton/y-scale demonstration project. An alkaline electrolyzer was modeled using the ACM framework, achieving a hydrogen production capacity of 1000 Nm³/h. For the ammonia synthesis section, the REquil reactor model was employed to calculate the equilibrium reaction heat and component mole fractions within temperature (340–540°C) and pressure (7–20 MPa) ranges. Results indicate that the equilibrium reaction heat decreases with rising temperature but increases with elevated pressure. A comparative analysis of ruthenium-based, iron-based, and iron-ruthenium cascade catalysts revealed superior overall activity for ruthenium-based catalysts, while iron-based catalysts exhibited higher sensitivity to ammonia concentration. Considering operational costs and catalytic performance, the iron-ruthenium cascade system was selected for ammonia synthesis at 400°C and 7 MPa. Full-process material and energy balances were conducted to guide industrial-scale implementation. The material balance demonstrated an ammonia concentration of 21.88% at the synthesis reactor outlet, corresponding to a production rate of 1.25 t/h. Energy balance calculations indicated a specific energy consumption of ~11000 kWh/t NH₃, with electrolysis and compression identified as major energy-intensive units.
Co-author/s:
Hongzhi Chen, Chief System Scientist, Kunlun digital technology, CNPC.
Dr. Yue Zeng, Senior Engineer, CNPC.
Dr. Qingxun Li, Professor Level Engineer, CNPC.
Xiwen Song, Engineer, CNPC.
Co-author/s:
Hongzhi Chen, Chief System Scientist, Kunlun digital technology, CNPC.
Dr. Yue Zeng, Senior Engineer, CNPC.
Dr. Qingxun Li, Professor Level Engineer, CNPC.
Xiwen Song, Engineer, CNPC.
Hydrogen (H2) is set to become a dominant energy carrier to decarbonize global energy systems. The environmental footprint and cost of H2 strictly depend on the method by which it is obtained. Among the production routes, green H2 stands out by being produced by splitting water with renewable electricity, emitting almost no carbon emissions. In contrast to green H2, dark hydrogen depends on fossil-fuel feedstocks to be produced. The production methods include grey (natural-gas SMR without capture), brown (lignite gasification), and black (bituminous or anthracite coal gasification) hydrogen, which is the most utilized method to produce hydrogen today. Blue hydrogen stands in the middle; it is made via a steam methane reforming (SMR) process, but it integrates carbon capture, utilization, and storage (CCUS). The introduction of the CCUS is set to mitigate a significant portion of life-cycle emissions, taking advantage of existing natural-gas infrastructure while saving residual carbon footprint. This study uses a techno-economic analysis (TEA) and life-cycle assessments (LCA) to compare the levelized cost of hydrogen (LCOH) and greenhouse-gas (GHG) footprints across these production routes. The results demonstrate that green hydrogen can reach the highest LCOH between 2.7 and 4.3 USD/kg, with extremely low carbon emissions between 0.6 and 4.34 kg of CO2 per kg of H2. Blue hydrogen with high-rate CCUS approaches ≈ 4 USD/kg, with moderate carbon emissions between 3.97 and 12 kg of CO2 per kg of H2. By contrast, black hydrogen offers a lower LCOH of 1.6–2.2 USD/kg but has the highest CO2 emissions, up to 20 kg of CO2 per kg of H2, making it an inexpensive but high-emission method. These comparative results are set to refine the hydrogen decarbonization roadmap. Under the framework set for the net zero target, future policy instruments such as carbon pricing, long-term offtake agreements, and export incentives can accelerate the scale-up of low-carbon hydrogen routes.
Co-author/s:
Mohammed Alyousef, Associate Petroleum Engineer, Saudi Aramco.
Luis Vazquez, Graduate Student, KAUST.
Co-author/s:
Mohammed Alyousef, Associate Petroleum Engineer, Saudi Aramco.
Luis Vazquez, Graduate Student, KAUST.
Design of highly efficient cost effective and self-supported electrocatalyst for the production of green hydrogen with reduced CAPEX and OPEX is significant for renewable and sustainable energy conversion to achieve future carbon neutral. Meanwhile, as we know that the overall water splitting is an uphill reaction requires 285.8 kJ of energy, corresponds to the HHV of hydrogen, state-of-the-art developments are necessary to greatly improve the efficiency by rationally designing non-precious metal-based robust bi-functional catalysts for promoting both the cathodic hydrogen evolution and anodic oxygen evolution reactions.
Here, first time we report the hybrid nanocomposite of Iron and Nickel phosphides based electrocatalyst directly grown on metal foam as an integrated electrode by a simple facile one step phosphidation process giving rise to highly crystalline composite with predominantly exposed [121] facets of nickel phosphide and [211] facets of iron phosphide, which accounts for the high electrocatalytic activities. The performance of metal phosphide towards hydrogen and oxygen evolution was examined under application relevant conditions in an anion exchange membrane electrolyzer and Alkaline electrolyzer cell stack. The formulated electrocatalyst outperforms other precious and non-precious electrodes operated at similar operating conditions. Evaluation of the in-house developed electrocatalyst in the prototype in-house design electrolyzer stack is conducted, and the efficiency of the electrolyzers are better, with the electrocatalyst cost is significantly cheaper compare to the commercial one.
We have observed 14% less energy consumption compares to the commercial electrodes. We have achieved the increased efficiency by limiting 27% heat loss compare to commercial minimum of 50% by controlling the activation loss. We have carried out the mass balance and achieved close to 100% Faradic efficiency by minimizing the ohmic loss. Mass loss is also controlled by tuning the electron modulation followed by work function. By using the in-house developed electrode materials and technologies, we have successfully demonstrated prototype 1 kW alkaline and anion exchange membrane (AEM) electrolyzer cell stack module. We have evaluated the prototype 1 to 10 kW alkaline and AEM electrolyzers for more than 6 months to analyze the stability study. We have successfully established the increase in overpotential is less than 0.021 V with a constant current density of 0.6-1.1 A/cm2. The stability test is carried out with a potential range from 1.8 to 2.4 Volt and current density range of 0.1 to 1 A/cm2. For each case it is stable for more than 2000 hours. The in-house designed stacked electrolyzer exhibited stable performances with a hydrogen production rate of few Nm3 per hour without any decay, pave the path towards large scale application with 35% reduction in CAPEX and OPEX cost.
Here, first time we report the hybrid nanocomposite of Iron and Nickel phosphides based electrocatalyst directly grown on metal foam as an integrated electrode by a simple facile one step phosphidation process giving rise to highly crystalline composite with predominantly exposed [121] facets of nickel phosphide and [211] facets of iron phosphide, which accounts for the high electrocatalytic activities. The performance of metal phosphide towards hydrogen and oxygen evolution was examined under application relevant conditions in an anion exchange membrane electrolyzer and Alkaline electrolyzer cell stack. The formulated electrocatalyst outperforms other precious and non-precious electrodes operated at similar operating conditions. Evaluation of the in-house developed electrocatalyst in the prototype in-house design electrolyzer stack is conducted, and the efficiency of the electrolyzers are better, with the electrocatalyst cost is significantly cheaper compare to the commercial one.
We have observed 14% less energy consumption compares to the commercial electrodes. We have achieved the increased efficiency by limiting 27% heat loss compare to commercial minimum of 50% by controlling the activation loss. We have carried out the mass balance and achieved close to 100% Faradic efficiency by minimizing the ohmic loss. Mass loss is also controlled by tuning the electron modulation followed by work function. By using the in-house developed electrode materials and technologies, we have successfully demonstrated prototype 1 kW alkaline and anion exchange membrane (AEM) electrolyzer cell stack module. We have evaluated the prototype 1 to 10 kW alkaline and AEM electrolyzers for more than 6 months to analyze the stability study. We have successfully established the increase in overpotential is less than 0.021 V with a constant current density of 0.6-1.1 A/cm2. The stability test is carried out with a potential range from 1.8 to 2.4 Volt and current density range of 0.1 to 1 A/cm2. For each case it is stable for more than 2000 hours. The in-house designed stacked electrolyzer exhibited stable performances with a hydrogen production rate of few Nm3 per hour without any decay, pave the path towards large scale application with 35% reduction in CAPEX and OPEX cost.
To meet the growing global demand for ammonia—driven by its essential role in agriculture and low-carbon energy systems—there is a critical need for scalable and efficient production technologies. The continuous upscaling of ammonia production facilities necessitates the development of innovative engineering solutions to address the limitations of traditional reactor designs.
Traditional ammonia production facilities, with capacities ranging between 1,000 - 3,000 metric tons per day (MTPD), comprise of conventional reactor designs, which rely on single catalyst beds, encounter major limitations in reactor design, including excessive reactor diameters, space constraints, and complex material requirements when using same design approach for giga-scale plants exceeding 3000 such as for 6000 MTPD.
These challenges hinder the scalability, cost efficiency, and environmental compliance of high—capacity ammonia plants, necessitating innovative reactor designs to address these limitations. First, the reactor diameters increase significantly, complicating manufacturing, transportation, and site installation leading to logistical issues. Then, the larger catalyst beds result in increased pressure drops leading to higher energy consumption and thus impacting energy efficiency. Third, the expanded reactor sizes require larger plot areas, which may not be feasible in existing facilities and results in space constraints and finally, there are material challenges resulting from increased shell thickness for larger reactors creates difficulties in material procurement and fabrication.
This paper introduces the Split Flow Reactor (SFR), an innovative solution developed by KBR to address these challenges in catalyst converters such as High Temperature Shift (HTS) converters, Low Temperature Shift (LTS) converters, and Methanation Units. Unlike conventional design, the SFR splits the syngas and catalyst bed into two parallel flow sections within a single reactor shell.
By using the parallel bed configuration with optimized flow distribution- without compromising on flow rates, the SFR achieves reduced pressure drop, compact reactor dimensions – addresses manufacturing and logistics constraints, superior energy efficiency, reduced rector footprints – eliminating the need of multiple reactors and up to 25% savings in cost and plot area.
Computational Fluid Dynamics (CFD) simulations validate the reactor's performance, confirming improvements in velocity profiles, temperature distribution, and pressure management compared to traditionally designed reactor setups.
Specifically tailored for large capacity ammonia plants, the SFR marks a transformative step in reactor design, offering a scalable, energy-efficient, and cost-effective solution that sets a new industry standard for large-capacity ammonia plants.
Co-author/s:
Sudesh Joon, Technical Advisor, KBR.
Traditional ammonia production facilities, with capacities ranging between 1,000 - 3,000 metric tons per day (MTPD), comprise of conventional reactor designs, which rely on single catalyst beds, encounter major limitations in reactor design, including excessive reactor diameters, space constraints, and complex material requirements when using same design approach for giga-scale plants exceeding 3000 such as for 6000 MTPD.
These challenges hinder the scalability, cost efficiency, and environmental compliance of high—capacity ammonia plants, necessitating innovative reactor designs to address these limitations. First, the reactor diameters increase significantly, complicating manufacturing, transportation, and site installation leading to logistical issues. Then, the larger catalyst beds result in increased pressure drops leading to higher energy consumption and thus impacting energy efficiency. Third, the expanded reactor sizes require larger plot areas, which may not be feasible in existing facilities and results in space constraints and finally, there are material challenges resulting from increased shell thickness for larger reactors creates difficulties in material procurement and fabrication.
This paper introduces the Split Flow Reactor (SFR), an innovative solution developed by KBR to address these challenges in catalyst converters such as High Temperature Shift (HTS) converters, Low Temperature Shift (LTS) converters, and Methanation Units. Unlike conventional design, the SFR splits the syngas and catalyst bed into two parallel flow sections within a single reactor shell.
By using the parallel bed configuration with optimized flow distribution- without compromising on flow rates, the SFR achieves reduced pressure drop, compact reactor dimensions – addresses manufacturing and logistics constraints, superior energy efficiency, reduced rector footprints – eliminating the need of multiple reactors and up to 25% savings in cost and plot area.
Computational Fluid Dynamics (CFD) simulations validate the reactor's performance, confirming improvements in velocity profiles, temperature distribution, and pressure management compared to traditionally designed reactor setups.
Specifically tailored for large capacity ammonia plants, the SFR marks a transformative step in reactor design, offering a scalable, energy-efficient, and cost-effective solution that sets a new industry standard for large-capacity ammonia plants.
Co-author/s:
Sudesh Joon, Technical Advisor, KBR.
This paper addresses the critical issue of safely managing ammonia storage, focusing on consequence and risk modeling using Integral Models. Ammonia is increasingly considered an alternative for hydrogen storage due to its higher energy density, easier liquefaction process, and established infrastructure for handling and transportation. However, large-scale accidental releases pose significant challenges, primarily due to the toxicity of dispersed vapor clouds, while fire and explosion risks are less significant. The methodology involves evaluating different tank configurations under various scenarios, including Toxic Vapor Cloud, Flammable Extension Area, and Vapor Cloud Explosion.
Key findings demonstrate that implementing full containment tanks with bund protection significantly mitigates the risk of ammonia releases, reducing the impact area and the likelihood of hazardous vapor cloud formation. In contrast, single tanks without bunds expose populations to higher ammonia concentrations, potentially causing severe casualties. This study introduces the Containment Efficiency Ratio (CER), a critical metric for optimizing bund heights to maximize hazard containment. This ratio measures the containment efficiency per meter of bund height, providing a straightforward metric for safety assessment. The optimal bund height, informed by the findings, ranges between 7 to 8 meters, where safety and cost-efficiency align for the tank being studied.
Recommendations highlight the effectiveness of full containment tanks with bunding, regular maintenance, the use of corrosion-resistant materials, advanced monitoring systems, and comprehensive emergency response plans. Sensitivity analysis confirms the robustness of these conclusions under varying conditions. The cost-benefit analysis supports the feasibility of these measures, emphasizing their effectiveness in minimizing the risk of ammonia releases. This strategic approach enhances safety management, aligns with regulatory frameworks and industry best practices, and addresses the urgent need for safer hydrogen storage solutions. The findings of this study are significant for advancing the safety of ammonia storage and have potential applications in improving regulatory standards and industry practices.
Key findings demonstrate that implementing full containment tanks with bund protection significantly mitigates the risk of ammonia releases, reducing the impact area and the likelihood of hazardous vapor cloud formation. In contrast, single tanks without bunds expose populations to higher ammonia concentrations, potentially causing severe casualties. This study introduces the Containment Efficiency Ratio (CER), a critical metric for optimizing bund heights to maximize hazard containment. This ratio measures the containment efficiency per meter of bund height, providing a straightforward metric for safety assessment. The optimal bund height, informed by the findings, ranges between 7 to 8 meters, where safety and cost-efficiency align for the tank being studied.
Recommendations highlight the effectiveness of full containment tanks with bunding, regular maintenance, the use of corrosion-resistant materials, advanced monitoring systems, and comprehensive emergency response plans. Sensitivity analysis confirms the robustness of these conclusions under varying conditions. The cost-benefit analysis supports the feasibility of these measures, emphasizing their effectiveness in minimizing the risk of ammonia releases. This strategic approach enhances safety management, aligns with regulatory frameworks and industry best practices, and addresses the urgent need for safer hydrogen storage solutions. The findings of this study are significant for advancing the safety of ammonia storage and have potential applications in improving regulatory standards and industry practices.
As renewable energy expands beyond centralised grids, decentralised hydrogen production emerges as a strategic solution for regional energy autonomy, industrial decarbonisation, and transport applications. This paper presents a systems-level study on the implementation of modular electrolysis units powered by distributed renewable energy sources for green hydrogen production.
The research focuses on the technical design, operation, and infrastructure integration of decentralised electrolysis units, particularly PEM-based systems. The Water and Oxygen Management System (WOMS) is analysed in detail, including failure modes and operational optimisation through digital twin modelling. Flexibility is assessed in terms of dynamic load-following, renewable variability, and integration with energy storage systems.
Infrastructure challenges such as water supply, grid interconnection, compression, and hydrogen storage are mapped across multiple deployment environments—industrial parks, rural communities, and island systems. Geospatial and economic modelling is used to identify optimal node placement, delivery logistics, and scalability scenarios. A modular design approach is highlighted to ensure compatibility with evolving demand and technological maturity.
The study also includes a techno-economic sensitivity analysis of system CAPEX, electrolyser utilisation rate, renewable electricity pricing, and policy incentives. Case studies from Europe and MENA regions are incorporated to compare regulatory frameworks and support mechanisms.
Findings indicate that decentralised modular hydrogen production can enhance resilience, reduce transmission losses, and provide flexibility services to local energy systems. Moreover, digital tools for performance monitoring, predictive maintenance, and system control are crucial for reliability and efficiency. The paper concludes with recommendations for harmonised standards, digital integration, and targeted investment to accelerate deployment.
Keywords:
Green Hydrogen, Modular Electrolysis, Decentralised Energy, System Integration, Infrastructure Planning, PEM Electrolysers, Digital Twin, Flexibility, Local Production, Techno-Economics
The research focuses on the technical design, operation, and infrastructure integration of decentralised electrolysis units, particularly PEM-based systems. The Water and Oxygen Management System (WOMS) is analysed in detail, including failure modes and operational optimisation through digital twin modelling. Flexibility is assessed in terms of dynamic load-following, renewable variability, and integration with energy storage systems.
Infrastructure challenges such as water supply, grid interconnection, compression, and hydrogen storage are mapped across multiple deployment environments—industrial parks, rural communities, and island systems. Geospatial and economic modelling is used to identify optimal node placement, delivery logistics, and scalability scenarios. A modular design approach is highlighted to ensure compatibility with evolving demand and technological maturity.
The study also includes a techno-economic sensitivity analysis of system CAPEX, electrolyser utilisation rate, renewable electricity pricing, and policy incentives. Case studies from Europe and MENA regions are incorporated to compare regulatory frameworks and support mechanisms.
Findings indicate that decentralised modular hydrogen production can enhance resilience, reduce transmission losses, and provide flexibility services to local energy systems. Moreover, digital tools for performance monitoring, predictive maintenance, and system control are crucial for reliability and efficiency. The paper concludes with recommendations for harmonised standards, digital integration, and targeted investment to accelerate deployment.
Keywords:
Green Hydrogen, Modular Electrolysis, Decentralised Energy, System Integration, Infrastructure Planning, PEM Electrolysers, Digital Twin, Flexibility, Local Production, Techno-Economics
Low-carbon hydrogen—particularly electrolytic “green” hydrogen generated from renewable electricity—features in many national net-zero strategies because it promises lower carbon emissions in traditional uses and decarbonization across a wide range of sectors, including heat, power, and mobility. Yet the strict regulations frequently proposed to ensure hydrogen’s “green” credentials, such as hourly time-matching of electrolyzer power consumption to local renewable generation, can drive up costs significantly. This work investigates whether policies that demand perfect, hourly time-matching with renewable electricity are truly necessary or whether more relaxed strategies could enable affordable low-carbon hydrogen production.
We use a resource-task network modelling framework, which links hydrogen production—via water electrolysis—with regional renewable generation and energy storage at an hourly resolution. We use 20 years of weather data to capture inter- and intra-annual variability of renewable sources. Using this framework, the least-cost system design and operation can be determined based on differing time-matching constraints. By comparing scenarios that allow partial reliance on grid electricity against those requiring perfect hourly time-matching with renewables, we can quantify the trade-offs in production cost and environmental impact.
Our findings show that strict hourly time-matching requirements can substantially increase hydrogen production costs while providing only marginal emissions reductions, leading to CO2 avoidance costs higher than other expensive mitigation options such as direct air capture. This suggests that overly strict time-matching rules yield limited climate benefits relative to their cost, whereas a modest relaxation of these requirements offers a more pragmatic and cost-effective pathway to low-carbon hydrogen production—and thus potentially enabling a broader adoption.
Moreover, in jurisdictions with credible near- to medium-term decarbonization targets, fully grid-powered electrolysis may have a lifetime carbon intensity comparable to, or even lower than, that of other low-carbon hydrogen pathways. This underscores the importance of rapid, broader grid decarbonization as a key policy priority.
Co-author/s:
Matthias Mersch, Research Associate, Clean Energy Processes (CEP) Laboratory, Department of Chemical Engineering, Imperial College London.
Niall Mac Dowell, Professor, Centre for Environmental Policy, Imperial College London.
We use a resource-task network modelling framework, which links hydrogen production—via water electrolysis—with regional renewable generation and energy storage at an hourly resolution. We use 20 years of weather data to capture inter- and intra-annual variability of renewable sources. Using this framework, the least-cost system design and operation can be determined based on differing time-matching constraints. By comparing scenarios that allow partial reliance on grid electricity against those requiring perfect hourly time-matching with renewables, we can quantify the trade-offs in production cost and environmental impact.
Our findings show that strict hourly time-matching requirements can substantially increase hydrogen production costs while providing only marginal emissions reductions, leading to CO2 avoidance costs higher than other expensive mitigation options such as direct air capture. This suggests that overly strict time-matching rules yield limited climate benefits relative to their cost, whereas a modest relaxation of these requirements offers a more pragmatic and cost-effective pathway to low-carbon hydrogen production—and thus potentially enabling a broader adoption.
Moreover, in jurisdictions with credible near- to medium-term decarbonization targets, fully grid-powered electrolysis may have a lifetime carbon intensity comparable to, or even lower than, that of other low-carbon hydrogen pathways. This underscores the importance of rapid, broader grid decarbonization as a key policy priority.
Co-author/s:
Matthias Mersch, Research Associate, Clean Energy Processes (CEP) Laboratory, Department of Chemical Engineering, Imperial College London.
Niall Mac Dowell, Professor, Centre for Environmental Policy, Imperial College London.
Daulet Zhakupov
Chair
Acting Director, Department of Alternative Energy
KMG Engineering LLP
Hydrogen (H2) is set to become a dominant energy carrier to decarbonize global energy systems. The environmental footprint and cost of H2 strictly depend on the method by which it is obtained. Among the production routes, green H2 stands out by being produced by splitting water with renewable electricity, emitting almost no carbon emissions. In contrast to green H2, dark hydrogen depends on fossil-fuel feedstocks to be produced. The production methods include grey (natural-gas SMR without capture), brown (lignite gasification), and black (bituminous or anthracite coal gasification) hydrogen, which is the most utilized method to produce hydrogen today. Blue hydrogen stands in the middle; it is made via a steam methane reforming (SMR) process, but it integrates carbon capture, utilization, and storage (CCUS). The introduction of the CCUS is set to mitigate a significant portion of life-cycle emissions, taking advantage of existing natural-gas infrastructure while saving residual carbon footprint. This study uses a techno-economic analysis (TEA) and life-cycle assessments (LCA) to compare the levelized cost of hydrogen (LCOH) and greenhouse-gas (GHG) footprints across these production routes. The results demonstrate that green hydrogen can reach the highest LCOH between 2.7 and 4.3 USD/kg, with extremely low carbon emissions between 0.6 and 4.34 kg of CO2 per kg of H2. Blue hydrogen with high-rate CCUS approaches ≈ 4 USD/kg, with moderate carbon emissions between 3.97 and 12 kg of CO2 per kg of H2. By contrast, black hydrogen offers a lower LCOH of 1.6–2.2 USD/kg but has the highest CO2 emissions, up to 20 kg of CO2 per kg of H2, making it an inexpensive but high-emission method. These comparative results are set to refine the hydrogen decarbonization roadmap. Under the framework set for the net zero target, future policy instruments such as carbon pricing, long-term offtake agreements, and export incentives can accelerate the scale-up of low-carbon hydrogen routes.
Co-author/s:
Mohammed Alyousef, Associate Petroleum Engineer, Saudi Aramco.
Luis Vazquez, Graduate Student, KAUST.
Co-author/s:
Mohammed Alyousef, Associate Petroleum Engineer, Saudi Aramco.
Luis Vazquez, Graduate Student, KAUST.
This paper addresses the critical issue of safely managing ammonia storage, focusing on consequence and risk modeling using Integral Models. Ammonia is increasingly considered an alternative for hydrogen storage due to its higher energy density, easier liquefaction process, and established infrastructure for handling and transportation. However, large-scale accidental releases pose significant challenges, primarily due to the toxicity of dispersed vapor clouds, while fire and explosion risks are less significant. The methodology involves evaluating different tank configurations under various scenarios, including Toxic Vapor Cloud, Flammable Extension Area, and Vapor Cloud Explosion.
Key findings demonstrate that implementing full containment tanks with bund protection significantly mitigates the risk of ammonia releases, reducing the impact area and the likelihood of hazardous vapor cloud formation. In contrast, single tanks without bunds expose populations to higher ammonia concentrations, potentially causing severe casualties. This study introduces the Containment Efficiency Ratio (CER), a critical metric for optimizing bund heights to maximize hazard containment. This ratio measures the containment efficiency per meter of bund height, providing a straightforward metric for safety assessment. The optimal bund height, informed by the findings, ranges between 7 to 8 meters, where safety and cost-efficiency align for the tank being studied.
Recommendations highlight the effectiveness of full containment tanks with bunding, regular maintenance, the use of corrosion-resistant materials, advanced monitoring systems, and comprehensive emergency response plans. Sensitivity analysis confirms the robustness of these conclusions under varying conditions. The cost-benefit analysis supports the feasibility of these measures, emphasizing their effectiveness in minimizing the risk of ammonia releases. This strategic approach enhances safety management, aligns with regulatory frameworks and industry best practices, and addresses the urgent need for safer hydrogen storage solutions. The findings of this study are significant for advancing the safety of ammonia storage and have potential applications in improving regulatory standards and industry practices.
Key findings demonstrate that implementing full containment tanks with bund protection significantly mitigates the risk of ammonia releases, reducing the impact area and the likelihood of hazardous vapor cloud formation. In contrast, single tanks without bunds expose populations to higher ammonia concentrations, potentially causing severe casualties. This study introduces the Containment Efficiency Ratio (CER), a critical metric for optimizing bund heights to maximize hazard containment. This ratio measures the containment efficiency per meter of bund height, providing a straightforward metric for safety assessment. The optimal bund height, informed by the findings, ranges between 7 to 8 meters, where safety and cost-efficiency align for the tank being studied.
Recommendations highlight the effectiveness of full containment tanks with bunding, regular maintenance, the use of corrosion-resistant materials, advanced monitoring systems, and comprehensive emergency response plans. Sensitivity analysis confirms the robustness of these conclusions under varying conditions. The cost-benefit analysis supports the feasibility of these measures, emphasizing their effectiveness in minimizing the risk of ammonia releases. This strategic approach enhances safety management, aligns with regulatory frameworks and industry best practices, and addresses the urgent need for safer hydrogen storage solutions. The findings of this study are significant for advancing the safety of ammonia storage and have potential applications in improving regulatory standards and industry practices.
Marcos López Járrega
Speaker
Andalusian Green Hydrogen Valley Project Development
Moeve
As renewable energy expands beyond centralised grids, decentralised hydrogen production emerges as a strategic solution for regional energy autonomy, industrial decarbonisation, and transport applications. This paper presents a systems-level study on the implementation of modular electrolysis units powered by distributed renewable energy sources for green hydrogen production.
The research focuses on the technical design, operation, and infrastructure integration of decentralised electrolysis units, particularly PEM-based systems. The Water and Oxygen Management System (WOMS) is analysed in detail, including failure modes and operational optimisation through digital twin modelling. Flexibility is assessed in terms of dynamic load-following, renewable variability, and integration with energy storage systems.
Infrastructure challenges such as water supply, grid interconnection, compression, and hydrogen storage are mapped across multiple deployment environments—industrial parks, rural communities, and island systems. Geospatial and economic modelling is used to identify optimal node placement, delivery logistics, and scalability scenarios. A modular design approach is highlighted to ensure compatibility with evolving demand and technological maturity.
The study also includes a techno-economic sensitivity analysis of system CAPEX, electrolyser utilisation rate, renewable electricity pricing, and policy incentives. Case studies from Europe and MENA regions are incorporated to compare regulatory frameworks and support mechanisms.
Findings indicate that decentralised modular hydrogen production can enhance resilience, reduce transmission losses, and provide flexibility services to local energy systems. Moreover, digital tools for performance monitoring, predictive maintenance, and system control are crucial for reliability and efficiency. The paper concludes with recommendations for harmonised standards, digital integration, and targeted investment to accelerate deployment.
Keywords:
Green Hydrogen, Modular Electrolysis, Decentralised Energy, System Integration, Infrastructure Planning, PEM Electrolysers, Digital Twin, Flexibility, Local Production, Techno-Economics
The research focuses on the technical design, operation, and infrastructure integration of decentralised electrolysis units, particularly PEM-based systems. The Water and Oxygen Management System (WOMS) is analysed in detail, including failure modes and operational optimisation through digital twin modelling. Flexibility is assessed in terms of dynamic load-following, renewable variability, and integration with energy storage systems.
Infrastructure challenges such as water supply, grid interconnection, compression, and hydrogen storage are mapped across multiple deployment environments—industrial parks, rural communities, and island systems. Geospatial and economic modelling is used to identify optimal node placement, delivery logistics, and scalability scenarios. A modular design approach is highlighted to ensure compatibility with evolving demand and technological maturity.
The study also includes a techno-economic sensitivity analysis of system CAPEX, electrolyser utilisation rate, renewable electricity pricing, and policy incentives. Case studies from Europe and MENA regions are incorporated to compare regulatory frameworks and support mechanisms.
Findings indicate that decentralised modular hydrogen production can enhance resilience, reduce transmission losses, and provide flexibility services to local energy systems. Moreover, digital tools for performance monitoring, predictive maintenance, and system control are crucial for reliability and efficiency. The paper concludes with recommendations for harmonised standards, digital integration, and targeted investment to accelerate deployment.
Keywords:
Green Hydrogen, Modular Electrolysis, Decentralised Energy, System Integration, Infrastructure Planning, PEM Electrolysers, Digital Twin, Flexibility, Local Production, Techno-Economics
To meet the growing global demand for ammonia—driven by its essential role in agriculture and low-carbon energy systems—there is a critical need for scalable and efficient production technologies. The continuous upscaling of ammonia production facilities necessitates the development of innovative engineering solutions to address the limitations of traditional reactor designs.
Traditional ammonia production facilities, with capacities ranging between 1,000 - 3,000 metric tons per day (MTPD), comprise of conventional reactor designs, which rely on single catalyst beds, encounter major limitations in reactor design, including excessive reactor diameters, space constraints, and complex material requirements when using same design approach for giga-scale plants exceeding 3000 such as for 6000 MTPD.
These challenges hinder the scalability, cost efficiency, and environmental compliance of high—capacity ammonia plants, necessitating innovative reactor designs to address these limitations. First, the reactor diameters increase significantly, complicating manufacturing, transportation, and site installation leading to logistical issues. Then, the larger catalyst beds result in increased pressure drops leading to higher energy consumption and thus impacting energy efficiency. Third, the expanded reactor sizes require larger plot areas, which may not be feasible in existing facilities and results in space constraints and finally, there are material challenges resulting from increased shell thickness for larger reactors creates difficulties in material procurement and fabrication.
This paper introduces the Split Flow Reactor (SFR), an innovative solution developed by KBR to address these challenges in catalyst converters such as High Temperature Shift (HTS) converters, Low Temperature Shift (LTS) converters, and Methanation Units. Unlike conventional design, the SFR splits the syngas and catalyst bed into two parallel flow sections within a single reactor shell.
By using the parallel bed configuration with optimized flow distribution- without compromising on flow rates, the SFR achieves reduced pressure drop, compact reactor dimensions – addresses manufacturing and logistics constraints, superior energy efficiency, reduced rector footprints – eliminating the need of multiple reactors and up to 25% savings in cost and plot area.
Computational Fluid Dynamics (CFD) simulations validate the reactor's performance, confirming improvements in velocity profiles, temperature distribution, and pressure management compared to traditionally designed reactor setups.
Specifically tailored for large capacity ammonia plants, the SFR marks a transformative step in reactor design, offering a scalable, energy-efficient, and cost-effective solution that sets a new industry standard for large-capacity ammonia plants.
Co-author/s:
Sudesh Joon, Technical Advisor, KBR.
Traditional ammonia production facilities, with capacities ranging between 1,000 - 3,000 metric tons per day (MTPD), comprise of conventional reactor designs, which rely on single catalyst beds, encounter major limitations in reactor design, including excessive reactor diameters, space constraints, and complex material requirements when using same design approach for giga-scale plants exceeding 3000 such as for 6000 MTPD.
These challenges hinder the scalability, cost efficiency, and environmental compliance of high—capacity ammonia plants, necessitating innovative reactor designs to address these limitations. First, the reactor diameters increase significantly, complicating manufacturing, transportation, and site installation leading to logistical issues. Then, the larger catalyst beds result in increased pressure drops leading to higher energy consumption and thus impacting energy efficiency. Third, the expanded reactor sizes require larger plot areas, which may not be feasible in existing facilities and results in space constraints and finally, there are material challenges resulting from increased shell thickness for larger reactors creates difficulties in material procurement and fabrication.
This paper introduces the Split Flow Reactor (SFR), an innovative solution developed by KBR to address these challenges in catalyst converters such as High Temperature Shift (HTS) converters, Low Temperature Shift (LTS) converters, and Methanation Units. Unlike conventional design, the SFR splits the syngas and catalyst bed into two parallel flow sections within a single reactor shell.
By using the parallel bed configuration with optimized flow distribution- without compromising on flow rates, the SFR achieves reduced pressure drop, compact reactor dimensions – addresses manufacturing and logistics constraints, superior energy efficiency, reduced rector footprints – eliminating the need of multiple reactors and up to 25% savings in cost and plot area.
Computational Fluid Dynamics (CFD) simulations validate the reactor's performance, confirming improvements in velocity profiles, temperature distribution, and pressure management compared to traditionally designed reactor setups.
Specifically tailored for large capacity ammonia plants, the SFR marks a transformative step in reactor design, offering a scalable, energy-efficient, and cost-effective solution that sets a new industry standard for large-capacity ammonia plants.
Co-author/s:
Sudesh Joon, Technical Advisor, KBR.
Bharati Panigrahy
Speaker
Senior Scientist
HP Green R&D Center, Hindustan Petroleum Corporation Limited (HPCL), Bangalore, India
Design of highly efficient cost effective and self-supported electrocatalyst for the production of green hydrogen with reduced CAPEX and OPEX is significant for renewable and sustainable energy conversion to achieve future carbon neutral. Meanwhile, as we know that the overall water splitting is an uphill reaction requires 285.8 kJ of energy, corresponds to the HHV of hydrogen, state-of-the-art developments are necessary to greatly improve the efficiency by rationally designing non-precious metal-based robust bi-functional catalysts for promoting both the cathodic hydrogen evolution and anodic oxygen evolution reactions.
Here, first time we report the hybrid nanocomposite of Iron and Nickel phosphides based electrocatalyst directly grown on metal foam as an integrated electrode by a simple facile one step phosphidation process giving rise to highly crystalline composite with predominantly exposed [121] facets of nickel phosphide and [211] facets of iron phosphide, which accounts for the high electrocatalytic activities. The performance of metal phosphide towards hydrogen and oxygen evolution was examined under application relevant conditions in an anion exchange membrane electrolyzer and Alkaline electrolyzer cell stack. The formulated electrocatalyst outperforms other precious and non-precious electrodes operated at similar operating conditions. Evaluation of the in-house developed electrocatalyst in the prototype in-house design electrolyzer stack is conducted, and the efficiency of the electrolyzers are better, with the electrocatalyst cost is significantly cheaper compare to the commercial one.
We have observed 14% less energy consumption compares to the commercial electrodes. We have achieved the increased efficiency by limiting 27% heat loss compare to commercial minimum of 50% by controlling the activation loss. We have carried out the mass balance and achieved close to 100% Faradic efficiency by minimizing the ohmic loss. Mass loss is also controlled by tuning the electron modulation followed by work function. By using the in-house developed electrode materials and technologies, we have successfully demonstrated prototype 1 kW alkaline and anion exchange membrane (AEM) electrolyzer cell stack module. We have evaluated the prototype 1 to 10 kW alkaline and AEM electrolyzers for more than 6 months to analyze the stability study. We have successfully established the increase in overpotential is less than 0.021 V with a constant current density of 0.6-1.1 A/cm2. The stability test is carried out with a potential range from 1.8 to 2.4 Volt and current density range of 0.1 to 1 A/cm2. For each case it is stable for more than 2000 hours. The in-house designed stacked electrolyzer exhibited stable performances with a hydrogen production rate of few Nm3 per hour without any decay, pave the path towards large scale application with 35% reduction in CAPEX and OPEX cost.
Here, first time we report the hybrid nanocomposite of Iron and Nickel phosphides based electrocatalyst directly grown on metal foam as an integrated electrode by a simple facile one step phosphidation process giving rise to highly crystalline composite with predominantly exposed [121] facets of nickel phosphide and [211] facets of iron phosphide, which accounts for the high electrocatalytic activities. The performance of metal phosphide towards hydrogen and oxygen evolution was examined under application relevant conditions in an anion exchange membrane electrolyzer and Alkaline electrolyzer cell stack. The formulated electrocatalyst outperforms other precious and non-precious electrodes operated at similar operating conditions. Evaluation of the in-house developed electrocatalyst in the prototype in-house design electrolyzer stack is conducted, and the efficiency of the electrolyzers are better, with the electrocatalyst cost is significantly cheaper compare to the commercial one.
We have observed 14% less energy consumption compares to the commercial electrodes. We have achieved the increased efficiency by limiting 27% heat loss compare to commercial minimum of 50% by controlling the activation loss. We have carried out the mass balance and achieved close to 100% Faradic efficiency by minimizing the ohmic loss. Mass loss is also controlled by tuning the electron modulation followed by work function. By using the in-house developed electrode materials and technologies, we have successfully demonstrated prototype 1 kW alkaline and anion exchange membrane (AEM) electrolyzer cell stack module. We have evaluated the prototype 1 to 10 kW alkaline and AEM electrolyzers for more than 6 months to analyze the stability study. We have successfully established the increase in overpotential is less than 0.021 V with a constant current density of 0.6-1.1 A/cm2. The stability test is carried out with a potential range from 1.8 to 2.4 Volt and current density range of 0.1 to 1 A/cm2. For each case it is stable for more than 2000 hours. The in-house designed stacked electrolyzer exhibited stable performances with a hydrogen production rate of few Nm3 per hour without any decay, pave the path towards large scale application with 35% reduction in CAPEX and OPEX cost.
Marwan Sendi
Speaker
Senior Engineer
Life Cycle Assessment Group, Technology Strategy & Planning Department, Saudi Aramco. Department of Chemical Engineering, Imperial College London, United Kingdom
Low-carbon hydrogen—particularly electrolytic “green” hydrogen generated from renewable electricity—features in many national net-zero strategies because it promises lower carbon emissions in traditional uses and decarbonization across a wide range of sectors, including heat, power, and mobility. Yet the strict regulations frequently proposed to ensure hydrogen’s “green” credentials, such as hourly time-matching of electrolyzer power consumption to local renewable generation, can drive up costs significantly. This work investigates whether policies that demand perfect, hourly time-matching with renewable electricity are truly necessary or whether more relaxed strategies could enable affordable low-carbon hydrogen production.
We use a resource-task network modelling framework, which links hydrogen production—via water electrolysis—with regional renewable generation and energy storage at an hourly resolution. We use 20 years of weather data to capture inter- and intra-annual variability of renewable sources. Using this framework, the least-cost system design and operation can be determined based on differing time-matching constraints. By comparing scenarios that allow partial reliance on grid electricity against those requiring perfect hourly time-matching with renewables, we can quantify the trade-offs in production cost and environmental impact.
Our findings show that strict hourly time-matching requirements can substantially increase hydrogen production costs while providing only marginal emissions reductions, leading to CO2 avoidance costs higher than other expensive mitigation options such as direct air capture. This suggests that overly strict time-matching rules yield limited climate benefits relative to their cost, whereas a modest relaxation of these requirements offers a more pragmatic and cost-effective pathway to low-carbon hydrogen production—and thus potentially enabling a broader adoption.
Moreover, in jurisdictions with credible near- to medium-term decarbonization targets, fully grid-powered electrolysis may have a lifetime carbon intensity comparable to, or even lower than, that of other low-carbon hydrogen pathways. This underscores the importance of rapid, broader grid decarbonization as a key policy priority.
Co-author/s:
Matthias Mersch, Research Associate, Clean Energy Processes (CEP) Laboratory, Department of Chemical Engineering, Imperial College London.
Niall Mac Dowell, Professor, Centre for Environmental Policy, Imperial College London.
We use a resource-task network modelling framework, which links hydrogen production—via water electrolysis—with regional renewable generation and energy storage at an hourly resolution. We use 20 years of weather data to capture inter- and intra-annual variability of renewable sources. Using this framework, the least-cost system design and operation can be determined based on differing time-matching constraints. By comparing scenarios that allow partial reliance on grid electricity against those requiring perfect hourly time-matching with renewables, we can quantify the trade-offs in production cost and environmental impact.
Our findings show that strict hourly time-matching requirements can substantially increase hydrogen production costs while providing only marginal emissions reductions, leading to CO2 avoidance costs higher than other expensive mitigation options such as direct air capture. This suggests that overly strict time-matching rules yield limited climate benefits relative to their cost, whereas a modest relaxation of these requirements offers a more pragmatic and cost-effective pathway to low-carbon hydrogen production—and thus potentially enabling a broader adoption.
Moreover, in jurisdictions with credible near- to medium-term decarbonization targets, fully grid-powered electrolysis may have a lifetime carbon intensity comparable to, or even lower than, that of other low-carbon hydrogen pathways. This underscores the importance of rapid, broader grid decarbonization as a key policy priority.
Co-author/s:
Matthias Mersch, Research Associate, Clean Energy Processes (CEP) Laboratory, Department of Chemical Engineering, Imperial College London.
Niall Mac Dowell, Professor, Centre for Environmental Policy, Imperial College London.
This study designs a renewable energy-powered hydrogen production via water electrolysis and low-temperature/low-pressure ammonia synthesis process using Aspen Plus simulation software, providing technical support for the construction and operation of a 10,000-ton/y-scale demonstration project. An alkaline electrolyzer was modeled using the ACM framework, achieving a hydrogen production capacity of 1000 Nm³/h. For the ammonia synthesis section, the REquil reactor model was employed to calculate the equilibrium reaction heat and component mole fractions within temperature (340–540°C) and pressure (7–20 MPa) ranges. Results indicate that the equilibrium reaction heat decreases with rising temperature but increases with elevated pressure. A comparative analysis of ruthenium-based, iron-based, and iron-ruthenium cascade catalysts revealed superior overall activity for ruthenium-based catalysts, while iron-based catalysts exhibited higher sensitivity to ammonia concentration. Considering operational costs and catalytic performance, the iron-ruthenium cascade system was selected for ammonia synthesis at 400°C and 7 MPa. Full-process material and energy balances were conducted to guide industrial-scale implementation. The material balance demonstrated an ammonia concentration of 21.88% at the synthesis reactor outlet, corresponding to a production rate of 1.25 t/h. Energy balance calculations indicated a specific energy consumption of ~11000 kWh/t NH₃, with electrolysis and compression identified as major energy-intensive units.
Co-author/s:
Hongzhi Chen, Chief System Scientist, Kunlun digital technology, CNPC.
Dr. Yue Zeng, Senior Engineer, CNPC.
Dr. Qingxun Li, Professor Level Engineer, CNPC.
Xiwen Song, Engineer, CNPC.
Co-author/s:
Hongzhi Chen, Chief System Scientist, Kunlun digital technology, CNPC.
Dr. Yue Zeng, Senior Engineer, CNPC.
Dr. Qingxun Li, Professor Level Engineer, CNPC.
Xiwen Song, Engineer, CNPC.
