Publications
Evaluation of the Impact of Gaseous Hydrogen on Pipeline Steels Utilizing Hollow Specimen Technique and μCT
Feb 2024
Publication
The high potential of hydrogen as a key factor on the pathway towards a climate neutral economy leads to rising demand in technical applications where gaseous hydrogen is used. For several metals hydrogen-metal interactions could cause a degradation of the material properties. This is especially valid for low carbon and highstrength structural steels as they are commonly used in natural gas pipelines and analyzed in this work. This work provides an insight to the impact of hydrogen on the mechanical properties of an API 5L X65 pipeline steel tested in 60 bar gaseous hydrogen atmosphere. The analyses were performed using the hollow specimen technique with slow strain rate testing (SSRT). The nature of the crack was visualized thereafter utilizing μCT imaging of the sample pressurized with gaseous hydrogen in comparison to one tested in an inert atmosphere. The combination of the results from non-conventional mechanical testing procedures and nondestructive imaging techniques has shown unambiguously how the exposure to hydrogen under realistic service pressure influences the mechanical properties of the material and the appearance of failure.
Future of Hydrogen in the U.S. Energy Sector: MARKAL Modeling Results
Mar 2024
Publication
Hydrogen is an attractive energy carrier which could play a role in decarbonizing process heat power or transport applications. Though the U.S. already produces about 10 million metric tons of H2 (over 1 quadrillion BTUs or 1% of the U.S. primary energy consumption) production technologies primarily use fossil fuels that release CO2 and the deployment of other cleaner H2 production technologies is still in the very early stages in the U.S. This study explores (1) the level of current U.S. hydrogen production and demand (2) the importance of hydrogen to accelerate a net-zero CO2 future and (3) the challenges that must be overcome to make hydrogen an important part of the U.S. energy system. The study discusses four scenarios and hydrogen production has been shown to increase in the future but this growth is not enough to establish a hydrogen economy. In this study the characteristics of hydrogen technologies and their deployments in the long-term future are investigated using energy system model MARKAL. The effects of strong carbon constraints do not cause higher hydrogen demand but show a decrease in comparison to the business-as-usual scenario. Further according to our modeling results hydrogen grows only as a fuel for hard-to-decarbonize heavy-duty vehicles and is less competitive than other decarbonization solutions in the U.S. Without improvements in reducing the cost of electrolysis and increasing the performance of near-zero carbon technologies for hydrogen production hydrogen will remain a niche player in the U.S. energy system in the long-term future. This article provides the reader with a comprehensive understanding of the role of hydrogen in the U.S. energy system thereby explaining the long-term future projections.
Multiplier Effect on Reducing Carbon Emissions of Joint Demand and Supply Side Measures in the Hydrogen Market
Jun 2024
Publication
Hydrogen energy is critical in replacing fossil fuels and achieving net zero carbon emissions by 2050. Three measures can be implemented to promote hydrogen energy: reduce the cost of low-carbon hydrogen through technological improvements increase the production capacity of low-carbon hydrogen by stimulating investment and enhance hydrogen use as an energy carrier and in industrial processes by demand-side policies. This article examines how effective these measures are if successfully implemented in boosting the hydrogen market and reducing global economy-wide carbon emissions using a global computable general equilibrium model. The results show that all the measures increase the production and use of low-carbon hydrogen whether implemented alone or jointly. Notably the emissions reduced by joint implementation of all the measures in 2050 become 2.5 times the sum of emissions reduced by individual implementation indicating a considerable multiplier effect. This suggests supply and demand side policies be implemented jointly to maximize their impact on reducing emissions.
Integrating Scenario-based Stochastic-model Predictive Control and Load Forecasting for Energy Management of Grid-connected Hybrid Energy Storage Systems
Jun 2023
Publication
In the context of renewable energy systems microgrids (MG) are a solution to enhance the reliability of power systems. In the last few years there has been a growing use of energy storage systems (ESSs) such as hydrogen and battery storage systems because of their environmentally-friendly nature as power converter devices. However their short lifespan represents a major challenge to their commercialization on a large scale. To address this issue the control strategy proposed in this paper includes cost functions that consider the degradation of both hydrogen devices and batteries. Moreover the proposed controller uses scenarios to reflect the stochastic nature of renewable energy resources (RESs) and load demand. The objective of this paper is to integrate a stochastic model predictive control (SMPC) strategy for an economical/environmental MG coupled with hydrogen and battery ESSs which interacts with the main grid and external consumers. The system's participation in the electricity market is also managed. Numerical analyses are conducted using RESs profiles and spot prices of solar panels and wind farms in Abu Dhabi UAE to demonstrate the effectiveness of the proposed controller in the presence of uncertainties. Based on the results the developed control has been proven to effectively manage the integrated system by meeting overall constraints and energy demands while also reducing the operational cost of hydrogen devices and extending battery lifetime.
Hydrogen Storage in Depleted Gas Reservoirs with Carbon Dioxide as a Cushion Gas: Exploring a Lateral Gas Seperation Strategy to Reduce Gas Mixing
Jan 2025
Publication
Large-scale H2 storage in depleted hydrocarbon reservoirs offers a practical way to use existing energy infra structure to address renewable energy intermittency. Cushion gases often constitute a large initial investment especially when expensive H2 is used. Cheaper alternatives such as CO2 or in-situ CH4 can reduce costs and in the case of CO2 integrate within carbon capture and storage systems. This study explored cushion and working gas dynamics through numerically modelling a range of storage scenarios in laterally extensive reservoirs – such as those in the Southern North Sea. In all simulations the cushion and working gases were separated laterally to limit contact surface area and therefore mixing. This work provides valuable insights into (i) capacity estima tions of CO2 storage and H2 withdrawal (ii) macro-scale fluid dynamics and (iii) the effects of gas mixing trends on H2 purity. The results underscore key trade-offs between CO2 storage volumes and H2 withdrawal and purity
A Hybrid Robust-stochastic Approach for Optimal Scheduling of Interconnected Hydrogen-based Energy Hubs
Jan 2021
Publication
The energy hub (EH) concept is an efficient way to integrate various energy carriers. Inaddition demand response programmes (DRPs) are complementary to improving anEH's efficiency and increase energy system flexibility. The hydrogen storage system as agreen energy carrier has an essential role in balancing supply and demand preciselysimilar to other storage systems. A hybrid robust‐stochastic approach is applied herein toaddress fluctuations in wind power generation multiple demands and electricity marketprice in a hydrogen‐based smart micro‐energy hub (SMEH) with multi‐energy storagesystems. The proposed hybrid approach enables the operator to manage the existinguncertainties with more flexibility. Also flexible electrical and thermal demands under anintegrated demand response programme (IDRP) are implemented in the proposedSMEH. The optimal scheduling of the hydrogen‐based SMEH problem considering windpower generation and electricity market price fluctuations as well as IDRP is modelledvia a mixed‐integer linear programming problem. Finally the validity and applicability ofthe proposed model are verified through simulation and numerical results.
Development of Effective Hydrogen Production and Process Electrification Systems to Reduce the Environmental Impacts of the Methanol Production Process
Jun 2025
Publication
The methanol industry responsible for around 10% of GHG emissions in the chemical sector faces growing challenges due to its environmental impacts. This article aims to reduce the lifecycle environmental impacts of the CO2-to-methanol process by exploring advanced electrification methods for hydrogen production and CO2 conversion. The process analysis and comprehensive life cycle assessment (LCA) are conducted on four different methanol production pathways: conventional natural gas CO2 hydrogenation trireforming of methane (TRM) and the novel electrified combined reforming (ECRM) by including two hydrogen production routes: PEM electrolysis and the innovative plasma-assisted methane pyrolysis. The LCA was performed using the ReCiPe method covering midpoint and endpoint categories across four Canadian provinces—British Columbia Alberta Ontario and Quebec. The efficient plasma technology improves environmental performance for all pathways. The plasma-assisted CO2 hydrogenation pathway in British Columbia and Quebec shows the lowest GHG emissions achieving -2.01 and -1.72 kg CO2/kg MeOH respectively. In Alberta the conventional pathway has the lowest impact followed by plasmaassisted TRM. The CO2 hydrogenation with the PEM pathway shows the highest GHG emissions at 8.00 kg CO2/kg MeOH highlighting the challenges of using hydrogen from PEM electrolysis in regions with carbon-intensive electricity grids. However the inclusion of carbon black as a byproduct further reduces the environmental impact making these plasma-assisted pathways more viable. This LCA study underscores the influence of regional factors and technology choices on the sustainability of methanol production with an example of a 107% reduction in GHG emissions when plasma-assisted ECRM is shifting from Alberta to Quebec.
Hydrogen in Burners: Economic and Environmental Implications
Nov 2024
Publication
For centuries fossil fuels have been the primary energy source but their unchecked use has led to significant environmental and economic challenges that now shape the global energy landscape. The combustion of these fuels releases greenhouse gases which are critical contributors to the acceleration of climate change resulting in severe consequences for both the environment and human health. Therefore this article examines the potential of hydrogen as a sustainable alternative energy source capable of mitigating these climate impacts. It explores the properties of hydrogen with particular emphasis on its application in industrial burners and furnaces underscoring its clean combustion and high energy density in comparison to fossil fuels and also examines hydrogen production through thermochemical and electrochemical methods covering green gray blue and turquoise pathways. It discusses storage and transportation challenges highlighting methods like compression liquefaction chemical carriers (e.g. ammonia) and transport via pipelines and vehicles. Hydrogen combustion mechanisms and optimized burner and furnace designs are explored along with the environmental benefits of lower emissions contrasted with economic concerns like production and infrastructure costs. Additionally industrial and energy applications safety concerns and the challenges of large-scale adoption are addressed presenting hydrogen as a promising yet complex alternative to fossil fuels.
Determining Onshore or Offshore Hydrogen Storage for Large Offshore Wind Parks: The North Sea Wind Power Hub Case
Aug 2024
Publication
The large-scale integration of renewable energy sources leads to daily and seasonal mismatches between supply and demand and the curtailment of wind power. Hydrogen produced from surplus wind power offers an attractive solution to these challenges. In this paper we consider a large offshore wind park and analyze the need for hydrogen storage at the onshore and offshore sides of a large transportation pipeline that connects the wind park to the mainland. The results show that the pipeline with line pack storage though important for day-to-day fluctuations will not offer sufficient storage capacity to bridge seasonal differences. Furthermore the results show that if the pipeline is sufficiently sized additional storage is only needed on one side of the pipeline which would limit the needed investments. Results show that the policy which determines what part of the wind power is fed into the electricity grid and what part is converted into hydrogen has a significant influence on these seasonal storage needs. Therefore investment decisions for hydrogen systems should be made by considering both the onshore and offshore storage requirements in combination with electricity transport to the mainland.
Zone Negligible Extent: Example of Specific Detailed Risk Assessment for Low Pressure Equipment in a Hydrogen Refuelling Station
Sep 2023
Publication
The MultHyFuel project aims to develop evidence-based guidelines for the safe implementation of Hydrogen Refueling Stations (HRS) in a multi-fuel context. As a part of the generation of good practice guidelines for HRS Hazardous Area Classification (HAC) methodologies were analyzed and applied to case studies representing example configurations of HRS. It has been anticipated that Negligible Extent (NE) classifications might be applicable for sections of the HRS for instance a hydrogen generator. A NE zone requires that an ignition of a flammable cloud would result in negligible consequences. In addition depending on the pressure of the system IEC 60079-10-1:2020 establishes specific requirements in order to classify the hazardous area as being of NE. One such requirement is that a zone of NE shall not be applied for releases from flammable gas systems at pressures above 2000 kPag (20 barg) unless a specific detailed risk assessment is documented. However there is no definition within the standard as to the requirements of the specific detailed risk assessment. In this work an example for a specific detailed risk assessment for the NE classification is presented:<br/>• Firstly the requirements of cloud volume dilution and background concentration for a zone of NE classification from IEC 60079-10-1:2020 are analyzed for hydrogen releases from equipment placed in a mechanically ventilated enclosure.<br/>• Secondly the consequences arising from the ignition of the localized cloud are estimated and compared to acceptable harm criteria in order to assess if negligible consequences are obtained from the scenario.<br/>• In addition a specific qualitative risk assessment for the ignition of the cloud in the enclosure was considered incorporating the estimated consequences and analyzing the available safeguards in the example system.<br/>Recommendations for the specific detailed risk assessment are proposed for this scenario with the intention to support improved definition of the requirement in future revisions of IEC 60079-10-1.
Hydrogen Sampling Systems Adapted to Heavy-duty Refuelling Stations' Current and Future Specifications - A Review
Sep 2024
Publication
To meet the new regulation for the deployment of alternative fuels infrastructure which sets targets for electric recharging and hydrogen refuelling infrastructure by 2025 or 2030 a large infrastructure comprising trucksuitable hydrogen refuelling stations will soon be required. However further standardisation is required to support the uptake of hydrogen for heavy-duty transport for Europe’s green energy future. Hydrogen-powered vehicles require pure hydrogen as some contaminants can reduce the performance of the fuel cell even at very low levels. Even if previous projects have paved the way for the development of the European quality infrastructure for hydrogen conformity assessment sampling systems and methods have yet to be developed for heavy-duty hydrogen refuelling stations (HD-HRS). This study reviews different aspects of the sampling of hydrogen at heavy-duty hydrogen refuelling stations for purity assessment with a focus on the current and future specifications and operations at HD-HRS. This study describes the state-of-the art of sampling systems currently under development for use at HD-HRS and highlights a number of aspects which must be taken into consideration to ensure safe and accurate sampling: risk assessment for the whole sampling exercise selection of cylinders methods to prepare cylinders before the sampling filling pressure and venting of the sampling systems.
Evaluation of Green and Blue Hydrogen Production Potential in Saudi Arabia
Sep 2024
Publication
The Kingdom of Saudi Arabia has rich renewable energy resources specifically wind and solar in addition to geothermal beside massive natural gas reserves. This paper investigates the potential of both green and blue hydrogen production for five selected cities in Saudi Arabia. To accomplish the said objective a techno-economic model is formulated. Four renewable energy scenarios are evaluated for a total of 1.9 GW installed capacity to reveal the best scenario of Green Hydrogen Production (GHP) in each city. Also Blue Hydrogen Production (BHP) is investigated for three cases of Steam Methane Reforming (SMR) with different percentages of carbon capture. The economic analysis for both GHP and BHP is performed by calculating the Levelized Cost of Hydrogen (LCOH) and cash flow. The LCOH for GHP range for all cities ($3.27/kg -$12.17/kg)) with the lowest LCOH is found for NEOM city (50% PV and 50% wind) ($3.27/kg). LCOH for BHP are $0.534/kg $0.647/kg and $0.897/kg for SMR wo CCS/U SMR 55% CCS/U and SMR 90% CCS/U respectively.
A Numerial Study on Hydrogen Blending in Natural Gas Pipeline by a T-pipe
Mar 2024
Publication
In order to study the flow blending and transporting process of hydrogen that injects into the natural gas pipelines a three-dimensional T-pipe blending model is established and the flow characteristics are investigated systematically by the large eddy simulation (LES). Firstly the mathematical formulation of hydrogen-methane blending process is provided and the LES method is introduced and validated by a benchmark gas blending model having experimental data. Subsequently the T-pipe blending model is presented and the effects of key parameters such as the velocity of main pipe hydrogen blending ratio diameter of hydrogen injection pipeline diameter of main pipe and operating pressure on the hydrogen-methane blending process are studied systematically. The results show that under certain conditions the gas mixture will be stratified downstream of the blending point with hydrogen at the top of the pipeline and methane at the bottom of the pipeline. For the no-stratified scenarios the distance required for uniformly mixing downstream the injection point increases when the hydrogen mixing ratio decreases the diameter of the hydrogen injection pipe and the main pipe increase. Finally based on the numerical results the underlying physics of the stratification phenomenon during the blending process are explored and an indicator for stratification is proposed using the ratio between the Reynolds numbers of the natural gas and hydrogen.
Novel Model Reference-based Hybrid Decoupling Control of Multiport-isolated DC-DC Converter for Hydrogen Energy Storage System Integration
Dec 2024
Publication
Hydrogen energy storage systems (HESS) are increasingly recognised for their role in sustainable energy ap plications though their performance depends on efficient power electronic converter (PEC) interfaces. In this paper a multiport-isolated DC-DC converter characterised by enhanced power density reduced component count and minimal conversion stages is implemented for HESS applications. However the high-frequency multiwinding transformer in this converter introduces cross-coupling effects complicating control and result ing in large power deviations from nominal values due to step changes on other ports which adversely impact system performance. To address this issue a novel model reference-based decoupling control technique is pro posed to minimise the error between the actual plant output and an ideal decoupling reference model which represents the cross-coupling term. This model reference-based decoupling control is further extended into a hybrid decoupling control technique by integrating a decoupling matrix achieving more robust decoupling across a wider operating region. The hybrid decoupling technique mathematically ensures an improved control performance with the cross-coupling term minimised through a proportional-derivative controller. The proposed hybrid decoupling controller achieves a maximum power deviation.
Impact of an Electrode-diaphragm Gap on Diffusive Hydrogen Crossover in Alkaline Water Electrolysis
Oct 2023
Publication
Hydrogen crossover limits the load range of alkaline water electrolyzers hindering their integration with renewable energy. This study examines the impact of the electrode-diaphragm gap on crossover focusing on diffusive transport. Both finite-gap and zero-gap designs employing the state-of-the-art Zirfon UTP Perl 500 and UTP 220 diaphragms were investigated at room temperature and with a 12 wt% KOH electrolyte. Experimental results reveal a relatively high crossover for a zero-gap configuration which corresponds to supersaturation levels at the diaphragm-electrolyte interface of 8–80 with significant fluctuations over time and between experiments due to an imperfect zero-gap design. In contrast a finite-gap (500 μm) has a significantly smaller crossover corresponding to supersaturation levels of 2–4. Introducing a cathode gap strongly decreases crossover unlike an anode gap. Our results suggest that adding a small cathode-gap can significantly decrease gas impurity potentially increase the operating range of alkaline electrolyzers while maintaining good efficiency.
Status and Perspectives of Key Materials for PEM Electrolyzer
Sep 2024
Publication
Proton exchange membrane water electrolyzer (PEMWE) represents a promising technology for the sustainable production of hydrogen which is capable of efficiently coupling to intermittent electricity from renewable energy sources (e.g. solar and wind). The technology with compact stack structure has many notable advantages including large current density high hydrogen purity and great conversion efficiency. However the use of expensive electrocatalysts and construction materials leads to high hydrogen production costs and limited application. In this review recent advances made in key materials of PEMWE are summarized. First we present a brief overview about the basic principles thermodynamics and reaction kinetics of PEMWE. We then describe the cell components of PEMWE and their respective functions as well as discuss the research status of key materials such as membrane electrocatalysts membrane electrode assemblies gas diffusion layer and bipolar plate. We also attempt to clarify the degradation mechanisms of PEMWE under a real operating environment including catalyst degradation membrane degradation bipolar plate degradation and gas diffusion layer degradation. We finally propose several future directions for developing PEMWE through devoting more efforts to the key materials.
Optimization of Hydrogen Production System Performance Using Photovoltaic/Thermal-Coupled PEM
Oct 2024
Publication
A proton exchange membrane electrolyzer can effectively utilize the electricity generated by intermittent solar power. Different methods of generating electricity may have different efficiencies and hydrogen production rates. Two coupled systems namely PV/T- and CPV/T-coupling PEMEC respectively are presented and compared in this study. A maximum power point tracking algorithm for the photovoltaic system is employed and simulations are conducted based on the solar irradiation intensity and ambient temperature of a specific location on a particular day. The simulation results indicate that the hydrogen production is relatively high between 11:00 and 16:00 with a peak between 12:00 and 13:00. The maximum hydrogen production rate is 99.11 g/s and 29.02 g/s for the CPV/T-PEM and PV/T-PEM systems. The maximum energy efficiency of hydrogen production in CPV/T-PEM and PV/T-PEM systems is 66.7% and 70.6%. Under conditions of high solar irradiation intensity and ambient temperature the system demonstrates higher total efficiency and greater hydrogen production. The CPV/T-PEM system achieves a maximum hydrogen production rate of 2240.41 kg/d with a standard coal saving rate of 15.5 tons/day and a CO2 reduction rate of 38.0 tons/day. Compared to the PV/T-PEM system the CPV/T-PEM system exhibits a higher hydrogen production rate. These findings provide valuable insights into the engineering application of photovoltaic/thermal-coupled hydrogen production technology and contribute to the advancement of this field.
Nanomaterials for Hydrogen Storage Applications: A Review
Sep 2008
Publication
Nanomaterials have attracted great interest in recent years because of the unusual mechanical electrical electronic opticalmagnetic and surface properties. The high surface/volume ratio of these materials has significant implications with respectto energy storage. Both the high surface area and the opportunity for nanomaterial consolidation are key attributes of thisnew class of materials for hydrogen storage devices. Nanostructured systems including carbon nanotubes nano-magnesiumbased hydrides complex hydride/carbon nanocomposites boron nitride nanotubes TiS2/MoS2 nanotubes alanates polymernanocomposites and metal organic frameworks are considered to be potential candidates for storing large quantities of hydrogen.Recent investigations have shown that nanoscale materials may offer advantages if certain physical and chemical effects related tothe nanoscale can be used efficiently. The present review focuses the application of nanostructured materials for storing atomicor molecular hydrogen. The synergistic effects of nanocrystalinity and nanocatalyst doping on the metal or complex hydrides forimproving the thermodynamics and hydrogen reaction kinetics are discussed. In addition various carbonaceous nanomaterialsand novel sorbent systems (e.g. carbon nanotubes fullerenes nanofibers polyaniline nanospheres and metal organic frameworksetc.) and their hydrogen storage characteristics are outlined.
Advancements in Hydrogen Storage Technologies: Integrating with Renewable Energy and Innovative Solutions for a Sustainable Future
Apr 2025
Publication
Hydrogen storage plays a crucial role in achieving net-zero emissions by enabling large-scale energy storage balancing renewable energy fluctuations and ensuring a stable supply for various applications. This study provides a comprehensive analysis of hydrogen storage technologies with a particular focus on underground storage in geological formations such as salt caverns depleted gas reservoirs and aquifers. These formations offer high-capacity storage solutions with salt caverns capable of holding up to 6 TWh of hydrogen and depleted gas reservoirs exceeding 1 TWh per site. Case studies from leading projects demonstrate the feasibility of underground hydrogen storage (UHS) in reducing energy intermittency and enhancing supply security. Challenges such as hydrogen leakage groundwater contamination induced seismicity and economic constraints remain critical concerns. Our findings highlight the technical economic and regulatory considerations for integrating UHS into the oil and gas industry emphasizing its role in sustainable energy transition and decarbonization strategies.
Development of a Novel Renewable Energy-based Integrated System Coupling Biomass and H2S Sources for Clean Hydrogen Production
Oct 2024
Publication
The present work aims to develop a novel integrated energy system to produce clean hydrogen power and biochar. The Palmaria palmata a type of seaweed and hydrogen sulfide from the industrial gaseous waste streams are taken as potential feedstock. A combined thermochemical approach is employed for the processing of both feedstocks. For clean hydrogen production the zinc sulfide thermochemical cycle is employed. Both stoichiometric and non-stoichiometric equilibrium-based models of the proposed plant design are developed in the Aspen Plus software and a comprehensive thermodynamic analysis of the system is also performed by evaluating energy and exergy efficiencies. The study further explores the modeling simulation and parametric analyses of various subsections to enhance the hydrogen and biochar production rate. The parametric analyses show that the first step of the thermochemical cycle (sulfurization reaction) follows stoichiometric pathway and the ZnO to H2S ratio of 1 represents the optimal point for reactant conversion. On the other hand the second step of the thermochemical cycle (regeneration reaction) does not follow a stoichiometric pathway and ZnS conversion of 12.87% is achieved at a high temperature of 1400oC. It is found that a hydrogen production rate of 0.71 mol/s is achieved with the introduction of 0.27 mol/s of H2S. The energy and exergy efficiencies of the zinc sulfide thermochemical cycle are found to be 65.23% and 35.58% respectively. A biochar production rate of 0.024 kg/s is obtained with the Palmaria palmata fed rate of 0.097 kg/s. The Palmaria to biochar energy and exergy efficiencies are found to be 55.43% and 45.91% respectively. The overall energy and exergy efficiencies of the proposed plant are determined to be 72.88% and 50.03% respectively.
Integrating Alkaline Electrolysis with Oxyfuel Combustion for Hydrogen and Electricity Production
Feb 2024
Publication
The present study explores the potential of integrating the NET Zero Cycle (NZC) with hydrogen production by alkaline electrolyzers. To achieve this an Aspen Plus model was developed for the NZC and its accuracy was first confirmed by comparing it with literature data. The creation of a model for an alkaline electrolyzer was achieved using Aspen Custom Modeler and later imported into Aspen Plus. A comprehensive simulation was conducted in Aspen Plus to examine the synergies between the NZC and the alkaline electrolyzer. In this integration the oxygen demand of the NZC is met by a combination of an air separation unit (ASU) and the electrolyzer. The electrolyzer not only partially fulfills the oxygen requirements but also acts as an external heat supplier for the regenerator. Additionally the NZC supplies deionized water to the electrolyzer. A thermodynamic analysis in dicates that the integration of the NZC and alkaline electrolyzers results in a higher efficiency of 56.5 % compared to the stand-alone NZC an improvement of 2.3 %. Assuming that the NZC and alkaline electrolyzer operate at the same power production and input levels the alkaline electrolyzer can generate substantial oxygen to reduce the energy consumption of the ASU significantly. This aspect represents one of the primary reasons for the enhanced efficiency observed in this study. However the ASU still needs to be operated to provide the full oxygen demands of the process. To identify the key parameters influencing the integration of the NZC and alkaline electrolyzers a sensitivity analysis was performed. To enhance the system efficiency a comprehensive investigation was conducted to analyze the influence of key parameters such as combustor outlet temperature (COT) turbine outlet pressure (TOP) and combustor outlet pressure (COP) on the thermodynamic first law efficiency of the cycle. An increase in electrolyzer input power and a reduction in electrolyzer inlet feed were associated with a higher cycle effi ciency. The results also highlight that the TOP COT and the electrolyzer input power have a more significant impact on the cycle thermodynamic first law efficiency within the range of 5.7 4.0 and 2.6 % respectively while COP only causes a 0.4 % change in cycle efficiency. The integrated system demonstrates an impressive system first law thermodynamic efficiency of 62.5 % and exergy efficiency of 60.6 %.
A Review of Hydrogen Leak Detection Regulations and Technologies
Aug 2024
Publication
Hydrogen (H2 ) is positioned as a key solution to the decarbonization challenge in both the energy and transportation sectors. While hydrogen is a clean and versatile energy carrier it poses significant safety risks due to its wide flammability range and high detonation potential. Hydrogen leaks can occur throughout the hydrogen value chain including production storage transportation and utilization. Thus effective leak detection systems are essential for the safe handling storage and transportation of hydrogen. This review aims to survey relevant codes and standards governing hydrogen-leak detection and evaluate various sensing technologies based on their working principles and effectiveness. Our analysis highlights the strengths and limitations of the current detection technologies emphasizing the challenges in achieving sensitive and specific hydrogen detection. The results of this review provide critical insights into the existing technologies and regulatory frameworks informing future advancements in hydrogen safety protocols.
Evaluating the Economic Viability of Decentralised Solar PV-based Green Hydrogen for Cooking in Ghana
Jul 2024
Publication
Developing countries including Ghana face challenges ensuring access to clean and reliable cooking fuels and technologies. Traditional biomass sources mainly used in most developing countries for cooking contribute to deforestation and indoor air pollution necessitating a shift towards environmentally friendly alternatives. The study’s primary objective is to evaluate the economic viability of using solar PV-based green hydrogen as a sustainable fuel for cooking in Ghana. The study adopted well-established equations to investigate the economic performance of the proposed system. The findings revealed that the levelized cost of hydrogen using the discounted cash flow approach is about 89% 155% and 190% more than electricity liquefied petroleum gas (LPG) and charcoal. This implies that using the hydrogen produced for cooking fuel is not cost-competitive compared to LPG charcoal and electricity. However with sufficient capital subsidies to lower the upfront costs the analysis suggests solar PV-based hydrogen could become an attractive alternative cooking fuel. In addition switching from firewood to solar PVbased hydrogen for cooking yields the highest carbon dioxide (CO2) emissions savings across the cities analysed. Likewise replacing charcoal with hydrogen also offers substantial CO2 emissions savings though lower than switching from firewood. Correspondingly switching from LPG to hydrogen produces lower CO2 emissions savings than firewood and charcoal. The study findings could contribute to the growing body of knowledge on sustainable energy solutions offering practical insights for policymakers researchers and industry stakeholders seeking to promote clean cooking adoption in developing economies.
Projecting Technological Advancement of Electrolyzers and the Impact on the Competitiveness of Hydrogen
Dec 2024
Publication
Green hydrogen has the potential to decarbonize hard-to-abate sectors and processes and should therefore play an important role in the energy system in achieving climate goals. However the main hydrogen supply is still based on fossil fuels and only limited amounts of electrolyzers have been installed. Switching from fossil-based fuel sources to green hydrogen is highly dependent on when and at what price green hydrogen will become available which in turn is dependent on the technological development of electrolyzers. In this paper we apply the experience curve methodology to project the capital expenditure and electrical consumption developments of the three main electrolysis technologies: alkaline proton exchange membrane and solid oxide electrolysis. Based on our calculations we expect that both AEL and PEM will reach similar costs by 2030 of around 300 e per kW and SOEC will remain the most expensive technology with a considerable cost reduction down to 828 e per kW. The electrical consumptions will fall to 4.23 kWh per Nm3 for AEL 3.86 kWh per Nm3 for PEM and 3.05 kWh per Nm3 for SOEC. Based on this technological progress we calculate that the levelized cost of hydrogen will be reduced to 2.43–3.07 e per kg. To reach lower levelized cost of hydrogen notable reductions in electricity (purchase) cost are required.
Simulations of Blast Wave and Fireball Occurring due to Rupture oj High-Pressure Hydrogen Tank
Jun 2017
Publication
In the present study pilot simulations of the phenomena of blast wave and fireball generated by the rupture of a high-pressure (35 MPa) hydrogen tank (volume 72 L) due to fire were carried out. The computational fluid dynamics (CFD) model includes the realizable k-ε model for turbulence and the eddy dissipation model coupled with the one-step chemical reaction mechanism for combustion. The simulation results were compared with experimental data on a stand-alone hydrogen tank rupture in a bonfire test. The simulations provided insights into the interaction between the blast wave propagation and combustion process. The simulated blast wave decay is approximately identical to the experimental data concerning pressure at various distances. Fireball is first ignited at the ground level which is considered to be due to stagnation flow conditions. Subsequently the flame propagates toward the interface between hydrogen and air.
Experimental Study on the Effect of the Ignition Location on Vented Deflagration of Hydrogen-air Mixtures in Enclosure
Sep 2023
Publication
No countermeasures exist for accidents that might occur in hydrogen-based facilities (leaks fires explosions etc.). In South Korea discussions are underway regarding measures to ensure safety from such accidents such as the construction of underground hydrogen storage tank facilities. However explosion vents with a minimum ventilation area are required in such facilities to minimize damage to buildings and other structures due to accidental explosions. These explosion vents allow the generated overpressure and flames to be safely dispersed outside; however a safe separation distance must be secured to minimize damage to humans. This study aimed to determine the safe separation distance to minimize human damage after analyzing the dispersed overpressure and flame behavior following a vent explosion. Explosion experiments were conducted to investigate the influence of the ignition source location on internal and external overpressure and external flame behavior using a cuboid concrete structure with a volume of 20.33 m3 filled with a hydrogen-air mixture (29.0 vol.%). The impact on overpressure and flame was increased with the increasing distance of the ignition source from the vent. Importantly depending on the ignition location the incident pressure was up to 24.4 times higher while the reflected pressure was 8.7 times higher. Additionally a maximum external overpressure of 30.01 kPa was measured at a distance of 2.4 m from the vent predicting damage to humans at the “Injury” level (1 % fatality probability). Whereas no significant damage would occur at a distance of 7.4 m or more from the vent.
Green Hydrogen Techno-economic Assessments from Simulated and Measured Solar Photovoltaic Power Profiles
Nov 2024
Publication
Studies estimating the production cost of hydrogen-based fuels known as e-fuels often use renewable power profile time series obtained from open-source simulation tools that rely on meteorological reanalysis and satellite data such as Renewables.ninja or PVGIS. These simulated time series contain errors compared to real on-site measured data which are reflected in e-fuels cost estimates plant design and operational performance increasing the risk of inaccurate plant design and business models. Focusing on solar-powered e-fuels this study aims to quantify these errors using high-quality on-site power production data. A state-of-the-art optimization techno-economic model was used to estimate e-fuel production costs by utilizing either simulated or high-quality measured PV power profiles across four sites with different climates. The results indicate that in cloudy climates relying on simulated data instead of measured data can lead to an underestimation of the fuel production costs by 36 % for a hydrogen user requiring a constant supply considering an original error of 1.2 % in the annual average capacity factor. The cost underestimation can reach 25 % for a hydrogen user operating between 40 % and 100 % load and 17.5 % for a fully flexible user. For comparison cost differences around 20 % could also result from increasing the electrolyser or PV plant costs by around 55 % which highlights the importance of using high-quality renewable power profiles. To support this an open-source collaborative repository was developed to facilitate the sharing of measured renewable power profiles and provide tools for both time series analysis and green hydrogen techno-economic assessments.
A Prospective Approach to the Optimal Deployment of a Hydrogen Supply Chain for Sustainable Mobility in Island Territories: Application to Corsica
Oct 2024
Publication
This study develops a framework for designing hydrogen supply chains (HSC) in island territories using Mixed Integer Linear Programming (MILP) with a multi-period approach. The framework minimizes system costs greenhouse gas emissions and a risk-based index. Corsica is used as a case study with a Geographic Information System (GIS) identifying hydrogen demand regions and potential sites for production storage and distribution. The results provide an optimal HSC configuration for 2050 specifying the size location and technology while accounting for techno-economic factors. This work integrates the unique geographical characteristics of islands using a GIS-based approach incorporates technology readiness levels and utilizes renewable electricity from neighboring regions. The model proposes decentralized configurations that avoid hydrogen transport between grids achieving a levelized cost of hydrogen (LCOH) of €8.54/kg. This approach offers insight into future options and incentive mechanisms to support the development of hydrogen economies in isolated territories.
Deflagration-to-detonation Transition Due to a Pressurised Release of a Hydrogen Jet. First Results of the Ongoing TAU_NRCN-CEA Project
Sep 2023
Publication
A sudden release of compressed gases and the formation of a jet flow can occur in nature and various engineering applications. In particular high-pressure hydrogen jets can spontaneously ignite when released into an environment that contains oxygen. For some scenarios these high-pressure hydrogen jets can be released into a mixture containing hydrogen and oxygen. This scenario can possibly lead to a wide range of combustion regimes such as jet flames slow or fast deflagrations or even hazardous detonations. Each combustion regime is characterized by typical pressures and temperatures however fast transition between regimes is also possible.<br/>A common project between Tel Aviv University (TAU) Nuclear Research Center Negev (NRCN) and Commissariat à l’Energie Atomique et aux énergies alternatives (CEA) has been recently launched in order to understand these phenomena from experimental modelling and numerical points of view. The main goal is to investigate the dynamics and combustion regimes that arise once a pressurized hydrogen jet is released into a reactive environment that contains inhomogeneous concentrations of hydrogen steam and air.<br/>In this paper we present the first numerical results describing high-pressure hydrogen release obtained using a massively parallel compressible structured-grid flow solver. The experimental arrangements devoted to this phenomenon will also be described.
The Potential for the Use of Hydrogen Storage in Energy Cooperatives
Oct 2024
Publication
According to the European Hydrogen Strategy hydrogen will solve many of the problems with energy storage for balancing variable renewable energy sources (RES) supply and demand. At the same time we can see increasing popularity of the so-called energy communities (e.g. cooperatives) which (i) enable groups of entities to invest in manage and benefit from shared RES energy infrastructure; (ii) are expected to increase the energy independence of local communities from large energy corporations and increase the share of RES. Analyses were conducted on 2000 randomly selected energy cooperatives and four energy cooperatives formed on the basis of actual data. The hypotheses assumed in the research and positively verified in this paper are as follows: (i) there is a relationship between hydrogen storage capacity and the power of RES which allows an energy community to build energy independence; (ii) the type of RES generating source is meaningful when optimizing hydrogen storage capacity. The paper proves it is possible to build “island energy independence” at the local level using hydrogen storage and the efficiency of the power-to-power chain. The results presented are based on simulations carried out using a dedicated optimization model implemented by mixed integer programming. The authors’ next research projects will focus on optimizing capital expenditures and operating costs using the Levelized Cost of Electricity and Levelized Cost of Hydrogen methodologies.
Experimental Study of the Mitigation of Hydrogen-Air Explosions by Aqueous Foam
Sep 2023
Publication
The development of hydrogen production technologies as well as new uses represents an opportunity both to accelerate the ecological transition and to create an industrial sector. However the risks associated with the use of hydrogen must not be overlooked. The mitigation of a hydrogen explosion in an enclosure is partly based on prevention strategies such as detection and ventilation but also on protection strategies such as explosion venting. However in several situations such as in highly constrained urban environments the discharge of the explosion through blast walls could generate significant overpressure effects outside the containment which are unacceptable. Thus having alternative mitigation solutions can make the effects of the explosion acceptable by reducing the flame speed and the overpressure loading or suppressing the secondary explosion. The objective of this paper is to present the experimental study of the mitigation of hydrogen-air deflagration in a 4 m3 vented enclosure by injection of aqueous foam. After a description of the experimental set-up the main experimental results are presented showing the influence of aqueous foam on flame propagation (Fig. 1). Different foam expansion ratios were investigated. An interpretation of the mitigating effect of foam on the explosion effects is proposed based on the work of Kichatov [5] and Zamashchikov [2].
The Technopolitics of Hydrogen: Arab Gulf States' Pursuit of Significance in a Climate-Constrained World
Nov 2024
Publication
Despite uncertainties surrounding the hydrogen economy’s emergence in terms of technological innovation production storage and transport policy and regulation economic viability and environmental impact coun tries worldwide actively pursue initiatives to engage in this critical energy transition. Politicians analysts and global experts see ‘clean’ hydrogen as the ultimate solution for addressing the climate crisis. This optimism is shared by several major oil and gas-exporting nations which are investing heavily in hydrogen infrastructure to establish themselves as future global hubs. Oman Saudi Arabia and the United Arab Emirates (UAE) are especially well-positioned benefiting from strategic advantages over other hydrogen-producing regions in the Global South. Advocates in these countries view hydrogen as a potential ‘silver bullet’ for sustaining political and economic influence in a world increasingly shaped by climate constraints. Western technology and expertise play a significant role in supporting these efforts. By using various qualitative methods this paper employs and expand the concept of technopolitics to evaluate the role of industrialized nations in endorsing the Gulf states’ authoritarian top-down techno-optimistic approach to their sustainability agenda.
How Would Structural Change in Electricity and Hydrogen End Use Impact Low-Carbon Transition of an Energy System? A Case Study of China
Feb 2024
Publication
Driven by global targets to reduce greenhouse gas emissions energy systems are expected to undergo fundamental changes. In light of carbon neutrality policies China is expected to significantly increase the proportion of hydrogen and electricity in its energy system in the future. Nevertheless the future trajectory remains shrouded in uncertainty. To explore the potential ramifications of varying growth scenarios pertaining to hydrogen and electricity on the energy landscape this study employs a meticulously designed bottom-up model. Through comprehensive scenario calculations the research aims to unravel the implications of such expansions and provide a nuanced analysis of their effects on the energy system. Results show that with an increase in electrification rates cumulative carbon dioxide emissions over a certain planning horizon could be reduced at the price of increased unit reduction costs. By increasing the share of end-use electricity and hydrogen from 71% to 80% in 2060 the unit carbon reduction cost will rise by 17%. Increasing shares of hydrogen could shorten the carbon emission peak time by approximately five years but it also brings an increase in peak shaving demand.
Synergy-based Hydrogen Pricing in Hydrogen-Integrated Electric Power System: Sensititivy Analysis
Nov 2024
Publication
Hydrogen price significantly impacts its potential as a viable alternative in the sustainable energy transition. This study introduces a synergy-based Hydrogen Pricing Mechanism (HPM) within an integrated framework. The HPM leverages synergy between a Renewable-Penetrated Electric Power System (RP-EPS) and a Hydrogen Energy System (HES). Utilizing the Alternating Direction Method of Multipliers (ADMM) it facilitates data exchange quantifying integration levels and simplifying the complexities. The study assesses the HPM’s operational sensitivity across various scenarios of hydrogen generation transportation and storage. It also evaluates the benefits of synergy-based versus stand-alone HPMs. Findings indicate that the synergy-based HPM effectively integrates infrastructure and operational improvements from both EPS and HES leading to optimized hydrogen pricing.
A Hydrogen Vision for the UK
Apr 2023
Publication
This report shows how the infrastructure that exists today can evolve from one based on the supply of fossil fuels to one providing the backbone of a clean hydrogen system. The ambitious government hydrogen targets across the UK will only be met with clarity focus and partnership. The gas networks are ready to play their part in the UK’s energy future. They have a plan know what is needed to deliver it and are taking the necessary steps to do just that.
SSEXHY Experimental Results on Pressure Dynamics from Head-on Reflections of Hydrogen Flames
Sep 2023
Publication
In the past few years CEA has been fully involved at both experimental and modeling levels in projects related to hydrogen safety in nuclear and chemical industries and has carried out a test program using the experimental bench SSEXHY (Structure Submitted to an EXplosion of HYdrogen) in order to build a database of the deformations of simple structures following an internal hydrogen explosion. Different propagation regimes of explosions were studied varying from detonations to slow deflagrations.<br/>During the experimental campaign it was found that high-speed deflagrations corresponding to relatively poor hydrogen-air mixtures resulted in higher specimen deformation compared to those related to detonations of nearly stoichiometric mixtures. This paper explains this counter-intuitive result from qualitative and quantitative points of view. It is shown that the overpressure and impulse from head-on reflections of hydrogen flames corresponding to poor mixtures of specific concentrations could have very high values at the tube end.
Towards a Resilience Evaluation Framework for Hydrogen Supply Chains: A Systematic Literature Review and Future Research Agenda
Dec 2024
Publication
Hydrogen energy is crucial for achieving net zero targets making the resilience of hydrogen supply chains (HSCs) increasingly important. Understanding current research on HSC resilience is key to enhancing it. Few studies summarise HSC resilience evaluation methods and link them to the general supply chain resilience and complex adaptive system (CAS) evaluation approaches. This study addresses this gap by systematically reviewing the literature on HSC resilience evaluations defining HSC resilience and conducting content analysis. It proposes a conceptual framework integrating technical operational and organisational perspectives. Each perspective is further subdivided based on the course of events resulting in a system-based HSC resilience evaluation frame work with three layers of analysis. By linking HSC indicators with CAS theory and supply chain performance metrics the study offers novel insights into HSC resilience evaluations identifies research gaps provides prac tical guidance for practitioners and outlines future research directions for advancing HSC resilience understanding.
Industrial Waste Gases as a Resource for Sustainable Hydrogen Production: Resource Availability, Production Potential, Challenges, and Prospects
May 2024
Publication
Industrial sectors pivotal for the economic prosperity of nations rely heavily on affordable reliable and environmentally friendly energy sources. Industries like iron and steel oil refineries and coal-fired power plants while instrumental to national economies are also the most significant contributors to waste gases that contain substantial volumes of carbon monoxide (CO). CO can be converted to a highly efficient and carbon free fuel hydrogen (H2) through a well-known water gas shift reaction. However the untapped potential of H2 from waste industrial streams is yet to be explored. This is the first article that investigates the potential of H2 production from industrial waste gases. The available resource (i.e. CO) and its H2 production potential are estimated. The article also provides insights into the principal challenges and potential avenues for long-term adoption. The results showed that 249.14 MTPY of CO are available to produce 17.44 MTPY of H2 annually. This suggests a significant potential for H2 production from waste gases to revolutionize industrial waste management and contribute significantly towards Sustainable Development Goals 7 9 and 13ensuring access to affordable reliable sustainable and modern energy for all and taking decisive climate action respectively.
Towards a Multi-color Hydrogen Production Network? Competing Imaginaries of Development in Northern Patagonia, Argentina
Feb 2024
Publication
Green hydrogen has recently gained importance as a key element in the transition to a low-carbon energy future sparking a boom in possible production regions. This article aims at situating incipient hydrogen production in the Argentine province of Río Negro within a global production network (GPN). The early configuration of the hydrogen-GPN includes several stakeholders and is contested in many ways. To explore the possible materialization of the hydrogen economy in Argentina this article links GPN literature to the concept of sociotechnical imaginaries. In so doing this study finds three energy imaginaries linked to hydrogen development: First advocates of green hydrogen (GH2) project a sociotechnical imaginary in which GH2 is expected to promote scientific and technological progress. Second proponents of blue hydrogen point to Vaca Muerta and the role of natural gas for energy autonomy. Third opponents of the GH2 project question the underlying growth and export model emphasizing conservation and domestic energy sovereignty. The competition between different capital fractions i.e. green and fossil currently poses the risk of pro-fossil path decisions and lock-in effects. Current power constellations have led to the replacement of green with low-emission resulting in the promotion of multi-colored hydrogen. This is particularly evident in the draft for the new national hydrogen law and the actors involved in defining the national hydrogen strategy. The conceptual combination of actors and their interests their current power relations and the sociotechnical imaginaries they deploy illustrates how Argentina's energy future is already being shaped today.
Profitability Model of Green Hydrogen Production on an Existing Wind Power Plant Location
Feb 2024
Publication
This paper presents a new economic profitability model for a power-to-gas plant producing green hydrogen at the site of an existing wind power plant injected into the gas grid. The model is based on a 42 MW wind power plant for which an optimal electrolyzer of 10 MW was calculated based on the 2500 equivalent full load hours per year and the projection of electricity prices. The model is calculated on an hourly level for all variables of the 25 years of the model. With the calculated breakeven electricity price of 74.23 EUR/MWh and the price of green hydrogen production of 99.44 EUR/MWh in 2045 the wind power plant would produce 22410 MWh of green hydrogen from 31% of its total electricity production. Green hydrogen injected into the gas system would reduce the level of CO2 emissions by 4482 tons. However with the projected prices of natural gas and electricity the wind power plant would cover only 20% of the income generated by the electricity delivered to the grid by producing green hydrogen. By calculating different scenarios in the model the authors concluded that the introduction of a premium subsidy model is necessary to accelerate deployment of electrolyzers at the site of an existing wind power plant in order to increase the wind farm profitability.
Hydrogen Production from Municipal Waste and Low Grade Lignite Blend
Nov 2024
Publication
The updraft rotating bed gasifier (URBG) offers a sustainable solution for waste-to-energy conversion utilizing low-grade lignite and municipal solid waste (MSW) from metropolitan dumping sites. This study investigates the co-gasification of lignite with various MSW components demonstrating a significant enhancement in gasification efficiency due to the synergistic effects arising from their higher hydrogen-to-carbon (H/C) ratios. We find feedstock blending is key to maximizing gasification efficiency from 11% to 52% while reducing SO emissions from 739 mg/kg to 155 mg/kg. Increasing the combustion zone temperature to 1100 K resulted in a peak hydrogen yield which was 19% higher than at 800 K. However steam management is complicated as increasing it improves hydrogen fraction in produced gas but gasification efficiency is compromised. These findingsshowcase the URBG’s potential to address both energy production and waste management challenges guiding fossil-reliant regions toward a more sustainable energy future.
Numerical Simulation of Transition to Detonation in a Hydrogen-air Mixture Due to Shock Wave Focusing on a 90-Deg Wedge
Sep 2023
Publication
The interaction of a shock wave with a specific angle or concave wall due to its reflection and focusing is a way to onset the detonation provided sufficiently strong shock wave. In this work we present numerical simulation results of the detonation initiation due to the shock reflection and focusing in a 90-degree wedge for mixtures of H2 and air. The code used was ddtFoam [1–3] that is a component of the larger OpenFOAM open-source CFD package of density-based code for solving the unsteady compressible Navier-Stokes equations. The numerical model represents the 2-D geometry of the experiments performed by Rudy [4]. The numerical results revealed three potential scenarios in the corner after reflection: shock wave reflection without ignition deflagrative ignition with intermediate transient regimes with a delayed transition to detonation in lagging combustion zone at around 1.8 mm from the apex of the wedge and ignition with an instantaneous transition to detonation with the formation of the detonation wave in the corner tip. In the experimental investigation the transition velocity for the stoichiometric mixture was approximately 715 m/s while in the numerical simulation the transition velocity for the stoichiometric mixture was 675.65 m/s 5.5% decrease in velocity.
Study on the Application of a Multi-Energy Complementary Distributed Energy System Integrating Waste Heat and Surplus Electricity for Hydrogen Production
Feb 2024
Publication
To improve the recovery of waste heat and avoid the problem of abandoning wind and solar energy a multi-energy complementary distributed energy system (MECDES) is proposed integrating waste heat and surplus electricity for hydrogen storage. The system comprises a combined cooling heating and power (CCHP) system with a gas engine (GE) solar and wind power generation and miniaturized natural gas hydrogen production equipment (MNGHPE). In this novel system the GE’s waste heat is recycled as water vapor for hydrogen production in the waste heat boiler while surplus electricity from renewable sources powers the MNGHPE. A mathematical model was developed to simulate hydrogen production in three building types: offices hotels and hospitals. Simulation results demonstrate the system’s ability to store waste heat and surplus electricity as hydrogen thereby providing economic benefit energy savings and carbon reduction. Compared with traditional energy supply methods the integrated system achieves maximum energy savings and carbon emission reduction in office buildings with an annual primary energy reduction rate of 49.42–85.10% and an annual carbon emission reduction rate of 34.88–47.00%. The hydrogen production’s profit rate is approximately 70%. If the produced hydrogen is supplied to building through a hydrogen fuel cell the primary energy reduction rate is further decreased by 2.86–3.04% and the carbon emission reduction rate is further decreased by 12.67–14.26%. This research solves the problem of waste heat and surplus energy in MECDESs by the method of hydrogen storage and system integration. The economic benefits energy savings and carbon reduction effects of different building types and different energy allocation scenarios were compared as well as the profitability of hydrogen production and the factors affecting it. This has a positive technical guidance role for the practical application of MECDESs.
Optimizing Sustainable Energy Systems: A Comparative Study of Geothermal-powered Desalination for Green Hydrogen Production
Oct 2024
Publication
The synergy between hydrogen and water is crucial in moving towards a sustainable energy future. This study explores the integration of geothermal energy with desalination and hydrogen production systems to address water and clean energy demands. Two configurations one using multi-effect distillation (MED) and the other reverse osmosis (RO) were designed and compared. Both configurations utilized geothermal energy with MED directly using geothermal heat and RO converting geothermal energy into electricity to power desalination. The systems are evaluated based on various performance indicators including net power output desalinated water production hydrogen production exergy efficiency and levelized costs. Multi-objective optimization using an artificial neural network (ANN) and genetic algorithm (GA) was conducted to identify optimal operational conditions. Results highlighted that the RO-based system demonstrated higher water production efficiency achieving a broader range of optimal solutions and lower levelized costs of water (LCOW) and hydrogen production while the MED-based system offered economic advantages under specific conditions. A case study focused on Canada illustrated the potential benefits of these systems in supporting hydrogen-powered vehicles and residential water needs emphasizing the significant impact of using high-quality desalinated water to enhance the longevity and efficiency of proton exchange membrane electrolyzers (PEME). This research provides valuable insights into the optimal use of geothermal energy for sustainable water and hydrogen production.
Hydrogen Engine Conversion Aspects
Oct 2024
Publication
The transition from traditional petrol-based combustion engines to hydrogen-powered systems represents a promising advancement in sustainable and clean energy solutions. This review paper explores the intricacies of converting a conventional internal combustion engine to operate on hydrogen gas. Key topics include the performance limitations of hydrogen engines the role of water injection in combustion modulation and the investigation of direct injection and port injection systems. This review also examines challenges associated with lean and rich mixtures risks of backfire and pre-ignition and the conversion’s overall impact on engine performance and longevity. Additionally this paper discusses hydrogen lubrication to prevent mechanical wear and addresses emission-related considerations.
The Integration of Thermal Energy Storage Within Metal Hydride Systems: A Comprehensive Review
Dec 2024
Publication
Hydrogen storage technologies are key enablers for the development of low-emission sustainable energy supply chains primarily due to the versatility of hydrogen as a clean energy carrier. Hydrogen can be utilized in both stationary and mobile power applications and as a lowenvironmental-impact energy source for various industrial sectors provided it is produced from renewable resources. However efficient hydrogen storage remains a significant technical challenge. Conventional storage methods such as compressed and liquefied hydrogen suffer from energy losses and limited gravimetric and volumetric energy densities highlighting the need for innovative storage solutions. One promising approach is hydrogen storage in metal hydrides which offers advantages such as high storage capacities and flexibility in the temperature and pressure conditions required for hydrogen uptake and release depending on the chosen material. However these systems necessitate the careful management of the heat generated and absorbed during hydrogen absorption and desorption processes. Thermal energy storage (TES) systems provide a means to enhance the energy efficiency and cost-effectiveness of metal hydride-based storage by effectively coupling thermal management with hydrogen storage processes. This review introduces metal hydride materials for hydrogen storage focusing on their thermophysical thermodynamic and kinetic properties. Additionally it explores TES materials including sensible latent and thermochemical energy storage options with emphasis on those that operate at temperatures compatible with widely studied hydride systems. A detailed analysis of notable metal hydride–TES coupled systems from the literature is provided. Finally the review assesses potential future developments in the field offering guidance for researchers and engineers in advancing innovative and efficient hydrogen energy systems.
Multi-Physics Digital Model of an Aluminum 2219 Liquid Hydrogen Aircraft Tank
Feb 2024
Publication
Future liquid hydrogen-powered aircraft requires the design and optimization of a large number of systems and subsystems with cryogenic tanks being one of the largest and most critical. Considering previous space applications these tanks are usually stiffened by internal members such as stringers frames and stiffeners resulting in a complex geometry that leads to an eventual reduction in weight. Cryogenic tanks experience a variety of mechanical and thermal loading conditions and are usually constructed out of several different materials. The complexity of the geometry and the loads highlights the necessity for a computational tool in order to conduct analysis. In this direction the present work describes the development of a multi-physics finite element digital simulation conducting heat transfer and structural analysis in a fully parametric manner in order to be able to support the investigation of different design concepts materials geometries etc. The capabilities of the developed model are demonstrated by the design process of an independent-type aluminum 2219 cryogenic tank for commuter aircraft applications. The designed tank indicates a potential maximum take-off weight reduction of about 8% for the commuter category and demonstrates that aluminum alloys are serious candidate materials for future aircraft.
Hydrogen Storage Performance During Underground Hydrogen Storage in Depleted Gas Reservoirs: A Review
Mar 2024
Publication
Hydrogen has emerged as a promising alternative to meet the growing demand for sustainable and renewable energy sources. Underground hydrogen storage (UHS) in depleted gas reservoirs holds significant potential for large-scale energy storage and the seamless integration of intermittent renewable energy sources due to its capacity to address challenges associated with the intermittent nature of renewable energy sources ensuring a steady and reliable energy supply. Leveraging the existing infrastructure and well-characterized geological formations depleted gas reservoirs offer an attractive option for large-scale hydrogen storage implementation. However significant knowledge gaps regarding storage performance hinder the commercialization of UHS operation. Hydrogen deliverability hydrogen trapping and the equation of state are key areas with limited understanding. This literature review critically analyzes and synthesizes existing research on hydrogen storage performance during underground storage in depleted gas reservoirs; it then provides a high-level risk assessment and an overview of the techno-economics of UHS. The significance of this review lies in its consolidation of current knowledge highlighting unresolved issues and proposing areas for future research. Addressing these gaps will advance hydrogen-based energy systems and support the transition to a sustainable energy landscape. Facilitating efficient and safe deployment of UHS in depleted gas reservoirs will assist in unlocking hydrogen’s full potential as a clean and renewable energy carrier. In addition this review aids policymakers and the scientific community in making informed decisions regarding hydrogen storage technologies.
A Comprehensive Overview of Technologies Applied in Hydrogen Valleys
Dec 2024
Publication
Hydrogen valleys are encompassed within a defined geographical region with various technologies across the entire hydrogen value chain. The scope of this study is to analyze and assess the different hydrogen technologies for their application within the hydrogen valley context. Emphasizing on the coupling of renewable energy sources with electrolyzers to produce green hydrogen this study is focused on the most prominent electrolysis technologies including alkaline proton exchange membrane and solid oxide electrolysis. Moreover challenges related to hydrogen storage are explored alongside discussions on physical and chemical storage methods such as gaseous or liquid storage methanol ammonia and liquid organic hydrogen carriers. This article also addresses the distribution of hydrogen within valley operations especially regarding the current status on pipeline and truck transportation methods. Furthermore the diverse applications of hydrogen in the mobility industrial and energy sectors are presented showcasing its potential to integrate renewable energy into hard-to-abate sectors.
Economic Analysis of Hydrogen Energy Systems: A Global Perspective
Aug 2024
Publication
In the realm of renewable energy the integration of wind power and hydrogen energy systems represents a promising avenue towards environmental sustainability. However the development of cost-effective hydrogen energy storage solutions is crucial to fully realize the potential of hydrogen as a renewable energy source. By combining wind power generation with hydrogen storage a comprehensive hydrogen energy system can be established. This study aims to devise a physiologically inspired optimization approach for designing a standalone wind power producer that incorporates a hydrogen energy system on a global scale. The optimization process considers both total cost and capacity loss to determine the optimal configuration for the system. The optimal setup for an off-grid solution involves the utilization of eight distinct types of compact horizontal-axis wind turbines. Additionally a sensitivity analysis is conducted by varying component capital costs to assess their impact on overall cost and load loss. Simulation results indicate that at a 15% loss the cost of energy (COE) is $1.3772 while at 0% loss it stands at $1.6908. Capital expenses associated with wind turbines and hydrogen storage systems significantly contribute to the overall cost. Consequently the wind turbine-hydrogen storage system emerges as the most cost-effective and reliable option due to its low cost of energy.
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