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Assessment of the Co-combustion Process of Ammonia with Hydrogen in a Research VCR Piston Engine
Oct 2022
Publication
The presented work concerns experimental research of a spark-ignition engine with variable compression ratio (VCR) adapted to dual-fuel operation in which co-combustion of ammonia with hydrogen was conducted and the energy share of hydrogen varied from 0% to 70%. The research was aimed at assessing the impact of the energy share of hydrogen co-combusted with ammonia on the performance stability and emissions of an engine operating at a compression ratio of 8 (CR 8) and 10 (CR 10). The operation of the engine powered by ammonia alone for both CR 8 and CR 10 is associated with either a complete lack of ignition in a significant number of cycles or with significantly delayed ignition and the related low value of the maximum pressure pmax. Increasing the energy share of hydrogen in the fuel to 12% allows to completely eliminate the instability of the ignition process in the combustible mixture which is confirmed by a decrease in the IMEP uniqueness and a much lower pmax dispersion. For 12% of the energy share of hydrogen co-combusted with ammonia the most favorable course of the combustion process was obtained the highest engine efficiency and the highest IMEP value were recorded. The conducted research shows that increasing the H2 share causes an increase in NO emissions for both analyzed compression ratios
Lessons Learned and Recommendations from Analysis of Hydrogen Incidents and Accidents to Support Risk Assessment for the Hydrogen Economy
Feb 2024
Publication
This study addresses challenges associated with hydrogen’s physio-chemical characteristics and the need for safety and public acceptance as a precursor to the emerging hydrogen economy. It highlights the gap in existing literature regarding lessons learned from events in the green hydrogen production value chain. The study aims to use the documented lessons learned from previous hydrogen-related events to assist in enhancing safety measures and to guide stakeholders on how to avoid and mitigate future hydrogen-related events. Given the potential catastrophic consequences robust safety systems are essential for hydrogen economy development. The work underscores the importance of human and operational factors as root causes of these events. The paper recommends establishing a specialized hydrogen-related event database to support risk assessment and risk mitigation thus catering to the growing hydrogen industry’s needs and facilitating quick access to critical information for stakeholders in the private and public sectors.
Adaptive Network Fuzzy Inference System and Particle Swarm Optimization of Biohydrogen Production Process
Sep 2022
Publication
Green hydrogen is considered to be one of the best candidates for fossil fuels in the near future. Bio-hydrogen production from the dark fermentation of organic materials including organic wastes is one of the most cost-effective and promising methods for hydrogen production. One of the main challenges posed by this method is the low production rate. Therefore optimizing the operating parameters such as the initial pH value operating temperature N/C ratio and organic concentration (xylose) plays a significant role in determining the hydrogen production rate. The experimental optimization of such parameters is complex expensive and lengthy. The present research used an experimental data asset adaptive network fuzzy inference system (ANFIS) modeling and particle swarm optimization to model and optimize hydrogen production. The coupling between ANFIS and PSO demonstrated a robust effect which was evident through the improvement in the hydrogen production based on the four input parameters. The results were compared with the experimental and RSM optimization models. The proposed method demonstrated an increase in the biohydrogen production of 100 mL/L compared to the experimental results and a 200 mL/L increase compared to the results obtained using ANOVA.
Modern Hydrogen Technologies in the Face of Climate Change—Analysis of Strategy and Development in Polish Conditions
Aug 2023
Publication
The energy production market based on hydrogen technologies is an innovative solution that will allow the industry to achieve climate neutrality in the future in Poland and in the world. The paper presents the idea of using hydrogen as a modern energy carrier and devices that in cooperation with renewable energy sources produce the so-called green hydrogen and the applicable legal acts that allow for the implementation of the new technology were analyzed. Energy transformation is inevitable and according to reports on good practices in European Union countries hydrogen and the hydrogen value chain (production transport and transmission storage use in transport and energy) have wide potential. Thanks to joint projects and subsidies from the EU initiatives supporting hydrogen technologies are created such as hydrogen clusters and hydrogen valleys and EU and national strategic programs set the main goals. Poland is one of the leaders in hydrogen production both in the world and in Europe. Domestic tycoons from the energy refining and chemical industries are involved in the projects. Eight hydrogen valleys that have recently been created in Poland successfully implement the assumptions of the “Polish Hydrogen Strategy until 2030 with a perspective until 2040” and “Energy Policy of Poland until 2040” which are in line with the assumptions of the most important legal acts of the EU including the European Union’s energy and climate policy the Green Deal and the Fit for 55 Package. The review of the analysis of the development of hydrogen technologies in Poland shows that Poland does not differ from other European countries. As part of the assumptions of the European Hydrogen Strategy and the trend related to the management of energy surpluses electrolyzers with a capacity of at least 6 GW will be installed in Poland in 2020–2024. It is also assumed that in the next phase planned for 2025–2030 hydrogen will be a carrier in the energy system in Poland. Poland as a member of the EU is the creator of documents that take into account the assumptions of the European Union Commission and systematically implement the assumed goals. The strategy of activities supporting the development of hydrogen technologies in Poland and the value chain includes very extensive activities related to among others obtaining hydrogen using hydrogen in transport energy and industry developing human resources for the new economy supporting the activities of hydrogen valley stakeholders building hydrogen refueling stations and cooperation among Poland Slovakia and the Czech Republic as part of the HydrogenEagle project.
Numerical Analysis of Dual Fuel Combustion in a Medium Speed Marine Engine Supplied with Methane/Hydrogen Blends
Sep 2023
Publication
Compression ignition engines will still be predominant in the naval sector: their high efficiency high torque and heavy weight perfectly suit the demands and architecture of ships. Nevertheless recent emission legislations impose limitations to the pollutant emissions levels in this sector as well. In addition to post-treatment systems it is necessary to reduce some pollutant species and therefore the study of combustion strategies and new fuels can represent valid paths for limiting environmental harmful emissions such as CO2 . The use of methane in dual fuel mode has already been implemented on existent vessels but the progressive decarbonization will lead to the utilization of carbon-neutral or carbon-free fuels such as in the last case hydrogen. Thanks to its high reactivity nature it can be helpful in the reduction of exhaust CH4 . On the contrary together with the high temperatures achieved by its oxidation hydrogen could cause uncontrolled ignition of the premixed charge and high emissions of NOx. As a matter of fact a source of ignition is still necessary to have better control on the whole combustion development. To this end an optimal and specific injection strategy can help to overcome all the before-mentioned issues. In this study three-dimensional numerical simulations have been performed with the ANSYS Forte® software (version 19.2) in an 8.8 L dual fuel engine cylinder supplied with methane hydrogen or hydrogen–methane blends with reference to experimental tests from the literature. A new kinetic mechanism has been used for the description of diesel fuel surrogate oxidation with a set of reactions specifically addressed for the low temperatures together with the GRIMECH 3.0 for CH4 and H2 . This kinetics scheme allowed for the adequate reproduction of the ignition timing for the various mixtures used. Preliminary calculations with a one-dimensional commercial code were performed to retrieve the initial conditions of CFD calculations in the cylinder. The used approach demonstrated to be quite a reliable tool to predict the performance of a marine engine working under dual fuel mode with hydrogen-based blends at medium load. As a result the system modelling shows that using hydrogen as fuel in the engine can achieve the same performance as diesel/natural gas but when hydrogen totally replaces methane CO2 is decreased up to 54% at the expense of the increase of about 76% of NOx emissions.
Optimal Scheduling of Power Systems with High Proportions of Renewable Energy Accounting for Operational Flexibility
Jul 2023
Publication
Yi Lin,
Wei Lin,
Wei Wu and
Zhenshan Zhu
The volatility and uncertainty of high-penetration renewable energy pose significant challenges to the stability of the power system. Current research often fails to consider the insufficient system flexibility during real-time scheduling. To address this issue this paper proposes a flexibility scheduling method for high-penetration renewable energy power systems that considers flexibility index constraints. Firstly a quantification method for flexibility resources and demands is introduced. Then considering the constraint of the flexibility margin index optimization scheduling strategies for different time scales including day-ahead scheduling and intra-day scheduling are developed with the objective of minimizing total operational costs. The intra-day optimization is divided into 15 min and 1 min time scales to meet the flexibility requirements of different time scales in the power system. Finally through simulation studies the proposed strategy is validated to enhance the system’s flexibility and economic performance. The daily operating costs are reduced by 3.1% and the wind curtailment rate is reduced by 4.7%. The proposed strategy not only considers the economic efficiency of day-ahead scheduling but also ensures a sufficient margin to cope with the uncertainty of intra-day renewable energy fluctuations.
Capacity Configuration Optimization for Green Hydrogen Generation by Solar-wind Hybrid Power Based on Comprehensive Performance Criteria
Aug 2023
Publication
Green hydrogen generation driven by solar-wind hybrid power is a key strategy for obtaining the low-carbon energy while by considering the fluctuation natures of solar-wind energy resource the system capacity configuration of power generation hydrogen production and essential storage devices need to be comprehensively optimized. In this work a solar-wind hybrid green hydrogen production system is developed by combining the hydrogen storage equipment with the power grid the coordinated operation strategy of solar-wind hybrid hydrogen production is proposed furthermore the NSGA-III algorithm is used to optimize the system capacity configuration with the comprehensive performance criteria of economy environment and energy efficiency. Through the implemented case study with the hydrogen production capacity of 20000 tons/year the abandoned energy power rate will be reduced to 3.32% with the electrolytic cell average load factor of 64.77% and the system achieves the remarkable carbon emission reduction. In addition with the advantage of connect to the power grid the generated surplus solar/wind power can be readily transmitted with addition income when the sale price of produced hydrogen is suggested to 27.80 CNY/kgH2 the internal rate of return of the system reaches to 8% which present the reasonable economic potential. The research provides technical and methodological suggestions and guidance for the development of solar-wind hybrid hydrogen production schemes with favorable comprehensive performance.
Development of a Hydrogen Supplement for use with IGEM/SR/25
Nov 2022
Publication
In response to the UK Government’s commitment to achieve net-zero carbon emissions by 2050 a range of research and demonstration projects are underway to investigate the feasibility of using hydrogen in place of natural gas within the national transmission and distribution system. In order for these projects to achieve their full scope of work a mechanism for performing hazardous area classification for hydrogen installations is required. At present IGEM/SR/25 is used to undertake such assessments for natural gas installations but the standard is not currently applicable to hydrogen or hydrogen/natural gas blends.<br/>This report presents updated data and a summary of the recommended methodologies for hazardous area classification of installations using hydrogen or blends of up to 20% hydrogen in natural gas. The contents of this report are intended to provide a technical commentary and the data for a hydrogen-specific supplement to IGEM/SR/25. The supplement will specifically cover 100% hydrogen and a 20/80% by volume blend of hydrogen/natural gas. Reference to intermediate blends is included in this report where appropriate to cover the anticipated step-wise introduction of hydrogen into the natural gas network.<br/>This report is divided into a series of appendices each of which covers a specific area of the IGEM standard. Each appendix includes a summary of specific recommendations made to enable IGEM/SR/25 to be applied to hydrogen and blends of up to 20% hydrogen in natural gas. The reader is encouraged to review the individual appendices for specific conclusions associated with the topic areas addressed in this report.<br/>In general the existing methodologies and approaches used for area classification in IGEM/SR/25 have been deemed appropriate for installations using either hydrogen or blends of up to 20% hydrogen in natural gas. Where necessary revised versions of the equations and zoning distances used in the standard are presented which account for the influence of material property differences between natural gas and the two alternative fuels considered in this work.
Carbon-negative Hydrogen: Exploring the Techno-economic Potential of Biomass Co-gasification with CO2 Capture
Sep 2021
Publication
The hydrogen economy is receiving increasing attention as a complement to electrification in the global energy transition. Clean hydrogen production is often viewed as a competition between natural gas reforming with CO2 capture and electrolysis using renewable electricity. However solid fuel gasification with CO2 capture presents another viable alternative especially when considering the potential of biomass to achieve negative CO2 emissions. This study investigates the techno-economic potential of hydrogen production from large-scale coal/ biomass co-gasification plants with CO2 capture. With a CO2 price of 50 €/ton the benchmark plant using commercially available technologies achieved an attractive hydrogen production cost of 1.78 €/kg with higher CO2 prices leading to considerable cost reductions. Advanced configurations employing hot gas clean-up membrane-assisted water-gas shift and more efficient gasification with slurry vaporization and a chemical quench reduced the hydrogen production cost to 1.50–1.62 €/kg with up to 100% CO2 capture. Without contingencies added to the pre-commercial technologies the lowest cost reduces to 1.43 €/kg. It was also possible to recover waste heat in the form of hot water at 120 ◦C for district heating potentially unlocking further cost reductions to 1.24 €/kg. In conclusion gasification of locally available solid fuels should be seriously considered next to natural gas and electrolysis for supplying the emerging hydrogen economy.
Decarbonisation of Heat and the Role of ‘Green Gas’ in the United Kingdom
May 2018
Publication
This paper looks at the possible role of ‘green gas’ in the decarbonisation of heat in the United Kingdom. The option is under active discussion at the moment because of the UK’s rigorous carbon reduction targets and the growing realisation that there are problems with the ‘default’ option of electrifying heat. Green gas appears to be technically and economically feasible. However as the paper discusses there are major practical and policy obstacles which make it unlikely that the government will commit itself to developing ‘green gas’ in the foreseeable future.
Green Hydrogen Production: Integrating Environmental and Social Criteria to Ensure Sustainability
Jul 2023
Publication
Hydrogen is experiencing an unprecedented global hype. Hydrogen is globally discussed as a possible future energy carrier and regarded as the urgently needed building block for the much needed carbon-neutral energy transition of hard-to-abate sectors to mitigate the effects of global warming. This article provides synthesised measurable sustainability criteria for analysing green hydrogen production proposals and strategies. Drawn from expert interviews and an extensive literature review this article proposes that a sustainable hydrogen production should consider six impact categories; Energy transition Environment Basic needs Socio-economy Electricity supply and Project planning. The categories are broken down into sixteen measurable sustainability criteria which are determined with related indicators. The article concludes that low economic costs can never be the only decisive criterion for the hydrogen production; social aspects must be integrated along the entire value chain. The compliance with the criteria may avoid social and ecological injustices in the planning of green hydrogen projects and increases inter alia the social welfare of the affected population.
Performance Evaluation of a Fuel Cell mCHP System under Different Configurations of Hydrogen Origin and Heat Recovery
Sep 2023
Publication
Motivated by the growing importance of fuel cell systems as the basis for distributed energy generation systems this work considers a micro-combined heat and power (mCHP) generation system based on a fuel cell integrated to satisfy the (power and thermal) energy demands of a residential application. The main objective of this work is to compare the performance of several CHP configurations with a conventional alternative in terms of primary energy consumption greenhouse gas (GHG) emissions and economic viability. For that a simulation tool has been developed to easily estimate the electrical and thermal energy generated by a hydrogen fuel cell and all associated results related to the hydrogen production alternatives: excess or shortfall of electrical and thermal energy CO2 emission factor overall performance operating costs payback period etc. A feasibility study of different configuration possibilities of the micro-CHP generation system has been carried out considering different heat-to-power ratios (HPRs) in the possible demands and analyzing primary energy savings CO2 emissions savings and operating costs. An extensive parametric study has been performed to analyze the effect of the fuel cell’s electric power and number of annual operation hours as parameters. Finally a study of the influence of the configuration parameters on the final results has been carried out. Results show that in general configurations using hydrogen produced from natural gas save more primary energy than configurations with hydrogen production from electricity. Furthermore it is concluded that the best operating points are those in which the generation system and the demand have similar HPR. It has also been estimated that a reduction in renewable hydrogen price is necessary to make these systems profitable. Finally it has been determined that the most influential parameters on the results are the fuel cell electrical efficiencies hydrogen production efficiency and hydrogen cost.
Can Hydrogen Storage in Metal Hydrides be Economically Competitive with Compressed and Liquid Hydrogen Storage? A Techno-economical Perspective for the Maritime Sector
Aug 2023
Publication
The aim of this work is to evaluate if metal hydride hydrogen storage tanks are a competitive alternative for onboard hydrogen storage in the maritime sector when compared to compressed gas and liquid hydrogen storage. This is done by modelling different hydrogen supply and onboard storage scenarios and evaluating their levelized cost of hydrogen variables. The levelized cost of hydrogen for each case is calculated considering the main components that are required for the refueling infrastructure and adding up the costs of hydrogen production compression transport onshore storage dispensing and the cost of the onboard tanks when known. The results show that the simpler refueling needs of metal hydride-based onboard tanks result in a significant cost reduction of the hydrogen handling equipment. This provides a substantial leeway for the investment costs of metal hydride-based storage which depending on the scenario can be between 3400 - 7300 EUR/kgH2 while remaining competitive with compressed hydrogen storage.
What Does the Public Know About Technological Solutions for Achieving Carbon Neutrality? Citizens' Knowledge of Energy Transition and the Role of Media
Aug 2023
Publication
The present study explores the relation between media use and knowledge in the context of the energy transition. To identify relevant knowledge categories we relied on the expertise of an interdisciplinary research team. Based on this expertise we identified awareness-knowledge of changes in the energy system and principles-knowledge of hydrogen as important knowledge categories. With data obtained from a nationwide online survey of the German-speaking population (n = 2025) conducted in August 2021 we examined the level of knowledge concerning both categories in the German population. Furthermore we studied its associations with exposure to journalistic media and direct communication from non-media actors (e.g. scientists). Our results revealed a considerable lack of knowledge for both categories. Considering the media variables we found only weak and in some cases even negative relations with the use of journalistic media or other actors that spread information online. However we found comparably strong associations between both knowledge categories and the control variables of sex education and personal interest. We use these results to open up a general discussion of the role of the media in knowledge acquisition processes.
Coupling Green Hydrogen Production to Community Benefits: A Pathway to Social Acceptance?
Feb 2024
Publication
Hydrogen energy technologies are forecasted to play a critical supporting role in global decarbonisation efforts as reflected by the growth of national hydrogen energy strategies in recent years. Notably the UK government published its Hydrogen Strategy in August 2021 to support decarbonisation targets and energy security ambitions. While establishing techno-economic feasibility for hydrogen energy systems is a prerequisite of the prospective transition social acceptability is also needed to support visions for the ‘hydrogen economy’. However to date societal factors are yet to be embedded into policy prescriptions. Securing social acceptance is especially critical in the context of ‘hydrogen homes’ which entails replacing natural gas boilers and hobs with low-carbon hydrogen appliances. Reflecting the nascency of hydrogen heating and cooking technologies the dynamics of social acceptance are yet to be explored in a comprehensive way. Similarly public perceptions of the hydrogen economy and emerging national strategies remain poorly understood. Given the paucity of conceptual and empirical insights this study develops an integrated acceptance framework and tests its predictive power using partial least squares structural equation modelling. Results highlight the importance of risk perceptions trust dynamics and emotions in shaping consumer perceptions. Foremost prospects for deploying hydrogen homes at scale may rest with coupling renewable-based hydrogen production to local environmental and socio-economic benefits. Policy prescriptions should embed societal factors into the technological pursuit of large-scale sustainable energy solutions to support socially acceptable transition pathways.
Application and Limitations of Batteries and Hydrogen in Heavy Haul Rail using Australian Case Studies
Oct 2022
Publication
Decarbonisation of heavy haul rail is an essential contributor to a zero-emissions future. However the transition from diesel to battery locomotives is not always practical given the unique characteristics of each haul. This paper demonstrates the limitations of state-of-the-art batteries using real-world data from multiple locomotives operating in Australian rail freight. An energy model was developed to assess each route’s required energy and potential regenerated energy. The tractive and regenerative battery energy mass and cost were determined using data from the energy model coupled with battery specifications. The feasibility of implementing lithium iron phosphate (LFP) nickel manganese cobalt (NMC) and lithium titanium oxide (LTO) chemistries was explored based on cost energy density cycle lifespan and locomotive data. LFP was identified as the most suitable current battery solution based on current chemistries. Further examination of the energy demands and associated mass/volume constraints concluded that three platforms are required for heavy haul rail decarbonisation i) a battery electric locomotive for low-energy demands which can be coupled with either ii) a battery electric tender for medium energy demands or iii) a hydrogen fuel cell electric tender for higher energy demands. A future-looking techno-economic assessment of battery and hydrogen fuel cell platforms concludes that the lowest cost solution for low-energy hauls is a battery-only system and for high-energy hauls a battery-hydrogen system.
Environmental and Material Criticality Assessment of Hydrogen Production via Anion Exchange Membrane Electrolysis
Oct 2023
Publication
The need to drastically reduce greenhouse gas emissions is driving the development of existing and new technologies to produce and use hydrogen. Anion exchange membrane electrolysis is one of these rapidly developing technologies and presents promising characteristics for efficient hydrogen production. However the environmental performance and the material criticality of anion exchange membrane electrolysis must be assessed. In this work prospective life cycle assessment and criticality assessment are applied first to identify environmental and material criticality hotspots within the production of anion exchange membrane electrolysis units and second to benchmark hydrogen production against proton exchange membrane electrolysis. From an environmental point of view the catalyst spraying process heavily dominates the ozone depletion impact category while the production of the membrane represents a hotspot in terms of the photochemical ozone formation potential. For the other categories the environmental impacts are distributed across different components. The comparison of hydrogen production via anion exchange membrane electrolysis and proton exchange membrane electrolysis shows that both technologies involve a similar life-cycle environmental profile due to similar efficiencies and the leading role of electricity generation for the operation of electrolysis. Despite the fact that for proton exchange membrane electrolysis much less material is required due to a higher lifetime anion exchange membrane electrolysis shows significantly lower raw material criticality since it does not rely on platinum-group metals. Overall a promising environmental and material criticality performance of anion exchange membrane electrolysis for hydrogen production is concluded subject to the expected technical progress for this technology.
Green Fleet: A Prototype Biogas and Hydrogen Refueling Management System for Private Fleet Stations
Aug 2023
Publication
Biogas and hydrogen (H2 ) are breaking through as alternative energy sources in road transport specifically for heavy-duty vehicles. Until a public network of service stations is deployed for such vehicles the owners of large fleets will need to build and manage their own refueling facilities. Fleet refueling management and remote monitoring at these sites will become key business needs. This article describes the construction of a prototype system capable of solving those needs. During the design and development process of the prototype the standard industry protocols involved in these installations have been considered and the latest expertise in information technology systems has been applied. This prototype has been essential to determine the Strengths Challenges Opportunities and Risks (SCOR) of such a system which is the first step of a more ambitious project. A second stage will involve setting up a pilot study and developing a commercial system that can be widely installed to provide a real solution for the industry.
An Overview of Application-orientated Multifunctional Large-scale Stationary Battery and Hydrogen Hybrid Energy Storage System
Dec 2023
Publication
The imperative to address traditional energy crises and environmental concerns has accelerated the need for energy structure transformation. However the variable nature of renewable energy poses challenges in meeting complex practical energy requirements. To address this issue the construction of a multifunctional large-scale stationary energy storage system is considered an effective solution. This paper critically examines the battery and hydrogen hybrid energy storage systems. Both technologies face limitations hindering them from fully meeting future energy storage needs such as large storage capacity in limited space frequent storage with rapid response and continuous storage without loss. Batteries with their rapid response (90%) excel in frequent short-duration energy storage. However limitations such as a selfdischarge rate (>1%) and capacity loss (~20%) restrict their use for long-duration energy storage. Hydrogen as a potential energy carrier is suitable for large-scale long-duration energy storage due to its high energy density steady state and low loss. Nevertheless it is less efficient for frequent energy storage due to its low storage efficiency (~50%). Ongoing research suggests that a battery and hydrogen hybrid energy storage system could combine the strengths of both technologies to meet the growing demand for large-scale long-duration energy storage. To assess their applied potentials this paper provides a detailed analysis of the research status of both energy storage technologies using proposed key performance indices. Additionally application-oriented future directions and challenges of the battery and hydrogen hybrid energy storage system are outlined from multiple perspectives offering guidance for the development of advanced energy storage systems.
A Review on Production and Implementation of Hydrogen as a Green Fuel in Internal Combustion Engines
Nov 2022
Publication
Huge and continuously growing non-renewable energy consumption due to human daily activities is accountable for the fossil fuel source crisis in recent decades. The growing concern about the emissions from internal combustion engines also impels the development of new energy sources to replace or reduce conventional non-renewable energy usage. In this context hydrogen is found to be a promising solution in internal combustion engines to address these issues. The novelty of this review is to provide an overview of the use of hydrogen as internal combustion fuel covering the operations in both spark-ignition (SI) and compression-ignition (CI) engines. Majority of the studies had shown that hydrogen enrichment fuels marked incredible engine performance in terms of thermal efficiency fuel consumption and energy consumption. In addition reductions in exhaust emissions such as smoke soot HC CO CO2 and NOx can be achieved in both SI and CI engines with proper operating conditions. Moreover outstanding combustion behaviours were observed in both internal combustion engines with the application of hydrogen fuel. These enhancements were mainly attributed to the physico-chemical properties of hydrogen which exhibits higher calorific value and rapid flaming speed as discussed in this paper. To summarize hydrogen utilisation in the IC and SI engines aided improvements in engine performance exhaust emissions and combustion behaviours under appropriate operating conditions and minor engine modifications such as ignition system and iridium spark plug for SI engines.
Lab-Scale Investigation of the Integrated Backup/Storage System for Wind Turbines Using Alkaline Electrolyzer
Apr 2023
Publication
The depletion of fossil fuel sources has encouraged the authorities to use renewable resources such as wind energy to generate electricity. A backup/storage system can improve the performance of wind turbines due to fluctuations in power demand. The novelty of this study is to utilize a hybrid system for a wind farm using the excess electricity generated by the wind turbines to produce hydrogen in an alkaline electrolyzer (AEL). The hydrogen storage tank stores the produced hydrogen and provides hydrogen to the proton-exchange membrane fuel cell (PEMFC) to generate electricity once the power demand is higher than the electricity generated by the wind turbines. The goal of this study is to use the wind profile of a region in Iran namely the Cohen region to analyze the performance of the suggested integrated system on a micro scale. The output results of this study can be used as a case study for construction in the future based on the exact specification of NTK300 wind turbines. The results indicate that with the minimum power supply of 30 kW from the wind turbines on a lab scale the generated power by the PEMFC will be 1008 W while the maximum generated hydrogen will be 304 mL/h.
Dynamic Quality Tracking of Natural Gas and Hydrogen Mixture in a Portion of Natural Gas Grid
Aug 2015
Publication
Direct injection of alternative fuels (biomethane hydrogen) in the natural gas grid appears to be a promising solution to reach environmental objectives of CO2 emission reduction in the current energy scenario. This approach is justified by the large amount of biogas producible which can be upgraded to biomethane; while another proposed solution to increase renewable energy sources exploitation lies in producing hydrogen from excess wind energy followed by injection in the natural gas grid. Nevertheless compliance with composition limits and quality constraints in the resulting natural gas mixture has to be analysed in both stationary and dynamic operations tracking the gas quality downstream the injection point of the alternative fuels. A model was developed to simulate unsteady operation of a portion of gas grid dealing with realistic industrial and residential consumptions concentrated in offtake points. Two case studies were investigated focusing on the comparison between different amounts of hydrogen injection in the pure natural gas flow yielding composition flow rate and pressure profiles. The analysis shows how imposed quality thresholds can be respected although the hydrogen fraction within the natural gas mixture is highly sensitive to the profile and size of the loads connected to the gas pipeline.
Enhancing Safety through Optimal Placement of Components in Hydrogen Tractor: Rollover Angle Analysis
Feb 2024
Publication
Hydrogen tractors are being developed necessitating consideration of the variation in the center of gravity depending on the arrangement of components such as power packs and cooling modules that replace traditional engines. This study analyzes the effects of component arrangement on stability and rollover angle in hydrogen tractors through simulations and proposes an optimal configuration. Stability is evaluated by analyzing rollover angles in various directions with rotations around the tractor’s midpoint. Based on the analysis of rollover angles for Type 1 Type 2 and Type 3 hydrogen tractors Type 2 demonstrates superior stability compared to the other types. Specifically when comparing lateral rollover angles at 0◦ rotation Type 2 exhibits a 2% increase over Type 3. Upon rotations at 90◦ and 180◦ Type 2 consistently displays the highest rollover angles with differences ranging from approximately 6% to 12% compared to the other types. These results indicate that Type 2 with its specific component arrangement offers the most stable configuration among the three types of tractors. It is confirmed that the rollover angle changes based on component arrangement with a lower center of gravity resulting in greater stability. These findings serve as a crucial foundation for enhancing stability in the future design and manufacturing phases of hydrogen tractors.
Impact of Large-scale Hydrogen Electrification and Retrofitting of Natural Gas Infrastructure on the European Power System
Nov 2023
Publication
In this paper we aim to analyse the impact of hydrogen production decarbonisation and electrification scenarios on the infrastructure development generation mix CO2 emissions and system costs of the European power system considering the retrofit of the natural gas infrastructure. We define a reference scenario for the European power system in 2050 and use scenario variants to obtain additional insights by breaking down the effects of different assumptions. The scenarios were analysed using the European electricity market model COMPETES including a proposed formulation to consider retrofitting existing natural gas networks to transport hydrogen instead of methane. According to the results 60% of the EU’s hydrogen demand is electrified and approximately 30% of the total electricity demand will be to cover that hydrogen demand. The primary source of this electricity would be non-polluting technologies. Moreover hydrogen flexibility significantly increases variable renewable energy investment and production and reduces CO2 emissions. In contrast relying on only electricity transmission increases costs and CO2 emissions emphasising the importance of investing in an H2 network through retrofitting or new pipelines. In conclusion this paper shows that electrifying hydrogen is necessary and cost-effective to achieve the EU’s objective of reducing long-term emissions.
Review on the Thermal Neutrality of Application-orientated Liquid Organic Hydrogen Carrier for Hydrogen Energy Storage and Delivery
Aug 2023
Publication
The depletion and overuse of fossil fuels present formidable challenge to energy supply system and environment. The human society is in great need of clean renewable and sustainable energy which can guarantee the long-term utilization without leading to escalation of greenhouse effect. Hydrogen as an extraordinary secondary energy is capable of realizing the target of environmental protection and transferring the intermittent primary energy to the application terminal while its nature of low volumetric energy density and volatility need suitable storage method and proper carrier. In this context liquid organic hydrogen carrier (LOHC) among a series of storage methods such as compressed and liquefied hydrogen provokes a considerable amount of research interest since it is proven to be a suitable carrier for hydrogen with safety and stability. However the dehydrogenation of hydrogen-rich LOHC materials is an endothermic process and needs large energy consumption which hampers the scale up of the LOHC system. The heat issue is thus essential to be addressed for fulfilling the potential of LOHC. In this work several strategies of heat intensification and management for LOHC system including the microwave irradiation circulation of exhaust heat and direct LOHC fuel cell are summarized and analyzed to provide suggestions and directions for future research.
Experimental Study on the Self-ignition of Pressurized Hydrogen Released into Three-way Tubes
Sep 2021
Publication
To explore the effect of bifurcation structures on the spontaneous ignition and shock wave result from the sudden release of pressurized hydrogen. Three-way tubes with different bifurcation angles (90° 120° 150°) were used in the experiments. They are two Y-shape tubes and one T-shape tube. The photoelectric and pressure signals in the tube were recorded by the sensor. The results show that the reflected shock wave will be formed at the bifurcation. In addition the intensity and velocity of the leading shock wave will attenuate sharply when it passes through the bifurcation.The smaller bifurcation angle of tubethe smaller overpressure decay rate of shock wave at bifurcation position.The smaller the bifurcation angle of tubes the weaker the reflected shock wave transmitted downstream and the greater attenuation of shock wave intensity. Experimental results have reference value for the safety of hydrogen storage at high-pressure and are helpful to understand the influence of different tube structures on spontaneous ignition when hydrogen is transported at high pressure.
Knock Mitigation and Power Enhancement of Hydrogen Spark-Ignition Engine through Ammonia Blending
Jun 2023
Publication
Hydrogen and ammonia are primary carbon-free fuels that have massive production potential. In regard to their flame properties these two fuels largely represent the two extremes among all fuels. The extremely fast flame speed of hydrogen can lead to an easy deflagration-to-detonation transition and cause detonation-type engine knock that limits the global equivalence ratio and consequently the engine power. The very low flame speed and reactivity of ammonia can lead to a low heat release rate and cause difficulty in ignition and ammonia slip. Adding ammonia into hydrogen can effectively modulate flame speed and hence the heat release rate which in turn mitigates engine knock and retains the zero-carbon nature of the system. However a key issue that remains unclear is the blending ratio of NH3 that provides the desired heat release rate emission level and engine power. In the present work a 3D computational combustion study is conducted to search for the optimal hydrogen/ammonia mixture that is knock-free and meanwhile allows sufficient power in a typical spark-ignition engine configuration. Parametric studies with varying global equivalence ratios and hydrogen/ammonia blends are conducted. The results show that with added ammonia engine knock can be avoided even under stoichiometric operating conditions. Due to the increased global equivalence ratio and added ammonia the energy content of trapped charge as well as work output per cycle is increased. About 90% of the work output of a pure gasoline engine under the same conditions can be reached by hydrogen/ammonia blends. The work shows great potential of blended fuel or hydrogen/ammonia dual fuel in high-speed SI engines.
Green Hydrogen and Electrical Power Production through the Integration of CO2 Capturing from Biogas: Process Optimization and Dynamic Control
Jun 2021
Publication
This study describes the optimization of a modelling process concerning biogas’ use to generate green hydrogen and electrical power. The Aspen Plus simulation tool is used to model the procedure and the approach employed to limit the emissions of gas from the hydrogen production process will be the CO2 capture method. This technique uses slack lime (Ca(OH)2) to absorb CO2 capture since it is readily available. The study analyzes many critical parameters in the process including the temperature and pressure in the steam reforming (SR) and the water gas shift (WGS) reactions along with the steam to carbon ratio (S/C) to determine how the production of green hydrogen and electrical power will be influenced. Electricity generation is achieved by taking the residual water from the SR WGS carbonation reactions and converting it to the vapour phase allowing the steam to pass through the turbine to generate electricity. To examine the effects of the synchronized critical parameters response surface methodology (RSM) was used thus allowing the optimal operational conditions to be determined in the form of an optimized zone for operation. The result of parameter optimization gave the maximum green hydrogen production of 211.46 kmol/hr and electric power production of 2311.68 kWh representing increases of 34.86% and 5.62% respectively when using 100 kmol/hr of biogas. In addition control structures were also built to control the reactors’ temperature in the dynamic section. The tuning parameters can control the SR and WGS system’s reactor to maintain the system in approximately 0.29 h and 0.32 h respectively.
Research Progress on Corrosion and Hydrogen Embrittlement in Hydrogen-Natural Gas Pipeline Transportation
Jun 2023
Publication
Hydrogen clean efficient and zero-carbon is seen as a most promising energy source. The use of existing gas pipelines for hydrogenenatural gas transportation is considered to be an effective way to achieve long-distance large-scale efficient and economical hydrogen transportation. However the pipelines for hydrogenenatural gas transportation contain lots of impurities (e.g. CH4 high-pressure H2 H2S and CO2) and free water which will inevitably lead to corrosion and hydrogen embrittlement. This paper presents a systematic review of research and an outlook for corrosion and hydrogen embrittlement in hydrogenenatural gas pipeline transportation. The results show that gasphase hydrogen charging is suitable for hydrogenenatural gas transportation but this technique lacks technical standards. By contrast the liquid-phase hydrogen charging technique is more mature but has large deviation from the engineering reality. In the hydrogenenatural gas transportation pipelines corrosion and hydrogen embrittlement are synergetic and competitive but the failure mechanism and change law when corrosion and hydrogen embrittlement coexist remain unclear which need to be further clarified by experiments. The failure mechanism is believed to be mainly sensitive to three key factors i.e. the H2S/CO2 partial pressure ratio the hydrogen blending ratio and material strength. The increase of the three factors will make the pipeline materials more corrosive and more sensitive to hydrogen embrittlement. The research findings can be used as a reference for research and development of long-distance hydrogenenatural gas transportation technology and will drive the high-quality development of the hydrogenenatural gas blending industry.
The New Model of Energy Cluster Management and Functioning
Sep 2022
Publication
This article was aimed to answer the question of whether local energy communities have a sufficient energy surplus for storage purposes including hydrogen production. The article presents an innovative approach to current research and a discussion of the concepts of the collective prosumer and virtual prosumer that have been implemented in the legal order and further amended in the law. From this perspective it was of utmost importance to analyze the model of functioning of an energy cluster consisting of energy consumers energy producers and hydrogen storage whose goal is to maximize the obtained benefits assuming the co-operative nature of the relationship. The announced and clear perspective of the planned benefits will provide the cluster members a measurable basis for participation in such an energy community. However the catalogue of benefits will be conditioned by the fulfillment of several requirements related to both the scale of covering energy demand from own sources and the need to store surplus energy. As part of the article the results of analyses together with a functional model based on real data of the local energy community are presented.
Low Carbon Optimal Operation of Integrated Energy Systems Considering Air Pollution Emissions
Apr 2023
Publication
To reduce carbon sulfur dioxide (SO2) and nitrogen oxide (NOX) emissions from the integrated energy system (IES) a low carbon optimization strategy for the IES is proposed taking into account carbon SO2 and NOX emissions. Firstly hydrogen production storage and use equipment such as methane reactor electrolysis tank hydrogen fuel cell and hydrogen energy storage are added to the traditional IES to build a multi-energy complementary system of electricity gas cooling thermal and hydrogen. Then this paper introduces a stepped carbon trading mechanism and the model of the emissions of SO2 and NOX. Finally to further reduce its pollutant emissions the model of combined heat and power units and hydrogen fuel cells with adjustable thermoelectric ratio is built. To compare and account for the impact of air pollutant emissions on the optimal low-carbon operation of IES this paper construsted three scenarios with the lowest cost of carbon trading the lowest penalty cost for SO2 and NOX emissions and total operation cost as objective functions respectively The results show that the strategy is effective in reducing air pollutant emissions from integrated energy systems and the outputs of CHP and HFC with adjustable thermoelectric ratios are more flexible and can effectively achieve carbon reduction and pollutant emission reduction.
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.
Reversible Molten Catalytic Methane Cracking Applied to Commercial Solar-Thermal Receivers
Nov 2020
Publication
When driven by sunlight molten catalytic methane cracking can produce clean hydrogen fuel from natural gas without greenhouse emissions. To design solar methane crackers a canonical plug flow reactor model was developed that spanned industrially relevant temperatures and pressures (1150–1350 Kelvin and 2–200 atmospheres). This model was then validated against published methane cracking data and used to screen power tower and beam-down reactor designs based on “Solar Two” a renewables technology demonstrator from the 1990s. Overall catalytic molten methane cracking is likely feasible in commercial beam-down solar reactors but not power towers. The best beam-down reactor design was 9% efficient in the capture of sunlight as fungible hydrogen fuel which approaches photovoltaic efficiencies. Conversely the best discovered tower methane cracker was only 1.7% efficient. Thus a beam-down reactor is likely tractable for solar methane cracking whereas power tower configurations appear infeasible. However the best simulated commercial reactors were heat transfer limited not reaction limited. Efficiencies could be higher if heat bottlenecks are removed from solar methane cracker designs. This work sets benchmark conditions and performance for future solar reactor improvement via design innovation and multiphysics simulation.
Towards a Sustainable Future: Bio-hydrogen Production from Food Waste for Clean Energy Generation
Jan 2024
Publication
To address climate change energy security and waste management new sustainable energy sources must be developed. This study uses Aspen Plus software to extract bio-H2 from food waste with the goal of efficiency and environmental sustainability. Anaerobic digestion optimised to operate at 20-25°C and keep ammonia at 3% greatly boosted biogas production. The solvent [Emim][FAP] which is based on imidazolium had excellent performance in purifying biogas. It achieved a high level of methane purity while consuming a minimal amount of energy with a solvent flow rate of 13.415 m³/h. Moreover the utilization of higher temperatures (600-700°C) during the bio-H2 generation phase significantly enhanced both the amount and quality of hydrogen produced. Parametric and sensitivity assessments were methodically performed at every stage. This integrated method was practicable and environmentally friendly according to the economic assessment. H2 generation using steam reforming results in a TCC of 1.92×106 USD. The CO2 separation step has higher costs (TCC of 2.15×107 USD) due to ionic liquid washing and CO2 liquefaction. Compressor electricity consumption significantly impacts total operating cost (TOC) totaling 4.73×108 USD. showing its ability to reduce greenhouse gas emissions optimize resource utilization and promote energy sustainability. This study presents a sustainable energy solution that addresses climate and waste challenges.
Ammonia as Green Fuel in Internal Combustion Engines: State-of-the-Art and Future Perspectives
Jul 2022
Publication
Ammonia (NH3) is among the largest-volume chemicals produced and distributed in the world and is mainly known for its use as a fertilizer in the agricultural sector. In recent years it has sparked interest in the possibility of working as a high-quality energy carrier and as a carbon-free fuel in internal combustion engines (ICEs). This review aimed to provide an overview of the research on the use of green ammonia as an alternative fuel for ICEs with a look to the future on possible applications and practical solutions to related problems. First of all the ammonia production process is discussed. Present ammonia production is not a “green” process; the synthesis occurs starting from gaseous hydrogen currently produced from hydrocarbons. Some ways to produce green ammonia are reviewed and discussed. Then the chemical and physical properties of ammonia as a fuel are described and explained in order to identify the main pros and cons of its use in combustion systems. Then the most viable solutions for fueling internal combustion engines with ammonia are discussed. When using pure ammonia high boost pressure and compression ratio are required to compensate for the low ammonia flame speed. In spark-ignition engines adding hydrogen to ammonia helps in speeding up the flame front propagation and stabilizing the combustion. In compression-ignition engines ammonia can be successfully used in dual-fuel mode with diesel. On the contrary an increase in NOx and the unburned NH3 at the exhaust require the installation of apposite aftertreatment systems. Therefore the use of ammonia seems to be more practicable for marine or stationary engine application where space constraints are not a problem. In conclusion this review points out that ammonia has excellent potential to play a significant role as a sustainable fuel for the future in both retrofitted and new engines. However significant further research and development activities are required before being able to consider large-scale industrial production of green ammonia. Moreover uncertainties remain about ammonia safe and effective use and some technical issues need to be addressed to overcome poor combustion properties for utilization as a direct substitute for standard fuels.
Thermal Design of a System for Mobile Powersupply
Sep 2023
Publication
Ever more stringent emission regulations for vehicles encourage increasing numbers of battery electric vehicles on the roads. A drawback of storing electric energy in a battery is the comparable low energy density low driving range and the higher propensity to deplete the energy storage before reaching the destination especially at low ambient temperatures. When the battery is depleted stranded vehicles can either be towed or recharged with a mobile recharging station. Several technologies of mobile recharging stations already exist however most of them use fossil fuels to recharge battery electric vehicles. The proposed novel zero emission solution for mobile charging is a combined high voltage battery and hydrogen fuel cell charging station. Due to the thermal characteristics of the fuel cell and high voltage battery (which allow only comparable low coolant temperatures) the thermal design for this specific application (available heat exchanger area zero vehicle speed air flow direction) becomes challenging and is addressed in this work. Experimental methods were used to obtain reliable thermal and electric power measurement data of a 30 kW fuel cell system which is used in the Mobile Hydrogen Powersupply. Subsequently simulation methods were applied for the thermal design and optimisation of the coolant circuits and heat exchangers. It is shown that an battery electric vehicle charging power of 22 kW requires a heat exchanger area of 1 m2 of which 60 % is used by the fuel cell heat exchanger and the remainder by the battery heat exchanger to achieve steady state operation at the highest possible ambient temperature of 436 °C. Furthermore the simulation showed that when the charging power of 22 kW is solely provided by the high voltage battery the highest possible ambient temperature is 42 °C. When the charging power is decreased operation up to the maximum ambient temperatures of 45 °C can be achieved. The results of maximum charging power and limiting ambient temperature give insights for further system improvements which are: sizing of fuel cell or battery trailer design and heat exchanger area operation strategy of the system (power split between high voltage battery and fuel cell) as well as possible dynamic operation scenarios.
Designing a Future-proof Gas and Hydrogen Infrastructure for Europe - A Modelling-based Approach
Jun 2023
Publication
Hydrogen has been at the centre of attention since the EU kicked-off its decarbonization agenda at full speed. Many consider it a silver bullet for the deep decarbonization of technically challenging sectors and industries but it is also an attractive option for the gas industry to retain and future-proof its well-developed infrastructure networks. The modelling methodology presented in this report systematically tests the feasibility and cost of different pipeline transportation methods – blending repurposing and dedicated hydrogen pipelines - under different decarbonization pathways and concludes that blending is not a viable solution and pipeline repurposing can lead to excessive investment outlays in the range of EUR 19–25 bn over the modelled period (2020–2050) for the EU-27.
Investigation of Performance of Anion Exchange Membrane (AEM) Electrolysis with Different Operating Conditions
Mar 2023
Publication
In this work the performance of anion exchange membrane (AEM) electrolysis is evaluated. A parametric study is conducted focusing on the effects of various operating parameters on the AEM efficiency. The following parameters—potassium hydroxide (KOH electrolyte concentration (0.5–2.0 M) electrolyte flow rate (1–9 mL/min) and operating temperature (30–60 ◦C)—were varied to understand their relationship to AEM performance. The performance of the electrolysis unit is measured by its hydrogen production and energy efficiency using the AEM electrolysis unit. Based on the findings the operating parameters greatly influence the performance of AEM electrolysis. The highest hydrogen production was achieved with the operational parameters of 2.0 M electrolyte concentration 60 ◦C operating temperature and 9 mL/min electrolyte flow at 2.38 V applied voltage. Hydrogen production of 61.13 mL/min was achieved with an energy consumption of 48.25 kW·h/kg and an energy efficiency of 69.64%.
Technoeconomic Analysis for Green Hydrogen in Terms of Production, Compression, Transportation and Storage Considering the Australian Perspective
Jul 2023
Publication
This current article discusses the technoeconomics (TE) of hydrogen generation transportation compression and storage in the Australian context. The TE analysis is important and a prerequisite for investment decisions. This study selected the Australian context due to its huge potential in green hydrogen but the modelling is applicable to other parts of the world adjusting the price of electricity and other utilities. The hydrogen generation using the most mature alkaline electrolysis (AEL) technique was selected in the current study. The results show that increasing temperature from 50 to 90 ◦C and decreasing pressure from 13 to 5 bar help improve electrolyser performance though pressure has a minor effect. The selected range for performance parameters was based on the fundamental behaviour of water electrolysers supported with literature. The levelised cost of hydrogen (LCH2 ) was calculated for generation compression transportation and storage. However the majority of the LCH2 was for generation which was calculated based on CAPEX OPEX capital recovery factor hydrogen production rate and capacity factor. The LCH2 in 2023 was calculated to be 9.6 USD/kgH2 using a base-case solar electricity price of 65–38 USD/MWh. This LCH2 is expected to decrease to 6.5 and 3.4 USD/kgH2 by 2030 and 2040 respectively. The current LCH2 using wind energy was calculated to be 1.9 USD/kgH2 lower than that of solar-based electricity. The LCH2 using standalone wind electricity was calculated to be USD 5.3 and USD 2.9 in 2030 and 2040 respectively. The LCH2 predicted using a solar and wind mix (SWM) was estimated to be USD 3.2 compared to USD 9.6 and USD 7.7 using standalone solar and wind. The LCH2 under the best case was predicted to be USD 3.9 and USD 2.1 compared to USD 6.5 and USD 3.4 under base-case solar PV in 2030 and 2040 respectively. The best case SWM offers 33% lower LCH2 in 2023 which leads to 37% 39% and 42% lower LCH2 in 2030 2040 and 2050 respectively. The current results are overpredicted especially compared with CSIRO Australia due to the higher assumption of the renewable electricity price. Currently over two-thirds of the cost for the LCH2 is due to the price of electricity (i.e. wind and solar). Modelling suggests an overall reduction in the capital cost of AEL plants by about 50% in the 2030s. Due to the lower capacity factor (effective energy generation over maximum output) of renewable energy especially for solar plants a combined wind- and solar-based electrolysis plant was recommended which can increase the capacity factor by at least 33%. Results also suggest that besides generation at least an additional 1.5 USD/kgH2 for compression transportation and storage is required.
Energy Assessment of an Integrated Hydrogen Production System
Dec 2022
Publication
Hydrogen is believed to be the future energy carrier that will reduce environmental pollution and solve the current energy crisis especially when produced from a renewable energy source. Solar energy is a renewable source that has been commonly utilized in the production process of hydrogen for years because it is inexhaustible clean and free. Generally hydrogen is produced by means of a water splitting process mainly electrolysis which requires energy input provided by harvesting solar energy. The proposed model integrates the solar harvesting system into a conventional Rankine cycle producing electrical and thermal power used in domestic applications and hydrogen by high temperature electrolysis (HTE) using a solid oxide steam electrolyzer (SOSE). The model is divided into three subsystems: the solar collector(s) the steam cycle and an electrolysis subsystem where the performance of each subsystem and their effect on the overall efficiency is evaluated thermodynamically using first and second laws. A parametric study investigating the hydrogen production rate upon varying system operating conditions (e.g. solar flux and area of solar collector) is conducted on both parabolic troughs and heliostat fields as potential solar energy harvesters. Results have shown that heliostat-based systems were able to attain optimum performance with an overall thermal efficiency of 27% and a hydrogen production rate of 0.411 kg/s whereas parabolic trough-based systems attained an overall thermal efficiency of 25.35% and produced 0.332 kg/s of hydrogen.
Plastic and Waste Tire Pyrolysis Focused on Hydrogen Production—A Review
Dec 2022
Publication
In this review we compare hydrogen production from waste by pyrolysis and bioprocesses. In contrast the pyrolysis feed was limited to plastic and tire waste unlikely to be utilized by biological decomposition methods. Recent risks of pyrolysis such as pollutant emissions during the heat decomposition of polymers and high energy demands were described and compared to thresholds of bioprocesses such as dark fermentation. Many pyrolysis reactors have been adapted for plastic pyrolysis after successful investigation experiences involving waste tires. Pyrolysis can transform these wastes into other petroleum products for reuse or for energy carriers such as hydrogen. Plastic and tire pyrolysis is part of an alternative synthesis method for smart polymers including semi-conductive polymers. Pyrolysis is less expensive than gasification and requires a lower energy demand with lower emissions of hazardous pollutants. Short-time utilization of these wastes without the emission of metals into the environment can be solved using pyrolysis. Plastic wastes after pyrolysis produce up to 20 times more hydrogen than dark fermentation from 1 kg of waste. The research summarizes recent achievements in plastic and tire waste pyrolysis development.
Recent Developments in Methane Decomposition over Heterogenous Catalysts: An Overview
Apr 2020
Publication
The production of hydrogen to be used as an alternative renewable energy has been widely explored. Among various methods for producing hydrogen from hydrocarbons methane decomposition is suitable for generating hydrogen with zero greenhouse gas emissions. The use of high temperatures as a result of strong carbon and hydrogen (C–H) bonds may be reduced by utilizing a suitable catalyst with appropriate catalyst support. Catalysts based on transition metals are preferable in terms of their activeness handling and low cost in comparison with noble metals. Further development of catalysts in methane decomposition has been investigated. In this review the recent progress on methane decomposition in terms of catalytic materials preparation method the physicochemical properties of the catalysts and their performance in methane decomposition were presented. The formation of carbon as part of the reaction was also discussed.
Operating Characteristics Analysis and Capacity Configuration Optimization of Wind-Solar-Hydrogen Hybrid Multi-energy Complementary System
Dec 2023
Publication
Wind and solar energy are the important renewable energy sources while their inherent natures of random and intermittent also exert negative effect on the electrical grid connection. As one of multiple energy complementary route by adopting the electrolysis technology the wind-solar-hydrogen hybrid system contributes to improving green power utilization and reducing its fluctuation. Therefore the moving average method and the hybrid energy storage module are proposed which can smooth the wind-solar power generation and enhance the system energy management. Moreover the optimization of system capacity configuration and the sensitive analysis are implemented by the MATLAB program platform. The results indicate that the 10-min grid-connected volatility is reduced by 38.7% based on the smoothing strategy and the internal investment return rate can reach 13.67% when the electricity price is 0.04 $/kWh. In addition the annual coordinated power and cycle proportion of the hybrid energy storage module are 80.5% and 90% respectively. The developed hybrid energy storage module can well meet the annual coordination requirements and has lower levelized cost of electricity. This method provides reasonable reference for designing and optimizing the wind-solar-hydrogen complementary system.
Operation Optimization of Wind/Battery Storage/Alkaline Electrolyzer System Considering Dynamic Hydrogen Production Efficiency
Aug 2023
Publication
Hydrogen energy is regarded as a key path to combat climate change and promote sustainable economic and social development. The fluctuation of renewable energy leads to frequent start/stop cycles in hydrogen electrolysis equipment. However electrochemical energy storage with its fast response characteristics helps regulate the power of hydrogen electrolysis enabling smooth operation. In this study a multi-objective constrained operation optimization model for a wind/battery storage/alkaline electrolyzer system is constructed. Both profit maximization and power abandonment rate minimization are considered. In addition some constraints such as minimum start/stop times upper and lower power limits and input fluctuation limits are also taken into account. Then the non-dominated sorting genetic algorithm II (NSGA-II) algorithm and the entropy method are used to optimize the operation strategy of the hybrid energy system by considering dynamic hydrogen production efficiency and through optimization to obtain the best hydrogen production power of the system under the two objectives. The change in dynamic hydrogen production efficiency is mainly related to the change in electrolyzer power and the system can be better adjusted according to the actual supply of renewable energy to avoid the waste of renewable energy. Our results show that the distribution of Pareto solutions is uniform which indicates the suitability of the NSGA-II algorithm. In addition the optimal solution indicates that the battery storage and alkaline electrolyzer can complement each other in operation and achieve the absorption of wind power. The dynamic hydrogen production efficiency can make the electrolyzer operate more efficiently which paves the way for system optimization. A sensitivity analysis reveals that the profit is sensitive to the price of hydrogen energy.
Optimized Scheduling of Integrated Energy Systems Accounting for Hydrogen Energy Multi-Utilization Models
Jan 2024
Publication
To cope with the growing penetration rate of renewable energy and to enhance the absorption capacity of wind power this paper investigates the applications of an Integrated Energy System (IES) Hydrogen Compressed Natural Gas (HCNG) and power-to-hydrogen (P2H) devices within the IES. It employs power-to-gas and gas blending with hydrogen to construct an efficient electricity–gas–electricity energy flow loop establishing a Natural Gas–Electricity Coupling System (NGECS) model. On this basis a coordinated scheduling method for gas–electric coupling systems using gas blended with hydrogen is proposed. A carbon trading mechanism is introduced to constrain carbon emissions further reducing the system’s carbon footprint. Multiple scenarios are set up for a comparative analysis in order to validate the effectiveness of the proposed model. This study also analyzes the impact of different hydrogen blending ratios and methods on the low-carbon and economic performance of IES.
Geomechanics of Hydrogen Storage in a Depleted Gas Field
Feb 2024
Publication
We perform a simulation study of hydrogen injection in a depleted gas reservoir to assess the geomechanical impact of hydrogen storage relative to other commonly injected gases (methane CO2). A key finding is that the differences in hydrogen density compressibility viscosity and thermal properties compared to the other gases result in significantly less thermal perturbation at reservoir level. The risks of fault reactivation and wellbore fractures due to thermally-induced stress changes are significantly lower when storing hydrogen compared to results observed in CO2 scenarios. This implies that hydrogen injection and production has a much smaller geomechanical footprint with benefits for operational safety. We also find that use of nitrogen cushion gas ensures efficient deliverability and phase separation in the reservoir. However in this study a large fraction of cushion gas was back-produced in each cycle demonstrating the need for further studies of the surface processing requirements and economic implications.
An Overview on the Technologies Used to Storage Hydrogen
Aug 2023
Publication
Hydrogen energy has a significant potential in mitigating the intermittency of renewable energy generation by converting the excess of renewable energy into hydrogen through many technologies. Also hydrogen is expected to be used as an energy carrier that contribute to the global decarbonization in transportation industrial and building sectors. Many technologies have been developed to store hydrogen energy. Hydrogen can be stored to be used when needed and thus synchronize generation and consumption. The current paper presents a review on the different technologies used to store hydrogen. The storage capacity advantages drawbacks and development stages of various hydrogen storage technologies were presented and compared.
Geochemical Effects on Storage Gases and Reservoir Rock during Underground Hydrogen Storage: A Depleted North Sea Oil Reservoir Case Study
May 2023
Publication
In this work geochemical modelling using PhreeqC was carried out to evaluate the effects of geochemical reactions on the performance of underground hydrogen storage (UHS). Equilibrium exchange and mineral reactions were considered in the model. Moreover reaction kinetics were considered to evaluate the geochemical effect on underground hydrogen storage over an extended period of 30 years. The developed model was first validated against experimental data adopted from the published literature by comparing the modelling and literature values of H2 and CO2 solubility in water at varying conditions. Furthermore the effects of pressure temperature salinity and CO2% on the H2 and CO2 inventory and rock properties in a typical sandstone reservoir were evaluated over 30 years. Results show that H2 loss over 30 years is negligible (maximum 2%) through the studied range of conditions. The relative loss of CO2 is much more pronounced compared to H2 gas with losses of up to 72%. Therefore the role of CO2 as a cushion gas will be affected by the CO2 gas losses as time passes. Hence remedial CO2 gas injections should be considered to maintain the reservoir pressure throughout the injection and withdrawal processes. Moreover the relative volume of CO2 increases with the increase in temperature and decrease in pressure. Furthermore the reservoir rock properties porosity and permeability are affected by the underground hydrogen storage process and more specifically by the presence of CO2 gas. CO2 dissolves carbonate minerals inside the reservoir rock causing an increase in the rock’s porosity and permeability. Consequently the rock’s gas storage capacity and flow properties are enhanced
Lifetime Greenhouse Gas Emissions from Offshore Hydrogen Production
Aug 2023
Publication
With a limited global carbon budget it is imperative that decarbonisation decisions are based on accurate holistic accounts of all greenhouse gas (GHG) emissions produced to assess their validity. Here the upstream GHG emissions of potential UK offshore Green and Blue hydrogen production are compared to GHG emissions from hydrogen produced through electrolysis using UK national grid electricity and the ‘business-as-usual’ case of continuing to combust methane. Based on an operational life of 25 years and producing 0.5MtH2 per year for each hydrogen process the results show that Blue hydrogen will emit between 200-262MtCO2e of GHG emissions depending on the carbon capture rates achieved (39%–90%) Green hydrogen produced via electrolysis using 100% renewable electricity from offshore wind will emit 20MtCO2e and hydrogen produced via electrolysis powered by the National Grid will emit between 103-168MtCO2e depending of the success of its NetZero strategy. The ‘business-as-usual’ case of continuing to combust methane releases 250MtCO2e over the same lifetime. This study finds that Blue hydrogen at scale is not compatible with the Paris Agreement reduces energy security and will require a substantial GHG emissions investment which excludes it from being a ‘low carbon technology’ and should not be considered for any decarbonisation strategies going forward.
Hydrogen Impact: A Review on Diffusibility, Embrittlement Mechanisms, and Characterization
Feb 2024
Publication
Hydrogen embrittlement (HE) is a broadly recognized phenomenon in metallic materials. If not well understood and managed HE may lead to catastrophic environmental failures in vessels containing hydrogen such as pipelines and storage tanks. HE can affect the mechanical properties of materials such as ductility toughness and strength mainly through the interaction between metal defects and hydrogen. Various phenomena such as hydrogen adsorption hydrogen diffusion and hydrogen interactions with intrinsic trapping sites like dislocations voids grain boundaries and oxide/matrix interfaces are involved in this process. It is important to understand HE mechanisms to develop effective hydrogen resistant strategies. Tensile double cantilever beam bent beam and fatigue tests are among the most common techniques employed to study HE. This article reviews hydrogen diffusion behavior mechanisms and characterization techniques.
Are Green and Blue Hydrogen Competitive or Complementary? Insights from a Decarbonised European Power System Analysis
Jun 2023
Publication
Hydrogen will be important in decarbonized energy systems. The primary ways to produce low emission hydrogen are from renewable electricity using electrolyzers called green hydrogen and by reforming natural gas and capturing and storing the CO2 known as blue hydrogen. In this study the degrees to which blue and green hydrogen are complementary or competitive are analyzed through a sensitivity analysis on the electrolyzer costs and natural gas price. This analysis is performed on four bases: what is the cost-effective relative share between blue and green hydrogen deployment how their deployment influences the price of hydrogen how the price of CO2 changes with the deployment of these two technologies and whether infrastructure can economically be shared between these two technologies. The results show that the choice of green and blue hydrogen has a tremendous impact where an early deployment of green leads to higher hydrogen costs and CO2 prices in 2030. Allowing for blue hydrogen thus has notable benefits in 2030 giving cheaper hydrogen with smaller wider socioeconomic impacts. In the long term these competitive aspects disappear and green and blue hydrogen can coexist in the European market without negatively influencing one another.
Cost Projection of Global Green Hydrogen Production Scenarios
Nov 2023
Publication
A sustainable future hydrogen economy hinges on the development of green hydrogen and the shift away from grey hydrogen but this is highly reliant on reducing production costs which are currently too high for green hydrogen to be competitive. This study predicts the cost trajectory of alkaline and proton exchange membrane (PEM) electrolyzers based on ongoing research and development (R&D) scale effects and experiential learning consequently influencing the levelized cost of hydrogen (LCOH) projections. Electrolyzer capital costs are estimated to drop to 88 USD/kW for alkaline and 60 USD/kW for PEM under an optimistic scenario by 2050 or 388 USD/kW and 286 USD/kW respectively under a pessimistic scenario with PEM potentially dominating the market. Through a combination of declining electrolyzer costs and a levelized cost of electricity (LCOE) the global LCOH of green hydrogen is projected to fall below 5 USD/kgH2 for solar onshore and offshore wind energy sources under both scenarios by 2030. To facilitate a quicker transition the implementation of financial strategies such as additional revenue streams a hydrogen/carbon credit system and an oxygen one (a minimum retail price of 2 USD/kgO2 ) and regulations such as a carbon tax (minimum 100 USD/tonCO2 for 40 USD/MWh electricity) and a contract-for-difference scheme could be pivotal. These initiatives would act as financial catalysts accelerating the transition to a greener hydrogen economy.
PEM Water Electrolysis for Hydrogen Production: Fundamentals, Advances, and Prospects
Jun 2022
Publication
Hydrogen as a clean energy carrier is of great potential to be an alternative fuel in the future. Proton exchange membrane (PEM) water electrolysis is hailed as the most desired technology for high purity hydrogen production and self-consistent with volatility of renewable energies has ignited much attention in the past decades based on the high current density greater energy efficiency small mass-volume characteristic easy handling and maintenance. To date substantial efforts have been devoted to the development of advanced electrocatalysts to improve electrolytic efficiency and reduce the cost of PEM electrolyser. In this review we firstly compare the alkaline water electrolysis (AWE) solid oxide electrolysis (SOE) and PEM water electrolysis and highlight the advantages of PEM water electrolysis. Furthermore we summarize the recent progress in PEM water electrolysis including hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) electrocatalysts in the acidic electrolyte. We also introduce other PEM cell components (including membrane electrode assembly current collector and bipolar plate). Finally the current challenges and an outlook for the future development of PEM water electrolysis technology for application in future hydrogen production are provided.
Numerical Simulation of Hydrogen–Coal Blending Combustion in a 660 MW Tangential Boiler
Feb 2024
Publication
With the adjustment of energy structure the utilization of hydrogen energy has been widely attended. China’s carbon neutrality targets make it urgent to change traditional coal-fired power generation. The paper investigates the combustion of pulverized coal blended with hydrogen to reduce carbon emissions. In terms of calorific value the pulverized coal combustion with hydrogen at 1% 5% and 10% blending ratios is investigated. The results show that there is a significant reduction in CO2 concentration after hydrogen blending. The CO2 concentration (mole fraction) decreased from 15.6% to 13.6% for the 10% hydrogen blending condition compared to the non-hydrogen blending condition. The rapid combustion of hydrogen produces large amounts of heat in a short period which helps the ignition of pulverized coal. However as the proportion of hydrogen blending increases the production of large amounts of H2O gives an overall lower temperature. On the other hand the temperature distribution is more uniform. The concentrations of O2 and CO in the upper part of the furnace increased. The current air distribution pattern cannot satisfy the adequate combustion of the fuel after hydrogen blending.
Optimizing the Operational Efficiency of the Underground Hydrogen Storage Scheme in a Deep North Sea Aquifer through Compositional Simulations
Aug 2023
Publication
In this study we evaluate the technical viability of storing hydrogen in a deep UKCS aquifer formation through a series of numerical simulations utilising the compositional simulator CMG-GEM. Effects of various operational parameters such as injection and production rates number and length of storage cycles and shut-in periods on the performance of the underground hydrogen storage (UHS) process are investigated in this study. Results indicate that higher H2 operational rates degrade both the aquifer's working capacity and H2 recovery during the withdrawal phase. This can be attributed to the dominant viscous forces at higher rates which lead to H2 viscous fingering and gas gravity override of the native aquifer water resulting in an unstable displacement of water by the H2 gas. Furthermore analysis of simulation results shows that longer and less frequent storage cycles lead to higher storage capacity and decreased H2 retrieval. We conclude that UHS in the studied aquifer is technically feasible however a thorough evaluation of the operational parameters is necessary to optimise both storage capacity and H2 recovery efficiency.
Modelling Methodologies to Design and Control Renewables and Hydrogen-Based Telecom Towers Power Supply Systems
Aug 2023
Publication
Proton exchange membrane fuel cell (PEMFCS) and electrolyser (PEMELS) systems together with a hydrogen storage tank (HST) are suitable to be integrated with renewable microgrids to cover intermittency and fully exploit the excess of electrical energy. Such an integration perfectly fits telecom tower power supply needs both in off-grid and grid-connected sites. In this framework a model-based tool enabling both optimal sizing and proper year-through energy management of both the above applications is proposed. Respectively the islanded optimisation is performed considering two economic indices i.e. simple payback (SPB) and levelised cost of energy (LCOE) together with two strategies of hydrogen tank management charge sustaining and depleting and also accounting for the impact of grid extension distance. On the other hand the grid connection is addressed through the dynamic programming method while downsizing PEMELS and HST sizes to improve techno-economic effectiveness thanks to grid contribution towards renewables curtailment issues mitigation. For both the above introduced HST management strategies a reduction of more than 70% of the nominal PEMELS power and 90% of the HST size which will in turn lead to SPB and LCOE being reduced by 80% and 60% in comparison to the islanded case respectively is achieved. Furthermore the charge depleting strategy relying on possible hydrogen purchase interestingly provides an SPB and LCOE of 9% and 7% lower than the charge sustaining one.
Regional Capabilities and Hydrogen Adoption Barriers
Dec 2023
Publication
Hydrogen is gaining importance to decarbonize the energy system and tackle the climate crisis. This exploratory study analyzes three focus groups with representatives from relevant organizations in a Northern German region that has unique beneficial characteristics for the transition to a hydrogen economy. Based upon this data (1) a category system of innovation adoption barriers for hydrogen technologies is developed (2) decision levels associated with the barriers are identified (3) detailed insights on how decision levels contribute to the adoption barriers are provided and (4) the barriers are evaluated in terms of their importance. Our analysis adds to existing literature by focusing on short-term barriers and exploring relevant decision levels and their associated adoption barriers. Our main results comprise the following: flaws in the funding system complex approval procedures lack of networks and high costs contribute to hydrogen adoption barriers. The (Sub-)State level is relevant for the uptake of the hydrogen economy. Regional entities have leeway to foster the hydrogen transition especially with respect to the distribution infrastructure. Funding policy technological suitability investment and operating costs and the availability of distribution infrastructure and technical components are highly important adoption barriers that alone can impede the transition to a hydrogen economy.
Numerical Modelling of Hydrogen Release and Dispersion in Under-deck Compressed Hydrogen Storage of Marine Ships
Feb 2024
Publication
There is growing interest in using hydrogen (H2) as a marine fuel. Fire and explosion risks depend on hydrogen release and dispersion characteristics. Based on a validated Computational Fluid Dynamics (CFD) model this study performed hydrogen release and dispersion analysis on an under-deck compressed H2 storage system for a Live-Fish Carrier. A realistic under-deck H2 storage room was modelled based on the ship’s main dimensions and operational profile. Det Norske Veritas (DNV) Rules and Regulations for natural gas storage as a marine fuel were employed as base design guidelines. Case studies were developed to study the effect of two ceiling types (flat and slanted) in terms of flammable cloud formation and dissipation. During the leak’s duration it was found that the recommended ventilation rate was insufficient to dilute the average H2 concentration below 25% of the flammable range as required by DNV (1.2% required against 1.3% slanted and 1.4% flat). However after 35 s of gas extraction the H2 concentration was reduced to 0.5% and 0.6% in the slanted and flat cases respectively. The proposed methodology remains valid to improve the ventilation system and assess mitigation alternatives or other leakage scenarios in confined or semi-confined spaces containing compressed hydrogen gas.
Development of Electric Power Generator by Using Hydrogen
Nov 2023
Publication
In this research we developed a hydrogen (H2 ) electric generator in an H2 generation system based on chemical reactions. In the experiment we tested the performance of the H2 electric generator and measured the amount of H2 generated. The maximum output was 700 W and the thermal efficiency was 18.2%. The theoretical value and measured value were almost the same and the maximum error was 4%.
Hydrogen Production, Storage, Utilisation and Environmental Impacts: A Review
Oct 2021
Publication
Dihydrogen (H2) commonly named ‘hydrogen’ is increasingly recognised as a clean and reliable energy vector for decarbonisation and defossilisation by various sectors. The global hydrogen demand is projected to increase from 70 million tonnes in 2019 to 120 million tonnes by 2024. Hydrogen development should also meet the seventh goal of ‘affordable and clean energy’ of the United Nations. Here we review hydrogen production and life cycle analysis hydrogen geological storage and hydrogen utilisation. Hydrogen is produced by water electrolysis steam methane reforming methane pyrolysis and coal gasification. We compare the environmental impact of hydrogen production routes by life cycle analysis. Hydrogen is used in power systems transportation hydrocarbon and ammonia production and metallugical industries. Overall combining electrolysis-generated hydrogen with hydrogen storage in underground porous media such as geological reservoirs and salt caverns is well suited for shifting excess of-peak energy to meet dispatchable on-peak demand.
Towards a Future Hydrogen Supply Chain: A Review of Technologies and Challenges
Feb 2024
Publication
The overuse of fossil fuels has caused a serious energy crisis and environmental pollution. Due to these challenges the search for alternative energy sources that can replace fossil fuels is necessary. Hydrogen is a widely acknowledged future energy carrier because of its nonpolluting properties and high energy density. To realize a hydrogen economy in the future it is essential to construct a comprehensive hydrogen supply chain that can make hydrogen a key energy carrier. This paper reviews the various technologies involved in the hydrogen supply chain encompassing hydrogen production storage transportation and utilization technologies. Then the challenges of constructing a hydrogen supply chain are discussed from techno-economic social and policy perspectives and prospects for the future development of a hydrogen supply chain are presented in light of these challenges.
Potential Cost Savings of Large-scale Blue Hydrogen Production via Sorption-enhanced Steam Reforming Process
Jan 2024
Publication
As countries work towards achieving net-zero emissions the need for cleaner fuels has become increasingly urgent. Hydrogen produced from fossil fuels with carbon capture and storage (blue hydrogen) has the potential to play a significant role in the transition to a low-carbon economy. This study examined the technical and economic potential of blue hydrogen produced at 600 MWth(LHV) and scaled up to 1000 MWth(LHV) by benchmarking sorption-enhanced steam reforming process against steam methane reforming (SMR) autothermal gasheated reforming (ATR-GHR) integrated with carbon capture and storage (CCS) and SMR with CCS. Aspen Plus® was used to develop the process model which was validated using literature data. Cost sensitivity analyses were also performed on two key indicators: levelised cost of hydrogen and CO2 avoidance cost by varying natural gas price electricity price CO2 transport and storage cost and carbon price. Results indicate that at a carbon price of 83 £/tCO2e the LCOH for SE-SR of methane is the lowest at 2.85 £/kgH2 which is 12.58% and 22.55% lower than that of ATR-GHR with CCS and SMR plant with CCS respectively. The LCOH of ATR-GHR with CCS and SMR plant with CCS was estimated to be 3.26 and 3.68 £/kgH2 respectively. The CO2 avoidance cost was also observed to be lowest for SE-SR followed by ATR-GHR with CCS then SMR plant with CCS and was observed to reduce as the plant scaled to 1000 MWth(LHV) for these technologies.
A Brief on Nano-Based Hydrogen Energy Transition
Sep 2023
Publication
Considering the clean renewable and ecologically friendly characteristics of hydrogen gas as well as its high energy density hydrogen energy is thought to be the most potent contender to locally replace fossil fuels. The creation of a sustainable energy system is currently one of the critical industrial challenges and electrocatalytic hydrogen evolution associated with appropriate safe storage techniques are key strategies to implement systems based on hydrogen technologies. The recent progress made possible through nanotechnology incorporation either in terms of innovative methods of hydrogen storage or production methods is a guarantee of future breakthroughs in energy sustainability. This manuscript addresses concisely and originally the importance of including nanotechnology in both green electroproduction of hydrogen and hydrogen storage in solid media. This work is mainly focused on these issues and eventually intends to change beliefs that hydrogen technologies are being imposed only for reasons of sustainability and not for the intrinsic value of the technology itself. Moreover nanophysics and nano-engineering have the potential to significantly change the paradigm of conventional hydrogen technologies.
Natural Hydrogen in the Energy Transition: Fundamentals, Promise, and Enigmas
Oct 2023
Publication
Beyond its role as an energy vector a growing number of natural hydrogen sources and reservoirs are being discovered all over the globe which could represent a clean energy source. Although the hydrogen amounts in reservoirs are uncertain they could be vast and they could help decarbonize energy-intensive economic sectors and facilitate the energy transition. Natural hydrogen is mainly produced through a geochemical process known as serpentinization which involves the reaction of water with low-silica ferrous minerals. In favorable locations the hydrogen produced can become trapped by impermeable rocks on its way to the atmosphere forming a reservoir. The safe exploitation of numerous natural hydrogen reservoirs seems feasible with current technology and several demonstration plants are being commissioned. Natural hydrogen may show variable composition and require custom separation purification storage and distribution facilities depending on the location and intended use. By investing in research in the mid-term more hydrogen sources could become exploitable and geochemical processes could be artificially stimulated in new locations. In the long term it may be possible to leverage or engineer the interplay between microorganisms and geological substrates to obtain hydrogen and other chemicals in a sustainable manner.
Utilization of Hydrogen in Gas Turbines: A Comprehensive Review
Feb 2022
Publication
The concerns regarding the consumption of traditional fuels such as oil and coal have driven the proposals for several cleaner alternatives in recent years. Hydrogen energy is one of the most attractive alternatives for the currently used fossil fuels with several superiorities such as zero-emission and high energy content. Hydrogen has numerous advantages compared to conventional fuels and as such has been employed in gas turbines (GTs) in recent years. The main benefit of using hydrogen in power generation with the GT is the considerably lower emission of greenhouse gases. The performance of the GTs using hydrogen as a fuel is influenced by several factors including the performance of the components the operating condition ambient condition etc. These factors have been investigated by several scholars and scientists in this field. In this article studies on hydrogen-fired GTs are reviewed and their results are discussed. Furthermore some recommendations are proposed for the upcoming works in this field.
China and Italy’s Energy Development Trajectories: Current Landscapes and Future Cooperation Potential
Feb 2024
Publication
In order to achieve the ambitious goal of “carbon neutrality” countries around the world are striving to develop clean energy. Against this background this paper takes China and Italy as representatives of developing and developed countries to summarize the energy structure composition and development overview of the two countries. The paper analyzes the serious challenges facing the future energy development of both countries and investigates the possibilities of energy cooperation between the two countries taking into account their respective advantages in energy development. By comparing the policies issued by the two governments to encourage clean energy development this paper analyzes the severe challenges faced by the two countries’ energy development in the future and combines their respective energy development advantages to look forward to the possibility of energy cooperation between the two countries in the future. This lays the foundation for China and Italy to build an “Energy Road” after the “Silk Road”.
Batteries or Hydrogen or Both for Grid Electricity Storage Upon Full Electrification of 145 Countries with Wind-Water-Solar?
Jan 2024
Publication
Grids require electricity storage. Two emerging storage technologies are battery storage (BS) and green hydrogen storage (GHS) (hydrogen produced and compressed with clean-renewable electricity stored then returned to electricity with a fuel cell). An important question is whether GHS alone decreases system cost versus BS alone or BS+GHS. Here energy costs are modeled in 145 countries grouped into 24 regions. Existing conventional hydropower (CH) storage is used along with new BS and/or GHS. A method is developed to treat CH for both baseload and peaking power. In four regions only CH is needed. In five CH+BS is lowest cost. Otherwise CH+BS+GHS is lowest cost. CH+GHS is never lowest cost. A metric helps estimate whether combining GHS with BS reduces cost. In most regions merging (versus separating) grid and non-grid hydrogen infrastructure reduces cost. In sum worldwide grid stability may be possible with CH+BS or CH+BS+GHS. Results are subject to uncertainties.
A Bibliometric Study on the Research Trends and Hotspots of Proton Exchange Membrane Electrolyzer
Jan 2024
Publication
The application of hydrogen energy produced by proton exchange membrane electrolyzer (PEMEC) is conducive to the solution of the greenhouse effect and the energy crisis. In order to understand the development trends and research hotspot of PEMEC in recent years a total of 1874 research articles related to this field from 2003 to 2023 were obtained from the Web of Science Core Collection (WoS CC) database. The visualization software VOSviewer is used for bibliometric analysis and the research progress hotspots and trends in the PEMEC field are summarized. It was found that in the past two decades literature in the PEMEC field has shown a trend of stable increase at first and then rapidly increasing. And it is in a stage of rapid growth after 2021.Renewable Energy previously published research articles related to PEMEC with the highest frequency of citations. There are a total of 6128 researchers in this field but core authors only account for 4.5% of the total. Although China entered this field later than the United States and Canada it has the largest number of research articles. The research results provide a comprehensive overview of various aspects in the PEMEC field which is beneficial for researchers to grasp the development hotspots of PEMEC.
Prospects and Impediments for Hydrogen Fuel Cell Buses
Jun 2021
Publication
The number of demonstration projects with fuel cell buses has been increasing worldwide. The goal of this paper is to analyse prospects and barriers for fuel cell buses focusing on their economic- technical- and environmental performance. Our results show that the prices of fuel cell buses although decreasing over time are still about 40% higher than those of diesel buses. With the looming ban of diesel vehicles and current limitations of battery electric vehicles fuel cell buses could become a viable alternative in the mid-to long-term. With the requirements for a better integration of renewable energy sources in the transport system interest in hydrogen is rising. Hydrogen produced from renewables used in fuel cell buses has the potential to save about 93% of CO2 emissions in comparison to diesel buses. Yet from environmental point-of-view it has to be ensured that hydrogen is produced from renewables. Currently the major barrier for a faster penetration of fuel cell buses are their high purchase prices which could be significantly reduced with the increasing number of buses through technological learning. The final conclusion is that a tougher transport policy framework is needed which fully reflects the environmental impact of different buses used.
Performance, Emissions, and Combustion Characteristics of a Hydrogen-Fueled Spark-Ignited Engine at Different Compression Ratios: Experimental and Numerical Investigation
Jul 2023
Publication
This paper investigates the performance of hydrogen-fueled spark-ignited single-cylinder Cooperative Fuel Research using experimental and numerical approaches. This study examines the effect of the air–fuel ratio on engine performance emissions and knock behaviour across different compression ratios. The results indicate that λ significantly affects both engine performance and emissions with a λ value of 2 yielding the highest efficiency and lowest emissions for all the tested compression ratios. Combustion analysis reveals normal combustion at λ ≥ 2 while knocking combustion occurs at λ < 2 irrespective of the tested compression ratios. The Livenwood–Wu integral approach was evaluated to assess the likelihood of end-gas autoignition based on fuel reactivity demonstrating that both normal and knocking combustion possibilities are consistent with experimental investigations. Combustion analysis at the ignition timing for maximum brake torque conditions demonstrates knock-free stable combustion up to λ = 3 with increased end-gas autoignition at lower λ values. To achieve knock-free combustion at those low λs the spark timings are significantly retarded to after top dead center crank angle position. Engine-out NOx emissions consistently increase in trend with a decrease in the air–fuel ratio of up to λ = 3 after which a distinct variation in NOx is observed with an increase in the compression ratio.
Hydrogen Pipelines vs. HVDC Lines: Should We Transfer Green Molecules or Electrons?
Nov 2023
Publication
As the world races to decarbonize its energy systems the choice between transmitting green energy as electrons through high-voltage direct current (HVDC) lines or as molecules via hydrogen pipelines emerges as a critical decision. This paper considers this pivotal choice and compares the technoeconomic characteristics of these two transmission technologies. Hydrogen pipelines offer the advantage of transporting larger energy volumes but existing projects are dwarfed by the vast networks of HVDC transmission lines. Advocates for hydrogen pipelines see potential in expanding these networks capitalizing on hydrogen’s physical similarities to natural gas and the potential for cost savings. However hydrogen’s unique characteristics such as its small molecular size and compression requirements present construction challenges. On the other hand HVDC lines while less voluminous excel in efficiently transmitting green electrons over long distances. They already form an extensive global network and their efficiency makes them suitable for various applications. Yet intermittent renewable energy sources pose challenges for both hydrogen and electricity systems necessitating solutions like storage and blending. Considering these technologies as standalone competitors belies their complementary nature. In the emerging energy landscape they will be integral components of a complex system. Decisions on which technology to prioritize depend on factors such as existing infrastructure adaptability risk assessment and social acceptance. Furthermore while both HVDC lines and hydrogen pipelines are expected to proliferate other factors such as market maturity of the relevant energy vector government policies and regulatory frameworks around grid development and utilization are also expected to play a crucial role. Energy transition is a multifaceted challenge and accommodating both green molecules and electrons in our energy infrastructure may be the key to a sustainable future. This paper’s insights underline the importance of adopting a holistic perspective and recognising the unique strengths of each technology in shaping a resilient and sustainable energy ecosystem.
Modeling the Long-term Evolution of the Italian Power Sector: The Role of Renewable Resources and Energy Storage Facilities
Feb 2024
Publication
The aim of this study is to investigate the long-term planning of the Italian power sector from 2021 to 2050. The key role of photovoltaic and wind technologies in combination with power-to-power systems based on hydrogen and batteries is investigated. An updated version of the OSeMOSYS tool is used which employs a clustering method for the representation of time-varying input data. First the potential of variable renewable energy sources (VRES) is assessed. A sensitivity analysis is also performed on the temporal resolution of the model to determine an adequate trade-off between the computation time and the accuracy of the results. Then a technoeconomic optimization scenario is carried out resulting in a total net present cost of about 233.7 B€. A high penetration of VRES technologies is foreseen by 2050 with a total VRES installed capacity of 272.9 GW (mainly photovoltaic and onshore wind). Batteries are found to be the preferable energy storage solution in the first part of the energy transition while the hydrogen storage starts to be convenient from about the year 2040. Indeed the role of hydrogen storage becomes fundamental as the VRES penetration increases thanks to its cost-effective long-term storage capability. By 2050 74.6 % of electricity generation will be based on VRES which will also enable a significant reduction in CO2 emissions of about 87 %.
Experimental Comparison of Hydrogen Refueling with Directly Pressurized vs. Cascade Method
Aug 2023
Publication
This paper presents a comparative analysis of two hydrogen station configurations during the refueling process: the conventional “directly pressurized refueling process” and the innovative “cascade refueling process.” The objective of the cascade process is to refuel vehicles without the need for booster compressors. The experiments were conducted at the Hydrogen Research and Fueling Facility located at California State University Los Angeles. In the cascade refueling process the facility buffer tanks were utilized as high-pressure storage enabling the refueling operation. Three different scenarios were tested: one involving the cascade refueling process and two involving compressor-driven refueling processes. On average each refueling event delivered 1.6 kg of hydrogen. Although the cascade refueling process using the high-pressure buffer tanks did not achieve the pressure target it resulted in a notable improvement in the nozzle outlet temperature trend reducing it by approximately 8 ◦C. Moreover the overall hydrogen chiller load for the two directly pressurized refuelings was 66 Wh/kg and 62 Wh/kg respectively whereas the cascading process only required 55 Wh/kg. This represents a 20% and 12% reduction in energy consumption compared to the scenarios involving booster compressors during fueling. The observed refueling range of 150–350 bar showed that the cascade process consistently required 12–20% less energy for hydrogen chilling. Additionally the nozzle outlet temperature demonstrated an approximate 8 ◦C improvement within this pressure range. These findings indicate that further improvements can be expected in the high-pressure region specifically above 350 bar. This research suggests the potential for significant improvements in the high-pressure range emphasizing the viability of the cascade refueling process as a promising alternative to the direct compression approach.
Model for Hydrogen Production Scheduling Optimisation
Feb 2024
Publication
This scientific article presents a developed model for optimising the scheduling of hydrogen production processes addressing the growing demand for efficient and sustainable energy sources. The study focuses on the integration of advanced scheduling techniques to improve the overall performance of the hydrogen electrolyser. The proposed model leverages constraint programming and satisfiability (CP-SAT) techniques to systematically analyse complex production schedules considering factors such as production unit capacities resource availability and energy costs. By incorporating real-world constraints such as fluctuating energy prices and the availability of renewable energy the optimisation model aims to improve overall operational efficiency and reduce production costs. The CP-SAT was applied to achieve more efficient control of the electrolysis process. The optimisation of the scheduling task was set for a 24 h time period with time resolutions of 1 h and 15 min. The performance of the proposed CP-SAT model in this study was then compared with the Monte Carlo Tree Search (MCTS)-based model (developed in our previous work). The CP-SAT was proven to perform better but has several limitations. The model response to the input parameter change has been analysed.
Blue Hydrogen and Industrial Base Products: The Future of Fossil Fuel Exporters in a Net-zero World
May 2022
Publication
Is there a place for today’s fossil fuel exporters in a low-carbon future? This study explores trade channels between energy exporters and importers using a novel electricity-hydrogen-steel energy systems model calibrated to Norway a major natural gas producer and Germany a major energy consumer. Under tight emission constraints Norway can supply Germany with electricity (blue) hydrogen or natural gas with re-import of captured CO2. Alternatively it can use hydrogen to produce steel through direct reduction and supply it to the world market an export route not available to other energy carriers due to high transport costs. Although results show that natural gas imports with CO2 capture in Germany is the least-cost solution avoiding local CO2 handling via imports of blue hydrogen (direct or embodied in steel) involves only moderately higher costs. A robust hydrogen demand would allow Norway to profitably export all its natural gas production as blue hydrogen. However diversification into local steel production as one example of easy-to-export industrial base products offers an effective hedge against the possibility of lower European blue hydrogen demand. Looking beyond Europe the findings of this study are also relevant for the world’s largest energy exporters (e.g. OPEC+) and importers (e.g. developing Asia). Thus it is recommended that large hydrocarbon exporters consider a strategic energy export transition to a diversified mix of blue hydrogen and climate-neutral industrial base products.
Technoeconomic, Environmental and Multi-criteria Decision Making Investigations for Optimisation of Off-grid Hybrid Renewable Energy System with Green Hydrogen Production
Jan 2024
Publication
The current study presents a comprehensive investigation of different energy system configurations for a remote village community in India with entirely renewable electricity. Excess electricity generated by the systems has been stored using two types of energy storage options: lithium-ion batteries and green hydrogen production through the electrolysers. The hybrid renewable energy system (HRES) configurations have been sized by minimising the levelised cost of energy (LCOE). In order to identify the best-performing HRES configuration economic and environmental performance indicators has been analysed using the multi-criteria decision-making method (MCDM) TOPSIS. Among the evaluated system configurations system-1 with a photovoltaic panel (PV) size of 310.24 kW a wind turbine (WT) size of 690 kW a biogas generator (BG) size of 100 kW a battery (BAT) size of 174 kWh an electrolyser (ELEC) size of 150 kW a hydrogen tank (HT) size of 120 kg and a converter (CONV) size of 106.24 kW has been found to be the best-performing system since it provides the highest relative closeness (RC) value (∼0.817) and also has the lowest fuel consumption rate of 2.31 kg/kWh. However system-6 shows the highest amount of CO2 (143.97 kg/year) among all the studied system configurations. Furthermore a detailed technical economic and environmental analysis has been conducted on the optimal HRES configuration. The minimum net present cost (NPC) LCOE and cost of hydrogen (COH) for system 1 has been estimated to be $1960584 $0.44/kWh and $22.3/kg respectively.
Design of a Hydrogen Aircraft for Zero Persistent Contrails
Jul 2023
Publication
Contrails are responsible for a significant proportion of aviation’s climate impact. This paper uses data from the European Centre for Medium-Range Weather Forecasts to identify the altitudes and latitudes where formed contrails will not persist. This reveals that long-lived contrails may be prevented by flying lower in equatorial regions and higher in non-equatorial regions. Subsequently it is found that the lighter fuel and reduced seating capacity of hydrogen-powered aircraft lead to a reduced aircraft weight which increases the optimal operating altitude by about 2 km. In non-equatorial regions this would lift the aircraft’s cruise point into the region where long-lived contrails do not persist unlocking hydrogen-powered low-contrails operation. The baseline aircraft considered is an A320 retrofitted with in-fuselage hydrogen tanks. The impacts of the higher-altitude cruise on fuel burn and the benefits unlocked by optimizing the wing geometry for this altitude are estimated using a drag model based on theory proposed by Cavcar Lock and Mason and verified against existing aircraft. The weight penalty associated with optimizing wing geometry for this altitude is estimated using Torenbeek’s correlation. It is found that thinner wings with higher aspect ratios are particularly suited to this high-altitude operation and are enabled by the relaxation of the requirement to store fuel in the wings. An example aircraft design for the non-equatorial region is provided which cruises at a 14 km altitude at Mach 0.75 with a less than 1% average probability of generating long-lived contrails when operating at latitudes more than 35◦ from the equator. Compared to the A320 this concept design is estimated to have a 20% greater cruise lift–drag ratio due to the 33% thinner wings with a 50% larger aspect ratio enabling just 5% more energy use per passenger-km despite fitting 40% fewer seats.
The Influence of the Changes in Natural Gas Supplies to Poland on the Amount of Hydrogen Produced in the SMR Reactor
Mar 2024
Publication
Thanks to investments in diversifying the supply of natural gas Poland did not encounter any gas supply issues in 2022 when gas imports from Russia were ceased due to the Russian Federation’s armed intervention in Ukraine. Over the past few years the supply of gas from routes other than the eastern route has substantially grown particularly the supplies of liquefied natural gas (LNG) via the LNG terminal in Swinouj´scie. The growing proportion of LNG in Poland’s gas supply ´ leads to a rise in ethane levels in natural gas as verified by the review of data taken at a specific location within the gas system over the years 2015 2020 and 2022. Using measurements of natural gas composition the effectiveness of the steam hydrocarbon reforming process was simulated in the Gibbs reactor via Aspen HYSYS. The simulations confirmed that as the concentration of ethane in the natural gas increased the amount of hydrogen produced and the heat required for reactions in the reformer also increased. This article aims to analyze the influence of the changes in natural gas quality in the Polish transmission network caused by changes in supply structures on the mass and heat balance of the theoretical steam reforming reactor. Nowadays the chemical composition of natural gas may be significantly different from that assumed years ago at the plant’s design stage. The consequence of such a situation may be difficulties in operating especially when controlling the quantity of incoming natural gas to the reactor based on volumetric flow without considering changes in chemical composition.
Factors Driving the Decarbonisation of Industrial Clusters: A Rapid Evidence Assessment of International Experience
Sep 2023
Publication
Reducing industrial emissions to achieve net-zero targets by the middle of the century will require profound and sustained changes to how energy intensive industries operate. Preliminary activity is now underway with governments of several developed economies starting to implement policy and providing funding to support the deployment of low carbon infrastructure into high emitting industrial clusters. While clusters appear to offer the economies of scale and institutional capacity needed to kick-start the industrial transition to date there has been little systematic assessment of the factors that may influence the success of these initiatives. Drawing from academic and grey literature this paper presents a rapid evidence assessment of the approaches being used to drive the development of low carbon industrial clusters internationally. Many projects are still at the scoping stage but it is apparent that current initiatives focus on the deployment of carbon capture technologies alongside hydrogen as a future secondary revenue stream. This model of decarbonisation funnels investment into large coastal clusters with access to low carbon electricity and tends to obscure questions about the integration of these technologies with other decarbonisation interventions such as material efficiency and electrification. The technology focus also omits the importance that a favourable location and shared history and culture appears to have played in helping progress the most advanced initiatives; factors that cannot be easily replicated elsewhere. If clusters are to kick-start the low-carbon industrial transition then greater attention is needed to the social and political dimensions of this process and to a broader range of decarbonisation interventions and cluster types than represented by current projects.
Toward Green Steel: Modelling and Environmental Economic Analysis of Iron Direct Reduction with Different Reducing Gases
Sep 2023
Publication
The objective of the paper is to simulate the whole steelmaking process cycle based on Direct Reduced Iron and Electric Arc Furnace technologies by modeling for the first time the reduction furnace based on kinetic approach to be used as a basis for the environmental and techno-economic plant analysis by adopting different reducing gases. In addition the impact of carbon capture section is discussed. A complete profitability analysis has been conducted for the first time adopting a Monte Carlo simulation approach.<br/>In detail the use of syngas from methane reforming syngas and hydrogen from gasification of municipal solid waste and green hydrogen from water electrolysis are analyzed. The results show that the Direct Reduced Iron process with methane can reduce CO2 emissions by more than half compared to the blast furnace based-cycle and with the adoption of carbon capture greenhouse gas emissions can be reduced by an additional 40%. The use of carbon capture by amine scrubbing has a limited economic disadvantage compared to the scenario without it becoming profitable once carbon tax is included in the analysis. However it is with the use of green hydrogen from electrolyzer that greenhouse gas emissions can be cut down almost completely. To have an environmental benefit compared with the methane-based Direct Reduced Iron process the green hydrogen plant must operate for at least 5136 h per year (64.2% of the plant's annual operating hours) on renewable energy.<br/>In addition the use of syngas and separated hydrogen from municipal solid waste gasification is evaluated demonstrating its possible use with no negative effects on the quality of produced steel. The results show that hydrogen use from waste gasification is more economic with respect to green hydrogen from electrolysis but from the environmental viewpoint the latter results the best alternative. Comparing the use of hydrogen and syngas from waste gasification it can be stated that the use of the former reducing gas results preferable from both the economic and environmental viewpoint.
Identification of Hydrogen-Energy-Related Emerging Technologies Based on Text Mining
Dec 2023
Publication
As a versatile energy carrier hydrogen possesses tremendous potential to reduce greenhouse emissions and promote energy transition. Global interest in producing hydrogen from renewable energy sources and transporting storing and utilizing hydrogen is rising rapidly. However the high costs of producing clean hydrogen and the uncertain application scenarios for hydrogen energy result in its relatively limited utilization worldwide. It is necessary to find new promising technological paths to drive the development of hydrogen energy. As part of technological innovation emerging technologies have vital features such as prominent impact novelty relatively fast growth etc. Identifying emerging hydrogen-energy-related technologies is important for discovering innovation opportunities during the energy transition. Existing research lacks analysis of the characteristics of emerging technologies. Thus this paper proposes a method combining the latent Dirichlet allocation topic model and hydrogen-energy expert group decision-making. This is used to identify emerging hydrogen-related technology regarding two features of emerging technologies novelty and prominent impact. After data processing topic modeling and analysis the patent dataset was divided into twenty topics. Six emerging topics possess novelty and prominent impact among twenty topics. The results show that the current hotspots aim to promote the application of hydrogen energy by improving the performance of production catalysts overcoming the wide power fluctuations and large-scale instability of renewable energy power generation and developing advanced hydrogen safety technologies. This method efficiently identifies emerging technologies from patents and studies their development trends. It fills a gap in the research on emerging technologies in hydrogen-related energy. Research achievements could support the selection of technology pathways during the low-carbon energy transition.
A Comprehensive Review on Condition Monitoring and Fault Diagnosis in Fuel Cell Systems: Challenges and Issues
Jan 2024
Publication
The complexity of Fuel Cell (FC) systems demands a profound and sustained understanding of the various phenomena occurring inside of it. Thus far FCs especially Proton Exchange Membrane Fuel Cells (PEMFCs) have been recognized as being among the most promising technologies for reducing Green House Gas (GHG) emissions because they can convert the chemical energy bonded to hydrogen and oxygen into electricity and heat. However their efficiency remains limited. To enhance their efficiency two distinct factors are suggested. First the quality of materials plays a significant role in the development of more robust and efficient FCs. Second the ability to identify mitigate and reduce the occurrence of faults through the use of robust control algorithms is crucial. Therefore more focused on the second point this paper compiles distinguishes and analyzes several publications from the past 25 years related to faults and their diagnostic techniques in FCs. Furthermore the paper presents various schemes outlining different symptoms their causes and corresponding fault algorithms.
Techno-economic Modelling of AEM Electrolysis Systems to Identify Ideal Current Density and Aspects Requiring Further Research
Aug 2023
Publication
Hydrogen produced by water electrolysis using renewable energy is a sustainable alternative to steam reformation. As a nascent commercial technology performance and economic comparisons of anion exchange membrane water electrolyzers (AEMWE) to other electrolyzer technology benchmarks are not available. We present a techno-economic model estimating AEMWE's baseline levelized cost of hydrogen (LCOH) at $5.79/kg considering trade-offs between current density efficiency stability capital and operating costs. The optimal current density is 1.38 A cm2 balancing stability and performance for the lowest LCOH. Using low-cost electricity and larger stack sizes AEMWE could achieve $2/kg low-carbon hydrogen. Technical improvements targeting system efficiency particularly reducing overpotentials in hydrogen and oxygen evolution reactions could further reduce LCOH to $1.29/kg approaching U.S. Department of Energy cost targets. There are hopes this model could raise the profile of AEMWE's economic potential to produce green hydrogen and highlight its suitability for decarbonizing the energy sector.
A Complete Assessment of the Emission Performance of an SI Engine Fueled with Methanol, Methane and Hydrogen
Feb 2024
Publication
This study explores the potentiality of low/zero carbon fuels such as methanol methane and hydrogen for motor applications to pursue the goal of energy security and environmental sustainability. An experimental investigation was performed on a spark ignition engine equipped with both a port fuel and a direct injection system. Liquid fuels were injected into the intake manifold to benefit from a homogeneous charge formation. Gaseous fuels were injected in direct mode to enhance the efficiency and prevent abnormal combustion. Tests were realized at a fixed indicated mean effective pressure and at three different engine speeds. The experimental results highlighted the reduction of CO and CO2 emissions for the alternative fuels to an extent depending on their properties. Methanol exhibited high THC and low NOx emissions compared to gasoline. Methane and even more so hydrogen allowed for a reduction in THC emissions. With regard to the impact of gaseous fuels on the NOx emissions this was strongly related to the operating conditions. A surprising result concerns the particle emissions that were affected not only by the fuel characteristics and the engine test point but also by the lubricating oil. The oil contribution was particularly evident for hydrogen fuel which showed high particle emissions although they did not contain carbon atoms.
Techno-economic Analysis of Underground Hydrogen Storage in Europe
Dec 2023
Publication
Hydrogen storage is crucial to developing secure renewable energy systems to meet the European Union’s 2050 carbon neutrality objectives. However a knowledge gap exists concerning the site-specific performance and economic viability of utilizing underground gas storage (UGS) sites for hydrogen storage in Europe. We compile information on European UGS sites to assess potential hydrogen storage capacity and evaluate the associated current and future costs. The total hydrogen storage potential in Europe is 349 TWh of working gas energy (WGE) with site-specific capital costs ranging from $10 million to $1 billion. Porous media and salt caverns boasting a minimum storage capacity of 0.5 TWh WGE exhibit levelized costs of $1.5 and $0.8 per kilogram of hydrogen respectively. It is estimated that future levelized costs associated with hydrogen storage can potentially decrease to as low as $0.4 per kilogram after three experience cycles. Leveraging these techno-economic considerations we identify suitable storage sites.
Role of a Unitized Regenerative Fuel Cell in Remote Area Power Supply: A Review
Aug 2023
Publication
This manuscript presents a thorough review of unitized regenerative fuel cells (URFCs) and their importance in Remote Area Power Supply (RAPS). In RAPS systems that utilize solar and hydrogen power which typically include photovoltaic modules a proton exchange membrane (PEM) electrolyzer hydrogen gas storage and PEM fuel cells the cost of these systems is currently higher compared to conventional RAPS systems that employ diesel generators or batteries. URFCs offer a potential solution to reduce the expenses of solar hydrogen renewable energy systems in RAPS by combining the functionalities of the electrolyzer and fuel cell into a single unit thereby eliminating the need to purchase separate and costly electrolyzer and fuel cell units. URFCs are particularly well-suited for RAPS applications because the electrolyzer and fuel cell do not need to operate simultaneously. In electrolyzer mode URFCs function similarly to stand-alone electrolyzers. However in fuel cell mode the performance of URFCs is inferior to that of stand-alone fuel cells. The presented review summarizes the past present and future of URFCs with details on the operating modes of URFCs limitations and technical challenges and applications. Solar hydrogen renewable energy applications in RAPS and challenges facing solar hydrogen renewable energy in the RAPS is discussed in detail.
The Cost of Clean Hydrogen from Offshore Wind and Electrolysis
Feb 2024
Publication
The decarbonization of industry heating and transportation is a major challenge for many countries’ energy transition. Hydrogen is a direct low-carbon fuel alternative to natural gas offering a higher flexibility in the range of possible applications yet currently most hydrogen is produced using carbonintensive steam methane reforming due to cost considerations. Therefore this study explores the economics of a prominent low-carbon method of hydrogen production comparing the cost of hydrogen generation from offshore wind farms with and without grid electricity imports to conventional hydrogen production methods. A novel techno-economic model for offshore electrolysis production costs is presented which makes hydrogen production fully dispatchable leveraging geological salt-cavern storage. This model determines the lifetime costs aportioned across the system components as well as the Levelized Cost of Hydrogen (LCOH). Using the United Kingdom as a case study LCOH from offshore wind power is calculated to be €8.68 /kgH2 using alkaline electrolysis (AEL) €10.49 /kgH2 using proton exchange membrane electrolysis (PEMEL) and €10.88 /kgH2 with grid electricity to backup the offshore wind power. A stochastic Monte-Carlo model is used to asses the uncertainty on costs and identify the cost of capital electrolyser and wind farm capital costs and cost of electricity as the most important drivers of LCOH across the different scenarios. Reducing the capital cost to comparative levels observed on today’s wind farms alone could see AEL LCOH fall to €5.32 /kgH2 near competitive with conventional generation methods.
A New Generation of Hydrogen-Fueled Hybrid Propulsion Systems for the Urban Mobility of the Future
Dec 2023
Publication
The H2-ICE project aims at developing through numerical simulation a new generation of hybrid powertrains featuring a hydrogen-fueled Internal Combustion Engine (ICE) suitable for 12 m urban buses in order to provide a reliable and cost-effective solution for the abatement of both CO2 and criteria pollutant emissions. The full exploitation of the potential of such a traction system requires a substantial enhancement of the state of the art since several issues have to be addressed. In particular the choice of a more suitable fuel injection system and the control of the combustion process are extremely challenging. Firstly a high-fidelity 3D-CFD model will be exploited to analyze the in-cylinder H2 fuel injection through supersonic flows. Then after the optimization of the injection and combustion process a 1D model of the whole engine system will be built and calibrated allowing the identification of a “sweet spot” in the ultra-lean combustion region characterized by extremely low NOx emissions and at the same time high combustion efficiencies. Moreover to further enhance the engine efficiency well above 40% different Waste Heat Recovery (WHR) systems will be carefully scrutinized including both Organic Rankine Cycle (ORC)-based recovery units as well as electric turbo-compounding. A Selective Catalytic Reduction (SCR) aftertreatment system will be developed to further reduce NOx emissions to near-zero levels. Finally a dedicated torque-based control strategy for the ICE coupled with the Energy Management Systems (EMSs) of the hybrid powertrain both optimized by exploiting Vehicle-To-Everything (V2X) connection allows targeting H2 consumption of 0.1 kg/km. Technologies developed in the H2-ICE project will enhance the know-how necessary to design and build engines and aftertreatment systems for the efficient exploitation of H2 as a fuel as well as for their integration into hybrid powertrains.
Conflicts Between Economic and Low-carbon Reorientation Processes: Insights from a Contextual Analysis of Evolving Company Strategies in the United Kingdrom Petrochemical Industry (1970-2021)
Jul 2022
Publication
To situate its low-carbon transition process in longer-term real-world business contexts this article makes a longitudinal analysis of the UK petrochemical industry focusing on changing economic and socio-political environments and company strategies in the last 50 years. Using the Triple Embeddedness Framework the paper identifies two parallel and conflicting reorientation processes in the UK petrochemical industry. The first one which started in the 1970s and is driven by long-standing competitiveness problems led to retrenchment in the 1980s exit of incumbent companies (BP Shell ICI) and the entry of new firms (INEOS SABIC) in the 1990s and 2000s and diversification into upstream fossil fuel production and ethane imports in the 2010s. The second reorientation process which started in the 2010s is driven by climate change considerations and has led petrochemical firms to reluctantly explore low-carbon alternatives. Despite advancing ambitious visions and plans companies are weakly committed to low-carbon reorientation because this is layered on top of and conflicts with the deeper economically-motivated reorientation process. The paper further concludes that the industry's low-carbon plans and visions are partial because they focus more on some innovations (hydrogen-as-fuel CCS) than on other innovations (recycling bio-feedstocks synthetic feedstocks). Despite exploring alternatives firms also use political resistance strategies to hamper and delay deeper low-carbon reorientation
The Role of Hydrogen Storage in an Electricity System with Large Hydropower Resources
Feb 2024
Publication
Hydrogen is considered one of the key pillars of an effective decarbonization strategy of the energy sector; however the potential of hydrogen as an electricity storage medium is debated. This paper investigates the role of hydrogen as an electricity storage medium in an electricity system with large hydropower resources focusing on the Swiss electricity sector. Several techno-economic and climate scenarios are considered. Findings suggest that hydrogen storage plays no major role under most conditions because of the large hydropower resources. More specifically no hydrogen storage is installed in Switzerland if today’s values of net-transfer capacities and low load-shedding costs are assumed. This applies even to hydrogen-favorable climate scenarios (dry years with low precipitation and dam inflows) and economic assumptions (high learning rates for hydrogen technologies). In contrast hydrogen storage is installed when net-transfer capacities between countries are reduced below 30% of current values and load-shedding costs are above 1000 EUR/MWh. When installed hydrogen is deployed in a few large-scale installations near the national borders.
Hydrogen-Based Energy Systems: Current Technology Development Status, Opportunities and Challenges
Dec 2023
Publication
The use of hydrogen as an energy carrier within the scope of the decarbonisation of the world’s energy production and utilisation is seen by many as an integral part of this endeavour. However the discussion around hydrogen technologies often lacks some perspective on the currently available technologies their Technology Readiness Level (TRL) scope of application and important performance parameters such as energy density or conversion efficiency. This makes it difficult for the policy makers and investors to evaluate the technologies that are most promising. The present study aims to provide help in this respect by assessing the available technologies in which hydrogen is used as an energy carrier including its main challenges needs and opportunities in a scenario in which fossil fuels still dominate global energy sources but in which renewables are expected to assume a progressively vital role in the future. The production of green hydrogen using water electrolysis technologies is described in detail. Various methods of hydrogen storage are referred including underground storage physical storage and material-based storage. Hydrogen transportation technologies are examined taking into account different storage methods volume requirements and transportation distances. Lastly an assessment of well-known technologies for harnessing energy from hydrogen is undertaken including gas turbines reciprocating internal combustion engines and fuel cells. It seems that the many of the technologies assessed have already achieved a satisfactory degree of development such as several solutions for high-pressure hydrogen storage while others still require some maturation such as the still limited life and/or excessive cost of the various fuel cell technologies or the suitable operation of gas turbines and reciprocating internal combustion engines operating with hydrogen. Costs below 200 USD/kWproduced lives above 50 kh and conversion efficiencies approaching 80% are being aimed at green hydrogen production or electricity production from hydrogen fuel cells. Nonetheless notable advances have been achieved in these technologies in recent years. For instance electrolysis with solid oxide cells may now sometimes reach up to 85% efficiency although with a life still in the range of 20 kh. Conversely proton exchange membrane fuel cells (PEMFCs) working as electrolysers are able to sometimes achieve a life in the range of 80 kh with efficiencies up to 68%. Regarding electricity production from hydrogen the maximum efficiencies are slightly lower (72% and 55% respectively). The combination of the energy losses due to hydrogen production compression storage and electricity production yields overall efficiencies that could be as low as 25% although smart applications such as those that can use available process or waste heat could substantially improve the overall energy efficiency figures. Despite the challenges the foreseeable future seems to hold significant potential for hydrogen as a clean energy carrier as the demand for hydrogen continues to grow particularly in transportation building heating and power generation new business prospects emerge. However this should be done with careful regard to the fact that many of these technologies still need to increase their technological readiness level before they become viable options. For this an emphasis needs to be put on research innovation and collaboration among industry academia and policymakers to unlock the full potential of hydrogen as an energy vector in the sustainable economy.
Optimal Scheduling of an Electric-Hydrogen-Integrated Energy System Considering Virtual Energy Storage
Jan 2024
Publication
In this paper a two-layer optimization approach is proposed to facilitate the multi-energy complementarity and coupling and optimize the system configuration in an electric-hydrogen-integrated energy system (EH-IES). Firstly an EH-IES with virtual energy storage is proposed to reduce the cost of physical energy storage equipment. Secondly a two-layer optimal allocation method is proposed under a multi-timescale strategy to examine the comprehensive evaluation index of environmental protection and economy. The upper layer utilizes the NSGA-II multi-objective optimization method for system capacity allocation while the lower layer performs economic dispatch at the lowest cost. Ultimately the output includes the results of the equipment capacity allocation of the EH-IES that satisfies the reliability constraint interval and the daily scheduling results of the equipment. The results demonstrate that the electric-hydrogen-integrated energy system with the coupling of multiple energy equipment not only enhances the utilization of renewable energy sources but also reduces the usage of fossil energy and improves the system’s reliability.
Regime-driven Niches and Institutional Entrepreneurs: Adding Hydrogen to Regional Energy Systems in Germany
Nov 2023
Publication
In recent years production and supply of hydrogen has gained significant attention within the German energy transition. This is due to increasingly urgent pressures to mitigate climate change and geopolitical imperatives to substitute natural gas. Hydrogen is seen as an important cross-sectoral energy carrier serving multiple functions including heat production for industry and households fuel for transportation and energy storage for stabilization of electricity supply. In the context of various funding mechanisms on several administrative levels regional value chains for green hydrogen supply are emerging. To date however few studies analyzing regional hydrogen systems exist. Due to its high projected demand of energy sources for heating industrial processes and mobility Germany appears to be a very relevant research area in this emerging field. Situated within the concept of the multi-level perspective this article examines the way how regional “niches” of green hydrogen evolve and how they are organized. The study takes an evolutionary perspective in analyzing processes of embedding green hydrogen infrastructures in regional energy regimes which entered “re-configuration”-pathways. It argues that the congruence of available resources for renewable electricity established networks of institutional entrepreneurs and access to higher level funding are conditions which put incumbent regime-actors in favorable positions to implement green hydrogen niches. Conversely the embedding of green hydrogen infrastructures in regional energy systems is a case in point of how the attributes of niches in particular technological domains can be used to explain the transition pathway entered by a surrounding energy regime.
Renewable Energy Sources for Green Hydrogen Generation in Colombia and Applicable Case of Studies
Nov 2023
Publication
Electrification using renewable energy sources represents a clear path toward solving the current global energy crisis. In Colombia this challenge also involves the diversification of the electrical energy sources to overcome the historical dependence on hydropower. In this context green hydrogen represents a key energy carrier enabling the storage of renewable energy as well as directly powering industrial and transportation sectors. This work explores the realistic potential of the main renewable energy sources including solar photovoltaics (8172 GW) hydropower (56 GW) wind (68 GW) and biomass (14 GW). In addition a case study from abroad is presented demonstrating the feasibility of using each type of renewable energy to generate green hydrogen in the country. At the end an analysis of the most likely regions in the country and paths to deploy green hydrogen projects are presented favoring hydropower in the short term and solar in the long run. By 2050 this energy potential will enable reaching a levelized cost of hydrogen (LCOH) of 1.7 1.5 3.1 and 1.4 USD/kg-H2 for solar photovoltaic wind hydropower and biomass respectively.
Applying a 2 kW Polymer Membrane Fuel-Cell Stack to Building Hybrid Power Sources for Unmanned Ground Vehicles
Nov 2023
Publication
The novel constructions of hybrid energy sources using polymer electrolyte fuel cells (PEMFCs) and supercapacitors are developed. Studies on the energy demand and peak electrical power of unmanned ground vehicles (UGVs) weighing up to 100 kg were conducted under various conditions. It was found that the average electrical power required does not exceed ~2 kW under all conditions studied. However under the dynamic electrical load of the electric drive of mobile robots the short peak power exceeded 2 kW and the highest current load was in the range of 80–90 A. The electrical performance of a family of PEMFC stacks built in open-cathode mode was determined. A hydrogen-usage control strategy for power generation cleaning processes and humidification was analysed. The integration of a PEMFC stack with a bank of supercapacitors makes it possible to mitigate the voltage dips. These occur periodically at short time intervals as a result of short-circuit operation. In the second construction the recovery of electrical energy dissipated by a short-circuit unit (SCU) was also demonstrated in the integrated PEMFC stack and supercapacitor bank system. The concept of an energy-efficient mobile and environmentally friendly hydrogen charging unit has been proposed. It comprises (i) a hydrogen anion exchange membrane electrolyser (ii) a photovoltaic installation (iii) a battery storage (iv) a hydrogen buffer storage in a buffer tank (v) a hydrogen compression unit and (vi) composite tanks.
Eco-Sustainable Energy Production in Healthcare: Trends and Challenges in Renewable Energy Systems
Oct 2023
Publication
The shift from fossil fuels to renewable energy systems represents a pivotal step toward the realization of a sustainable society. This study aims to analyze representative scientific literature on eco-sustainable energy production in the healthcare sector particularly in hospitals. Given hospitals’ substantial electricity consumption the adoption of renewable energy offers a reliable low-CO2 emission solution. The COVID-19 pandemic has underscored the urgency for energyefficient and environmentally-responsible approaches. This brief review analyzes the development of experimental simulation and optimization projects for sustainable energy production in healthcare facilities. The analysis reveals trends and challenges in renewable energy systems offering valuable insights into the potential of eco-sustainable solutions in the healthcare sector. The findings indicate that hydrogen storage systems are consistently coupled with photovoltaic panels or solar collectors but only 14% of the analyzed studies explore this potential within hospital settings. Hybrid renewable energy systems (HRES) could be used to meet the energy demands of healthcare centers and hospitals. However the integration of HRES in hospitals and medical buildings is understudied.
Current Status and Economic Analysis of Green Hydrogen Energy Industry Chain
Feb 2024
Publication
Under the background of the power system profoundly reforming hydrogen energy from renewable energy as an important carrier for constructing a clean low-carbon safe and efficient energy system is a necessary way to realize the objectives of carbon peaking and carbon neutrality. As a strategic energy source hydrogen plays a significant role in accelerating the clean energy transition and promoting renewable energy. However the cost and technology are the two main constraints to green hydrogen energy development. Herein the technological development status and economy of the whole industrial chain for green hydrogen energy “production-storage-transportation-use” are discussed and reviewed. After analysis the electricity price and equipment cost are key factors to limiting the development of alkaline and proton exchange membrane hydrogen production technology; the quantity scale and distance of transportation are key to controlling the costs of hydrogen storage and transportation. The application of hydrogen energy is mainly concentrated in the traditional industries. With the gradual upgrading and progress of the top-level design and technology the application of hydrogen energy mainly including traffic transportation industrial engineering energy storage power to gas and microgrid will show a diversified development trend. And the bottleneck problems and development trends of the hydrogen energy industry chain are also summarized and viewed.
Thermal Design and Heat Transfer Optimisation of a Liquid Organic Hydrogen Carrier Batch Reactor for Hydrogen Storage
Aug 2023
Publication
Liquid organic hydrogen carriers (LOHCs) are considered a promising hydrogen storage technology. Heat must be exchanged with an external medium such as a heat transfer fluid for the required chemical reactions to occur. Batch reactors are simple but useful solutions for small-scale storage applications which can be modelled with a lumped parameter approach adequately reproducing their dynamic performance. For such reactors power is consumed to circulate the external heat transfer fluid and stir the organic liquid inside the reactor and heat transfer performance and power consumption are two key parameters in reactor optimisation. Therefore with reference to the hydrogen release phase this paper describes a procedure to optimise the reactor thermal design based on a lumped-parameter model in terms of heat transfer performance and minimum power consumption. Two batch reactors are analysed: a conventional jacketed reactor with agitation nozzles and a half-pipe coil reactor. Heat transfer performance is evaluated by introducing a newly defined dimensionless parameter the Heat Transfer Ratio (HTR) whose value directly correlates to the heat rate required by the carrier's dehydrogenation reaction. The resulting model is a valid tool for adequately reproducing the hydrogen storage behaviour within dynamic models of complex and detailed energy systems.
Techno-economic Analysis and Predictive Operation of a Power-to-hydrogen for Renewable Microgrids
Oct 2023
Publication
To enhance renewable energy (RE) generation and maintain power balance energy storage systems are of utmost importance. This research introduces a cutting-edge Power-to-Hydrogen (PtH) framework that harnesses hydrogen as a clean and versatile energy storage medium. The primary focus of this study lies in optimizing power flow within a microgrid (G) equipped with RE and energy storage systems considering various factors such as RE generation power demand battery charge cycles and operational costs. To achieve the optimal balance between power generation and consumption a sophisticated mathematical solution is devised. This solution governs the charging and discharging patterns for both battery and electrolyzer ensuring a harmonious power equilibrium. The use of short-term forecasting further refines the optimization process adapting the parameters based on anticipated RE sources and load requirements. To fine-tune the power management solution for day-to-day operations an artificial neural fuzzy inference system (ANFIS)-based shortterm prediction model is employed. The predictive analysis provides confidence intervals for crucial aspects including power generation demand battery charging cycles and hydrogen generation. This facilitates precise cost estimation across various hydrogen and heat price ranges. the proposed PtH optimization framework offers an efficient approach to balance power generation and consumption in Gs driven by RE sources and energy storage. To validate the proposed approach numerical simulations are performed based on data from wind and solar farms load requirements and cost of energy. The results show that the proposed energy management strategy significantly reduces operational costs and optimizes PtH generation while maintaining power balance within the microgrid (G). The predictive approach helps fine-tune the optimization process improving efficiency and cost-effectiveness. The research convincingly demonstrate the economic advantages of adopting hydrogen as an energy storage medium paving the way for a cleaner and more sustainable energy future.
Three-Stage Modeling Framework for Analyzing Islanding Capabilities of Decarbonized Energy Communities
May 2023
Publication
Contrary to microgrids (MGs) for which grid code or legislative support are lacking in the majority of cases energy communities (ECs) are one of the cornerstones of the energy transition backed up by the EU’s regulatory framework. The main difference is that unlike MGs ECs grow and develop organically through citizen involvement and investments in the existing low-voltage (LV) distribution networks. They are not planned and built from scratch as closed distribution systems that are independent of distribution system operator plans as assumed in the existing literature. An additional benefit of ECs could be the ability to transition into island mode contributing to the resilience of power networks. To this end this paper proposes a three-stage framework for analyzing the islanding capabilities of ECs. The framework is utilized to comprehensively assess and compare the islanding capabilities of ECs whose organic development is based upon three potential energy vectors: electricity gas and hydrogen. Detailed dynamic simulations clearly show that only fully electrified ECs inherently have adequate islanding capabilities without the need for curtailment or additional investments.
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