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Experimental Study on the Cycle Variation Characteristics of Direct Injection Hydrogen Engine
Jun 2022
Publication
Hydrogen energy is an important technical route to achieve carbon peak and carbon neutrality. Direct injection hydrogen engine is one of the ways of hydrogen energy application. It has the advantages of high thermal efficiency and limit/reduce abnormal combustion phenomena. In order to explore the cycle characteristics of direct injection hydrogen engine based on a 2.0L direct injection hydrogen engine an experimental study on the cycle characteristics of direct injection hydrogen engine was carried out. The experimental results show that cycle variation increases from 0.67% to 1.02% with the increasing of engine speed. The cycle variation decreases from 1.52% to 0.64% with the increasing of engine load. As the equivalence ratio increases the cycle variation first decreases significantly from 2.52% to 0.35% and then stabilizes. The ignition advance angle has a better angle to minimize the cycle variation. An experimental study on the influence of the start of injection on the cycle variation was carried out. As the engine speed/engine load is 2000rpm/4bar the cycle variation increases from 0.72% to 2.42% with the start of injection changing from -280°CA to -180°CA; then rapidly decreases to 0.99% and then increases to 2.26% with the start of injection changing from -180°CA to -100°CA. The experimental results show that SOI could cause significant influence on cycle variation because of intake valve closing and shortening mixing time and both the process of intake valve closing and lagging the SOI could cause the cycle variation to increase. The SOI remarkably affects the cycle variation at low engine load/equivalence ratio and high engine speed. This study lays the foundation for the follow-up research of hydrogen engine performance matching of the cycle variation.
Investigation of Mixing Behavior of Hydrogen Blended to Natural Gas in Gas Network
Apr 2021
Publication
Hydrogen is of great significance for replacing fossil fuels and reducing carbon dioxide emissions. The application of hydrogen mixing with natural gas in gas network transportation not only improves the utilization rate of hydrogen energy but also reduces the cost of large-scale updating household or commercial appliance. This paper investigates the necessity of a gas mixing device for adding hydrogen to existing natural gas pipelines in the industrial gas network. A three-dimensional helical static mixer model is developed to simulate the mixing behavior of the gas mixture. In addition the model is validated with experimental results. Parametric studies are performed to investigate the effect of mixer on the mixing performance including the coefficient of variation (COV) and pressure loss. The research results show that based on the the optimum number of mixing units is three. The arrangement of the torsion angle of the mixing unit has a greater impact on the COV. When the torsion angle θ = 120◦ the COV has a minimum value of 0.66% and when the torsion angle θ = 60◦ the COV has a maximum value of 8.54%. The distance of the mixing unit has little effect on the pressure loss of the mixed gas but has a greater impact on the COV. Consecutive arrangement of the mixing units (Case A) is the best solution. Increasing the distance of the mixing unit is not effective for the gas mixing effect. Last but not least the gas mixer is optimized to improve the mixing performance.
Deployment of Fuel Cell Vehicles and Hydrogen Refueling Station Infrastructure: A Global Overview and Perspectives
Jul 2022
Publication
Hydrogen fuel cell vehicles can complement other electric vehicle technologies as a zeroemission technology and contribute to global efforts to achieve the emission reduction targets. This article spotlights the current deployment status of fuel cells in road transport. For this purpose data collection was performed by the Advanced Fuel Cells Technology Collaboration Programme. Moreover the available incentives for purchasing a fuel cell vehicle in different countries were reviewed and future perspectives summarized. Based on the collected information the development trends in the last five years were analyzed and possible further trends that could see the realization of the defined goals derived. The number of registered vehicles was estimated to be 51437 units with South Korea leading the market with 90% of the vehicles being concentrated in four countries. A total of 729 hydrogen refueling stations were in operation with Japan having the highest number of these. The analysis results clearly indicate a very positive development trend for fuel cell vehicles and hydrogen refueling stations in 2021 with the highest number of new vehicles and stations in a single year paralleling the year’s overall economic recovery. Yet a more ambitious ramp-up in the coming years is required to achieve the set targets.
Influence of Hydrogen Environment on Fatigue Fracture Morphology of X80 Pipeline Steel
Dec 2022
Publication
The rapid development of hydrogen energy requires the use of natural gas infrastructure for hydrogen transportation. It is very important to study hydrogen-added natural gas transportation technology which is a key way to rapidly develop coal-based gas and renewable energy. This study aims to study the influence of X80 pipeline steel's fatigue performance in hydrogen environment and perform fatigue tests on notched round rod specimens under different hydrogen concentration. The experimental results show that hydrogen seriously affects the fatigue life of pipeline steel. After reaching a certain hydrogen concentration as the hydrogen concentration continues to increase the fatigue life decreases gradually. Combined with SEM analysis of fracture morphology the decrease in the size and density of the dimples reduces the displacement amplitude while the increase in the planar area increases the displacement during fatigue fracture due to accelerated crack propagation. From this study we can know the influence of hydrogen concentration on the fracture morphology of pipeline steel which provides an understanding of the effect of hydrogen on fatigue fracture morphology and a broader safety analysis.
Hydrogen Fuel for Future Mobility: Challenges and Future Aspects
Jul 2022
Publication
Nowadays the combustion of fossil fuels for transportation has a major negative impact on the environment. All nations are concerned with environmental safety and the regulation of pollution motivating researchers across the world to find an alternate transportation fuel. The transition of the transportation sector towards sustainability for environmental safety can be achieved by the manifestation and commercialization of clean hydrogen fuel. Hydrogen fuel for sustainable mobility has its own effectiveness in terms of its generation and refueling processes. As the fuel requirement of vehicles cannot be anticipated because it depends on its utilization choosing hydrogen refueling and onboard generation can be a point of major concern. This review article describes the present status of hydrogen fuel utilization with a particular focus on the transportation industry. The advantages of onboard hydrogen generation and refueling hydrogen for internal combustion are discussed. In terms of performance affordability and lifetime onboard hydrogen-generating subsystems must compete with what automobile manufacturers and consumers have seen in modern vehicles to date. In internal combustion engines hydrogen has various benefits in terms of combustive properties but it needs a careful engine design to avoid anomalous combustion which is a major difficulty with hydrogen engines. Automobile makers and buyers will not invest in fuel cell technology until the technologies that make up the various components of a fuel cell automobile have advanced to acceptable levels of cost performance reliability durability and safety. Above all a substantial advancement in the fuel cell stack is required.
A Brief Review of Hydrogen Production Methods and Their Challenges
Jan 2023
Publication
Hydrogen is emerging as a new energy vector outside of its traditional role and gaining more recognition internationally as a viable fuel route. This review paper offers a crisp analysis of the most recent developments in hydrogen production techniques using conventional and renewable energy sources in addition to key challenges in the production of Hydrogen. Among the most potential renewable energy sources for hydrogen production are solar and wind. The production of H2 from renewable sources derived from agricultural or other waste streams increases the flexibility and improves the economics of distributed and semi-centralized reforming with little or no net greenhouse gas emissions. Water electrolysis equipment driven by off-grid solar or wind energy can also be employed in remote areas that are away from the grid. Each H2 manufacturing technique has technological challenges. These challenges include feedstock type conversion efficiency and the need for the safe integration of H2 production systems with H2 purification and storage technologies.
Deep Reinforcement Learning Based Energy Management Strategy for Fuel Cell/Battery/Supercapacitor Powered Electric Vehicle
Sep 2022
Publication
Vehicles using a single fuel cell as a power source often have problems such as slow response and inability to recover braking energy. Therefore the current automobile market is mainly dominated by fuel cell hybrid vehicles. In this study the fuel cell hybrid commercial vehicle is taken as the research object and a fuel cell/ battery/supercapacitor energy topology is proposed and an energy management strategy based on a doubledelay deep deterministic policy gradient is designed for this topological structure. This strategy takes fuel cell hydrogen consumption fuel cell life loss and battery life loss as the optimization goals in which supercapacitors play the role of coordinating the power output of the fuel cell and the battery providing more optimization ranges for the optimization of fuel cells and batteries. Compared with the deep deterministic policy gradient strategy (DDPG) and the nonlinear programming algorithm strategy this strategy has reduced hydrogen consumption level fuel cell loss level and battery loss level which greatly improves the economy and service life of the power system. The proposed EMS is based on the TD3 algorithm in deep reinforcement learning and simultaneously optimizes a number of indicators which is beneficial to prolong the service life of the power system.
Effect of Hydrogen Blending on the Energy Capacity of Natural Gas Transmission Networks
Dec 2022
Publication
In this paper the effects of hydrogen on the transport of natural gas-hydrogen mixture in a high-pressure natural gas transmission system are investigated in detail. Our research focuses on the decrease in transferable energy content under identical operating conditions as hydrogen is blended in the gas transmission network. Based on the extensive literature review the outstanding challenges and key questions of using hydrogen in the natural gas system are introduced. In our research the transmissible energy factor - TEF - is defined that quantifies the relative energy capacity of the pipeline caused by hydrogen blending. A new equation is proposed in this paper to find the value of TEF at specific pressure and temperature conditions for different hydrogen concentrations. This practical equation helps the natural gas system operators in the decision-making process when hydrogen emerges in the gas transmission system. In this paper the change of the compression power requirement which increases significantly with hydrogen blending is investigated in detail.
High Technical and Temporal Resolution Integrated Energy System Modelling of Industrial Decarbonisation
Aug 2022
Publication
Owing to the complexity of the sector industrial activities are often represented with limited technological resolution in integrated energy system models. In this study we enriched the technological description of industrial activities in the integrated energy system analysis optimisation (IESA-Opt) model a peer-reviewed energy system optimisation model that can simultaneously provide optimal capacity planning for the hourly operation of all integrated sectors. We used this enriched model to analyse the industrial decarbonisation of the Netherlands for four key activities: high-value chemicals hydrocarbons ammonia and steel production. The analyses performed comprised 1) exploring optimality in a reference scenario; 2) exploring the feasibility and implications of four extreme industrial cases with different technological archetypes namely a bio-based industry a hydrogen-based industry a fully electrified industry and retrofitting of current assets into carbon capture utilisation and storage; and 3) performing sensitivity analyses on key topics such as imported biomass hydrogen and natural gas prices carbon storage potentials technological learning and the demand for olefins. The results of this study show that it is feasible for the energy system to have a fully bio-based hydrogen-based fully electrified and retrofitted industry to achieve full decarbonisation while allowing for an optimal technological mix to yield at least a 10% cheaper transition. We also show that owing to the high predominance of the fuel component in the levelled cost of industrial products substantial reductions in overnight investment costs of green technologies have a limited effect on their adoption. Finally we reveal that based on the current (2022) energy prices the energy transition is cost-effective and fossil fuels can be fully displaced from industry and the national mix by 2050
Renewable-based Zero-carbon Fuels for the Use of Power Generation: A Case Study in Malaysia Supported by Updated Developments Worldwide
Apr 2021
Publication
The existing combustion-centered energy mix in Malaysia has shown that replacing fossil fuels with zero-carbon alternative fuels could be a better approach to achieve the reduction of the carbon footprint of the power generation industry. In this study the potential of zero-carbon alternative fuels generated from renewable sources such as green hydrogen and green ammonia was addressed in terms of the production transport storage and utilization in Malaysia’s thermal power plants. The updated developments associated to green hydrogen and green ammonia across the globe have also been reviewed to support the existing potential in Malaysia. Though green hydrogen and green ammonia are hardly commercialized in Malaysia for the time being numerous potentialities have been identified in utilizing these fuels to achieve the zero-carbon power generation market in Malaysia. The vast and strategic location of natural gas network in Malaysia has the potential to deliver green hydrogen with minimal retrofitting required. Moreover there are active participation of Malaysia’s academic institutions in the development of water electrolysis that is the core process to convert the electricity from renewables plant into hydrogen. Malaysia also has the capacity to use its abundance of depleted gas reservoirs for the storage of green hydrogen. A large number of GT plants in Malaysia would definitely have the potential to utilize hydrogen co-firing with natural gas to minimize the amount of carbon dioxide (CO2) released. The significant number of ammonia production plants in Malaysia could provide a surplus of ammonia to be used as an alternative fuel for power plants. With regard to the energy policy in Malaysia positive acceptance of the implementation of renewable energy has been shown with the introduction of various energy policies aimed at promoting the incorporation of renewables into the energy mix. However there is still inadequate support for the implementation of alternative zero-carbon fuels in Malaysia.
Mathematical Modeling of Unstable Transport in Underground Hydrogen Storage
Apr 2015
Publication
Within the framework of energy transition hydrogen has a great potential as a clean energy carrier. The conversion of electricity into hydrogen for storage and transport is an efficient technological solution capable of significantly reducing the problem of energy shortage. Underground hydrogen storage (UHS) is the best solution to store the large amount of excess electrical energy arising from the excessive over-production of electricity with the objective of balancing the irregular and intermittent energy production typical of renewable sources such as windmills or solar. Earlier studies have demonstrated that UHS should be qualitatively identical to the underground storage of natural gas. Much later however it was revealed that UHS is bound to incur peculiar difficulties as the stored hydrogen is likely to be used by the microorganisms present in the rocks for their metabolism which may cause significant losses of hydrogen. This paper demonstrates that besides microbial activities the hydrodynamic behavior of UHS is very unique and different from that of a natural gas storage.
Economic Analysis of a Zero-carbon Liquefied Hydrogen Tanker Ship
Jun 2022
Publication
The green hydrogen economy is considered one of the sustainable solutions to mitigate climate change. This study provides an economic analysis of a novel liquified hydrogen (LH2) tanker fuelled by hydrogen with a total capacity of ~280000 m3 of liquified hydrogen named ‘JAMILA’. An established economic method was applied to investigate the economic feasibility of the JAMILA ship as a contribution to the future zero-emission target. The systematic economic evaluation determined the net present value of the LH2 tanker internal rate of return payback period and economic value added to support and encourage shipyards and the industrial sector in general. The results indicate that the implementation of the LH2 tanker ship can cover the capital cost of the ship within no more than 2.5 years which represents 8.3% of the assumed 30-year operational life cycle of the project in the best maritime shipping prices conditions and 6 years in the worst-case shipping marine economic conditions. Therefore the assessment of the economic results shows that the LH2 tankers may be a worthwhile contribution to the green hydrogen economy.
Comparison of Alternative Marine Fuels
Sep 2019
Publication
The overall ambition of the study has been to assess the commercial and operational viability of alternative marine fuels based on review existing academic and industry literature. The approach assesses how well six alternative fuels perform compared to LNG fuel on a set of 11 key parameters. Conventional fuels are not covered in this study however 2020 compliant fuels (HFO+scrubber and low sulphur fuels are included in the conclusion for comparative purposes.
A Review of Key Components of Hydrogen Recirculation Subsystem for Fuel Cell Vehicles
Jul 2022
Publication
Hydrogen energy and fuel cell technology are critical clean energy roads to pursue carbon neutrality. The proton exchange membrane fuel cell (PEMFC) has a wide range of commercial application prospects due to its simple structure easy portability and quick start-up. However the cost and durability of the PEMFC system are the main barriers to commercial applications of fuel cell vehicles. In this paper the core hydrogen recirculation components of fuel cell vehicles including mechanical hydrogen pumps ejectors and gas–water separators are reviewed in order to understand the problems and challenges in the simulation design and application of these components. The types and working characteristics of mechanical pumps used in PEMFC systems are summarized. Furthermore corresponding design suggestions are given based on the analysis of the design challenges of the mechanical hydrogen pump. The research on structural design and optimization of ejectors for adapting wide power ranges of PEMFC systems is analyzed. The design principle and difficulty of the gas–water separator are summarized and its application in the system is discussed. In final the integration and control of hydrogen recirculation components controlled cooperatively to ensure the stable pressure and hydrogen supply of the fuel cell under dynamic loads are reviewed.
NewGasMet - Flow Metering of Renewable Gases (Biogas, Biomethane, Hydrogen, Syngas and Mixtures with Natural Gas): Report on the Usable Technologies for Calibrating Gas Meters with Renewable Gases and Currently Available Flow Standards Suitable for Use with Methane, Crude Biogas, Hydrogen and Mixtures of these gases
Mar 2021
Publication
The main goal stated at the Paris agreement is to limit the global temperature rise well below 2 °C above pre-industrial levels. Limiting the increase of global average temperature to 1.5 °C is striven since risks and impacts of the climate change would be reduced drastically. To face these challenges the European Green Deal was invented by the European Commission. The “Green Deal” is a growth strategy which aims to transform the economy of the EU into a resource-efficient modern and competitive one [1-1 1-2]. Figure 1: The key elements of the European Green Deal [1-2] In this context the European Commission proposed that the amount of renewable energy within the EU’s overall energy mix should reach 20 % by 2020 and therefore producing energy by solar and wind plants become even more important. For example the cumulative installed wind farm capacity increased from 117.3 GW in 2013 to a total capacity of 182.163 GW in 2018 within the EU [1-4-1-6]. Due to the fluctuations in energy produced by wind farms storage of electricity is crucial. One possibility for storage is the production of hydrogen via electrolysis using renewable energy sources like wind farms. The hydrogen is then either directly added to the gas distribution grid or is converted to methane with external CO or CO2 which is then added to the gas distribution grid as a substitute [1-4]. Increasing the knowledge about the impact of renewable gases on available gas meters in terms of accuracy and durability is the main object of the EMPIR NEWGASMET project. Therefore in activity A3.1.1 a literature study was performed to provide information on which technologies can be used to calibrate gas meters when using renewable gases.
Enabling the Scale Up of Green Hydrogen in Ireland by Decarbonising the Haulage Sector
Jul 2022
Publication
The current research on green hydrogen can focus from the perspective of production but understanding the demand side is equally important to the initial creation of a hydrogen ecosystem in countries with low industrial activities that can utilise large amounts of hydrogen in the short term. Early movers in these countries must create a demand market in parallel with the green hydrogen plant commissioning. This paper presents research that explores the heavy-duty transport sector as a market-of-interest for early deployment of green hydrogen in Ireland. Conducting a survey-based market research amongst this sector indicate significant interest in hydrogen on the island of Ireland and the barriers the participants presented have been overcome in other jurisdictions. The study develops a model to estimate 1.) the annual hydrogen demand and 2.) the corresponding delivery cost to potential hydrogen consumers either directly or to central hydrogen fuelling hubs.
Operation of Power-to-X-Related Processes Based on Advanced Data-Driven Methods: A Comprehensive Review
Oct 2022
Publication
This study is a systematic analysis of selected research articles about power-to-X (P2X)- related processes. The relevance of this resides in the fact that most of the world’s energy is produced using fossil fuels which has led to a huge amount of greenhouse gas emissions that are the source of global warming. One of the most supported actions against such a phenomenon is to employ renewable energy resources some of which are intermittent such as solar and wind. This brings the need for large-scale longer-period energy storage solutions. In this sense the P2X process chain could play this role: renewable energy can be converted into storable hydrogen chemicals and fuels via electrolysis and subsequent synthesis with CO2. The main contribution of this study is to provide a systematic articulation of advanced data-driven methods and latest technologies such as the Internet of Things (IoT) big data analytics and machine learning for the efficient operation of P2X-related processes. We summarize our findings into different working architectures and illustrate them with a numerical result that employs a machine learning model using historic data to define operational parameters for a given P2X process.
A Review on Numerical Simulation of Hydrogen Production from Ammonia Decomposition
Jan 2023
Publication
Ammonia (NH3 ) is regarded as a promising medium of hydrogen storage due to its large hydrogen storage density decent performance on safety and moderate storage conditions. On the user side NH3 is generally required to decompose into hydrogen for utilization in fuel cells and therefore it is vital for the NH3 -based hydrogen storage technology development to study NH3 decomposition processes and improve the decomposition efficiency. Numerical simulation has become a powerful tool for analyzing the NH3 decomposition processes since it can provide a revealing insight into the heat and mass transfer phenomena and substantial guidance on further improving the decomposition efficiency. This paper reviews the numerical simulations of NH3 decomposition in various application scenarios including NH3 decomposition in microreactors coupled combustion chemical reactors solid oxide fuel cells and membrane reactors. The models of NH3 decomposition reactions in various scenarios and the heat and mass transport in the reactor are elaborated. The effects of reactor structure and operating conditions on the performance of NH3 decomposition reactor are analyzed. It can be found that NH3 decomposition in microchannel reactors is not limited by heat and mass transfer and NH3 conversion can be improved by using membrane reactors under the same conditions. Finally research prospects and opportunities are proposed in terms of model development and reactor performance improvement for NH3 decomposition.
Multilevel Governance, PV Solar Energy, and Entrepreneurship: The Generation of Green Hydrogen as a Fuel of Renewable Origin
Sep 2022
Publication
In Spain the institutional framework for photovoltaic energy production has experienced distinct stages. From 2007 to 2012 the feed-in-tariff system led to high annual growth rates of this renewable energy but after the suppression of the policy of public subsidies the sector stagnated. In recent years green hydrogen an innocuous gas in the atmosphere has become a driving force that stimulates photovoltaic energy production. Since 2020 encouraged by the European energy strategies and corresponding funds Spain has established a regulation to promote green hydrogen as a form of energy resource. Adopting the new institutional economics (NIE) approach this article investigates the process of changing incentives for the energy business sector and its impact on photovoltaic energy production. The results show an increase in the number of both projects approved or on approval and companies involved in green hydrogen that are planning to use photovoltaic energy in Spain thus engendering the creation of a new photovoltaic business environment based on innovation and sustainability.
Centralized and Decentralized Electrolysis-based Hydrogen Supply Systems for Road Transportation - A Modeling Study of Current and Future Costs
Oct 2022
Publication
This work compares the costs of three electrolysis-based hydrogen supply systems for heavy road transportation: a decentralized off-grid system for hydrogen production from wind and solar power (Dec-Sa); a decentralized system connected to the electricity grid (Dec-Gc); and a centralized grid-connected electrolyzer with hydrogen transported to refueling stations (Cen-Gc). A cost-minimizing optimization model was developed in which the hydrogen production is designed to meet the demand at refueling stations at the lowest total cost for two timeframes: one with current electricity prices and one with estimated future prices. The results show that: For most of the studied geographical regions Dec-Gc gives the lowest costs of hydrogen delivery (2.2e3.3V/kgH2) while Dec-Sa entails higher hydrogen production costs (2.5e6.7V/kgH2). In addition the centralized system (Cen-Gc) involves lower costs for production and storage than the grid-connected decentralized system (Dec-Gc) although the additional costs for hydrogen transport increase the total cost (3.5e4.8V/kgH2).
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