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Designing Hydrogen Recirculation Ejectors for Proton Exchange Membrane Fuel Cell Systems
Jan 2023
Publication
The proton exchange membrane fuel cell (PEMFC) is a promising device in the fields of power generation energy storage aerospace and public transportation. The hydrogen recirculation ejector with the advantages of low cost high durability and no parasitic power is the key component of PEMFC systems. However it is challenging to design a hydrogen recirculation ejector to cover the wide operating conditions of PEMFC systems. In order to design an ejector for fuel cell systems a comprehensive understanding of ejector research is required. Consequently the state-of-the-art research work on the hydrogen recirculation ejector is analyzed including characteristics of the ejector in PEM fuel cell systems geometry design and optimization different types of ejectors and a comparison between them and system integration and control. Through a comprehensive analysis of ejectors further research suggestions on designing high-performance ejectors are presented.
Parametric Study and Electrocatalyst of Polymer Electrolyte Membrane (PEM) Electrolysis Performance
Jan 2023
Publication
An investigation was conducted to determine the effects of operating parameters for various electrode types on hydrogen gas production through electrolysis as well as to evaluate the efficiency of the polymer electrolyte membrane (PEM) electrolyzer. Deionized (DI) water was fed to a single-cell PEM electrolyzer with an active area of 36 cm2 . Parameters such as power supply (50–500 mA/cm2 ) feed water flow rate (0.5–5 mL/min) water temperature (25−80 ◦C) and type of anode electrocatalyst (0.5 mg/cm2 PtC [60%] 1.5 mg/cm2 IrRuOx with 1.5 mg/cm2 PtB 3.0 mg/cm2 IrRuOx and 3.0 mg/cm2 PtB) were varied. The effects of these parameter changes were then analyzed in terms of the polarization curve hydrogen flowrate power consumption voltaic efficiency and energy efficiency. The best electrolysis performance was observed at a DI water feed flowrate of 2 mL/min and a cell temperature of 70 ◦C using a membrane electrode assembly that has a 3.0 mg/cm2 IrRuOx catalyst at the anode side. This improved performance of the PEM electrolyzer is due to the reduction in activation as well as ohmic losses. Furthermore the energy consumption was optimal when the current density was about 200 mA/cm2 with voltaic and energy efficiencies of 85% and 67.5% respectively. This result indicates low electrical energy consumption which can lower the operating cost and increase the performance of PEM electrolyzers. Therefore the optimal operating parameters are crucial to ensure the ideal performance and durability of the PEM electrolyzer as well as lower its operating costs.
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.
Techno-economic Assessment of Electrolytic Hydrogen in China Considering Wind-solar-load Characteristic
Jan 2023
Publication
Hydrogen production by electrolysis is considered an essential means of consuming renewable energy in the future. However the current assessment of the potential of renewable energy electrolysis for hydrogen production is relatively simple and the perspective is not comprehensive. Here we established a Combined Wind and Solar Electrolytic Hydrogen system considering the influence of regional wind-solar-load characteristics and transmission costs to evaluate the hydrogen production potential of 31 provincial-level regions in China in 2050. The results show that in 2050 the levelized cost of hydrogen (LCOH) in China’s provincial regions will still be higher than 10 ¥/kg which is not cost-competitive compared to the current hydrogen production from fossil fuels. It is more cost-effective to deploy wind turbines than photovoltaic in areas with similar wind and solar resources or rich in wind resources. Wind-solar differences impact LCOH equipment capacity configuration and transmission cost composition while load fluctuation significantly impacts LCOH and electricity storage configuration. In addition the sensitivity analysis of 11 technical and economic parameters showed differences in the response performance of LCOH changes to different parameters and the electrolyzer conversion efficiency had the most severe impact. The analysis of subsidy policy shows that for most regions (except Chongqing and Xizang) subsidizing the unit investment cost of wind turbines can minimize LCOH. Nevertheless from the perspective of comprehensive subsidy effect subsidy cost and hydrogen energy development it is more cost-effective to take subsidies for electrolysis equipment with the popularization of hydrogen
“Bigger than Government”: Exploring the Social Construction and Contestation of Net-zero Industrial Megaprojects in England
Jan 2023
Publication
Industry is frequently framed as hard-to-decarbonize given its diversity of requirements technologies and supply chains many of which are unique to particular sectors. Net zero commitments since 2019 have begun to challenge the carbon intensity of these various industries but progress has been slow globally. Against this backdrop the United Kingdom has emerged as a leader in industrial decarbonization efforts. Their approach is based on industrial clusters which cut across engineering spatial and socio-political dimensions. Two of the largest of these clusters in England in terms of industrial emissions are the Humber and Merseyside. In this paper drawn from a rich mixed methods original dataset involving expert interviews (N = 46 respondents) site visits (N = 20) a review of project documents and the academic literature we explore ongoing efforts to decarbonize both the Humber and Merseyside through the lens of spatially expansive and technically complex megaprojects. Both have aggressive implementation plans in place for the deployment of net-zero infrastructure with Zero Carbon Humber seeking billions in investment to build the country’s first large-scale bioenergy with carbon capture and storage (BECCS) plant alongside a carbon transport network and hydrogen production infrastructure and HyNet seeking billions in investment to build green and blue hydrogen facilities along with a carbon storage network near Manchester and Liverpool. We draw from the social construction of technology (SCOT) literature to examine the relevant social groups interpretive flexibility and patterns of closure associated with Zero Carbon Humber and HyNet. We connect our findings to eight interpretive frames surrounding the collective projects and make connections to problems contestation and closure.
Towards a Safe Hydrogen Economy: An Absolute Climate Sustainability Assessment of Hydrogen Production
Jan 2023
Publication
Policymakers and global energy models are increasingly looking towards hydrogen as an enabling energy carrier to decarbonize hard-to-abate sectors (projecting growth in hydrogen consumption in the magnitude of hundreds of megatons). Combining scenarios from global energy models and life cycle impacts of different hydrogen production technologies the results of this work show that the life cycle emissions from proposed configurations of the hydrogen economy would lead to climate overshoot of at least 5.4–8.1x of the defined “safe” space for greenhouse gas emissions by 2050 and the cumulative consumption of 8–12% of the remaining carbon budget. This work suggests a need for a science-based definition of “clean” hydrogen agnostic of technology and compatible with a “safe” development of the hydrogen economy. Such a definition would deem blue hydrogen environmentally unviable by 2025–2035. The prolific use of green hydrogen is also problematic however due to the requirement of a significant amount of renewable energy and the associated embedded energy land and material impacts. These results suggest that demand-side solutions should be further considered as the large-scale transition to hydrogen which represents a “clean” energy shift may still not be sufficient to lead humanity into a “safe” space.
Green Hydrogen Production by Anion Exchange Membrane Water Electrolysis: Status and Future Perspectives
Jan 2023
Publication
Green hydrogen production i.e. produced on a CO2 -neutral basis through the electrolysis of water employing renewable electricity has attracted increasing attention. The electricity required is generated from Renewable Energy Sources (RES) for example wind energy hydropower or solar energy. Since neither the process of production nor the end products of H2 and O2 are harmful to the environment green hydrogen is climate neutral. Developing electrolysis technology is therefore a research topic to follow. Anion Exchange Membrane (AEM) Water Electrolysis (WE) is an innovative technology that couples the advantages of the more mature technologies of Proton Exchange Membrane (PEM) and conventional alkaline electrolysis with the potential to eliminate the drawbacks of both. AEMWE technology is in an evolutionary stage and involves more investigation on several research topics such as membrane and catalyst development and stability as well as alternative feeding solutions that do not compromise the availability of fresh water. These topics are addressed in this paper mentioning the state-of-the-art materials new promising ones and providing future research directions to improve AEMWE towards a most mature technology.
Going Offshore or Not: Where to Generate Hydrogen in Future Integrated Energy Systems?
Jan 2023
Publication
Hydrogen can be key in the energy system transition. We investigate the role of offshore hydrogen generation in a future integrated energy system. By performing energy system optimisation in a model application of the Northern-central European energy system and the North Sea offshore grid towards 2050 we find that offshore hydrogen generation may likely only play a limited role and that offshore wind energy has higher value when sent to shore in the form of electricity. Forcing all hydrogen generation offshore would lead to increased energy system costs. Under the assumed scenario conditions which result in deep decarbonisation of the energy system towards 2050 hydrogen generation – both onshore and offshore – follows solar PV generation patterns. Combined with hydrogen storage this is the most cost-effective solution to satisfy future hydrogen demand. Overall we find that the role of future offshore hydrogen generation should not simply be derived from minimising costs for the offshore sub-system but by also considering the economic value that such generation would create for the whole integrated energy system. We find as a no-regret option to enable and promote the integration of offshore wind in onshore energy markets via electrical connections.
Ammonia Production from Clean Hydrogen and the Implications for Global Natural Gas Demand
Jan 2023
Publication
Non-energy use of natural gas is gaining importance. Gas used for 183 million tons annual ammonia production represents 4% of total global gas supply. 1.5-degree pathways estimate an ammonia demand growth of 3–4-fold until 2050 as new markets in hydrogen transport shipping and power generation emerge. Ammonia production from hydrogen produced via water electrolysis with renewable power (green ammonia) and from natural gas with CO2 storage (blue ammonia) is gaining attention due to the potential role of ammonia in decarbonizing energy value chains and aiding nations in achieving their net-zero targets. This study assesses the technical and economic viability of different routes of ammonia production with an emphasis on a systems level perspective and related process integration. Additional cost reductions may be driven by optimum sizing of renewable power capacity reducing losses in the value chain technology learning and scale-up reducing risk and a lower cost of capital. Developing certification and standards will be necessary to ascertain the extent of greenhouse gas emissions throughout the supply chain as well as improving the enabling conditions including innovative finance and de-risking for facilitating international trade market creation and large-scale project development.
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.
Safety Assessment of Hydrogen Jet Fire Scenarios within Semi-Confined Spaces
Jan 2023
Publication
Hydrogen fuel cell vehicle (HFCV) technology poses great promise as an alternative to significantly reduce the environmental impact of the transport sector’s emissions. However hydrogen fuel cell technology is relatively new therefore confirmation of the reliability and safety analysis is still required particularly for fire scenarios within confined spaces such as tunnels. This study applied the computational fluid dynamics (CFD) simulations in conjunction with probabilistic calculation methods to determine the associated thermal risk of a hydrogen jet fire in a tunnel and its dependency on scenarios with different tunnel slopes longitudinal and transverse ventilation velocities and fire positions. A large-scale model of 102 m in which the effects of outlined parameter variations on the severity of the fire incident were analysed. It is found that both tunnel ventilation techniques and slope were critical for the effective ejection of accumulated heat. With ventilation playing a primary role in the ejection of heat and gas and slope ensuring the stability of the ejected heat probabilities of thermal burns were found to be reduced by up to approximately 35% with a strong suggestion of critical combinations to further reduce the dangers of hydrogen tunnel fires.
Solar Energy: Applications, Trends Analysis, Bibliometric Analysis and Research Contribution to Sustainable Development Goals (SDGs)
Jan 2023
Publication
Over the past decade energy demand has witnessed a drastic increase mainly due to huge development in the industry sector and growing populations. This has led to the global utilization of renewable energy resources and technologies to meet this high demand as fossil fuels are bound to end and are causing harm to the environment. Solar PV (photovoltaic) systems are a renewable energy technology that allows the utilization of solar energy directly from the sun to meet electricity demands. Solar PV has the potential to create a reliable clean and stable energy systems for the future. This paper discusses the different types and generations of solar PV technologies available as well as several important applications of solar PV systems which are “Large-Scale Solar PV” “Residential Solar PV” “Green Hydrogen” “Water Desalination” and “Transportation”. This paper also provides research on the number of solar papers and their applications that relate to the Sustainable Development Goals (SDGs) in the years between 2011 and 2021. A total of 126513 papers were analyzed. The results show that 72% of these papers are within SDG 7: Affordable and Clean Energy. This shows that there is a lack of research in solar energy regarding the SDGs especially SDG 1: No Poverty SDG 4: Quality Education SDG 5: Gender Equality SDG 9: Industry Innovation and Infrastructure SDG 10: Reduced Inequality and SDG 16: Peace Justice and Strong Institutions. More research is needed in these fields to create a sustainable world with solar PV technologies.
Green Hydrogen Production for Oil Refining - Finnish Case
Jan 2023
Publication
This study investigates the production of green hydrogen for use in oil refining as specified in the draft of European union delegated act published in May 2022. The European union plans to set strict requirements of additionality and reporting regarding the criteria of renewable electricity used in hydrogen production. Alkaline electrolyzer proton exchange membrane electrolyzer and solid oxide electrolyzer are evaluated in various scenarios supplied by wind power: power purchase agreement-based scenarios and wind power investment-based scenarios. In power purchase agreement-based scenarios baseload and pay as produced power purchase agreements (with and without electricity storage) are assessed. According to results the use of 600 MW compressed air energy storage could reduce the dependency on the grid by 7% but increase the cost of green hydrogen significantly. Investment-based scenarios produce green hydrogen with a lower operation cost but higher break-even price compared to power purchase agreement-based scenarios. The cheapest green hydrogen can be achieved by alkaline electrolyzer with baseload power purchase agreement. Direct ownership of wind power is outside the operation of oil refining industry thus power purchase agreements contracting is more likely to realize.
Numerical Study of Combustion and Emission Characteristics for Hydrogen Mixed Fuel in the Methane-Fueled Gas Turbine Combustor
Jan 2023
Publication
The aeroderivative gas turbine is widely used as it demonstrates many advantages. Adding hydrogen to natural gas fuels can improve the performance of combustion. Following this the effects of hydrogen enrichment on combustion characteristics were analyzed in an aeroderivative gas turbine combustor using CFD simulations. The numerical model was validated with experimental results. The conditions of the constant mass flow rate and the constant energy input were studied. The results indicate that adding hydrogen reduced the fuel residues significantly (fuel mass at the combustion chamber outlet was reduced up to 60.9%). In addition the discharge of C2H2 and other pollutants was reduced. Increasing the volume fraction of hydrogen in the fuel also reduced CO emissions at the constant energy input while increasing CO emissions at the constant fuel mass flow rate. An excess in the volume fraction of added hydrogen changed the combustion mode in the combustion chamber resulting in fuel-rich combustion (at constant mass flow rate) and diffusion combustion (at constant input power). Hydrogen addition increased the pattern factor and NOx emissions at the outlet of the combustion chamber.
A Review of Hydrogen Production and Supply Chain Modeling and Optmization
Jan 2023
Publication
This paper reviews recent optimization models for hydrogen supply chains and production. Optimization is a central component of systematic methodologies to support hydrogen expansion. Hydrogen production is expected to evolve in the coming years to help replace fossil fuels; these high expectations arise from the potential to produce low-carbon hydrogen via electrolysis using electricity generated by renewable sources. However hydrogen is currently mainly used in refinery and industrial operations; therefore physical infrastructures for transmission distribution integration with other energy systems and efficient hydrogen production processes are lacking. Given the potential of hydrogen the greenfield state of infrastructures and the variability of renewable sources systematic methodologies are needed to reach competitive hydrogen prices and design hydrogen supply chains. Future research topics are identified: 1) improved hydrogen demand projections 2) integrated sector modeling 3) improving temporal and spatial resolutions 4) accounting for climate change 5) new methods to address sophisticated models.
Techno-Economic Assessment of Green Hydrogen Production by an Off-Grid Photovoltaic Energy System
Jan 2023
Publication
Green hydrogen production is essential to meeting the conference of the parties’ (COP) decarbonization goals; however this method of producing hydrogen is not as cost-effective as hydrogen production from fossil fuels. This study analyses an off-grid photovoltaic energy system designed to feed a proton-exchange membrane water electrolyzer for hydrogen production to evaluate the optimal electrolyzer size. The system has been analyzed in Baghdad the capital of Iraq using experimental meteorological data. The 12 kWp photovoltaic array is positioned at the optimal annual tilt angle for the selected site. The temperature effect on photovoltaic modules is taken into consideration. Several electrolyzers with capacities in the range of 2–14 kW were investigated to assess the efficiency and effectiveness of the system. The simulation process was conducted using MATLAB and considering the project life span from 2021 to 2035. The results indicate that various potentially cost-competitive alternatives exist for systems with market combinations resembling renewable hydrogen wholesale. It has been found that the annual energy generated by the analyzed photovoltaic system is 18892 kWh at 4313 operating hours and the obtained hydrogen production cost ranges from USD 5.39/kg to USD 3.23/kg. The optimal electrolyzer capacity matches a 12 kWp PV system equal to 8 kW producing 37.5 kg/year/kWp of hydrogen for USD 3.23/kg.
Optimal Planning of Hybrid Electric-hydrogen Energy Storage Systems via Multi-objective Particle Swarm Optimization
Jan 2023
Publication
In recent years hydrogen is rapidly developing because it is environmentally friendly and sustainable. In this case hydrogen energy storage systems (HESSs) can be widely used in the distribution network. The application of hybrid electric-hydrogen energy storage systems can solve the adverse effects caused by renewable energy access to the distribution network. In order to ensure the rationality and effectiveness of energy storage systems (ESSs) configuration economic indicators of battery energy storage systems (BESSs) and hydrogen energy storage systems power loss and voltage fluctuation are chosen as the fitness function in this paper. Meanwhile multi-objective particle swarm optimization (MOPSO) is used to solve Pareto non-dominated set of energy storage systems’ optimal configuration scheme in which the technique for order preference by similarity to ideal solution (TOPSIS) based on information entropy weight (IEW) is used select the optimal solution in Pareto non-dominated solution set. Based on the extended IEEE-33 system and IEEE-69 system the rationality of energy storage systems configuration scheme under 20% and 35% renewable energy penetration rate is analyzed. The simulation results show that the power loss can be reduced by 7.9%–22.8% and the voltage fluctuation can be reduced by 40.0%–71% when the renewable energy penetration rate is 20% and 35% respectively in IEEE-33 and 69 nodes systems. Therefore it can be concluded that the locations and capacities of energy storage systems obtained by multi-objective particle swarm optimization can improve the distribution network stability and economy after accessing renewable generation.
The Challenges of Integrating the Principles of Green Chemistry and Green Engineering to Heterogeneous Photocatalysis to Treat Water and Produce Green H2
Jan 2023
Publication
Nowadays heterogeneous photocatalysis for water treatment and hydrogen production are topics gaining interest for scientists and developers from different areas such as environmental technology and material science. Most of the efforts and resources are devoted to the development of new photocatalyst materials while the modeling and development of reaction systems allowing for upscaling the process to pilot or industrial scale are scarce. In this work we present what is known on the upscaling of heterogeneous photocatalysis to purify water and to produce green H2. The types of reactors successfully used in water treatment plants are presented as study cases. The challenges of upscaling the photocatalysis process to produce green H2 are explored from the perspectives of (a) the adaptation of photoreactors (b) the competitiveness of the process and (c) safety. Throughout the text Green Chemistry and Engineering Principles are described and discussed on how they are currently being applied to the heterogeneous photocatalysis process along with the challenges that are ahead. Lastly the role of automation and high-throughput methods in the upscaling following the Green Principles is discussed.
An Innovative Approach for Energy Transition in China? Chinese National Hydrogen Policies from 2001 to 2020
Jan 2023
Publication
To accelerate clean energy transition China has explored the potential of hydrogen as an energy carrier since 2001. Until 2020 49 national hydrogen policies were enacted. This paper explores the relevance of these policies to the development of the hydrogen industry and energy transition in China. We examine the reasons impacts and challenges of Chinese national hydrogen policies through the conceptual framework of Thomas Dye’s policy analysis method and the European Training Foundation’s policy analysis guide. This research provides an ex‐post analysis for previous policies and an ex‐ante analysis for future options. We argue that the energy supply revolution and energy technology revolution highlight the importance of hydrogen development in China. Particularly the pressure of the automobile industry transition leads to experimentation concerning the application of hydrogen in the transportation sector. This paper also reveals that hydro‐ gen policy development coincides with an increase in resource input and has positive spill over effects. Furthermore we note that two challenges have impeded progress: a lack of regulations for the industry threshold and holistic planning. To address these challenges the Chinese government can design a national hydrogen roadmap and work closely with other countries through the Belt and Road Initiative.
Hydrogen Production Methods Based on Solar and Wind Energy: A Review
Jan 2023
Publication
Several research works have investigated the direct supply of renewable electricity to electrolysis particularly from photovoltaic (PV) and wind generator (WG) systems. Hydrogen (H2 ) production based on solar energy is considered to be the newest solution for sustainable energy. Different technologies based on solar energy which allow hydrogen production are presented to study their benefits and inconveniences. The technology of water decomposition based on renewable energy sources to produce hydrogen can be achieved by different processes (photochemical systems; photocatalysis systems photo-electrolysis systems bio-photolysis systems thermolysis systems thermochemical cycles steam electrolysis hybrid processes and concentrated solar energy systems). A comparison of the different methods for hydrogen production based on PV and WG systems was given in this study. A comparative study of different types of electrolyzers was also presented and discussed. Finally an economic assessment of green hydrogen production is given. The hydrogen production cost depends on several factors such as renewable energy sources electrolysis type weather conditions installation cost and the productivity of hydrogen per day. PV/H2 and wind/H2 systems are both suitable in remote and arid areas. Minimum maintenance is required and a power cycle is not needed to produce electricity. The concentrated CSP/H2 system needs a power cycle. The hydrogen production cost is higher if using wind/H2 rather than PV/H2 . The green energy sources are useful for multiple applications such as hydrogen production cooling systems heating and water desalination.
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