China, People’s Republic
Solar-driven, Highly Sustained Splitting of Seawater into Hydrogen and Oxygen Fuels
Mar 2019
Publication
Electrolysis of water to generate hydrogen fuel is an attractiverenewable energy storage technology. However grid-scale fresh-water electrolysis would put a heavy strain on vital water re-sources. Developing cheap electrocatalysts and electrodes that cansustain seawater splitting without chloride corrosion could ad-dress the water scarcity issue. Here we present a multilayer anodeconsisting of a nickel–iron hydroxide (NiFe) electrocatalyst layeruniformly coated on a nickel sulfide (NiSx) layer formed on porousNi foam (NiFe/NiSx-Ni) affording superior catalytic activity andcorrosion resistance in solar-driven alkaline seawater electrolysisoperating at industrially required current densities (0.4 to 1 A/cm2)over 1000 h. A continuous highly oxygen evolution reaction-active NiFe electrocatalyst layer drawing anodic currents towardwater oxidation and an in situ-generated polyatomic sulfate andcarbonate-rich passivating layers formed in the anode are respon-sible for chloride repelling and superior corrosion resistance of thesalty-water-splitting anode.
Life-cycle Carbon-intensity Mapping for Hydrogen-driven Energy and Economy
Aug 2024
Publication
Innovative approaches on clean alternative energy sources are important for future decarbonization. Electrification and hydrogen energy are crucial pathways for decarbonization in both transportation and buildings. However life-cycle stage-wise carbon intensity is still unclear for both hydrogen- and electricity-driven energy. Furthermore systematic evaluation on low-carbon transition pathways is insufficient specifically within the Internet of Energy that interfaces hydrogen and electricity. Here a generic approach is proposed for quantifying life-cycle stage-wise carbon intensity of both hydrogen- and electricity-driven energy internets. Life-cycle decarbonization effects on vehicle pathways are compared with traditional vehicles with internal-combustion engines. Techno-economic and environmental feasibility of the future advanced hydrogen-driven Internet of Energy is analyzed based on net present value. The region-wise carbon-intensity map and associated decarbonization strategies will help researchers and policymakers in promoting sustainable development with the hydrogen economy.
Towards Hydrogen-powered Electric Aircraft: Physics-informed Machine Learning Based Multi-domain Modelling and Real-time Digital Twin Emulation on FPGA
Mar 2025
Publication
In response to environmental concerns related to carbon and nitrogen emissions hydrogen-powered aircraft (HPA) are poised for significant development over the coming decades driven by advances in power electronics technology. However HPA systems present complex multi-domain challenges encompassing electrical hydraulic mechanical and chemical disciplines necessitating efficient modeling and robust validation platforms. This paper introduces a physics-informed machine learning (PIML) approach for multi-domain HPA system modeling enhanced by hardware accelerated parallel hardware emulation to construct a real-time digital twin. It delves into the physical analysis of various HPA subsystems whose equations form the basis for both traditional numerical solution methods like Euler’s and Runge-Kutta methods (RKM) as well as the physics-informed neural networks (PINN) components developed herein. By comparing physics-feature neural networks (PFNN) and PINN with conventional neural network strategies this paper elucidates their advantages and limitations in practical applications. The final implementation on the Xilinx® UltraScale+™ VCU128 FPGA platform showcases the PIML method’s high efficiency accuracy data independence and adherence to established physical laws demonstrating its potential for advancing real-time multi-domain HPA emulation.
Diffusive Mixing Between Hydrogen and Carbon Dioxide: Implications for Underground Hydrogen Storage
Feb 2025
Publication
The diffusive process between hydrogen (H2) and cushion gas affects the purity of H2 stored in the subsurface porous media. It is essential to understand the diffusive mass transfer and its impact on the migration of H2. Carbon dioxide (CO2) serves as a promising option for cushion gas. However due to experimental challenges there has been limited research conducted to quantify the diffusion between H2 and CO2 under reservoir conditions. For the first time we quantitatively measured the horizontal diffusive process between H2 and CO2 without convection interference in a high-pressure optical cell. The Raman spectroscopy is used to monitor the diffusive process in real-time and the diffusion coefficient is determined based on the measured concentration profiles. We showed that the Fick’s second law with a constant diffusion coefficient describes adequately the observed diffusive process. The resulting diffusion coefficient scales linearly with the reciprocal viscosity of CO2. Based on the measured diffusion coefficient we conducted a numerical study at field-scale. Results suggest that the dispersive mixing plays a role in the purity of produced H2.
Research on Energy Management in Hydrogen–Electric Coupled Microgrids Based on Deep Reinforcement Learning
Aug 2024
Publication
Hydrogen energy represents an ideal medium for energy storage. By integrating hydrogen power conversion utilization and storage technologies with distributed wind and photovoltaic power generation techniques it is possible to achieve complementary utilization and synergistic operation of multiple energy sources in the form of microgrids. However the diverse operational mechanisms varying capacities and distinct forms of distributed energy sources within hydrogen-coupled microgrids complicate their operational conditions making fine-tuned scheduling management and economic operation challenging. In response this paper proposes an energy management method for hydrogen-coupled microgrids based on the deep deterministic policy gradient (DDPG). This method leverages predictive information on photovoltaic power generation load power and other factors to simulate energy management strategies for hydrogen-coupled microgrids using deep neural networks and obtains the optimal strategy through reinforcement learning ultimately achieving optimized operation of hydrogen-coupled microgrids under complex conditions and uncertainties. The paper includes analysis using typical case studies and compares the optimization effects of the deep deterministic policy gradient and deep Q networks validating the effectiveness and robustness of the proposed method.
Multi-Objective Parameter Configuration Optimization of Hydrogen Fuel Cell Hybrid Power System for Locomotives
Sep 2024
Publication
Conventional methods of parameterizing fuel cell hybrid power systems (FCHPS) often rely on engineering experience which leads to problems such as increased economic costs and excessive weight of the system. These shortcomings limit the performance of FCHPS in real-world applications. To address these issues this paper proposes a novel method for optimizing the parameter configuration of FCHPS. First the power and energy requirements of the vehicle are determined through traction calculations and a real-time energy management strategy is used to ensure efficient power distribution. On this basis a multi-objective parameter configuration optimization model is developed which comprehensively considers economic cost and system weight and uses a particle swarm optimization (PSO) algorithm to determine the optimal configuration of each power source. The optimization results show that the system economic cost is reduced by 8.76% and 18.05% and the weight is reduced by 11.47% and 9.13% respectively compared with the initial configuration. These results verify the effectiveness of the proposed optimization strategy and demonstrate its potential to improve the overall performance of the FCHPS.
The Use of Alternative Fuels for Maritime Decarbonization: Special Marine Environmental Risks and Solutons from an International Law Perspective
Jan 2023
Publication
The introduction of several alternative marine fuels is considered an important strategy for maritime decarbonization. These alternative marine fuels include liquefied natural gas (LNG) liquefied biogas (LBG) hydrogen ammonia methanol ethanol hydrotreated vegetable oil (HVO) etc. In some studies nuclear power and electricity are also included in the scope of alternative fuels for merchant ships. However the operation of alternative-fuel-powered ships has some special risks such as fuel spills vapor dispersion and fuel pool fires. The existing international legal framework does not address these risks sufficiently. This research adopts the method of legal analysis to examine the existing international legal regime for regulating the development of alternative-fuel-powered ships. From a critical perspective it evaluates and predicts the consequences of these policies together with their shortcomings. Also this research explores the potential solutions and countermeasures that might be feasible to deal with the special marine environmental risks posed by alternative-fuel-powered ships in the future.
Low-Carbon Transition Pathway Planning of Regional Power Systems with Electricity-Hydrogen Synergy
Nov 2022
Publication
Hydrogen energy leads us in an important direction in the development of clean energy and the comprehensive utilization of hydrogen energy is crucial for the low-carbon transformation of the power sector. In this paper the demand for hydrogen energy in various fields is predicted based on the support vector regression algorithm which can be converted into an equivalent electrical load when it is all produced from water electrolysis. Then the investment costs of power generators and hydrogen energy equipment are forecast considering uncertainty. Furthermore a planning model is established with the forecast data initial installed capacity and targets for carbon emission reduction as inputs and the installed capacity as well as share of various power supply and annual carbon emissions as outputs. Taking Gansu Province of China as an example the changes of power supply structure and carbon emissions under different scenarios are analysed. It can be found that hydrogen production through water electrolysis powered by renewable energy can reduce carbon emissions but will increase the demand for renewable energy generators. Appropriate planning of hydrogen storage can reduce the overall investment cost and promote a low carbon transition of the power system
Assessment of Wind Energy Potential for the Production of Renewable Hydrogen in Sindh Province of Pakistan
Apr 2019
Publication
In this study we developed a new hybrid mathematical model that combines wind-speed range with the log law to derive the wind energy potential for wind-generated hydrogen production in Pakistan. In addition we electrolyzed wind-generated power in order to assess the generation capacity of wind-generated renewable hydrogen. The advantage of the Weibull model is that it more accurately reflects power generation potential (i.e. the capacity factor). When applied to selected sites we have found commercially viable hydrogen production capacity in all locations. All sites considered had the potential to produce an excess amount of wind-generated renewable hydrogen. If the total national capacity of wind-generated was used Pakistan could conceivably produce 51917000.39 kg per day of renewable hydrogen. Based on our results we suggest that cars and other forms of transport could be fueled with hydrogen to conserve oil and gas resources which can reduce the energy shortfall and contribute to the fight against climate change and global warming. Also hydrogen could be used to supplement urban energy needs (e.g. for Sindh province Pakistan) again reducing energy shortage effects and supporting green city programs.
Self-Sustaining Control Strategy for Proton-Exchange Membrane Electrolysis Devices Based on Gradient-Disturbance Observation Method
Mar 2023
Publication
This paper proposes a self-sustaining control model for proton-exchange membrane (PEM) electrolysis devices aiming to maintain the temperature of their internal operating environment and thus improve the electrolysis efficiency and hydrogen production rate. Based on the analysis of energy–substance balance and electrochemical reaction characteristics an electrothermal-coupling dynamic model for PEM electrolysis devices was constructed. Considering the influence of the input energy–substance and the output hydrogen and oxygen of PEM electrolysis devices on the whole dynamic equilibrium process the required electrical energy and water molar flow rate are dynamically adjusted so that the temperature of the cathode and the anode is maintained near 338.15 K. The analytical results show that the hydrogen production rate and electrolysis efficiency are increased by 0.275 mol/min and 3.9% respectively by linearly stacking 100 PEM electrolysis devices to form a hydrogen production system with constant cathode and anode operating temperatures around 338.15 K in the self-sustaining controlled mode
Optimal Capacity Configuration of Wind–Solar Hydrogen Storage Microgrid Based on IDW-PSO
Aug 2023
Publication
Because the new energy is intermittent and uncertain it has an influence on the system’s output power stability. A hydrogen energy storage system is added to the system to create a wind light and hydrogen integrated energy system which increases the utilization rate of renewable energy while encouraging the consumption of renewable energy and lowering the rate of abandoning wind and light. Considering the system’s comprehensive operation cost economy power fluctuation and power shortage as the goal considering the relationship between power generation and load assigning charging and discharging commands to storage batteries and hydrogen energy storage and constructing a model for optimal capacity allocation of wind–hydrogen microgrid system. The optimal configuration model of the wind solar and hydrogen microgrid system capacity is constructed. A particle swarm optimization with dynamic adjustment of inertial weight (IDW-PSO) is proposed to solve the optimal allocation scheme of the model in order to achieve the optimal allocation of energy storage capacity in a wind–hydrogen storage microgrid. Finally a microgrid system in Beijing is taken as an example for simulation and solution and the results demonstrate that the proposed approach has the characteristics to optimize the economy and improve the capacity of renewable energy consumption realize the inhibition of the fluctuations of power reduce system power shortage and accelerate the convergence speed.
CO2 Effect on the Fatigue Crack Growth of X80 Pipeline Steel in Hydrogen-Enriched Natural Gas: Experiment vs Density Functional Theory Calculation
Sep 2023
Publication
The influence of hydrogen-enriched natural gas (HENG) and CO2 on the mechanical property of X80 pipeline steel were investigated via fatigue crack growth rate (FCGR) tests and density functional theory (DFT) calculations. The results show that the FCGR in H2 was slightly faster than that in HENG while it was slower than that in the N2/CO2/H2 mixtures. The enhanced FCGR by CO2 further increased with the increasing CO2 content. DFT calculation results show that the adsorbed CO2 on the iron surface significantly increased the migration rate of H atoms from surface to subsurface. This promotes the entry of hydrogen into the steel.
Distributional Trends in the Generation and End-Use Sector of Low-Carbon Hydrogen Plants
Mar 2023
Publication
This paper uses established and recently introduced methods from the applied mathematics and statistics literature to study trends in the end-use sector and the capacity of low-carbon hydrogen projects in recent and upcoming decades. First we examine distributions in plants over time for various end-use sectors and classify them according to metric discrepancy observing clear similarity across all industry sectors. Next we compare the distribution of usage sectors between different continents and examine the changes in sector distribution over time. Finally we judiciously apply several regression models to analyse the association between various predictors and the capacity of global hydrogen projects. Across our experiments we see a welcome exponential growth in the capacity of zero-carbon hydrogen plants and significant growth of new and planned hydrogen plants in the 2020’s across every sector.
Study Progress on the Pipeline Transportation Safety of Hydrogen-blended Natural Gas
Oct 2023
Publication
The core of carbon neutrality is the energy structure adjustment and economic structure transformation. Hydrogen energy as a kind of clean energy with great potential has provided important support for the implementation of the carbon peaking and carbon neutrality goals of China. How to achieve the large-range safe and reliable transportation of hydrogen energy with good economic benefits remains the key to limiting the development of hydrogen energy. Using the existing natural gas pipeline network can save many infrastructure construction costs to transport hydrogen-blended natural gas. However due to great differences in the physical and chemical properties of hydrogen and natural gas the transportation of hydrogen-blended natural gas will bring safety risks to the pipeline network operation to a certain extent. In this paper the influences of pipeline transportation of hydrogen-blended natural gas on existing pipelines and parts along the pipelines are analyzed from two aspects of pipe compatibility and hydrogen blending ratio and the safety of pipeline transportation of hydrogen-blended natural gas is summarized from two aspects of leakage and accumulation as well as combustion and explosion. In addition the integrity management of hydrogen-blended natural gas pipelines and the existing relevant standards and specifications are reviewed. This paper points out the shortcomings of current hydrogen-blended natural gas pipeline transportation and gives some relevant suggestions. Hopefully this work can provide a useful reference for developing a hydrogen-blended natural gas pipeline transportation system.
Optimal Sizing of a Stand-Alone Hybrid Power System Based on Battery/Hydrogen with an Improved Ant Colony Optimization
Sep 2016
Publication
A distributed power system with renewable energy sources is very popular in recent years due to the rapid depletion of conventional sources of energy. Reasonable sizing for such power systems could improve the power supply reliability and reduce the annual system cost. The goal of this work is to optimize the size of a stand-alone hybrid photovoltaic (PV)/wind turbine (WT)/battery (B)/hydrogen system (a hybrid system based on battery and hydrogen (HS-BH)) for reliable and economic supply. Two objectives that take the minimum annual system cost and maximum system reliability described as the loss of power supply probability (LPSP) have been addressed for sizing HS-BH from a more comprehensive perspective considering the basic demand of load the profit from hydrogen which is produced by HS-BH and an effective energy storage strategy. An improved ant colony optimization (ACO) algorithm has been presented to solve the sizing problem of HS-BH. Finally a simulation experiment has been done to demonstrate the developed results in which some comparisons have been done to emphasize the advantage of HS-BH with the aid of data from an island of Zhejiang China.
Optimal Energy Management of an Integrated Energy System with Multiple Hydrogen Sources
Sep 2023
Publication
Hydrogen is considered a promising alternative to fossil fuels in an integrated energy system (IES). In order to reduce the cost of hydrogen energy utilization and the carbon emissions of the IES this paper proposes a low-carbon dispatching strategy for a coordinated integrated energy system using green hydrogen and blue hydrogen. The strategy takes into account the economic and low-carbon complementarity between hydrogen production by water electrolysis and hydrogen production from natural gas. It introduces the green hydrogen production–storage–use module (GH-PSUM) and the blue hydrogen production–storage–use module (BH-PSUM) to facilitate the refined utilization of different types of hydrogen energy. Additionally the flexibility in hydrogen load supply is analyzed and the dynamic response mechanism of the hydrogen load supply structure (DRM-HLSS) is proposed to further reduce operating costs and carbon emissions. Furthermore a carbon trading mechanism (CTM) is introduced to constrain the carbon emissions of the integrated energy system. By comprehensively considering the constraints of each equipment the proposed model aims to minimize the total economic cost which includes wind power operation and curtailment penalty costs energy purchase costs blue hydrogen purification costs and carbon transaction costs. The rationality of the established scheduling model is verified through a comparative analysis of the scheduling results across multiple operating scenarios.
An Economic Performance Improving and Analysis for Offshore Wind Farm-Based Islanded Green Hydrogen System
Jul 2024
Publication
When offshore wind farms are connected to a hydrogen plant with dedicated transmission lines for example high-voltage direct current the fluctuation of wind speed will influence the efficiency of the alkaline electrolyzer and deteriorate the techno-economic performance. To overcome this issue firstly an additional heating process is adopted to achieve insulation for the alkaline solution when power generated by wind farms is below the alkaline electrolyzer minimum power threshold while the alkaline electrolyzer overload feature is used to generate hydrogen when wind power is at its peak. Then a simplified piecewise model-based alkaline electrolyzer techno-economic analysis model is proposed. The improved economic performance of the islanded green hydrogen system with the proposed operation strategy is verified based on the wind speed data set simulation generated by the Weibull distribution. Lastly the sensitivity of the total return on investment to wind speed parameters was investigated and an islanded green hydrogen system capacity allocation based on the proposed analysis model was conducted. The simulation result shows the total energy utilization increased from 62.0768% to 72.5419% and the return on investment increased from 5.1303%/month to 5.9581%/month when the proposed control strategy is adopted.
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.
Investigation on the Compressibility Factor of Hydrogen-Doped Natural Gas Using GERG-2008 Equation of State
Dec 2024
Publication
The primary methods for hydrogen transportation include gaseous storage and transport liquid hydrogen storage and transport via organic liquid carriers. Among these pipeline transportation offers the lowest cost and the greatest potential for large-scale long-distance transport. Although the construction and operation costs of dedicated hydrogen pipelines are relatively high blending hydrogen into existing natural gas networks presents a viable alternative. This approach allows hydrogen to be transported to the end-users where it can be either separated for use or directly combusted thereby reducing hydrogen transport costs. This study based on the GERG-2008 equation of state conducts experimental tests on the compressibility factor of hydrogen-doped natural gas mixtures across a temperature range of −10 ◦C to 110 ◦C and a pressure range of 2 to 12 MPa with hydrogen blending ratios of 5% 10% 20% 30% and 40%. The results indicate that the hydrogen blending ratio temperature and pressure significantly affect the compressibility factor particularly under low-temperature and high-pressure conditions where an increase in the hydrogen blending ratio leads to a notable rise in the compressibility factor. These findings have substantial implications for the practical design of hydrogen-enriched natural gas pipelines as changes in the compressibility factor directly impact pipeline operational parameters compressor characteristics and other system performance aspects. Specifically the introduction of hydrogen alters the compressibility factor of the transported medium thereby affecting the pipeline’s flowability and compressibility which are crucial for optimizing and applying the performance of hydrogen-enriched natural gas in transportation channels. The research outcomes provide valuable insights for understanding combustion reactions adjusting pipeline operational parameters and compressor performance characteristics facilitating more precise decision-making in the design and operation of hydrogen-enriched natural gas pipelines.
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.
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