China, People’s Republic

The transformation from a fossil fuel economy to a low-carbon economy has reshaped the way energy is transmitted. As most renewable energy is obtained in the form of electricity using green electricity to produce hydrogen is considered a promising energy carrier. However most studies have not considered the transportation mode of hydrogen. In order to encourage the utilization of renewable energy and hydrogen this paper proposes a comprehensive energy system optimization operation strategy considering multi-mode hydrogen transport. Firstly to address the shortcomings in the optimization operation of existing systems regarding hydrogen transport modeling is conducted for multi-mode hydrogen transportation through hydrogen tube trailers and pipelines. This model reflects the impact of multi-mode hydrogen delivery channels on hydrogen utilization which helps promote the consumption of new energy in electrolysis cells to meet application demands. Based on this the constraints of electrolyzers combined heat and power units hydrogen fuel cells and energy storage systems in integrated energy systems (IESs) are further considered. With the objective of minimizing the daily operational cost of the comprehensive energy system an optimization model for the operation considering multi-mode hydrogen transport is constructed. Lastly based on simulation examples the impact of multi-mode hydrogen transportation on the operational cost of the system is analyzed in detail. The results indicate that the proposed optimization strategy can reduce the operational cost of the comprehensive energy system. Hydrogen tube trailers and pipelines will have a significant impact on operational costs. Properly allocating the quantity of hydrogen tube trailers and pipelines is beneficial for reducing the operational costs of the system. Reasonable arrangement of hydrogen transportation channels is conducive to further promoting the green and economic operation of the system.

In the vehicle-to-everything scenario the fuel cell bus can accurately obtain the surrounding traffic information and quickly optimize the energy management problem while controlling its own safe and efficient driving. This paper proposes an energy management strategy (EMS) that considers speed control based on deep reinforcement learning (DRL) in complex traffic scenarios. Using SUMO simulation software (Version 1.15.0) a two-lane urban expressway is designed as a traffic scenario and a hydrogen fuel cell bus speed control and energy management system is designed through the soft actor–critic (SAC) algorithm to effectively reduce the equivalent hydrogen consumption and fuel cell output power fluctuation while ensuring the safe efficient and smooth driving of the vehicle. Compared with the SUMO–IDM car-following model the average speed of vehicles is kept the same and the average acceleration and acceleration change value decrease by 10.22% and 11.57% respectively. Compared with deep deterministic policy gradient (DDPG) the average speed is increased by 1.18% and the average acceleration and acceleration change value are decreased by 4.82% and 5.31% respectively. In terms of energy management the hydrogen consumption of SAC–OPT-based energy management strategy reaches 95.52% of that of the DP algorithm and the fluctuation range is reduced by 32.65%. Compared with SAC strategy the fluctuation amplitude is reduced by 15.29% which effectively improves the durability of fuel cells.

The combustion of hydrogen increases the water content of the combustion products affecting the aerodynamic performance of turbines using hydrogen as a fuel. This study aims to design a radial turbine using the differential evolution (DE) algorithm to improve its characteristics and optimize its aerodynamic performance through an orthogonal experiment and analysis of means (ANOM). The effects of varying water content in combustion products ranging from 12% to 22% on the performance of the radial turbine are also investigated. After optimization the total–static efficiency of the radial turbine increased to 89.12% which was 1.59% higher than the preliminary design. The study found that flow loss in the impeller primarily occurred at the leading edge trailing edge and the inlet of the suction surface tip and outlet. With a 10% increase in water content the enthalpy dropped Mach number increased and turbine power increased by 4.64% 1.71% and 2.41% respectively. However the total static efficiency and mass flow rate decreased by 0.71% and 2.13% respectively. These findings indicate that higher water content in hydrogen combustion products enhances the turbine’s output power while reducing the combustion products’ mass flow rate.

Historically it has been a challenge to simulate the experimentally observed cellular structures and marginal behavior of multidimensional hydrogen-oxygen detonations in the presence of losses even with detailed chemistry models. Very recently a quasi-two-dimensional inviscid approach was pursued where losses due to viscous boundary layers were modeled by the inclusion of an equivalent mass divergence in the lateral direction using Fay’s source term formulation with Mirels’ compressible boundary layer solutions. The same approach was used for this study along with the inclusion of thermally perfect detailed chemistry in order to capture the correct ignition sensitivity of the gas to dynamic changes in the thermodynamic state behind the detonation front. In addition the strength of transverse waves and their impact on the detonation front was investigated. Here the detailed San Diego mechanism was applied and it has been found that the detonation cell sizes can be accurately predicted without the need to prescribe specific parameters for the combustion model. For marginal cases where the detonation waves approach their failure limit quasi-stable mode behavior was observed where the number of transverse waves monotonically decreased to a single strong wave over a long enough distance. The strong transverse waves were also found to be slightly weaker than the detonation front indicating that they are not overdriven in agreement with recent studies.

Hydrogen is a key pillar in the global Net Zero strategy. Rapid scaling up of hydrogen production transport distribution and utilization is expected. This entails that hydrogen which is traditionally an industrial gas will come into proximity of populated urban areas and in some situations handled by the untrained public. To realize all their benefits hydrogen and its technologies must be safely developed and deployed. The specific properties of hydrogen involving wide flammability range low ignition energy and fast flame speed implies that any accidental release of hydrogen can be easily ignited. Comparing with conventional fuels combustion systems fueled by hydrogen are also more prone to flame instability and abnormal combustion. This paper aims to provide a comprehensive review about combustion research related to hydrogen safety. It starts with a brief introduction which includes some overview about risk analysis codes and standards. The core content covers ignition fire explosions and deflagration to detonation transition (DDT). Considering that DDT leads to detonation and that detonation may also be induced directly under special circumstances the subject of detonation is also included for completeness. The review covers laboratory medium and large-scale experiments as well as theoretical analysis and numerical simulation results. While highlights are provided at the end of each section the paper closes with some concluding remarks highlighting the achievements and key knowledge gaps.

In the process of building a new power system with new energy sources as the mainstay wind power and photovoltaic energy enter the multiplication stage with randomness and uncertainty and the foundation and support role of large-scale long-time energy storage is highlighted. Considering the advantages of hydrogen energy storage in large-scale cross-seasonal and cross-regional aspects the necessity feasibility and economy of hydrogen energy participation in long-time energy storage under the new power system are discussed. Firstly power supply and demand production simulations were carried out based on the characteristics of new energy generation in China. When the penetration of new energy sources in the new power system reaches 45% long-term energy storage becomes an essential regulation tool. Secondly by comparing the storage duration storage scale and application scenarios of various energy storage technologies it was determined that hydrogen storage is the most preferable choice to participate in large-scale and long-term energy storage. Three long-time hydrogen storage methods are screened out from numerous hydrogen storage technologies including salt-cavern hydrogen storage natural gas blending and solid-state hydrogen storage. Finally by analyzing the development status and economy of the above three types of hydrogen storage technologies and based on the geographical characteristics and resource endowment of China it is pointed out that China will form a hydrogen storage system of “solid state hydrogen storage above ground and salt cavern storage underground” in the future.

With the goal of achieving “carbon peak in 2030 and carbon neutrality in 2060” as clearly proposed by China the transportation sector will face long–term pressure on carbon emissions and the application of hydrogen fuel cell vehicles will usher in a rapid growth period. However true “zero carbon” emissions cannot be separated from “green hydrogen”. Therefore it is of practical significance to explore the feasibility of renewable energy hydrogen production in the context of hydrogen refueling stations especially photovoltaic hydrogen production which is applied to hydrogen refueling stations (hereinafter referred to “photovoltaic hydrogen refueling stations”). This paper takes a hydrogen refueling station in Shanghai with a supply capacity of 500 kg/day as the research object. Based on a characteristic analysis of the hydrogen demand of the hydrogen refueling station throughout the day this paper studies and analyzes the system configuration operation strategy environmental effects and economics of the photovoltaic hydrogen refueling station. It is estimated that when the hydrogen price is no less than 6.23 USD the photovoltaic hydrogen refueling station has good economic benefits. Additionally compared with the conventional hydrogen refueling station it can reduce carbon emissions by approximately 1237.28 tons per year with good environmental benefits.

Methanol as a liquid phase hydrogen storage carrier has broad prospects. Although the on-board methanol reforming hydrogen fuel cell system (MRFC) has long been proposed to replace the traditional hydrogen fuel cell vehicle the inherent safety of the system itself has rarely been studied. This paper adopted the improved method of Inherently Safer Process Piping (ISPP) to evaluate the pipeline inherent safety of MRFC. The process data such as temperature pressure viscosity and density were obtained by simulating the MRFC in ASPEN HYSYS. The Process Stream Characteristic Index (PSCI) and risk assessment of jet fire and vapor cloud explosion was carried out for the key streams with those simulated data. The results showed the risk ranks of different pipelines in the MRFC and the countermeasures were given according to different risk ranks. Through the in-depth study of the evaluation results this paper demonstrates the risk degree of the system in more detail and reduces the fuzziness of risk rating. By applying ISPP to the small integrated system of MRFC this paper realizes the leap of inherent safety assessment method in the object and provides a reference for the inherent safety assessment of relevant objects in the future.

Innovation in key low-carbon technologies plays a supporting role in achieving a high-quality low-carbon transition in the power sector. This paper aims to integrate research on the power transition pathway under the “dual carbon” goals with key technological innovation layouts. First it deeply analyzes the development trends of three key low-carbon technologies in the power sector—new energy storage CCUS and hydrogen energy—and establishes a quantitative model for their technological support in the low-carbon transition of the power sector. On this basis the objective function and constraints of traditional power planning models are improved to create an integrated optimization model for the power transition pathway and key low-carbon technologies. Finally a simulation analysis is conducted using China’s power industry “dual carbon” pathway as a case study. The optimization results include the power generation capacity structure power generation mix carbon reduction pathway and key low-carbon technology development path for China from 2020 to 2060. Additionally the impact of uncertainties in breakthroughs in new energy storage CCUS and hydrogen technologies on the power “dual carbon” pathway is analyzed providing technological and decision-making support for the low-carbon transition of the power sector.

This paper describes a renewable energy system incorporating a hydrogen production unit to address the imbalance between energy supply and demand. The system utilizes renewable energy and hydrogen production energy to release energy to fill the power gap during peak demand power supply for demand peaking and valley filling. The system is optimized by analyzing marine predator behavioral logic and optimizing the system for maximum operational efficiency and best economic value. The results of the study show that after the optimized scheduling of the hydrogen production coupled renewable energy integrated energy system using the improved marine predator optimization algorithm the energy distribution of the whole energy system is good with the primary energy saving rate maintained at 24.75% the CO2 emission reduction rate maintained at 42.32% and the cost saving rate maintained at 0.78%. In addition this paper uses the Adaboost-BP prediction model to predictively analyze the system. The results show that as the price of natural gas increases the advantages of the combined hydrogen production renewable integrated energy system proposed in this paper become more obvious and the cumulative cost over three years is better than other related systems. These research results provide an important reference for the application and development of the system.

The pressing global challenge of climate change necessitates a concerted effort to limit greenhouse gas emissions particularly carbon dioxide. A critical pathway is to replace fossil fuel sources by electrification including transportation. While electrification of light-duty vehicles is rapidly expanding the heavy-duty vehicle sector is subject to challenges notably the logistical drawbacks of the size and weight of high-capacity batteries required for range as well as the time for battery charging. This Perspective highlights the potential of hydrogen fuel-cell vehicles as a viable alternative for heavy-duty road transportation. We evaluate the implications of hydrogen integration into the freight economy energy dynamics and CO2 mitigation and envision a roadmap for a holistic energy transition. Our critical opinion presented in this Perspective is that federal incentives to produce hydrogen could foster growth in the nascent hydrogen economy. The pathway that we propose is that initial focus on operators of large fleets that could control their own fueling infrastructure. This opinion was formed from private discussions with numerous stakeholders during the formation of one of the awarded hydrogen hubs if they focus on early adopters that could leverage the hydrogen supply chain.

Integrating carbon capture and storage (CCS) technology into an integrated energy system (IES) can reduce its carbon emissions and enhance its low-carbon performance. However the full CCS of flue gas displays a strong coupling between lean and rich liquor as carbon dioxide liquid absorbents. Its integration into IESs with a high penetration level of renewables results in insufficient flexibility and renewable curtailment. In addition integrating split-flow CCS of flue gas facilitates a short capture time giving priority to renewable energy. To address these limitations this paper develops a carbon capture utilization and storage (CCUS) method into which storage tanks for lean and rich liquor and a two-stage power-to-gas (P2G) system with multiple utilizations of hydrogen including a fuel cell and a hydrogen-blended CHP unit are introduced. The CCUS is integrated into an IES to build an electricity–heat–hydrogen–gas IES. Accordingly a deep low-carbon economic optimization strategy for this IES which considers stepwise carbon trading coal consumption renewable curtailment penalties and gas purchasing costs is proposed. The effects of CCUS the twostage P2G system and stepwise carbon trading on the performance of this IES are analyzed through a case-comparative analysis. The results show that the proposed method allows for a significant reduction in both carbon emissions and total operational costs. It outperforms the IES without CCUS with an 8.8% cost reduction and a 70.11% reduction in carbon emissions. Compared to the IES integrating full CCS the proposed method yields reductions of 6.5% in costs and 24.7% in emissions. Furthermore the addition of a two-stage P2G system with multiple utilizations of hydrogen further amplifies these benefits cutting costs by 13.97% and emissions by 12.32%. In addition integrating CCUS into IESs enables the full consumption of renewables and expands hydrogen utilization and the renewable consumption proportion in IESs can reach 69.23%.

The energy efficiency of water electrolysis is limited by the sluggish kinetics of the anodic oxygen evolution reaction (OER) which simultaneously produces a low-value product oxygen. A promising strategy to address this challenge is to replace OER with a more favorable oxidation reaction that yields a valuable co-product. In this study we investigate the electrochemical reforming of glycerol in alkaline media to simultaneously produce hydrogen at a Pt cathode and formate at a NiSe₂ anode. The NiSe₂ electrode achieves a glycerol oxidation reaction (GOR) current density of up to 100 mA cm−2 in a 1 M KOH solution containing 1 M glycerol significantly outperforming a reference elemental Ni electrode. Both electrodes exhibit high Faradaic efficiencies (FE) achieving around 93 % for formate production at an applied potential of 1.6 V vs. RHE. To rationalize this exceptional performance density functional theory (DFT) calculations were conducted revealing that the incorporation of Se into NiSe₂ enhances the glycerol adsorption and modulates the electron density thereby lowering the energy barrier for the initial dehydrogenation step in the formate formation pathway. These findings provide valuable insights for the design of cost-effective high-performance electrocatalysts for organic oxidation-assisted hydrogen production advancing a more sustainable and economically attractive route for hydrogen generation and chemical valorization.

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.

This paper mainly introduces the main pain point of China's civil hydrogen energy supply chain - the problem of storage and transportation and analyzes the safety economy and scale effect and other issues of the existing hydrogen energy storage and transportation compares with other storage and transportation technology solutions and comprehensively screens out the storage and transportation technology solution mainly based on liquid hydrogen technology. The liquid hydrogen technology solution has significant advantages over the existing compressed hydrogen system in terms of safety economy and scale effect especially for future large-scale hydrogen energy application scenarios. In addition the future hydrogen energy storage and transportation system based on liquid hydrogen technology can help improve the overall utilization efficiency of country’s renewable energy promote the country's energy transition promote the electrification of the country's transportation sector and help achieve China's carbon emission reduction 2030/2060 target.

Decarbonizing heavy-duty trucks (HDTs) is both challenging and crucial for achieving carbon neutrality in the transport sector. Renewable hydrogen (H2) methanol (MeOH) and ammonia (NH3) offer potential solutions yet their economic viability and emission benefits remain largely unexplored. This study presents for the first time a comprehensive techno-economic analysis of using these three renewable fuels to decarbonize HDTs through detailed fuel and vehicle modeling. Six pathways are compared: hydrogen fuel cell electric trucks (FCET-H2) internal combustion engine trucks using MeOH (ICET-MeOH) and NH3 (ICET-NH3) as well as three indirect pathways that utilize these fuels for power generation to charge battery electric trucks (BETs). A novel “target powertrain cost” metric is introduced to assess the economic viability of FCET-H2 ICET-NH3 and ICET-MeOH relative to BETs. The results reveal that while BET pathways demonstrate higher well-to-wheel efficiencies significant opportunities exist for ICET-MeOH and ICET-NH3 in medium- and long-haul applications. Further more FCET-H2 achieves the lowest life cycle carbon emissions while ICET-MeOH and ICET-NH3 become more cost-effective as electricity costs decline. This study offers valuable insights and benchmarks for powertrain developers and policymakers addressing a critical gap in the comparative analysis of these three fuels for decarbonizing HDTs.

Underground hydrogen (H2) storage (UHS) and carbon dioxide (CO2) geo-storage (CGS) are prominent methods of meeting global energy needs and enabling a low-carbon global economy. The pore-scale distribution reservoir-scale storage capacity and containment security of H2 and CO2 are significantly influenced by interfacial properties including the equilibrium contact angle (θE) and solid-liquid and solid-gas interfacial tensions (γSL and γSG). However due to the technical constraints of experimentally determining these parameters they are often calculated based on advancing and receding contact angle values. There is a scarcity of θE γSL and γSG data particularly related to the hydrogen structural sealing potential of caprock which is unavailable in the literature. Young's equation and Neumann's equation of state were combined in this study to theoretically compute these three parameters (θE γSL and γSG) at reservoir conditions for the H2 and CO2 geo-storage potential. Pure mica organic-aged mica and alumina nano-aged mica substrates were investigated to explore the conditions for rock wetting phenomena and the sealing potential of caprock. The results reveal that θE increases while γSG decreases with increasing pressure organic acid concentration and alkyl chain length. However γSG decreases with increasing temperatures for H2 gas and vice versa for CO2. In addition θE and γSL decrease whereas γSG increases with increasing alumina nanofluid concentration from 0.05 to 0.25 wt%. Conversely θE and γSL increase whereas γSG decreases with increasing alumina nanofluid concentration from 0.25 to 0.75 wt%. The hydrogen wettability of mica (a proxy of caprock) was generally less than the CO2 wettability of mica at similar physio-thermal conditions. The interfacial data reported in this study are crucial for predicting caprock wettability alterations and the resulting structural sealing capacity for UHS and CGS.

The liner of a carbon fiber fully reinforced composite tank with thermoplastic liner (type IV) works in a hydrogen environment with varying temperature and pressure profiles. The ageing performance of the thermoplastic liner may affect hydrogen permeability and the consequent storage capacity degrade the mechanical properties and even increase the leakage risks of type IV tanks. In this paper both testing procedures and evaluation parameters of an ageing test in a hydrogen environment required in several standards are compared and analyzed. Hydrogen static exposure in a high-temperature condition with a constant temperature and pressure is suggested to be a reasonable way to accelerate the ageing reaction of thermoplastic materials. A total of 192 h is considered a superior ageing test duration to balance the test economy and safety. The ageing test temperature in the high-temperature condition is suggested as no lower than 85 ◦C while the upper limit of test pressure is suggested to be 1.25 NWP. In addition the hydrogen permeation coefficient and mechanical properties are recognized as important parameters in ageing performance evaluation. Considering the actual service conditions the influence of temperature/pressure cycling depressurization rate and humidity on the ageing performance of thermoplastics in hydrogen are advised to be investigated experimentally.

Magnesium-based hydrogen storage alloys have attracted significant attention as promising materials for solid-state hydrogen storage due to their high hydrogen storage capacity abundant reserves low cost and reversibility. However the widespread application of these alloys is hindered by several challenges including slow hydrogen absorption/desorption kinetics high thermodynamic stability of magnesium hydride and limited cycle life. This comprehensive review provides an in-depth overview of the recent advances in magnesium-based hydrogen storage alloys covering their fundamental properties synthesis methods modification strategies hydrogen storage performance and potential applications. The review discusses the thermodynamic and kinetic properties of magnesium-based alloys as well as the effects of alloying nanostructuring and surface modification on their hydrogen storage performance. The hydrogen absorption/desorption properties of different magnesium-based alloy systems are compared and the influence of various modification strategies on these properties is examined. The review also explores the potential applications of magnesium-based hydrogen storage alloys including mobile and stationary hydrogen storage rechargeable batteries and thermal energy storage. Finally the current challenges and future research directions in this field are discussed highlighting the need for fundamental understanding of hydrogen storage mechanisms development of novel alloy compositions optimization of modification strategies integration of magnesium-based alloys into hydrogen storage systems and collaboration between academia and industry.

With the unprecedented development of green and renewable energy sources the proportion of clean hydrogen (H2 ) applications grows rapidly. Since H2 has physicochemical properties of being highly permeable and combustible high-performance H2 sensors to detect and monitor hydrogen concentration are essential. This review discusses a variety of fiber-optic-based H2 sensor technologies since the year 1984 including: interferometer technology fiber grating technology surface plasma resonance (SPR) technology micro lens technology evanescent field technology integrated optical waveguide technology direct transmission/reflection detection technology etc. These technologies have been evolving from simply pursuing high sensitivity and low detection limits (LDL) to focusing on multiple performance parameters to match various application demands such as: high temperature resistance fast response speed fast recovery speed large concentration range low cross sensitivity excellent long-term stability etc. On the basis of palladium (Pd)-sensitive material alloy metals catalysts or nanoparticles are proposed to improve the performance of fiberoptic-based H2 sensors including gold (Au) silver (Ag) platinum (Pt) zinc oxide (ZnO) titanium oxide (TiO2 ) tungsten oxide (WO3 ) Mg70Ti30 polydimethylsiloxane (PDMS) graphene oxide (GO) etc. Various microstructure processes of the side and end of optical fiber H2 sensors are also discussed in this review.

Aiming to solve the problems of insufficient dynamic responses the large loss of energy storage life of a single power cell and the large fluctuation in DC (direct current) bus voltage in fuel cell vessels this study takes a certain type of fuel cell ferry as the research object and proposes an improved equivalent minimum hydrogen consumption energy management strategy based on fuzzy logic control. First a hybrid power system including a fuel cell a lithium–iron–phosphate battery and a supercapacitor is proposed with the simulation of the power system of the modified mother ship. Second a power system simulation model and a double-closed-loop PI (proportion integration) control model are established in MATLAB/Simulink to design the equivalent hydrogen consumption model and fuzzy logic control strategy. The simulation results show that under the premise of meeting the load requirements the control strategy designed in this paper improves the Li-ion battery’s power the Li-ion battery’s SOC (state of charge) the bus voltage stability and the equivalent hydrogen consumption significantly compared with those before optimization which improves the stability and economy of the power system and has certain practical engineering value.

To cope with climate change emerging fuels- hydrogen ammonia and methanol- have been proposed as promising energy carriers that will replace part of the liquefied natural gas (LNG) in future maritime scenarios. Energy efficiency is an important indicator for evaluating the system but the maritime supply system for emerging fuels has yet to be revealed. In this study the energy efficiency of the maritime supply chain of hydrogen ammonia methanol and natural gas is investigated considering processes including production storage loading transport and unloading. A sensitivity analysis of parameters such as ambient temperature storage time pipeline length and sailing time is also carried out. The results show that hydrogen (2.366%) has the highest daily boil-off gas (BOG) rate and wastes more energy than LNG (0.413%) with ammonia and methanol both being lower than LNG. The recycling of BOG is of great importance to the hydrogen supply chain. When produced from renewable energy sources methanol (98.02%) is the most energy efficient followed by ammonia with hydrogen being the least (89.10%). This assessment shows from an energy efficiency perspective that ammonia and methanol have the potential to replace LNG as the energy carrier of the future and that hydrogen requires efficient BOG handling systems to increase competitiveness. This study provides some inspirations for the design of global maritime supply systems for emerging fuels.

Scaling up clean hydrogen supply in the near future is critical to achieving China’s hydrogen development target. This study established an electrolytic hydrogen development mechanism considering the generation mix and operation optimization of power systems with access to hydrogen. Based on the incremental cost principle we quantified the provincial and national clean hydrogen production cost performance levels in 2030. The results indicated that this mechanism could effectively reduce the production cost of clean hydrogen in most provinces with a national average value of less than 2 USD·kg−1 at the 40-megaton hydrogen supply scale. Provincial cooperation via power transmission lines could further reduce the production cost to 1.72 USD·kg−1. However performance is affected by the potential distribution of hydrogen demand. From the supply side competitiveness of the mechanism is limited to clean hydrogen production while from the demand side it could help electrolytic hydrogen fulfil a more significant role. This study could provide a solution for the ambitious development of renewables and the hydrogen economy in China.

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.

High-pressure hydrogen tanks which are composed of an aluminum alloy liner and a carbon fiber wound layer are currently the most popular means to store hydrogen on vehicles. Nevertheless the aluminum alloy is easily affected by high-pressure hydrogen which leads to the appearance of hydrogen embrittlement (HE). Serious HE of hydrogen tank represents a huge dangers to the safety of vehicles and passengers. It is critical and timely to outline the mainstream approach and point out potential avenues for further investigation of HE. An analysis including the mechanism (including hydrogen-enhanced local plasticity model hydrogen-enhanced decohesion mechanism and hydrogen pressure theory) the detection (including slow strain rate test linearly increasing stress test and so on) and methods for the prevention of HE on aluminum alloys of hydrogen vehicles (such as coating) are systematically presented in this work. Moreover the entire experimental detection procedures for HE are expounded. Ultimately the prevention measures are discussed in detail. It is believed that further prevention measures will rely on the integration of multiple prevention methods. Successfully solving this problem is of great significance to reduce the risk of failure of hydrogen storage tanks and improve the reliability of aluminum alloys for engineering applications in various industries including automotive and aerospace.