China, People’s Republic

The crisscross progress of transportation and energy carries the migrating track of human society development and the evolution of civilization among which the decarbonization strategy is a key issue. Traffic carbon emissions account for 16.2% of total energy carbon emissions while road traffic carbon emissions account for 11.8% of total energy carbon emissions. Therefore road traffic is a vital battlefield in attaining the goal of decarbonization. Employing clean energy as an alternative fuel is of great significance to the transformation of the energy consumption structure in road transportation. Hydrogen and ammonia are renewable energy with the characteristics of being widely distributed and clean. Both exist naturally in nature and the products of complete combustion are substances (water and nitrogen) that do not pollute the atmosphere. Because it can promote agricultural production ammonia has a long history in human society. Both have the potential to replace traditional fossil fuel energy. An overview of the advantages of hydrogen and ammonia as well as their development in different countries such as the United States the European Union Japan and other major development regions is presented in this paper. Related research topics of hydrogen and ammonia’s production storage and transferring technology have also been analyzed and collated to stimulate the energy production chain for road transportation. The current cost of green hydrogen is between $2.70–$8.80 globally which is expected to approach $2–$6 by 2030. Furthermore the technical development of hydrogen and ammonia as a fuel for engines and fuel cells in road transportation is compared in detail and the tests practical applications and commercial popularization of these technologies are summarized respectively. Opportunities and challenges coexist in the era of the renewable energy. Based on the characteristics and development track of hydrogen and ammonia the joint development of these two types of energy is meant to be imperative. The collaborative development mode of hydrogen and ammonia together with the obstacles to their development of them are both compared and discussed. Finally referring to the efforts and experiences of different countries in promoting hydrogen and ammonia in road transportation corresponding constructive suggestions have been put forward for reference. At the end of the paper a framework diagram of hydrogen and ammonia industry chains is provided and the mutual promotion development relationship of the two energy sources is systematically summarized.

Hydrogen energy vehicles are being increasingly widely used. To ensure the safety of hydrogenation stations research into the detection of hydrogen leaks is required. Offline analysis using data machine learning is achieved using Spark SQL and Spark MLlib technology. In this study to determine the safety status of a hydrogen refueling station we used multiple algorithm models to perform calculation and analysis: a multi-source data association prediction algorithm a random gradient descent algorithm a deep neural network optimization algorithm and other algorithm models. We successfully analyzed the data including the potential relationships internal relationships and operation laws between the data to detect the safety statuses of hydrogen refueling stations.

Transporting green hydrogen by existing natural gas networks has become a practical means to accommodate curtailed wind and solar power. Restricted by pipe materials and pressure levels there is an upper limit on the hydrogen blending ratio of hydrogen-enriched compressed natural gas (HCNG) that can be transported by natural gas pipelines which affects whether the natural gas network can supply energy safely and reliably. To this end this paper investigates the effects of the intermittent and fluctuating green hydrogen produced by different types of renewable energy on the dynamic distribution of hydrogen concentration after it is blended into natural gas pipelines. Based on the isothermal steady-state simulation results of the natural gas network two convection–diffusion models for the dynamic simulation of hydrogen injections are proposed. Finally the dynamic changes of hydrogen concentration in the pipelines under scenarios of multiple green hydrogen types and multiple injection nodes are simulated on a seven-node natural gas network. The simulation results indicate that compared with the solar-power-dominated hydrogen productionblending scenario the hydrogen concentrations in the natural gas pipelines are more uniformly distributed in the wind-power-dominated scenario and the solar–wind power balance scenario. To be specific in the solar-power-dominated scenario the hydrogen concentration exceeds the limit for more time whilst the overall hydrogen production is low and the local hydrogen concentration in the natural gas network exceeds the limit for nearly 50% of the time in a day. By comparison in the wind-power-dominated scenario all pipelines can work under safe conditions. The hydrogen concentration overrun time in the solar–wind power balance scenario is also improved compared with the solar-power-dominated scenario and the limit-exceeding time of the hydrogen concentration in Pipe 5 and Pipe 6 is reduced to 91.24% and 91.99% of the solar-power-dominated scenario. This work can help verify the day-ahead scheduling strategy of the electricity-HCNG integrated energy system (IES) and provide a reference for the design of local hydrogen production-blending systems.

Waste heat recovery was considered as a promising candidate for energy conservation and emission reduction. Methanol steam reforming was considered to be an effective means for hydrogen production because of its advantages. In this work a micro reactor was constructed and thermoelectric generation coupled with hydrogen production from methanol steam reforming was innovatively used to recycle waste heat which was simulated by hot air from a hot air gun. The waste heat was converted into electricity and hydrogen at the same time. The characteristic of thermoelectric generation coupled with methanol steam reforming was investigated. It was experimentally verified that both the hydrogen production rate and methanol conversion increased with the increasing inlet temperature but thermal efficiency increased firstly and then decreased with the increasing temperature. The methanol steam reforming could effectively maintain cold side temperature distribution of thermoelectric generation. In the case of the thermoelectric module (1) the highest temperature difference of 37 ◦C was determined and the maximum open circuit voltage of 2 V was observed. The highest methanol conversion of 64.26% was achieved at a space velocity of 0.98 h−1 when the temperature was 543 K comprehensively considering the CO content and thermal efficiency.

Hydrogen energy plays an important role in the transformation of low-carbon energy and electric–hydrogen coupling will become a typical energy scenario. Aiming at the operation flexibility of a low-carbon electricity–hydrogen coupling system with high proportion of wind power and photovoltaic this work studies the flexibility margin of an electricity–hydrogen coupling energy block based on model predictive control. By analyzing the power exchange characteristics of heterogeneous energy the homogenization models of various heterogeneous energy sources are established. According to the analysis of power system flexibility margin three dimensions of flexibility margin evaluation indexes are defined from the dimension of system operation and an electricity–hydrogen coupling energy block scheduling model is established. The model predictive control algorithm is used to optimize the power balance operation of the electro–hydrogen coupling energy block and the flexibility margin of the energy block is quantitatively analyzed and calculated. Through the example analysis it is verified that the calculation method proposed in this article can not only realize the online power balance optimization of the electric–hydrogen coupling energy block but also effectively quantify the operation flexibility margin of the electric–hydrogen coupling energy block.

A combined ultra-short-term wind power prediction strategy with high robustness based on least squares support vector machine (LSSVM) has been proposed in order to solve the wind abandonment caused by wind power randomness and realize efficient hydrogen production under wide power fluctuation. Firstly the original wind power data is decomposed into sub-modes with different bandwidth by variational modal decomposition (VMD) which reduces the influence of random noise and mode mixing significantly. Then dragonfly algorithm (DA) is introduced to optimize LSSVM kernel function and the combined ultra-short-term wind power prediction strategy which meets the time resolution and accuracy requirements of electrolytic cell control has been established finally. This model is validated by a wind power hydrogen production demonstration project output in the middle east of China. The superior prediction accuracy for high volatility wind power data is verified and the algorithm provides theoretical basis to improve the control of wind power hydrogen production system

The combination of methane steam reforming technology and CCS (Carbon Capture and Storage) technology has great potential to reduce carbon emissions in the process of hydrogen production. Different from the traditional idea of capturing CO2 (Carbon Dioxide) in the exhaust gas with high work consumption this study simultaneously focuses on CO2 separation from fuel gas and recycling. A new hydrogen production system is developed by methane steam reforming coupled with carbon capture. Separated and captured high-purity carbon dioxide could be recycled for methane dry reforming; on this basis a new methane-dry-reforming-driven hydrogen production system with a carbon dioxide reinjection unit is innovatively proposed. In this study the energy flow and irreversible loss in the two newly developed systems are analyzed in detail through energy and exergy balance analysis. The advantages are explored from the perspective of hydrogen production rate natural gas consumption and work consumption. In addition in consideration of the integrated performance an optimal design analysis was conducted. In terms of hydrogen production the new system based on dry reforming is better with an advantage of 2.41%; however it is worth noting that the comprehensive thermal performance of the new steam reforming system is better reaching 10.95%. This study provides new ideas for hydrogen production from a low carbon emission perspective and also offers a new direction for future distributed energy system integration.

The steel industry represents about 7% of the world’s anthropogenic CO2 emissions due to the high use of fossil fuels. The CO2 -lean direct reduction of iron ore with hydrogen is considered to offer a high potential to reduce CO2 emissions and this direct reduction of Fe2O3 powder is investigated in this research. The H2 reduction reaction kinetics and fluidization characteristics of fine and cohesive Fe2O3 particles were examined in a vibrated fluidized bed reactor. A smooth bubbling fluidization was achieved. An increase in external force due to vibration slightly increased the pressure drop. The minimum fluidization velocity was nearly independent of the operating temperature. The yield of the direct H2 -driven reduction was examined and found to exceed 90% with a maximum of 98% under the vibration of ~47 Hz with an amplitude of 0.6 mm and operating temperatures close to 500 ◦C. Towards the future of direct steel ore reduction cheap and “green” hydrogen sources need to be developed. H2 can be formed through various techniques with the catalytic decomposition of NH3 (and CH4 ) methanol and ethanol offering an important potential towards production cost yield and environmental CO2 emission reductions.

The uncertainty and volatility of wind power have led to large-scale wind curtailment during grid connections. The adoption of power-to-hydrogen (P2H) system in a microgrid (MG) can mitigate the renewable curtailment by hydrogen conversion and storage. This paper conducts unified modeling for different types of P2H systems and considers the multi-energy trading in a hydrogen-coupled power market. The proposed bi-level equilibrium model is beneficial to minimize the energy cost of microgrids. Firstly a microgrid operation model applied to different P2H systems including an alkaline electrolysis cell (AEC) a proton exchange membrane electrolysis cell (PEMEC) or a solid oxide electrolysis cell (SOEC) is proposed at the upper level. Secondly an electricity market–clearing model and a hydrogen market model are constructed at the lower level. Then the diagonalization algorithm is adopted to solve the multi-market equilibrium problem. Finally case studies based on an IEEE 14-bus system are conducted to validate the proposed model and the results show that the microgrid with a P2H system could gain more profits and help increase the renewable penetration.

Under the requirements of China's strategic goal of "carbon peaking and carbon neutrality" as a renewable clean and efficient secondary energy source hydrogen benefits from abundant resources a wide variety of sources a high combustion calorific value clean and non-polluting various forms of utilization energy storage mediums and good security etc. It will become a realistic way to help energy transportation petrochemical and other fields to achieve deep decarbonization and will turn into an important replacement energy source for China to build a modern clean energy system. It is clear that accelerating the development of hydrogen energy has become a global consensus. In order to provide a theoretical support for the accelerated transformation of hydrogen-related industries and energy companies and provide a basis and reference for the construction of "Hydrogen Energy China" this paper describes main key technological progresses in the hydrogen industry chain such as hydrogen production storage transportation and application. The status and development trends of hydrogen industrialization are analyzed and then the challenges faced by the development of the hydrogen industry are discussed. At last the development and future of the hydrogen industry are prospected. The following conclusions are achieved. (1) Hydrogen technologies of our country will become mature and enter the road of industrialization. The whole industry chain system of the hydrogen industry is gradually being formed and will realize the leap-forward development from gray hydrogen blue hydrogen to green hydrogen. (2) The overall development of the entire hydrogen industry chain such as hydrogen production storage and transportation fuel cells hydrogen refueling stations and other scenarios should be accelerated. Besides in-depth integration and coordination with the oil and gas industry needs more attention which will rapidly promote the high-quality development of the hydrogen industry system. (3) The promotion and implementation of major projects such as "north-east hydrogen transmission" "west-east hydrogen transmission" "sea hydrogen landing" and utilization of infrastructures such as gas filling stations can give full play to the innate advantages of oil and gas companies in industrial chain nodes such as hydrogen production and refueling etc. which can help to achieve the application of "oil gas hydrogen and electricity" four-station joint construction form a nationwide hydrogen resource guarantee system and accelerate the planning and promotion of the "Hydrogen Energy China" strategy.