Publications

The catalytic steam reforming of biodiesel was examined over Ni-alumina and Ni–ceria–zirconia catalysts at atmospheric pressure. Effects of temperatures of biodiesel preheating/vaporising (190–365 ◦C) and reforming (600–800 ◦C) molar steam to carbon ratio (S/C = 2–3) and residence time in the reformer represented by the weight hourly space velocity ‘WHSV’ of around 3 were examined for 2 h. Ni supported on calcium aluminate and on ceria–zirconia supports achieved steady state hydrogen product stream within 90% of the equilibrium yields although 4% and 1% of the carbon feed had deposited on the catalysts respectively during the combined conditions of start-up and steady state. Addition of dopants to ceria–zirconia supported catalyst decreased the performance of the catalyst. Increase in S/C ratio had the expected positive effects of higher H2 yield and lower carbon deposition.

With the development of the natural gas industry gas transmission pipelines have been developed rapidly in terms of safety economy and efficiency. Our recent studies have shown that an important factor of main pipelines serviceability loss under their long-term service is the in-bulk metal degradation of the pipe wall. This leads to the loss of the initial mechanical properties primarily resistance to brittle fracture which were set in engineering calculations at the pipeline design stage. At the same time stress corrosion cracking has been identified as one of the predominant failures in pipeline steels in humid environments which causes rupture of high-pressure gas transmission pipes as well as serious economic losses and disasters.

In the present work the low-carbon pipeline steels with different strength levels from the point of view of their susceptibility to stress corrosion cracking in the as-received state and after in-laboratory accelerated degradation under environmental conditions similar to those of an acidic soil were investigated. The main objectives of this study were to determine whether the development of higher strength materials led to greater susceptibility to stress corrosion cracking and whether degraded pipeline steels became more susceptible to stress corrosion cracking than in the as-received state. The procedure of accelerated degradation of pipeline steels was developed and introduced in laboratory under the combined action of axial loading and hydrogen charging. It proved to be reliable and useful to performed laboratory simulation of in-service degradation of pipeline steels with different strength. The in-laboratory degraded 17H1S and X60 pipeline steels tested in the NS4 solution saturated with CO₂ under open circuit potential revealed the susceptibility to stress corrosion cracking reflected in the degradation of mechanical properties and at the same time the degraded X60 steel showed higher resistance to stress corrosion cracking than the degraded 17H1S steel. Fractographic observation confirmed the pipeline steels hydrogen embrittlement caused by the permeated hydrogen.

There is growing interest in using hydrogen (H2) as a long-duration energy storage resource in a future electric grid dominated by variable renewable energy (VRE) generation. Modeling H2 use exclusively for grid-scale energy storage often referred to as ‘‘power-to-gas-to-power (P2G2P)’’ overlooks the cost-sharing and CO2 emission benefits from using the deployed H2 assets to decarbonize other end-use sectors where direct electrification is challenging. Here we develop a generalized framework for co-optimizing infrastructure investments across the electricity and H2 supply chains accounting for the spatio-temporal variations in energy demand and supply. We apply this sector-coupling framework to the U.S. Northeast under a range of technology cost and carbon price scenarios and find greater value of power-to-H2 (P2G) vs. P2G2P routes. Specifically P2G provides grid flexibility to support VRE integration without the round-trip efficiency penalty and additional cost incurred by P2G2P routes. This form of sector coupling leads to: (a) VRE generation increase by 13–56% and (b) total system cost (and levelized costs of energy) reduction by 7–16% under deep decarbonization scenarios. Both effects increase as H2 demand for other end-uses increases more than doubling for a 97% decarbonization scenario as H2 demand quadruples. We also find that the grid flexibility enabled by sector coupling makes deployment of carbon capture and storage (CCS) for power generation less cost-effective than its use for low-carbon H2 production. These findings highlight the importance of using an integrated energy system framework with multiple energy vectors in planning cost-effective energy system decarbonization

Due to its characteristics hydrogen is considered the energy carrier of the future. Its use as a fuel generates reduced pollution as if burned it almost exclusively produces water vapor. Hydrogen can be produced from numerous sources both of fossil and renewable origin and with as many production processes which can use renewable or non-renewable energy sources. To achieve carbon neutrality the sources must necessarily be renewable and the production processes themselves must use renewable energy sources. In this review article the main characteristics of the most used hydrogen production methods are summarized mainly focusing on renewable feedstocks furthermore a series of relevant articles published in the last year are reviewed. The production methods are grouped according to the type of energy they use; and at the end of each section the strengths and limitations of the processes are highlighted. The conclusions compare the main characteristics of the production processes studied and contextualize their possible use.

Insufficient active sites and fast charge carrier recombination are detrimental to photocatalytic activity of graphitic carbon nitride (g-C3N4). In this work a combination of pore creating with thermal exfoliation was employed to prepare porous g-C3N4 nanosheets for photocatalytic water splitting into hydrogen. Hexadecyl trimethyl ammonium chloride (CTAC) as the soft template promoted the formation of porous g-C3N4 during the thermal condensation of melamine. On further post-synthesis calcination the porous g-C3N4 aggregates were exfoliated into discrete nanosheets accompanied by an increase in specific surface area and defects. Optimal porous g-C3N4 nanosheets achieved 3.6 times the photocatalytic hydrogen evolution rate for bulk counterpart. The enhanced photocatalytic activity may be ascribed to TCN-1%CTAC has larger specific surface area stronger optical absorption intensity and higher photogenerated electron–hole separation efficiency. The external quantum efficiency of TCN-1%CTAC was measured to be 3.4% at 420 nm. This work provides a simple combinatorial strategy for the preparation of porous g-C3N4 nanosheets with low cost environmental friendliness and enhanced photocatalytic activity.

Two non-electrified railway lines one in Norway and the other in the USA are analysed for their potential to be electrified with overhead line equipment batteries hydrogen or hydrogen-battery hybrid powertrains. The energy requirements are established with single-train simulations including the altitude profiles of the lines air and rolling resistances and locomotive tractive-effort curves. The composition of the freight trains in terms of the number of locomotives battery wagons hydrogen wagons etc. is also calculated by the same model. The different technologies are compared by the criteria of equivalent annual costs benefit–cost ratio payback period and up-front investment based on the estimated techno-economic parameters for years 2020 2030 and 2050. The results indicate the potential of batteries and fuel cells to replace diesel on rail lines with low traffic volumes.

Written by Arup in collaboration with the GIIA this report is centred on the opinions of investors from around the world gathered through a survey of GIIA members and in-depth interviews. It therefore presents the sentiments of the world’s leading fund managers insurance investors pension funds and a sovereign wealth fund. Their opinions matter because these are the decision makers that hold the purse strings when it comes to private sector investment in hydrogen infrastructure. Many of the facts about hydrogen are well-known to many readers and these are presented in this report drawing on Arup’s research and experience as a global infrastructure advisory firm. However the novelty of this report is that it looks at hydrogen through the uncompromising eyes of investors with analysis of feedback which identifies barriers to investment in the infrastructure required to enable the hydrogen economy. Perhaps most importantly it also proposes interventions that policymakers and regulators could take to overcome the barriers currently faced.<br/>Introduction The sentiments of investors are at the heart of this study with results from the survey presented at the beginning of each section to serve as a launch pad for Arup’s analysis. But we want it to be more than an interesting read; it is a call to action for policy makers to create the right environment to catalyse private sector investment and kickstart the hydrogen economy.

Hydrogen as a strategy clean fuel is receiving more and more attention recently in China in addition to the policy emphasis on H2. In this work we conceive of a hydrogen production process based on a chemical regenerative coal gasification. Instead of using a lumped coal gasification as is traditional in the H2 production process herein we used a two-step gasification process that included coking and char-steam gasification. The sensible heat of syngas accounted for 15–20% of the total energy of coal and was recovered and converted into chemical energy of syngas through thermochemical reactions. Moreover the air separation unit was eliminated due to the adoption of steam as oxidant. As a result the efficiency of coal to H2 was enhanced from 58.9% in traditional plant to 71.6% in the novel process. Further the energy consumption decreased from 183.8 MJ/kg in the traditional plant to 151.2 MJ/kg in the novel process. The components of syngas H2 and efficiency of gasification are herein investigated through experiments in fixed bed reactors. Thermodynamic performance is presented for both traditional and novel coal to hydrogen plants.

Fossil fuels are being progressively substituted by a cleaner and more environmentally friendly form of energy where hydrogen fuel cells stand out. However the implementation of a competitive hydrogen economy still presents several challenges related to economic costs required infrastructures and environmental performance. In this context the objective of this work is to determine the environmental performance of the recovery of hydrogen from industrial waste gas streams to feed high-temperature proton exchange membrane fuel cells for stationary applications. The life-cycle assessment (LCA) analyzed alternative scenarios with different process configurations considering as functional unit 1 kg of hydrogen produced 1 kWh of energy obtained and 1 kg of inlet flow. The results make the recovery of hydrogen from waste streams environmentally preferable over alternative processes like methane reforming or coal gasification. The production of the fuel cell device resulted in high contributions in the abiotic depletion potential and acidification potential mainly due to the presence of platinum metal in the anode and cathode. The design and operation conditions that defined a more favorable scenario are the availability of a pressurized waste gas stream the use of photovoltaic electricity and the implementation of an energy recovery system for the residual methane stream.

Regarding the problem of hydrogen diffusion of the fuel cell vehicle (HFCV) when its hydrogen supply system leaks this research uses the FLUENT software to simulate numerical values in the process of hydrogen leakage diffusion in both open space and closed space. This paper analyzed the distribution range and concentration distribution characteristics of hydrogen in these two different spaces. Besides this paper also took a survey about the effects of leakage rate wind speed wind direction in open space and the role the air vents play on hydrogen safety in closed space which provides a reference for the hydrogen safety of HFCV. In conclusion the experiment result showed that: In open space hydrogen leakage rate has a great influence on its diffusion. When the leakage rate doubles the hydrogen leakage range will expand about 1.5 times simultaneously. The hydrogen diffusion range is the smallest when the wind blows at 90 degrees which is more conducive to hydrogen diffusion. However when the wind direction is against the direction of the leakage of hydrogen the range of hydrogen distribution is maximal. Under this condition the risk of hydrogen leakage is highest. In an enclosed space when the vent is set closest to the leakage position the volume fraction of hydrogen at each time is smaller than that at other positions so it is more beneficial to safety.

Predicting lower flammability limits (LFL) of hydrogen has become an ever-important task for safety of nuclear industry. While numerous experimental studies have been conducted LFL results applicable for the harsh environment are still lack of information. Our aim is to develop a calculated non-adiabatic flame temperature (CNAFT) model to better predict LFL of hydrogen mixtures in nuclear power plant. The developed model is unique for incorporating radiative heat loss during flame propagation using the CNAFT coefficient derived through previous studies of flame propagation. Our new model is more consistent with the experimental results for various mixtures compared to the previous model which relied on calculated adiabatic flame temperature (CAFT) to predict the LFL without any consideration of heat loss. Limitation of the previous model could be explained clearly based on the CNAFT coefficient magnitude. The prediction accuracy for hydrogen mixtures at elevated initial temperatures and high helium content was improved substantially. The model reliability was confirmed for H2-air mixtures up to 300 C and H2-air-He mixtures up to 50 vol % helium concentration. Therefore the CNAFT model developed based on radiation heat loss is expected as the practical method for predicting LFL in hydrogen risk analysis.

Recent years have seen a growing interest in water electrolysis as a way to store renewable electric energy into chemical energy through hydrogen production. However today the share of renewable energy is still limited and there is the need to have a continuous use of H2 for industrial chemicals applications. Firstly the paper discusses the use of electrolysis - connected to a conventional grid - for a continuous H2 production in terms of associated CO2 emissions and compares such emissions with conventional methane steam reforming (MSR). Therefore it explores the possibility to use electrical methane steam reforming (eMSR) as a way to reduce the CO2 emissions. As a way to have zero emissions carbon mineralization of CO2 is coupled - instead of in-situ carbon capture and storage technology (CCS) - to eMSR; associated relevant cost of production is evaluated for different scenarios. It appears that to minimize such production cost carbonate minerals must be reused in the making of other industrial products since the amount of carbonates generated by the process is quite significant.

Hydrogen will become a dominant energy carrier in the future and the efficiency and lifetime cost of its production through water electrolysis is a major research focus. Alongside efforts to offer optimum solutions through plant design and sizing it is also necessary to develop a flexible virtualised replica of renewable hydrogen plants that not only models compatibility with the “plug-and-play” nature of many facilities but that also identifies key elements for optimisation of system operation. This study presents a model for a renewable hydrogen production plant based on real-time historical and present-day datasets of PV connected to a virtualised grid-connected AC microgrid comprising different technologies of batteries electrolysers and fuel cells. Mathematical models for each technology were developed from chemical and physical metrics of the plant. The virtualised replica is the first step toward the implementation of a digital twin of the system and accurate validation of the system behaviour when updated with real-time data. As a case study a solar hydrogen pilot plant consisting of a 60 kW Solar PV a 40 kW PEM electrolyser a 15 kW LIB battery and a 5 kW PEM fuel cell were simulated and analysed. Two effective operational factors on the plant's performance are defined: (i) electrolyser power settings to determine appropriate hydrogen production over twilight periods and/or overnight and (ii) a user-defined minimum threshold for battery state of charge to prevent charge depletion overnight if the electrolyser load is higher than its capacity. The objective of this modelling is to maximise hydrogen yield while both loss of power supply probability (LPSP) and microgrid excess power are minimised. This analysis determined: (i) a hydrogen yield of 38e39% from solar DC energy to hydrogen energy produced (ii) an LPSP <2.6 104 and (iii) < 2% renewable energy lost to the grid as excess electricity for the case study.

The publication gives an overview of the production costs of synthetic methane in a Power-to-Gas process. The production costs depend in particularly on the electricity price and the full load hours of the plant sub-systems electrolysis and methanation. The full-load hours of electrolysis are given by the electricity supply concept. In order to increase the full-load hours of methanation the size of the intermediate hydrogen storage tank and the size of the methanation are optimised on the basis of the availability of hydrogen. The calculation of the production costs for synthetic methane are done with economics for 2030 and 2050 and the expenditures are calculated for one year of operation. The sources of volume of purchased electricity are the short-term market long-term contracts direct-coupled renewable energy sources or seasonal use of surpluses. Gas sales are either traded on the short-term market or guaranteed by long-term contracts. The calculations show that an intermediate storage tank for hydrogen adjustment of the methanation size and operating electrolysis and methanation separately increase the workload of the sub-system methanation. The gas production costs can be significantly reduced. With the future expected development of capital expenditures operational expenditure electricity prices gas costs and efficiencies an economic production of synthetic natural gas for the years 2030 especially for 2050 is feasible. The results show that Power-to-Gas is an option for long-term large-scale seasonal storage of renewable energy. Especially the cases with high operating hours for the sub-system methanation and low electricity prices show gas production costs below the expected market prices for synthetic gas and biogas.

This work reports a detailed chemical looping investigation of strontium ferrite (SrFeO_3−δ) a material with the perovskite structure type able to donate oxygen and stay in a nonstoichiometric form over a broad range of oxygen partial pressures starting at temperatures as low as 250°C (reduction in CO measured in TGA). SrFeO_3−δ is an economically attractive simple but remarkably stable material that can withstand repeated phase transitions during redox cycling. Mechanical mixing and calcination of iron oxide and strontium carbonate was evaluated as an effective way to obtain pure SrFeO_3−δ. In–situ XRD was performed to analyse structure transformations during reduction and reoxidation. Our work reports that much deeper reduction from SrFeO_3−δ to SrO and Fe is reversible and results in oxygen release at a chemical potential suitable for hydrogen production. Thermogravimetric experiments with different gas compositions were applied to characterize the material and evaluate its available oxygen capacity. In both TGA and in-situ XRD experiments the material was reduced below δ=0.5 followed by reoxidation either with CO₂ or air to study phase segregation and reversibility of crystal structure transitions. As revealed by in-situ XRD even deeply reduced material regenerates at 900°C to SrFeO_3−δ with a cubic structure. To investigate the catalytic behaviour of SrFeO_3−δ in methane combustion experiments were performed in a fluidized bed rig. These showed SrFeO_3−δ donates O₂ into the gas phase but also assists with CH4 combustion by supplying lattice oxygen. To test the material for combustion and hydrogen production long cycling experiments in a fluidized bed rig were also performed. SrFeO3−δ showed stability over 30 redox cycles both in experiments with a 2-step oxidation performed in CO₂ followed by air as well as a single step oxidation in CO₂ alone. Finally the influence of CO/CO₂ mixtures on material performance was tested; a fast and deep reduction in elevated pCO₂ makes the material susceptible to carbonation but the process can be reversed by increasing the temperature or lowering pCO₂.

This paper analyses the feasibility of power-to-gas in electricity markets dominated by renewables. The business case of a power-to-gas plant that is producing hydrogen is evaluated by determining the willingness to pay for electricity and by comparing this to the level and volatility of electricity prices in a number of European day-ahead markets. The short-term willingness to pay for electricity depends on the marginal costs and revenues of the plant while the long-term willingness to pay for electricity also takes into account investment and yearly fixed operational costs and therefore depends on the expected number of operating hours. The latter ultimately determines whether or not large-scale investments in the power-to-gas technology will take place.<br/>We find that power-to-gas plants are not profitable under current market conditions: even under the most optimistic assumptions for the cost and revenue parameters power-to-gas plants need to run for many hours during the year at very low prices (i.e. the long-term willingness to pay for electricity is very low) that do not currently exist in Europe. In an optimistic future scenario regarding investment costs efficiency and revenues of power-to-gas however the long-term willingness to pay for electricity is higher than the lowest recently observed day-ahead electricity prices. When prices remain at this low level investments in power-to-gas can thus become profitable.

The document provides information on safety planning implementation and reporting for projects involving hydrogen and/or fuel cell technologies. It does not intend to replace or contradict existing regulations which prevail under all circumstances. Neither is it meant to conflict with relevant international or national standards or to replace existing company safety policies codes and procedures. Instead this guidance document aims to assist projects and project partners in identifying hazards and associated risks in prevention and/or mitigation of them through a proper safety plan in implementing the safety plan and reporting safety related events. This shall help in safely delivering the project and ultimately producing inherently safer systems processes and infrastructure.

A viable hydrogen infrastructure is one of the main challenges for fuel cells in mobile applications. Several studies have investigated the most cost-efficient hydrogen supply chain structure with a focus on hydrogen transportation. However supply chain models based on hydrogen produced by electrolysis require additional seasonal hydrogen storage capacity to close the gap between fluctuation in renewable generation from surplus electricity and fuelling station demand. To address this issue we developed a model that draws on and extends approaches in the literature with respect to long-term storage. Thus we analyse Liquid Organic Hydrogen Carriers (LOHC) and show their potential impact on future hydrogen mobility. We demonstrate that LOHC-based pathways are highly promising especially for smaller-scale hydrogen demand and if storage in salt caverns remains uncompetitive but emit more greenhouse gases (GHG) than other gaseous or hydrogen ones. Liquid hydrogen as a seasonal storage medium offers no advantage compared to LOHC or cavern storage since lower electricity prices for flexible operation cannot balance the investment costs of liquefaction plants. A well-to-wheel analysis indicates that all investigated pathways have less than 30% GHG-emissions compared to conventional fossil fuel pathways within a European framework.

The volatility of renewable energy sources (RES) poses a growing problem for operation of electricity grids. In contrary the necessary decarbonisation of sectors such as heat supply and transport requires a rapid expansion of RES. Load management in the context of power-to-heat systems can help to simultaneously couple the electricity and heat sectors and stabilise the electricity grid thus enabling a higher share of RES. In addition power-to-hydrogen offers the possibility of long-term energy storage options. Within this work we present a novel optimization approach for heat pump operation with the aim to counteract the volatility and enable a higher usage of RES. For this purpose a detailed simulation model of buildings and their energy supply systems is created calibrated and validated based on a plus energy settlement. Subsequently the potential of optimized operation is determined with regard to PV and small wind turbine self-consumption. In addition the potential of seasonal hydrogen storage is examined. The results show that on a daily basis a 33% reduction of electricity demand from grid is possible. However the average optimization potential is reduced significantly by prediction inaccuracy. The addition of a hydrogen system for seasonal energy storage basically eliminates the carbon dioxide emissions of the cluster. However this comes at high carbon dioxide prevention costs of 1.76 e kg−1 .

This study seeks to answer a simple question: will we have enough renewable electricity to meet all of the EU's decarbonisation objectives and if not what should be the priorities and how to address the remaining needs for energy towards carbon neutrality? Indeed if not the policy push for green hydrogen would not be covered by enough green electricity to match the “energy efficiency and electrification first” approach outlined in the system integration communication and a prioritization of green electricity uses complemented by other solutions (import of green electricity or sustainable fuels CCS...) would be advisable [1]. On one hand we show that the principle “Energy efficiency and electrification first” results in an electricity demand which will be very difficult to satisfy domestically with renewable energy. On the other hand green hydrogen and other sustainable fuels will be needed for a carbon neutral industry for the replacement of the fuel for aviation and navigation and as strategic green energy reserves. The detailed modelling of these interactions is challenging given the large uncertainties on technology and infrastructure development. Therefore we offer a “15 minutes” decarbonization scenario based on general and transparent technical considerations and very straightforward “back-of-envelope” calculations. This working paper contains the calculations and assumptions in support of the accompanying policy brief with the same title which focuses instead on the main take-aways.

Different hydrogen production scenarios need to be compared in regard to multiple and often distinct aspects. It is well known that hydrogen production technologies based on environmentally-friendly renewable energy sources have higher values of the economic indicators than methods based on fossil fuels. Therefore how should this decision criterion (environmental) prevail over the other types of decision criteria (technical and economic) to make a scenario where hydrogen production only uses renewable energy sources the most attractive option for a decision-maker? This article presents the results of a multi-variant comparative analysis of scenarios to annually produce one million tons of pure hydrogen (99.999%) via electrolysis in Poland. The compared variants were found to differ in terms of electricity sources feeding the electrolyzers. The research demonstrated that the scenario where hydrogen production uses energy from photovoltaics only becomes the best option for the environmental criterion weighting value at 61%. Taking the aging effect of photovoltaic installation (PV) panels and electrolyzers after 10 years of operation into account the limit value of the environmental criterion rises to 63%. The carried out analyses may serve as the basis for the creation of systems supporting the development of clean and green hydrogen production technologies.

With the global warming of the planet new forms of energy are being sought as an alternative to fossil fuels. Currently hydrogen (H2) is seen as a strong alternative for fueling vehicles. However the major challenge in the use of H2 arises from its physical properties. An earlier study was conducted on the storage of H2 used as fuel in road vehicles powered by spark ignition engines or stacks of fuel cells stored under high pressure inside small spheres randomly packed in an envelope tank. Additionally the study evaluated the performance of this new storage system and compared it with other storage systems already applied by automakers in their vehicles. The current study aims to evaluate the H2 leaks from the same storage system when inserted in any road vehicle parked in conventional garages and to show the compliance of these leaks with European Standards provided that an appropriate choice of materials is made. The system’s compliance with safety standards was proved. Regarding the materials of each component of the storage system the best option from the pool of materials chosen consists of aluminum for the liner of the spheres and the envelope tank CFEP for the structural layer of the spheres and Si for the microchip.

This study advances several methods to evaluate the operation of a hydrogen generator plant. The model developed helps customize plants that contain multiple generators of varying powers using a decision module which determines the most efficient plant load distribution. Evaluation indices to assess individual devices within the plant are proposed and system flexibility maximizes the amount of renewable energy stored. Three case studies examined the variable load distribution of an electrolysis system connected to a 40 MW wind farm for energy storage purposes and incorporated a “night-valley” operational strategy. These methods facilitate the selection of the proper plant configuration and provide estimates for individual device effectiveness within the system.

The sustainable development of hydrogen energy is a priority task for a possible solution to 26 the global energy crisis. Hydrogen is a clean and renewable energy source that today is used 27 exclusively in the form of compressed gas or in liquefied form which prevents its widespread 28 use. Storing hydrogen in solid-state systems will not only increase the bulk density and 29 gravimetric capacity but will also have a positive impact on safety issues. From this point of 30 view the current review considers the latest research in the field of application of 1D 31 nanomaterials for solid-state hydrogen storage and also discusses the mechanisms of its 32 adsorption and desorption. Despite the high publication activity the use of 1D nanomaterials for 33 hydrogen storage has not been fully studied. In the current review modern developments in the 34 field of hydrogen storage using 1D nanomaterials and composites based on them are investigated 35 in detail and their problems and future prospects are discussed.

The hydrogen energy system based on the multi-energy complementary of renewable energy can improve the consumption of renewable energy reduce the adverse impact on the power grid system and has the characteristics of green low carbon sustainable etc. which is currently a global research hotspot. Based on the basic principles of hydrogen production technology this paper introduces the current hydrogen energy system topology and summarizes the technical advantages of renewable energy complementary hydrogen production and the complementary system energy coordination forms. The problems that have been solved or reached consensus are summarized and the current status of hydrogen energy system research at home and abroad is introduced in detail. On this basis the key technologies of multi-energy complementation of hydrogen energy system are elaborated especially in-depth research and discussion on coordinated control strategies energy storage and capacity allocation energy management and electrolysis water hydrogen production technology. The development trend of the multi-energy complementary system and the hydrogen energy industry chain is also presented which provides a reference for the development of hydrogen production technology and hydrogen energy utilization of the renewable energy complementary system.