Sustainability and challenges in hydrogen production: An advanced bibliometric analysis

Hydrogen has a high and diversified amount of feedstocks, methods, and improvement processes for its production. In recent years, studies on hydrogen production have been growing and diversifying to a greater extent. Hydrogen production can be based on renewable feedstocks such as biomass or fossil fuels such as petroleum. An analysis of 10,655 publications from the Web of Science Core Collection database (2010–2022) was performed using VOSviewer, CiteSpace and Microsoft excel. The top three organizations that had the highest number of publications in the field of hydrogen production included the Chinese Academy Of Sciences, Ontario Tech University and Xi An Jiaotong University. The journal with the largest number of publications is the International Journal Of Hydrogen Energy. In addition to organizations and journals, the most promising authors and literature in this field of research were analyzed. Through cluster analysis, it was found that two constant search fields were Photocatalytic hydrogen production and Fermentative hydrogen production. Future studies should focus on process design, continuous photo-hydrogen production and looping steam. This bibliometric study focused on illustrating the overview of hydrogen production research, conducting a systematic survey of current research, which could be used by industry professionals and researchers interested in this area.     

Hydrogen energy storage integrated battery and supercapacitor based hybrid power system: A statistical analysis towards future research directions

Environmentally friendly and pollution-free hydrogen cell, battery and supercapacitor hybrid power system has taken the attention of scientists in recent years. Several notable advancements in energy storage mechanisms with hybrid power systems have been made during the last decade, influencing innovation, research, and the possible direction for improving energy storage technologies. This paper represents a quantitative analysis of all knowledge carriers with mathematical and statistical methods of hydrogen energy storage to establish a hybrid power system. For selecting the top cited papers in this topic, related articles on energy storage mechanisms for hybrid power systems were searched in the Scopus database under specified predetermined parameters. The selection technique of the most cited paper was based on filtered keywords in the hybrid hydrogen energy storage-based hybrid power system and related research during 2008–2021. About 48% of all articles have been published between 2016 and 2019; 21% will have originated from China; and 29% of the papers have used batteries as a form of energy storage in the application of electric vehicles. Most of the articles contain experimental work (25.11%) followed by simulation analysis (25%) and systematic and nonsystematic review (18.75%). Related publications with the most citations were published in 35 different impactful journals from different publishers and nations. This research found that integrating hydrogen energy storage with battery and supercapacitor to establish a hybrid power system has provided valuable insights into the field's progress and development. Moreover, it is a thriving and expanding subject of study. Bibliometric analysis was used to identify the most significant research publications on the subject of hybrid energy storage, mapping the multidisciplinary character, illustrating nature and trends, and outlining areas for further research. The process of collecting, selecting, and analyzing the most cited articles is expected to contribute to a methodical foundation for future developments of hydrogen energy storage systems and provide viable research paths toward attaining a hybrid power system.     

Bibliometrical analysis of hydrogen storage

On the basis of literature research and expert consultation on hydrogen storage, this paper is the first to use the bibliometric method to conduct data mining and visualization analysis for the development of international hydrogen storage research. A total of 22612 publications on hydrogen storage published from 1900 to 2019 were obtained. The number of citations and research authors per year is also counted. Some indicators are used in this paper to evaluate countries, research institutions, researchers, journals and so on, such as IF, H-index, TC and CPA. We also use VOS viewer to visualize keywords. Results show that the literature on hydrogen storage has been recently increasing, particularly from 2009 to 2018. The study on hydrogen storage has entered a stable and high-frequency period, with a total of 16348 papers, which account for 72.3% of the total research papers on hydrogen storage. During this period, the number of authors who studied hydrogen storage exceeded 3000 and reached 3265 in 2008. The average number of citations per year was 2672.41. China's total volume of publications reached 7239, with 12 research institutions ranking among the top 20, and 9 researchers ranking among the top 10 in this field. China plays an important role in international research on hydrogen storage. However, the US accounts for the highest h-index (220), the highest TC (233734) and the highest CPA (59.86), which shows that the United States has the strongest influence on the research of hydrogen storage. In terms of the number of articles, the INTERNATIONAL JOURNAL OF HYDROGEN ENERGY ranked first with 3413 articles, followed by the JOURNAL OF ALLOYS AND COMPOUNDS with a total of 2131 articles. Notably, the average number of citations of the articles in the FORUM OF THE AMERICAN CHEMICAL SOCIETY and the ANGEWANDTE CHEMIE-INTERNATIONAL EDITION exceeded 150 times, that is, 165.2 and 157.14 with impact factors of 14.695 and 12.257, respectively. International hydrogen storage disciplines, such as chemistry (71.38%), materials science (38.81%), and energy science (22.10%), are distributed or related interdisciplinary research areas. The research hotspots of hydrogen storage are chemical and adsorption hydrogen storages, such as hydrogen fuel cells, metal hydride, metal–organic framework, and carbon nanotube. By contrast, research on high-pressure gaseous and liquid hydrogen storages is relatively few. Researchers are suggested to give more attention to high-pressure gaseous and liquid hydrogen storages and consider the entire process of hydrogen energy utilization. Moreover, they are suggested to propose the optimal hydrogen storage mode by combining various hydrogen storage methods. Researchers must not only increase the number of their published papers but also enhance the quality. Cooperation between countries and research institutions should be further strengthened, and exchange between different disciplines is also needed to promote the interdisciplinary development of hydrogen storage and transportation.     

System-level energy efficiency is the greatest barrier to development of the hydrogen economy

Current energy research investment policy in New Zealand is based on assumed benefits of transitioning to hydrogen as a transport fuel and as storage for electricity from renewable resources. The hydrogen economy concept, as set out in recent commissioned research investment policy advice documents, includes a range of hydrogen energy supply and consumption chains for transport and residential energy services. The benefits of research and development investments in these advice documents were not fully analyzed by cost or improvements in energy efficiency or green house gas emissions reduction. This paper sets out a straightforward method to quantify the system-level efficiency of these energy chains. The method was applied to transportation and stationary heat and power, with hydrogen generated from wind energy, natural gas and coal. The system-level efficiencies for the hydrogen chains were compared to direct use of conventionally generated electricity, and with internal combustion engines operating on gas- or coal-derived fuel. The hydrogen energy chains were shown to provide little or no system-level efficiency improvement over conventional technology. The current research investment policy is aimed at enabling a hydrogen economy without considering the dramatic loss of efficiency that would result from using this energy carrier.     

Progress in the production of hydrogen energy from food waste: A bibliometric analysis

The exponential increase in food waste generation has prompted the scientific community to convert it into value-added resources. Hydrogen energy provides a sustainable option to fossil fuels due to its purity, high energy content, with no emissions other than water vapor. Combining the two aspects, a bibliometric analysis was performed for the conversion of food waste to hydrogen energy to evaluate the research trends based on literature in the Scopus database over the last two decades. The cluster analysis supported with the visualization tool aided in conducting a systematic study revealing growing themes and hot issues. The results showed a growing interest in the conversion of food waste to hydrogen energy research with the number of publications increasing by nearly 50 times in the last two decades. Comprehensive journals like the International Journal of Hydrogen Energy were most popular in publishing articles contributing to almost 30% in the research area. The country-wise analysis revealed that China accounted for more than 25% of the articles published followed by South Korea and India while the USA dominated in terms of the number of citations. Lastly, keyword cluster analysis revealed five major research hotspots for future discussion. The study concludes that further perspectives on fuel delivery, environmental impacts, and social acceptance could aid in positive developments in the biohydrogen energy industry.     

Retrospective and prospective of the hydrogen supply chain: A longitudinal techno-historical analysis

The objective of this study was to investigate the evolution of hydrogen research and its international scientific collaboration network. From the Scopus database, 58,006 relevant articles, published from 1935 until mid-2018, were retrieved. To review this massive volume of publication records, we took a scientometric network analysis approach and investigated the social network of the publication contents based on keywords co-occurrence as well as international collaboration ties.An interesting observation is that despite publications on hydrogen occurring since 1935, the growth of this research field ignited with the Kyoto Protocol of 1997. The publication profile reveals that more than 93% of the existing records have been published over the last two decades. More recently, the accelerated growth of renewables has further motivated hydrogen research with almost 36,000 academic records having been indexed from 2010 till mid-2018. This accounts for ~62% of the total historical publications on hydrogen. The conventional hydrogen production pathway is fossil fuel-based, involving fossil fuel reforming for synthesis gas generation. The keyword analysis also shows a paradigm shift in hydrogen generation to renewables. While all components of hydrogen supply chain research are now growing, the topic areas of biohydrogen and photocatalysis seem to be growing the fastest.Analysis of international collaboration networks also reveals a strong correlation between the increase of collaboration ties on hydrogen research and the publications. Until the 1970s, only 25 countries had collaborated, while this has reached 108 countries as of 2018, with over 17,500 collaboration ties. The collaborations have also evolved into a substantially more integrated network, with a few strong clusters involving China, the United States, Germany, and Japan. The longitudinal network evolution maps also reveal a shift, over the last two decades, from US-Europe centred technology development-interaction to a world in which Asian economies play substantial roles.     

Techno-economic analysis of hydrogen transportation infrastructure using ammonia and methanol

The transformation from a fossil fuels economy to a low carbon economy reshapes how energy is transmitted. Since most renewable energy is harvested in the form of electricity, hydrogen obtained from water electrolysis using green electricity is considered a promising energy vector. However, the storage and transportation of hydrogen at large scales pose challenges to the existing energy infrastructures, both regarding technological and economic aspects. To facilitate the distribution of renewable energy, a set of candidate hydrogen transportation infrastructures using methanol and ammonia as hydrogen carriers were proposed. A systematical analysis reveals that the levelized costs of transporting hydrogen using methanol and ammonia in the best cases are $1879/t-H₂ and $1479/t-H₂, respectively. The levelized cost of energy transportation using proposed infrastructures in the best case is $10.09/GJ. A benchmark for hydrogen transportation infrastructure design is provided in this study.     

A critical review on the current technologies for the generation,storage, and transportation of hydrogen

Hydrogen production, storage, and transportation are the key issues to be addressed to realize a so-called clean and sustainable hydrogen economy. Various production methods, storage methods, and hydrogen transportations have been listed in the literature, along with their limitations. Therefore, to summarize the state of the art of these proposed technologies, a detailed discussion on hydrogen production, storage, and transportation is presented in this review. Also, to discuss the recent advancements of these methods including, hydrogen production, storage, and transportation on their kinetics, cyclic behavior, toxicity, pressure, thermal response, and cost-effectiveness. Moreover, new techniques such as ball milling, ultrasonic irradiation, ultrasonication, alloying, additives, cold rolling, alloying, and plasma metal reaction have been highlighted to address those drawbacks.Furthermore, the development of modern hydrogen infrastructure (reliability, safety, and low cost) is needed to scale up hydrogen delivery. This review summarizes promising techniques to enhance kinetic hydrogen production, storage, and transportation. Nevertheless, the search for the materials is still far from meeting the aimed target for production, storage, and transportation application. Therefore, more investigations are needed to identify promising areas for future H₂ production, storage, and transportation developments.     

Thermo-economic analysis of a hydrogen production system by sodium borohydride (NaBH4)

In the spectrum of current energy possibilities, hydrogen represents a solution of great interest toward a future sustainable energy system. No single technology can sustain the energy needs of the whole society, but integration and hybridization are two key strategic features for viable energy production based in hydrogen economy.In the present work, a hydrogen energy model is analyzed. In this model hydrogen is produced through the electrolysis of water, taking advantage of the electrical energy produced by a renewable generator (photovoltaic panels). The produced hydrogen is chemically stored by the synthesis of sodium borohydride (NaBH₄). NaBH₄ promising features in terms of safety and high volumetric density are exploited for transportation to a remote site where hydrogen is released from NaBH₄ hydrolysis and used for energy production.This model is compared from an economic standpoint with the traditional hydrogen storage and transportation technology (compressed hydrogen in tanks).This paper presents a thermodynamic and economic analysis of the process in order to determine its economic feasibility. Data employed for the realization of the model have been gathered from recent important progresses made on the subject.The innovative plant including NaBH₄ synthesis and transportation is compared from an economic standpoint with the traditional hydrogen storage and transportation technology (compressed hydrogen in tanks). As a final point, the best technology and the components' optimal sizes are evaluated for both cases in order to minimize production costs.     

Quantitative analysis of a successful public hydrogen station

Reliable hydrogen fueling stations will be required for the successful commercialization of fuel cell vehicles. An evolving hydrogen fueling station has been in operation in Irvine, California since 2003, with nearly five years of operation in its current form. The usage of the station has increased from just 1000 kg dispensed in 2007 to over 8000 kg dispensed in 2011 due to greater numbers of fuel cell vehicles in the area. The station regularly operates beyond its design capacity of 25 kg/day and enables fuel cell vehicles to exceed future carbon reduction goals today. Current limitations include a cost of hydrogen of $15 per kg, net electrical consumption of 5 kWh per kg dispensed, and a need for faster back-to-back vehicle refueling.     

A review of four case studies assessing the potential for hydrogen penetration of the future energy system

Hydrogen as an energy carrier allows the decarbonization of transport, industry, and space heating as well as storage for intermittent renewable energy. The objective of this paper is to assess the future engineering potential for hydrogen and provide insight to areas of research to help lower economic barriers for hydrogen adoption. This assessment was accomplished by creating top-level system models based on energy requirements for end-use services. Those models were used to investigate four case studies that provide a global view augmented with specific national examples. The first case study assesses the potential penetration of hydrogen using a global energy system model. The second applies the dynamic integrated climate–ecosystem–economics model to derive an estimate of the impact of the diffusion of hydrogen as an energy carrier. The third determines the required growth in renewable power and water usage to power transportation in the United States (US) with hydrogen. The fourth assesses the use of hydrogen for heating in the United Kingdom (UK). In all cases, there appeared to be significant potential for hydrogen adoption and net energetic benefit. Globally, hydrogen has the potential to account for approximately 3% of energy consumption by 2050. In the US, using hydrogen for on-road transportation could enable a reduction in rejected energy of nearly 10%. Also, hydrogen might provide the least cost alternative to decarbonizing space heating in the UK. The research highlights a challenge raised by widespread abandonment of nuclear power. It is currently unclear what the removal of nuclear would do to the cost of energy as nations attempt to limit global greenhouse gas emissions. Nuclear power has also been proposed as a source for large scale production of hydrogen. Finally, this analysis shows that with today's technological maturity making the transition to a hydrogen economy would incur significant costs.     

A bibliometric analysis of the hydrogen production from dark fermentation

Hydrogen energy plays an important role in solving the environmental problems caused by the fuel crisis and greenhouse gas emissions. However, hydrogen application on an industrial scale still requires technological advances, especially in choosing the best technological route for the recovery of renewable and cost-effective hydrogen. Therefore, this bibliometric review evaluated the research progress, trends, updates, and hotspots on hydrogen production from dark fermentation. The Web of Science© database was used to select the documents from 2000 to 2021, and the VOSviewer© and Bibliometrix softwares were used to carry out the bibliometric investigation. The results demonstrated that 3071 documents (2755 articles and 316 reviews) studied the hydrogen production from dark fermentation over the last 21 years. The number of publications exponentially increased in the last five years, which can be associated with the demand for new technologies to produce clean energy sources and decrease the environmental impacts caused by petroleum-based fuel. Keyword analysis revealed that the studies focused on the operational parameters, process optimization, pretreatment, and microbial community, aiming to increase the hydrogen yield during dark fermentation. Finally, this comprehensive review provides future directions for applying dark fermentation to produce hydrogen as a sustainable and renewable fuel in a biorefiney concept.     

Hydrogen economy for sustainable development in GCC countries: A SWOT analysis considering current situation,challenges, and prospects

The increasingly serious threat of climate change caused by the excessive use of fossil fuels have been prompting GCC (Gulf Cooperation Council) countries to aggressively seek a clean energy source in the future. Recently GCC countries announced their carbon emission targets e.g. Saudi Arabia & Bahrain's net-zero emissions by 2060, UAE and Oman net-zero emissions by 2050, Qatar 25% and Kuwait 7.4% reduction by 2035. In recent years, governments and energy companies across the world alike are placing large wagers on hydrogen, in an effort to lower emissions. Therefore, to achieve these long term stated emission targets of GCC countries, Hydrogen Economy is one of the areas where efforts must be ramped up. However, there are currently numerous obstacles to the scaled and to substitute the revenue of fossil fuel exports with green hydrogen economy in Gulf countries, such as high production costs of green hydrogen, a lack of infrastructure, storage and transportation problems, regulation and the necessary demand in the indigenous end-user sectors. The aim of this study is to analyze the existing obstacles and future prospects of hydrogen economy in GCC region using SWOT (Strengths, Weaknesses, Opportunities, and Threats) analysis approach. The results shows that GCC countries have the resources and opportunity to be a leader in hydrogen, but will need to take risks if it wants to compete globally. The uptake of hydrogen in short- and midterm will largely be based on blue hydrogen, however as it is expected a substantial fall green hydrogen production cost by 2030, it is therefore in the long term green hydrogen production offers the major route for the GCC, based on natural endowments. It is revealed that the scale and growth of the hydrogen economy in GCC countries will largely depend on external factors (i.e., global hydrogen adoption and demand) beyond their control.     

Analysis of Ontario's hydrogen economy demands from hydrogen fuel cell vehicles

The ‘Hydrogen Economy’ is a proposed system where hydrogen is produced from carbon dioxide free energy sources and is used as an alternative fuel for transportation. The utilization of hydrogen to power fuel cell vehicles (FCVs) can significantly decrease air pollutants and greenhouse gases emission from the transportation sector. In order to build the future hydrogen economy, there must be a significant development in the hydrogen infrastructure, and huge investments will be needed for the development of hydrogen production, storage, and distribution technologies. This paper focuses on the analysis of hydrogen demand from hydrogen FCVs in Ontario, Canada, and the related cost of hydrogen. Three potential hydrogen demand scenarios over a long period of time were projected to estimate hydrogen FCVs market penetration, and the costs associated with the hydrogen production, storage and distribution were also calculated. A sensitivity analysis was implemented to investigate the uncertainties of some parameters on the design of the future hydrogen infrastructure. It was found that the cost of hydrogen is very sensitive to electricity price, but other factors such as water price, energy efficiency of electrolysis, and plant life have insignificant impact on the total cost of hydrogen produced.     

The cost analysis of hydrogen life cycle in China

Currently, the increasing price of oil and the possibility of global energy crisis demand for substitutive energy to replace fossil energy. Many kinds of renewable energy have been considered, such as hydrogen, solar energy, and wind energy. Many countries including China have their own plan to support the research of hydrogen, because of its premier features. But, at present, the cost of hydrogen energy production, storage and transportation process is higher than that of fossil energy and its commercialization progress is slow. Life cycle cost analysis (LCCA) was used in this paper to evaluate the cost of hydrogen energy throughout the life cycle focused on the stratagem selection, to demonstrate the costs of every step and to discuss their relationship. Finally, the minimum cost program is as follows: natural gas steam reforming – high-pressure hydrogen bottles transported by car to hydrogen filling stations – hydrogen internal-combustion engines.     

A green hydrogen credit framework for international green hydrogen trading towards a carbon neutral future

Hydrogen as a low-carbon clean energy source is experiencing a global resurgence and has been recognized as an alternative energy carrier that can help bring the world to a carbon neutral future. However, getting to scale is one of the main challenges limiting the growth of the hydrogen economy. In particular, the high cost of transporting green hydrogen is bottlenecking the international trading and wider adoption of hydrogen for global carbon natural objectives. In order to explore incentives for the global hydrogen economy and develop new pathways towards the carbon neutral future, the concept of hydrogen credit is proposed by this research and a framework of trading hydrogen credits similar to carbon credits in the international market is established. This research aims to contribute to the overall uptake of green hydrogen financially rather than relying on the physical production, transportation, and storage of hydrogen. Case studies are presented to demonstrate the feasibility and efficiency of the proposed hydrogen credit framework, as well as the great potential of a global hydrogen credit market.     

Simulation analysis on the risk of hydrogen releases and combustion in subsea tunnels

Hydrogen is considered to be a very promising potential energy carrier due to its excellent characteristics such as abundant resources, high fuel value, clean and renewable. Its safety features greatly influence the potential use. Several safety problems need to be analyzed before using in transportation industry. With the development of the tunnel transportation technology, the safe use of hydrogen in tunnels will receive a lot of research attentions. In this article, the risk associated with hydrogen release from onboard high-pressure vessels and the induced combustion in tunnels was analyzed using the Partially Averaged Navier–Stokes (PANS) turbulence model. The influences of the tunnel ventilation facilities on the hydrogen flow characteristics and the flammable hydrogen cloud sizes were studied. The tunnel layouts were designed according to the subsea tunnel. And a range of longitudinal ventilation conditions had been considered to investigate the hydrogen releases and the sizes of the flammable hydrogen cloud. Then the hydrogen combustion simulation was carried out after the fixed leaking time. The overpressures induced after the ignition of leaking hydrogen were studied. The influences of ventilation and ignition delay time on the overpressure were also investigated. The main aim was to research the phenomena of hydrogen releases and combustion risk inside subsea tunnels, and to lay the foundation of risk assessment methodology developed for hydrogen energy applications on transportation.     

Economics of producing hydrogen as transportation fuel using offshore wind energy systems

Over the past few years, hydrogen has been recognized as a suitable substitute for present vehicular fuels. This paper covers the economic analysis of one of the most promising hydrogen production methods—using wind energy for producing hydrogen through electrolysis of seawater—with a concentration on the Indian transport sector. The analysis provides insights about several questions such as the advantages of offshore plants over coastal installations, economics of large wind-machine clusters, and comparison of cost of producing hydrogen with competing gasoline. Robustness of results has been checked by developing several scenarios such as fast/slow learning rates for wind systems for determining future trends. Results of this analysis show that use of hydrogen for transportation is not likely to be attractive before 2012, and that too with considerable learning in wind, electrolyzer and hydrogen storage technology.     

Hydrogen recovery,cleaning, compression,storage, dispensing,distribution system and End-Uses on the university campus from combined heat,hydrogen and power system

To address the problem of fossil fuel usage at the Missouri University of Science and Technology campus, using of alternative fuels and renewable energy sources can lower energy consumption and hydrogen use. Biogas, produced by anaerobic digestion of wastewater, organic waste, agricultural waste, industrial waste, and animal by-products is a potential source of renewable energy. In this work, we have discussed the design of combined heat, hydrogen and power (CHHP) system for the campus using local resources. An energy flow and resource availability study is hydrogen recovery, cleaning and energy End-Uses on the university campus from CHHP system. Following the resource assessment study, our team selects Fuel Cell Energy direct fuel cell (DFC) 1500TM unit as a molten carbonate fuel cell. The CHHP system provides the hydrogen for transportation, back-up power and other needs. The research presented in this paper was performed as part of the 2012 Hydrogen Student Design Contest. In conclusion, the CHHP system will be able to reduce fossil fuel usage, greenhouse gas (GHG) emissions and hydrogen generated is used to power different applications on the university campus.     

A global survey of hydrogen energy research,development and policy

Several factors have led to growing interest in a hydrogen energy economy, especially for transportation. A successful transition to a major role for hydrogen will require much greater cost-effectiveness, fueling infrastructure, consumer acceptance, and a strategy for its basis in renewable energy feedstocks. Despite modest attention to the need for a sustainable hydrogen energy system in several countries, in most cases in the short to mid term hydrogen will be produced from fossil fuels. This paper surveys the global status of hydrogen energy research and development (R&D) and public policy, along with the likely energy mix for making it. The current state of hydrogen energy R&D among auto, energy and fuel-cell companies is also briefly reviewed. Just two major auto companies and two nations have specific targets and timetables for hydrogen fuel cells or vehicle production, although the EU also has an aggressive, less specific strategy. Iceland and Brazil are the only nations where renewable energy feedstocks are envisioned as the major or sole future source of hydrogen. None of these plans, however, are very certain. Thus, serious questions about the sustainability of a hydrogen economy can be raised.