Emerging technologies by hydrogen: A review

The majority of energy being used is obtained from fossil fuels, which are not renewable resources and require a longer time to recharge or return to its original capacity. Energy from fossil fuels is cheaper but it faces some challenges compared to renewable energy resources. Thus, one of the most potential candidates to fulfil the energy requirements are renewable resources and the most environmentally friendly fuel is Hydrogen. Hydrogen is a clean and efficient energy carrier and a hydrogen-based economy is now widely regarded as a potential solution for the future of energy security and sustainability. Hydrogen energy became the most significant energy as the current demand gradually starts to increase. It is an important key solution to tackle the global temperature rise. The key important factor of hydrogen production is the hydrogen economy. Hydrogen production technologies are commercially available, while some of these technologies are still under development. Therefore, the global interest in minimising the effects of greenhouse gases as well as other pollutant gases also increases. In order to investigate hydrogen implementation as a fuel or energy carrier, easily obtained broad-spectrum knowledge on a variety of processes is involved as well as their advantages, disadvantages, and potential adjustments in making a process that is fit for future development. Aside from directly using the hydrogen produced from these processes in fuel cells, streams rich with hydrogen can also be utilised in producing ethanol, methanol, gasoline as well as various chemicals of high value. This paper provided a brief summary on the current and developing technologies of hydrogen that are noteworthy.     

Green hydrogen as feedstock: Financial analysis of a photovoltaic-powered electrolysis plant

The weather-dependent electricity generation from Renewable Energy Sources (RES), such as solar and wind power, entails that systems for energy storage are becoming progressively more important. Among the different solutions that are being explored, hydrogen is currently considered as a key technology allowing future long-term and large-scale storage of renewable power.Today, hydrogen is mainly produced from fossil fuels, and steam methane reforming (SMR) is the most common route for producing it from natural gas. None of the conventional methods used is GHG-free. The Power-to-Gas concept, based on water electrolysis using electricity coming from renewable sources is the most environmentally clean approach. Given its multiple uses, hydrogen is sold both as a fuel, which can produce electricity through fuel cells, and as a feedstock in several industrial processes. Just the feedstock could be, in the short term, the main market of RES-based hydrogen.In this paper, we present the results obtained from a techno-economic-financial evaluation of a system to produce green hydrogen to be sold as a feedstock for industries and research centres. A system which includes a 200 kW photovoltaic plant and a 180 kW electrolyser, to be located in Messina (Italy), is proposed as a case study. According to the analyses carried out, and taking into account the current development of technologies, it has been found that investment to realise a small-scale PV-based hydrogen production plant can be remunerative.     

Power management control for off-grid solar hydrogen production and utilisation system

Climate change concerns, increasing global energy demand, coupled with pending peak supply of fossil fuels, calls for development of new power source. The rapid price drops for solar technologies and combined with international and national policy changes makes solar energy more affordable and accessible for widespread adoption. Solar energy also contributes towards the reduction of greenhouse gas emissions. The combination of electrolysis of water and fuel cells, which use hydrogen as an energy carrier extends the utility of the solar energy. For an integrated solar powered hydrogen production, storage and utilisation system, one of the elements that needs to be designed carefully is the power management system. Power management strategy has a complex function in this type of solar hydrogen system. This paper presents a power management strategy based on fuzzy logic technology to address the problems.     

Recent advances in ammonia synthesis technologies: Toward future zero carbon emissions

As a carbon-free molecule, ammonia has gained great global interest in being considered a significant future candidate for the transition toward renewable energy. Numerous applications of ammonia as a fuel have been developed for energy generation, heavy transportation, and clean, distributed energy storage. There is a clear global target to achieve a sustainable economy and carbon neutrality. Therefore, most of the research's efforts are concentrated on generating cost-effective renewable energy on a large scale rather than fossil fuels. However, storage and transportation are still roadblocks for these technologies, for example, hydrogen technologies. Ammonia could be replaced as a viable fuel for a clean and sustainable future of global energy. More efforts from governments and scientists can lead to making ammonia a clean energy vector in most energy applications. In this review, ammonia synthesis was assessed, including conventional Haber–Bosch technology. Current hydrogen technologies as the key parameters for ammonia generation are also evaluated. The role of ammonia as a hydrogen-based fuel and generation roadmap are discussed for future utilization of energy mix. Further, ammonia generation processes are addressed in depth, including blue and green ammonia generation. A survey of ammonia synthesis catalytic materials was conducted and the role of catalyst materials in ammonia generation was compared, which showed that the Ru-based catalyst generated the maximum ammonia after 20 h of starting experiment. An end-use plan for using ammonia as a clean energy fuel in vehicles, marines, gas turbines as well as fuel cells, is briefly discussed to recognize the potential applications of ammonia use. The practical and future end-use vision of energy sources is proposed to achieve great benefits at low carbon emissions and costs. This review can provide prospective knowledge of large-scale aspects and environmental considerations of ammonia. Herein, we conclude that ammonia will become the “clean energy carrier link” that will achieve the global energy and economy sustainability targets.     

A review on hydrogen production and utilization: Challenges and opportunities

Environment-friendly, safe and reliable energy supplies are indispensable to society for sustainable development and high life quality where even though social, environmental, political and economic challenges may play a vital role in their provision. Our continuously growing energy demand is driven by extensive growth in economic development and population and places an ever-increasing burden on fossil fuel utilization that represent a substantial percentage of this increasing energy demand but also creates challenges associated with increased greenhouse gas (GHG) emissions and resource depletion. Such challenges make the global transition obligatory from conventional to renewable energy sources. Hydrogen is emerging as a new energy vector outside its typical role and receiving more recognition globally as a potential fuel pathway, as it offers advantages in use cases and unlike synthetic carbon-based fuels can be truly carbon neutral or even negative on a life cycle basis. This review paper provides critical analysis of the state-of-the-art in blue and green hydrogen production methods using conventional and renewable energy sources, utilization of hydrogen, storage, transportation, distribution and key challenges and opportunities in the commercial deployment of such systems. Some of the key promising renewable energy sources to produce hydrogen, such as solar and wind, are intermittent; hydrogen appears to be the best candidate to be employed for multiple purposes blending the roles of fuel energy carrier and energy storage modality. Furthermore, this study offers a comparative assessment of different non-renewable and renewable hydrogen production systems based on system design, cost, global warming potential (GWP), infrastructure and efficiency. Finally the key challenges and opportunities associated with hydrogen production, storage, transportation and distribution and commercial-scale deployment are addressed.     

Hydrogen storage and delivery: Review of the state of the art technologies and risk and reliability analysis

Among all introduced green alternatives, hydrogen, due to its abundance and diverse production sources is becoming an increasingly viable clean and green option for transportation and energy storage. Governments are considerably funding relevant researches and the public is beginning to talk about hydrogen as a possible future fuel. Hydrogen production, storage, delivery, and utilization are the key parts of the Hydrogen Economy (HE). In this paper, hydrogen storage and delivery options are discussed thoroughly. Then, since safety and reliability of hydrogen infrastructure is a necessary enabling condition for public acceptance of these technologies and any major accident involving hydrogen can be difficult to neutralize, we review the main existing safety and reliability challenges in hydrogen systems. The current state of the art in safety and reliability analysis for hydrogen storage and delivery technologies is discussed, and recommendations are mentioned to help providing a foundation for future risk and reliability analysis to support safe, reliable operation.     

Potential of renewable hydrogen production for energy supply in Hong Kong

Hong Kong is highly vulnerable to energy and economic security due to the heavy dependence on imported fossil fuels. The combustion of fossil fuels also causes serious environmental pollution. Therefore, it is important to explore the opportunities for clean renewable energy for long-term energy supply. Hong Kong has the potential to develop clean renewable hydrogen energy to improve the environmental performance. This paper reviews the recent development of hydrogen production technologies, followed by an overview of the renewable energy sources and a discussion about potential applications for renewable hydrogen production in Hong Kong. The results show that although renewable energy resources cannot entirely satisfy the energy demand in Hong Kong, solar energy, wind power, and biomass are available renewable sources for significant hydrogen production. A system consisting of wind turbines and photovoltaic (PV) panels coupled with electrolyzers is a promising design to produce hydrogen. Biomass, especially organic waste, offers an economical, environmental-friendly way for renewable hydrogen production. The achievable hydrogen energy output would be as much as 40% of the total energy consumption in transportation.     

Performance and emission studies of direct injection C.I. engine in duel fuel mode (hydrogen-diesel) with EGR

Presently majority of the world’s energy demand is met by fossil fuels. These fuels are depleting at an alarming rate. Thus in future, our energy systems will need to be renewable and sustainable, efficient and cost-effective, convenient and safe. Among the various alternative fuels, hydrogen is a long-term renewable and least polluting fuel (produced from renewable energy sources). Its clean burning characteristics help to meet the stringent emission norms. Majority of the work using hydrogen as a fuel is being done in spark ignition engine, however, in this experimental investigation efforts have been made to utilize it in compression ignition engine.     

Hydrogen in energy transition: A review

The energy transition is not something that awaits us in the next decade. On the contrary, it is a process in which we are already deeply enrolled. The main step towards the creation of a carbon-neutral society is the implementation of renewable energy sources (RES) as replacements for fossil fuels. Given the intermittency of RES, energy storage has an essential role to play in this transition. Hydrogen technology with its many advances was recognized to be the most promising choice. As multiple hydrogen applications were researched relatively recently, the current development of its technology is not yet on the large-scale implementation level. With the increasing number of studies and initiated projects, the utilization of hydrogen's immense ecological potential is to be expected in the next few decades. New innovative solutions of hydrogen technology that includes hydrogen production, storage, distribution, and usage, are permeating all industry sectors. In a rapidly changing world, technological advances bring forth public discussions, that are a deciding factor whether society will be able to adapt and accept those new contributions or reject them. Currently, hydrogen is the best associated with fuel cell electric vehicles which emit only water vapour and warm air, producing no harmful tailpipe emissions. As various scientists are stressing the gravity of climate change effects that are reaching the physical environment, ecosystems, and humanity in general, concern for the future is becoming the main global topic. Consequently, governments are implementing new sustainable policies that promote RES as a substitute for fossil fuels. Increasing progress in hydrogen technology instigated nations worldwide to incorporate hydrogen in their energy legislations and national development plans, which resulted in numerous national hydrogen strategies. This work shows the progress of hydrogen taking its place as a key factor of the future green energy society. It reviews recent developments of hydrogen technologies, their social, industrial, and environmental standing, as well as the stage of transitioning economies of both advanced and beginner countries. An example of the ongoing energy transition is Croatia, which is in the process of implementing a hydrogen strategy with the ambition to be able to one day equally participates in the rapidly emerging hydrogen market.     

Hydrogen electrolyser technologies and their modelling for sustainable energy production: A comprehensive review and suggestions

The advancement of hydrogen technology is driven by factors such as climate change, population growth, and the depletion of fossil fuels. Rather than focusing on the controversy surrounding the environmental friendliness of hydrogen production, the primary goal of the hydrogen economy is to introduce hydrogen as an energy carrier alongside electricity. Water electrolysis is currently gaining popularity because of the rising demand for environmentally friendly hydrogen production. Water electrolysis provides a sustainable, eco-friendly, and high-purity technique to produce hydrogen. Hydrogen and oxygen produced by water electrolysis can be used directly for fuel cells and industrial purposes. The review is urgently needed to provide a comprehensive analysis of the current state of water electrolysis technology and its modelling using renewable energy sources. While individual methods have been well documented, there has not been a thorough investigation of these technologies. With the rising demand for environmentally friendly hydrogen production, the review will provide insights into the challenges and issues with electrolysis techniques, capital cost, water consumption, rare material utilization, electrolysis efficiency, environmental impact, and storage and security implications. The objective is to identify current control methods for efficiency improvement that can reduce costs, ensure demand, increase lifetime, and improve performance in a low-carbon energy system that can contribute to the provision of power, heat, industry, transportation, and energy storage. Issues and challenges with electrolysis techniques, capital cost, water consumption, rare material utilization, electrolysis efficiency, environmental impact, and storage and security implications have been discussed and analysed. The primary objective is to explicitly outline the present state of electrolysis technology and to provide a critical analysis of the modelling research that had been published in recent literatures. The outcome that emerges is one of qualified promise: hydrogen is well-established in particular areas, such as forklifts, and broader applications are imminent. This evaluation will bring more research improvements and a road map to aid in the commercialization of the water electrolyser for hydrogen production. All the insights revealed in this study will hopefully result in enhanced efforts in the direction of the development of advanced hydrogen electrolyser technologies towards clean, sustainable, and green energy.     

Potential importance of hydrogen as a future solution to environmental and transportation problems

Air pollution is a serious public health problem throughout the world, especially in industrialized and developing countries. In industrialized and developing countries, motor vehicle emissions are major contributors to urban air quality. Hydrogen is one of the clean fuel options for reducing motor vehicle emissions. Hydrogen is not an energy source. It is not a primary energy existing freely in nature. Hydrogen is a secondary form of energy that has to be manufactured like electricity. It is an energy carrier. Hydrogen has a strategic importance in the pursuit of a low-emission, environment-benign, cleaner and more sustainable energy system. Combustion product of hydrogen is clean, which consists of water and a little amount of nitrogen oxides. Hydrogen has very special properties as a transportation fuel, including a rapid burning speed, a high effective octane number, and no toxicity or ozone-forming potential. It has much wider limits of flammability in air than methane and gasoline. Hydrogen has become the dominant transport fuel, and is produced centrally from a mixture of clean coal and fossil fuels (with C-sequestration), nuclear power, and large-scale renewables. Large-scale hydrogen production is probable on the longer time scale. In the current and medium term the production options for hydrogen are first based on distributed hydrogen production from electrolysis of water and reforming of natural gas and coal. Each of centralized hydrogen production methods scenarios could produce 40 million tons per year of hydrogen. Hydrogen production using steam reforming of methane is the most economical method among the current commercial processes. In this method, natural gas feedstock costs generally contribute approximately 52–68% to the final hydrogen price for larger plants, and 40% for smaller plants, with remaining expenses composed of capital charges. The hydrogen production cost from natural gas via steam reforming of methane varies from about 1.25 US$/kg for large systems to about 3.50 US$/kg for small systems with a natural gas price of 6 US$/GJ. Hydrogen is cheap by using solar energy or by water electrolysis where electricity is cheap, etc.     

Clean energy and energy storage research --The 2nd international conference on clean energy sciences

每3年举行1次的国际清洁能源会议(ICCES)旨在促进国际合作和交流,为在清洁能源和能源储存领域工作的国际研究者提供一个讨论清洁能源基础研究和技术革新的论坛.本文总结了2014年4月13~16日在中国青岛召开的第二届国际清洁能源会议的学术报告情况,特别是关于清洁能源和能源存储研究的最新进展及其未来科学发展所面临的挑战和根本问题.材料与纳米技术依然是解决清洁能源利用,转换和储存的关键;具有广泛应用基础的太阳能转化,电化学能量转化与储存,光催化与环境催化依然是研究热点;同时,清洁煤及化石燃料,生物燃料和生物质转化,生物和仿生系统的能源转化正在成为新的研究热点;而氢气制备与储存,二氧化碳捕获储存与使用等体系也引起了大家的广泛兴趣和关注.本文重点评述了清洁能源领域的研究重点,进展和热点问题.     

A comprehensive review on biohydrogen production pilot scale reactor technologies: Sustainable development and future prospects

The current study focuses on a comprehensive review of the pilot scale production of biohydrogen and various factors affecting the design experiments. Biohydrogen is a clean energy carrier that can be used as a potential alternative to fossil fuels. Biohydrogen as a fuel has several advantageous attributes, including; carbon-neutral or carbon-zero nature, easy renewability, eco-efficient productivity (via biological routes), eco-friendly conversion, and the highest energy content among all existing fuels. Pilot-scale production of biohydrogen is limited because it requires a better understanding of the possible interactions involved in the process. In this review, biohydrogen production on various types of reactors such as stirred tank reactors, packed bed reactors, fluidized bed reactors, trickling filter reactors, etc., have been discussed. However, biohydrogen production has been mostly studied on small scale, the most challenging issue concerning large-scale production of biohydrogen is its relatively high cost over fuels from fossil owing to high feedstock and manufacturing costs. Therefore, cost-effective and eco-friendly biohydrogen production technologies should be necessarily developed and continuously improved to make this biofuel more competitive over its counterpart. In comparison with fossil fuels, biohydrogen has a high energy yield and is highly renewable. It can fulfill the future demand as a transport fuel.     

Flexibility improvement evaluation of hydrogen storage based on electricity–hydrogen coupled energy model

To achieve carbon neutrality by 2060, decarbonization in the energy sector is crucial. Hydrogen is expected to be vital for achieving the aim of carbon neutrality for two reasons: use of power-to-hydrogen (P2H) can avoid carbon emissions from hydrogen production, which is traditionally performed using fossil fuels; Hydrogen from P2H can be stored for long durations in large scales and then delivered as industrial raw material or fed back to the power system depending on the demand. In this study, we focus on the analysis and evaluation of hydrogen value in terms of improvement in the flexibility of the energy system, particularly that derived from hydrogen storage. An electricity–hydrogen coupled energy model is proposed to realize the hourly-level operation simulation and capacity planning optimization aiming at the lowest cost of energy. Based on this model and considering Northwest China as the region of study, the potential of improvement in the flexibility of hydrogen storage is determined through optimization calculations in a series of study cases with various hydrogen demand levels. The results of the quantitative calculations prove that effective hydrogen storage can improve the system flexibility by promoting the energy demand balance over a long term, contributing toward reducing the investment cost of both generators and battery storage and thus the total energy cost. This advantage can be further improved when the hydrogen demand rises. However, a cost reduction by 20% is required for hydrogen-related technologies to initiate hydrogen storage as long-term energy storage for power systems. This study provides a suggestion and reference for the advancement and planning of hydrogen storage development in regions with rich sources of renewable energy.     

Development and environmental impact of hydrogen supply chain in Japan: Assessment by the CGE-LCA method in Japan with a discussion of the importance of biohydrogen

Hydrogen is an attractive and clean source of energy with a high energy content and environmentally friendly production using green power. Hydrogen is therefore considered to be one of the future alternatives to fossil fuels that can limit the damage done by climate change. A dynamic GTAP model with LCA method is utilized herein in this investigation to forecast the development of the hydrogen supply chain and CO₂ emissions in Japan. The supply chain incorporates six hydrogen-related industries – biohydrogen, steam reforming, electrolysis, hydrogen fuel cell vehicles (HFCV), hydrogen fuel cells (HFC), and hydrogen fueling stations.     

Hydrogen the fuel for 21st century

Non-Conventional Energy Sources, such as solar and hydrogen energy will remain available for infinite period. One of the reasons of great worry for all of us is reducing sources of conventional energies. The rate of fossil fuel consumption is higher than the rate of the fossil fuel production by the nature. The results will be the scarcity of automobile fuel in the world which will create lot of problems in transport sector. The other aspect is pollution added by these sources in our environment which increases with more use of these sources, resulting in the poor quality of life on this planet. There is constant search of alternate fuel to solve energy shortage which can provide us energy without pollution.Hence most frequently discussed source is hydrogen which when burnt in air produces a clean form of energy. In the last one decade hydrogen has attracted worldwide interest as a secondary energy carrier. This has generated comprehensive investigations on the technology involved and how to solve the problems of production, storage and transportation of hydrogen. The interest in hydrogen as energy of the future is due to it being a clean energy, most abundant element in the universe, the lightest fuel, richest in energy per unit mass and unlike electricity, it can be easily stored. Hydrogen gas is now considered to be the most promising fuel of the future. In future it will be used in various applications, e.g. it can generate Electricity, useful in cooking food, fuel for automobiles, hydrogen powered industries, Jet Planes, Hydrogen Village and for all our domestic energy requirements.Hydrogen as a fuel has already found applications in experimental cars and all the major car companies are in competition to build a commercial car and most probably they may market hydrogen fuel automobiles in near future but at a higher cost compared to gasoline cars but it is expected that with time the cost of hydrogen run cars will decrease with time. Long lasting, light and clean metal hydride batteries are already commercial for lap top computers. Larger capacity batteries are being developed for electrical cars. Hydrogen is already being used as the fuel of choice for space programmes around the world. It will be used to power aerospace transports to build the international space station, as well as to provide electricity and portable water for its inhabitants. Present article deals with the storage and applications of hydrogen in the present energy scenario.     

On-site hydrogen production from transportation fuels: An overview and techno-economic assessment

Hydrogen production for future transportation applications have received increased interest due to its inherent environmental and efficiency benefits. Currently, hydrogen is produced from natural gas and naphtha for its use in refineries for clean fuel production along with its use in ammonia production. The hydrogen demand will grow in future for hydrogen based fuel cell vehicles. Significant research is underway to produce hydrogen from renewable and fossil fuel sources. However, on-site hydrogen production using existing fuel and gas station infrastructure to support future hydrogen based fuel cell vehicles has advantages over other approaches. In this context, this study is focused on a techno-economic assessment of hydrogen production from transportation fuels using different conversion technologies. In addition, detailed economics with higher capacity and volume of the hydrogen stations are also discussed. Finally, a detailed roadmap is presented to produce on-site hydrogen at commercial scale.     

Impact of hydrogen on the environment

The present work considers the impact of hydrogen fuel on the environment within the cycles of its generation and combustion. Hydrogen has been portrayed by the media as a fuel that is environmentally clean because its combustion results in the formation of harmless water. However, hydrogen first must be generated. The effect of hydrogen generation on the environment depends on the production process and the related by-products. Hydrogen available on the market at present is mainly generated by using steam reforming of natural gas, which is a fossil fuel. Its by-product is CO₂, which is a greenhouse gas and its emission results in global warming and climate change. Therefore, hydrogen generated from fossil fuels is contributing to global warming to the similar extent as direct combustion of the fossil fuels. On the other hand hydrogen obtained from renewable energy, such solar energy, is environmentally clean during the cycles of its generation and combustion. Consequently, the introduction of hydrogen economy must be accompanied by the development of hydrogen that is environmentally friendly. The present work considers several aspects related to the generation and utilisation of hydrogen obtained by steam reforming and solar energy conversion (solar-hydrogen).     

Hydrogen quality from decarbonized fossil fuels to fuel cells

Increased focus on curbing carbon dioxide (CO₂) emissions and a limited and unstable supply of fossil fuel resources make diversification of energy resources a priority. Hydrogen has emerged as a promising energy vector for solving these issues. However, there are numerous challenges related to production, distribution and end use of hydrogen. Of particular importance is the link between hydrogen purity requirements for use in fuel cells and the capabilities of production. Impurities can adversely affect fuel cell performance and durability, and the fuel composition must therefore be carefully controlled. However, impurity specifications should be balanced against production and purification costs. This paper examines the effects of impurities on fuel cell performance and assesses the capabilities of hydrogen production from decarbonized fossil fuels to meet the purity requirements dictated by use in fuel cells. While carbon monoxide, hydrogen sulfide and ammonia impurities are shown to most negatively affect fuel cell performance, these species are also the most easily removed during purification. In hydrogen production from decarbonized fossil fuels, inert gases are the most limiting species in the separation. If inert gas specifications were relaxed, then carbon monoxide would become the most limiting factor.