Hydrogen Energy Conversion and Management

Hydrogen Energy Conversion and Management presents the challenges and solutions to the use of hydrogen as the significant energy
source of the future. With a focus on the theory and recent technological developments, this book comprehensively addresses the
production, storage, and real-world applications of hydrogen.
Divided into four sections, Section 1 provides an overview of hydrogen technology, including environmental sustainability and the
fundamentals of the hydrogen economy and future energy security. Section 2 examines the latest technologies for efficient and costeffective
production of hydrogen, while Section 3 examines the latest technologies for efficient storage and transportation. Finally, Section 4 critically analyzes the challenges, solutions, and implementation prospects for a hydrogen-based fuel economy.
Hydrogen Energy Conversion and Management is an invaluable resource for researchers and practitioners involved in the hydrogen economy and for graduates and research students on multidisciplinary subjects involving renewable energy.

• Examines the latest technological developments in hydrogen production, storage, and transportation alongside technological solutions to their real-world applications.
• Provides step-by-step guidance on new methods, processes, and simulations, supported by experimental data, including hydrogen production from waste.
• Focuses on green hydrogen generation methods, including novel approaches in production and storage and practical applications.

• Language: English
• Publisher: Elsevier Science
• Release date: Sep 24, 2023
• ISBN: 9780443161339

Book preview

Hydrogen Energy Conversion and Management

Edited by

Mohammad Masud Kamal Khan

School of Engineering, Computer and Mathematical Sciences, Auckland University of Technology, Auckland, New Zealand

Abul Kalam Azad

School of Engineering and Technology, Central Queensland University, Melbourne, VIC, Australia

Amanullah Maung Than Oo

School of Engineering, Macquarie University, Sydney, NSW, Australia

Table of Contents

Cover image

Title page

Copyright

Contributors

Preface

Section I. Overview of hydrogen energy

Chapter 1. Evolution of hydrogen energy and its potential opportunities around the globe

1. Introduction

2. Hydrogen key characteristics

3. Hydrogen economy

4. Hydrogen global demands

5. Future hydrogen application scope

6. Green hydrogen's role in energy transition

7. Hydrogen safety

8. Summary

Chapter 2. Hydrogen deployment potential in Colombia: an opportunity to decarbonize and diversify the economy

1. Introduction

2. Hydrogen production potential in Colombia

3. Prospects for hydrogen demand in Colombia

4. Hydrogen export potential

5. Conclusions

Section II. Production and conversion

Chapter 3. Hydrogen production by electrolysis: A sustainable pathway

1. Introduction

2. Scientific methods of hydrogen production

3. Why would electrolysis be the best option?

4. Conclusions

Chapter 4. Hydrogen production from municipal solid waste using gasification method

1. Introduction

2. Hydrogen energy

3. MSW gasification model for H2 production

4. Results and analysis

5. Conclusion

Chapter 5. Techno-economic prospects of green hydrogen production

1. Introduction

2. Methods of study

3. Green hydrogen production processes

4. Economic analysis

5. Conclusion

Chapter 6. Energy and exergy analysis of blue hydrogen production and conversion

1. Introduction

2. Hydrogen production technologies from hydrocarbon feedstock

3. Gasification process for hydrogen production from solid feeds

4. Hydrogen separation processes

5. Energy and exergy analysis of hydrogen production processes

6. The role of CO2 capture, utilization and storage

7. Conclusion

Chapter 7. Proton exchange membrane fuel cell system integration, modeling, and simulation for energy-efficient electric vehicle

1. Introduction

2. State of the art of fuel cell electric vehicles

3. Methodology

4. Results

5. Discussion

6. Conclusion

Chapter 8. Techno-economic analysis of a heat and power combination system based on hybrid photovoltaic-fuel cell systems using hydrogen as an energy vector

1. Introduction

2. System description

3. Methodology

4. Results and discussion

5. Conclusions

6. Appendix

Section III. Storage and transportation

Chapter 9. Hydrogen energy storage and transportation challenges: A review of recent advances

1. Introduction

2. Hydrogen production technologies

3. Hydrogen storage systems

4. Hydrogen transportation challenges

5. Hydrogen energy applications

6. Conclusion

Chapter 10. Application of multiphase heat transfer for efficient hydrogen storage and recovery

1. Introduction

2. Low temperature metal hydride reactors

3. High-temperature metal hydride reactors

4. Conclusions

Chapter 11. Large-scale hydrogen storage using underground hydrogen storage, metal hydride storage, and other emerging technologies

1. Introduction

2. Overview of large-scale hydrogen storage technologies

3. District-level hydrogen penetrated-IES planning method considering large-scale hydrogen storage

4. Regional hydrogen penetrated-IES planning method considering gas pipeline retrofit and expansion

5. Conclusion

Section IV. Applications and transition

Chapter 12. Hydrogen-based automotive applications: a promising future

1. Introduction

2. Background

3. Hydrogen as an energy vector

4. Automotive applications

5. Future challenges and trends

6. Conclusion

Chapter 13. Hydrogen use in high-efficiency compression ignition engines

1. Introduction

2. Combustion fundamentals

3. Implementation of H2 in CI engines

4. Practical applications

5. Summary and directions for future research and development

Index

Copyright

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Notices

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Contributors

Kawsar Ahmed,     Hydrogen Energy Laboratory, BCSIR Chittagong Laboratories, Chattogram, Bangladesh

Md Ahsan Kabir,     Department of Electrical, Electronic and Communication Engineering, Military Institute of Science and Technology, Dhaka, Bangladesh

K.C.A. Alam,     School of Mechanical and Mechatronic Engineering, University of Technology Sydney, Sydney, NSW, Australia

Md Sawkat Ali,     Department of Computer Science and Engineering, East West University, Dhaka, Bangladesh

Paul Arévalo,     Department of Electrical Engineering, University of Jaen, Jaen, Spain

M.T. Arif,     School of Engineering, Deakin University, Waurn Ponds, VIC, Australia

Abul Kalam Azad,     School of Engineering and Technology, Central Queensland University, Melbourne, VIC, Australia

César Barraza-Botet,     Energy, Materials and Environmental Laboratory, Faculty of Engineering, Universidad de La Sabana, Bogotá, Colombia

Emad Benhelal,     Chemical Engineering Department, The University of Newcastle, Newcastle, NSW, Australia

Nelly M. Cantillo,     Energy, Materials and Environmental Laboratory, Faculty of Engineering, Universidad de La Sabana, Bogotá, Colombia

Pranto Chakrabarty,     School of Mechanical and Mechatronic Engineering, University of Technology Sydney, Sydney, NSW, Australia

Tilak T Chandratilleke,     School of Civil and Mechanical Engineering, Curtin University, Bentley, WA, Australia

Apinya Chanthakett,     School of Engineering, Deakin University, Waurn Ponds, VIC, Australia

Jinyi Chen,     School of Electrical Engineering, Southeast University, Nanjing, Jiangsu, China

Martha Cobo,     Energy, Materials and Environmental Laboratory, Faculty of Engineering, Universidad de La Sabana, Bogotá, Colombia

Antonio Colmenar-Santos,     Department of Electrical Engineering, Electronics, Control, Telematics and Chemistry Applied to Engineering, UNED, Ciudad Universitaria, Madrid, Spain

Omar Farrok,     Department of Electrical and Electronic Engineering, Ahsanullah University of Science and Technology, Dhaka, Bangladesh

R. Farzam,     School of Sustainable Energy Engineering, Simon Fraser University, Surrey, BC, Canada

Felipe Galvis,     Energy, Materials and Environmental Laboratory, Faculty of Engineering, Universidad de La Sabana, Bogotá, Colombia

Kosala Gunawardane,     School of Electrical and Data Engineering, University of Technology Sydney, Sydney, NSW, Australia

Marziye Hoseinpour,     Biosystem Engineering Department, Shahrood University of Technology, Shahrood, Iran

M. Saddam Hossain Khan,     Department of Computer Science and Engineering, East West University, Dhaka, Bangladesh

Daniel Icaza-Álvarez,     Department of Electrical Engineering, University of Jaen, Jaen, Spain

Roubaiath Islam,     Department of Electrical, Electronic and Communication Engineering, Military Institute of Science and Technology, Dhaka, Bangladesh

Israt Jahan,     Department of Electrical and Electronic Engineering, Ahsanullah University of Science and Technology, Dhaka, Bangladesh

Francisco Jurado,     Department of Electrical Engineering, University of Jaen, Jaen, Spain

Md Ahsan Kabir,     Department of Electrical, Electronic and Communication Engineering, Military Institute of Science and Technology, Dhaka, Bangladesh

Rahim Karami

Oil and Gas Research Centre, Persian Gulf University, Bushehr, Iran

Technical & Vocational Training Organization (TVTO), Bushehr, Iran

Mohammad Masud Kamal Khan,     School of Engineering, Computer and Mathematical Sciences, Auckland University of Technology, Auckland, New Zealand

Md. Mahadi Hasan,     Department of Electrical, Electronic and Communication Engineering, Military Institute of Science and Technology, Dhaka, Bangladesh

Juan M. Manrique,     Energy, Materials and Environmental Laboratory, Faculty of Engineering, Universidad de La Sabana, Bogotá, Colombia

Marufuzzaman,     Hydrogen Energy Laboratory, BCSIR Chittagong Laboratories, Chattogram, Bangladesh

Arun Mathew,     School of Civil and Mechanical Engineering, Curtin University, Bentley, WA, Australia

G. McTaggart-Cowan,     School of Sustainable Energy Engineering, Simon Fraser University, Surrey, BC, Canada

Azadeh Mirvakili,     Chemical Engineering, School of Chemical and Petroleum Engineering, Persian Gulf University, Bushehr, Iran

Abu Shadat Muhammad Sayem,     Chittagong University of Engineering and Technology, Chittagong, Bangladesh

Nima Nadim,     School of Civil and Mechanical Engineering, Curtin University, Bentley, WA, Australia

Sanjoy Kumar Paul,     UTS Business School, University of Technology Sydney, Sydney, NSW, Australia

Sofía Peláez-Peláez,     Departamento de Ingeniería Eléctrica y de Sistemas y Automática, Universidad de León, Escuela de Ingenierías Industrial e Informática Campus de Vegazana, León, Spain

Yue Qiu,     NARI School of Electrical and Automation Engineering, Nanjing Normal University, Nanjing, Jiangsu, China

Eliana Quiroga,     Energy, Materials and Environmental Laboratory, Faculty of Engineering, Universidad de La Sabana, Bogotá, Colombia

Muhammad Imran Rashid,     University of Engineering and Technology, Lahore, Pakistan

Paula Riveros,     Energy, Materials and Environmental Laboratory, Faculty of Engineering, Universidad de La Sabana, Bogotá, Colombia

David Rodríguez-Fontalvo,     Energy, Materials and Environmental Laboratory, Faculty of Engineering, Universidad de La Sabana, Bogotá, Colombia

Enrique Rosales-Asensio,     Department of Electrical Engineering, School of Industrial and Civil Engineering, ULPGC, Las Palmas de Gran Canaria, Spain

M. Saddam Hossain Khan,     Department of Computer Science and Engineering, East West University, Dhaka, Bangladesh

S.R. Safavi,     School of Sustainable Energy Engineering, Simon Fraser University, Surrey, BC, Canada

Suvash C. Saha,     School of Mechanical and Mechatronic Engineering, University of Technology Sydney, Sydney, NSW, Australia

Md Abdus Salam

Hydrogen Energy Laboratory, BCSIR Chittagong Laboratories, Chattogram, Bangladesh

Institute of Mining, Mineralogy and Metallurgy, BCSIR, Joypurhat, Bangladesh

John Sánchez,     Energy, Materials and Environmental Laboratory, Faculty of Engineering, Universidad de La Sabana, Bogotá, Colombia

Néstor Sánchez,     Energy, Materials and Environmental Laboratory, Faculty of Engineering, Universidad de La Sabana, Bogotá, Colombia

Md Sawkat Ali,     Department of Computer Science and Engineering, East West University, Dhaka, Bangladesh

Mahbube Subhani,     School of Engineering, Deakin University, Waurn Ponds, VIC, Australia

Marcos Tostado-Véliz,     Department of Electrical Engineering, University of Jaen, Jaen, Spain

Rashedul Amin Tuhin,     Department of Computer Science and Engineering, East West University, Dhaka, Bangladesh

Suyang Zhou,     School of Electrical Engineering, Southeast University, Nanjing, Jiangsu, China

Wennan Zhuang,     School of Electrical Engineering, Southeast University, Nanjing, Jiangsu, China

Preface

The nonpolluting hydrogen found abundant in nature has the potential to become the fuel of the future and can make significant contributions to mitigate environmental degradation. This fuel that produces energy and harmless water when it reacts with oxygen can be extensively used to generate electricity, power industry and homes, drive fuel cell vehicles, and many more applications. However, conversion of hydrogen to usable fuel faces several challenges.

Some of the challenges include developing technologies to produce green hydrogen which generates no emission resulting from the production process from a variety of renewable energy sources, cost-effectively storing and transporting, and then using it in engineering applications.

This book presents a collection of chapters of new research and recent advancement in these areas presented by experts offering solution options for transition to hydrogen fuel economy. It covers topics on green hydrogen generation using novel approaches in production and storage, for example, producing fuel cells with increased efficiency using new technology and then using them in real applications. It also includes a collection of simulation and experimental investigations with new methods and processes.

With a focus on the theory and recent technological developments, the topics of the chapters have been divided into four sections. Section 1 provides an overview of hydrogen technology, including environmental sustainability, the hydrogen economy fundamentals, and future energy security. Section 2 examines the latest technologies for efficient and cost-effective hydrogen production, while Section 3 examines the latest technologies for efficient storage and transportation. Finally, Section 4 critically analyzes the challenges, solutions, and implementation prospects for a hydrogen-based fuel economy.

We believe this book will be a valuable resource for researchers and practitioners involved in the hydrogen economy and for graduates and research students on multidisciplinary subjects involving renewable energy.

Professor Mohammad Masud Kamal Khan

School of Engineering, Computer and Mathematical Sciences, Auckland University of Technology, Auckland, New Zealand

Dr. Abul Kalam Azad

School of Engineering and Technology, Central Queensland University, Melbourne, VIC, Australia

and

Professor Amanullah Maung Than Oo

School of Engineering, Macquarie University, Sydney, NSW, Australia

Section I

Overview of hydrogen energy

Outline

Chapter 1. Evolution of hydrogen energy and its potential opportunities around the globe

Chapter 2. Hydrogen deployment potential in Colombia: an opportunity to decarbonize and diversify the economy

Chapter 1: Evolution of hydrogen energy and its potential opportunities around the globe

Kosala Gunawardane     School of Electrical and Data Engineering, University of Technology Sydney, Sydney, NSW, Australia

Abstract

As an energy carrier, it has a long history. As an alternative to widely used fossil fuels, renewables have been introduced to reduce the carbon emission levels. However, since mostrenewables energy sources are highly dependent on environmental and geographical conditions, energy storage technologies alongside renewable energy sources have become a major topic of interest. Due to the high potential of hydrogen as an energy carrier, hydrogen once again has attracted attention in new applications. In the current context, hydrogen infrastructure and hydrogen-related technologies are undergoing rapid development, which will increase the possibility of hydrogen becoming one of the next major sources of energy. However, the hydrogen economy concept is still in the early stages of implementation. This concept has an anticipated future in which hydrogen is used as a fuel for heat and hydrogen vehicles, power generation, energy storage, and long-distance transport of energy.

Keywords

Electrolysis; Hydrogen application scope; Hydrogen economy; Hydrogen evolution; Hydrogen global demand; Hydrogen key characteristics

1. Introduction

Hydrogen is the most abundant element in the universe and one of the most abundant elements on earth [1]. Using hydrogen as an energy carrier has a long history, starting in the 18th century. Over 200 years ago, one of the very first internal combustion engines used a mixture of hydrogen and oxygen as the fuel. Hydrogen powered the Apollo missions to land on the moon in the 1960s [2].

The first major interest in hydrogen occurred during the oil price hikes and petroleum shortages in the 1970s. As a result, there was a developing interest in hydrogen production from coal or nuclear energy for use as a fuel in the transport sector. The international journal of hydrogen energy was established in 1976, and the International Energy Agency Hydrogen and Fuel Cell Technology Collaboration Program was formed in 1977 to collaborate and share worldwide the growing body of knowledge related to hydrogen technologies. However, when the oil price moderated, the interest in hydrogen faded away [3].

Once again, the world's interest in hydrogen was boosted by the increased attention paid to carbon capture and storage during the 1990s. As a result, consideration of hydrogen-based applications increased once again. Specifically, the automobile industry was keen to use hydrogen fuel, and many major car manufacturers unveiled their hydrogen-powered car designs. However, due to the lower oil prices and lack of availability of a hydrogen-based infrastructure, world attention to hydrogen yet again declined.

Global warming and climate change became a worldwide concern in the 2000s, and many global-level initiatives were started to regulate global warming to controlled levels, such as the Paris Agreement [4], Kyoto Protocol [5], and Kigali Amendment [6]. As a result, many countries have introduced new policies to control carbon emissions. As an alternative to widely used fossil fuels, renewables were introduced to reduce carbon emission levels. However, since the intermittent nature of renewable sources, energy storage techniques become a major topic of interest in the late 2000s. In the current context, due to the high potential of hydrogen as an energy carrier, hydrogen infrastructure and hydrogen-related technologies are undergoing rapid development once again. This will increase the possibility of hydrogen becoming one of the next major sources of energy for the power generation and transpiration industries.

As shown in Fig. 1.1, while global energy demand is increasing exponentially, coal and fossil fuel reserves eventually will start to diminish [7]. Therefore, globally, major attention is turned toward new sources of energy that replace fossil fuels. However, there are several key concerns when selecting a replacement for the fossil fuels, which are summarized below:

Figure 1.1  World energy consumption [7].

• Need to be capable of utilizing the available infrastructure to reduce the cost and time during the transition period to the new source of power.

• Need to be widely available and easy to produce to fulfill the exponentially growing future energy demands.

• Need to impact the environment to maintain the low carbon footprint goals.

• Need to have high conversion efficiency when converting to other forms of energies.

Interestingly, hydrogen is one of the best candidates for satisfying all the above needs. The following section provides a detailed discussion of hydrogen's suitability, extracted from current literature.

2. Hydrogen key characteristics

2.1. Utilizing the existing major infrastructure for hydrogen

Currently, there is a possibility of using the existing infrastructure of natural gas grids for the distribution of hydrogen. The Netherlands has done a study to evaluate the possibility of using its existing gas network to transmit hydrogen, and that study showed that with minor modifications, the existing network can be adapted to transmit hydrogen in the future [8]. Fig. 1.2 illustrates the current limits on hydrogen blending in natural gas networks worldwide [9].

Generally, for distances less than 1500 km, a pipeline is the cheapest option to transport hydrogen. For distances above 1500 km, shipping hydrogen is the most economical method, and hydrogen can be stored as ammonia or in the form of liquid organic hydrogen carriers to enhance the cost effectiveness [10].

Figure 1.2  Current limits on hydrogen blending in natural gas networks [9].

Worldwide, there are more than 3 million kilometers of gas transmission pipelines and even larger distribution pipe networks for distributing it [11]. These networks can be used to transmit hydrogen with only minor moderations or end-user equipment changes, which reduces the time and cost. Utilizing the existing pipeline may not be the only way to develop the hydrogen infrastructure; however, it can accelerate the timeframe while reducing the initial investment [3].

2.2. Availability and easy production

Hydrogen is naturally compounded in water or natural gas. Therefore, hydrogen has to be extracted from its composites. There are many technologies for hydrogen extraction from composites, such as natural gas reforming, electrolysis, renewable liquid reforming, and fermentation. The diversity of these extraction methods increases the opportunities for hydrogen to become the future’s major source of energy.

Hydrogen production methods can be summarized into four major categories:

1. Thermochemical processes

2. Electrolysis processes

3. Direct solar and water splitting processes

4. Biological processes

2.2.1. Thermochemical processes

In thermochemical processes, thermal energy is used to release hydrogen from the molecular structure of varied sources such as natural gas, coal, and biomass. Some of the commercially used thermochemical processes are:

(a) Natural gas reforming

(b) Biomass gasification

(c) Biomass-derived liquid reforming

(d) Solar thermochemical hydrogen

2.2.1.1. Natural gas reforming

Methane (CH4) is commonly available as natural gas. Thermal processes can be employed to extract hydrogen from methane. Steam methane reforming is a very well-developed process where high-temperature (700–1000°C) steam is used to produce hydrogen from methane. Maintaining a pressure between 3 and 25 bar is required for methane to react with the steam, and the corresponding chemical reaction can be expressed as Eq. (1.1). Steam methane reforming is the most common hydrogen production method in the USA [12].

Equation 1.1. (1.1)

Consequently, the generated carbon monoxide is reacted with steam and produced more hydrogen and carbon dioxide, as expressed in Eq. (1.2) [12]. This reaction is known as the water-gas shift reaction.

Equation 1.2. (1.2)

In the current context of hydrogen production, 70 Mt of hydrogen is produced worldwide, and 76% of the production is produced using natural gas, accounting for 6% of the world's natural gas consumption. Furthermore, 23% of the world's hydrogen is produced using coal, accounting for 2% of global coal consumption. Electrolysis-based hydrogen production is currently only 2%, a relatively very low proportion. However, electrolysis-based low-carbon hydrogen production is growing at a rapid rate and is especially focused on using surplus electrical energy generated from renewables, which provides a low-cost option.

2.2.1.2. Biomass gasification

Biomass includes renewable organic sources such as agricultural crop residues, forest residues, animal waste, municipal organic waste, etc. Biomass gasification is a well-established, controlled process that involves heat, steam, and oxygen. In order to start the reaction, the temperature has to be above 700°C. A simplified chemical reaction for the process can be expressed as in Eq. (1.3), and absorbers/special membranes are used to extract hydrogen from the steam [13]. Subsequently, the produced carbon monoxide is reacted with steam generating, carbon dioxide and more hydrogen according to the water-gas shift reaction as in Eq. (1.2).

Equation 1.3.

(1.3)

2.2.1.3. Biomass-derived liquid reforming

Liquid forms of biomass, such as ethanol and bio-oils, are used in this method to produce hydrogen using a similar method to natural gas reforming. The ethanol steam reforming chemical reaction can be expressed by Eq. (1.4) [14]. The resulting carbon monoxide and steam react again and produce more hydrogen and carbon dioxide, as described by the water-gas shift reaction in Eq. (1.2).

Equation 1.4. (1.4)

2.2.1.4. Solar thermochemical hydrogen

Thermochemical reactions require high temperatures in the range of 500–2000°C to generate hydrogen. High temperatures can be achieved using concentrated sunlight or the waste heat from an advanced nuclear reactor.

Solar thermochemical water splitting uses concentrated solar heat to perform a series of reactions whereby hydrogen and oxygen are produced as end-products. The entire process is a recycling process; only water and solar heat need to be provided. The two-step thermochemical water splitting cycle is the simplest method that uses metal oxide. Initially, metal oxide is transformed into reduced-valence metal oxide and oxygen. Subsequently, the reduced-valance metal oxide is reacted with water to generate hydrogen and regenerate the metal oxide, as shown in Eqs. (1.5) and (1.6), respectively [15].

Equation 1.5. (1.5)

Equation 1.6. (1.6)

As shown in Eqs. (1.5) and (1.6), the metal oxide is recycled, and a temperature above 15,00°C is required to perform the reaction.

There are other solar thermochemical water splitting methods that have been developed to produce hydrogen under low-temperature conditions. However, lower-temperature reactions have more cycles. For example, the general electric sulfhur-iodine (S–I) solar thermochemical water splitting cycle reaction is described in Eqs. (1.7), (1.8) and (1.9) [16].

Equation 1.7. (1.7)

Equation 1.8. (1.8)

Equation 1.9. (1.9)

Eqs. (1.7) and (1.9), the S–I solar thermochemical water splitting cycle reactions are endothermic reactions, and Eq. (1.8) is an exothermic reaction. Furthermore, a temperature of 850–900°C is required to initiate the reaction in Eq. (1.7), 100°C is needed for the reaction in Eq. (1.8), and the final reaction in Eq. (1.9) requires temperatures between 400 and 500°C. The efficiency of the reactions is proportional to the temperature. As an example, the efficiency of the reaction in Eq. (1.7) is around 52% at 900°C and increases to around 62% at a temperature of 1000°C [16].

2.2.2. Electrolysis processes

Electrolysis is one of the most developed, environmentally friendly, commercially available hydrogen production processes where electricity is used to split hydrogen and oxygen from water, as shown in Fig. 1.3 [17]. An electrolyzer is the device that generates hydrogen from the electrolysis process. Electrolyzers are available from megawatt (MW) to gigawatt (GW)-scale based on the application scope. Currently, electrolyzers are largely employed to generate hydrogen using renewable energy.

Figure 1.3  Different types of electrolyzers [13]: (A) Alkaline electrolysis, (B) proton exchange membrane electrolysis and (C) solid oxide electrolyzer.

The electrolysis process decomposes water into its basic components, hydrogen and oxygen, which store electrical energy in the form of chemical energy. Electrolyzers consist of an anode (positive) and a cathode (negative) separated by an electrolyte material. Depending on the characteristics of the electrolyte material numerous types of electrolysis are available, such as:

a. Alkaline electrolysis (AEL)

b. Proton exchange membrane (PEM) electrolysis

c. Solid oxide electrolyzer

d. Anion exchange membrane electrolysis

Table 1.1 provides a detailed comparison of the various types of electrolysis processes based on material use, anode and cathode reactions, and the operating temperatures.

The most commonly used commercialized electrolysis techniques to produce hydrogen are AEL, PEM electrolysis, and solid oxide electrolysis cells. The alkaline method has been used since 1902 and is commonly used in the fertilizer and chlorine industries. Compared to the other technologies, the AEL process requires less investment due to the avoidance of specific material requirements. In the last century, alkaline electrolyzers up to a capacity of 165 MW were installed in countries where hydropower is readily available, such as Canada, Norway, India, and Zimbabwe. However, with the increase in hydrogen production using natural gases and methane the alkaline electrolyzer plants were decommissioned in the 1970s.

In the 1960s, General Electric introduced PEM electrolyzers to overcome the drawbacks of alkaline electrolyzers. Instead of using potassium hydroxide electrolyte solution as in AEL, which requires recovery and recycling of water, in PEM electrolysis, purified water is the electrolyte solution. Compared with alkaline electrolyte processes, PEM electrolysis is much more compact and highly suitable for urban applications. Furthermore, it has a wide operating range and is capable of 160% of its design capacity for short periods. Additionally, PEM is able to produce hydrogen at high pressure (30–60 bar) without any additional compression, which is ideal for isolated hydrogen refueling or storage stations. However, irrespective of the aforementioned advantages, PEM electrolysis requires an expensive electrode catalyst such as platinum or iridium, which increases the overall cost. Furthermore, the lifetime of the PEM electrolysers is shorter compared to the alkaline electrolyzers. These drawbacks limit the deployment of PEMs in some applications.

Table 1.1

Solid oxide electrolysis cells are the latest type of electrolyzers which are at the early stage of commercialization. Due to the use of ceramics as the electrolyte, the production cost is very low. Furthermore, compared to the other two techniques, solid oxide electrolysis has higher efficiency. However, it requires a high temperature since steam is used for the electrolysis.

2.2.3. Direct solar water splitting processes

Direct solar water splitting, also known as the photolytic process, is the use of solar energy to split water into hydrogen and oxygen. This is a very environmentally friendly process. Currently, the process is in the early stages of development, and photoelectrochemical and photobiological are the main direct solar water splitting techniques. Both these techniques are still in the laboratory development stages, and they have indicated promising outcomes.

a. Photoelectrochemical process

In this process, a specialized semiconductor material called photoelectrochemical material is used to split hydrogen from water using solar energy. Since the semiconductor needs to be immersed in water, researchers are proposing a structure similar to solar panels [18].

b. Photobiological process

Photobiological systems use microorganisms such as green microalgae, cyanobacteria, etc., to split hydrogen from water using solar energy. But there are still technical challenges to be addressed for this technique, such as low flow rates and low solar-to-hydrogen efficiency [19].

2.2.4. Biological processes

Biological reactions can be used to produce hydrogen using microbes such as bacteria and microalgae. These technologies are also still at the research stage.

Microorganisms such as bacteria produce hydrogen while breaking down organic matter such as sugar, raw biomass, wastewater, etc. These are fermentation-based systems. The challenges of these technologies are the low hydrogen production rate and the low hydrogen yield [20].

2.3. Environmental friendliness

Hydrogen is colorless; however, nine color-coded hydrogen types are defined to evaluate the environmental impact based on the production methods, as shown in Table 1.2 [21].

a. Brown hydrogen

Brown hydrogen is often referred to as black hydrogen in some industries and publications. In this process coal is used as the energy source, and the process is gasification to produce hydrogen. However, this process emits CO2 and CO to the atmosphere, which creates a considerable impact on the environment.

b. Gray hydrogen

Currently, most of the produced hydrogen belongs to the gray hydrogen category, which is hydrogen generated using natural gas or methane by employing the steam methane reformation technique. CO2 is generated as a by-product in this process and ultimately released to the atmosphere, which also can create negative impacts on the environment.

Table 1.2

c. Blue hydrogen

Blue hydrogen refers to the hydrogen produced from fossil fuel. Likewise, for brown and gray hydrogen, CO2 is produced during the production of blue hydrogen. However, instead of releasing the produced CO2 to the atmosphere, new technologies are zused to capture the generated CO2 and store it underground. Due to this carbon capture, blue hydrogen has a high potential to become a low-carbon fuel.

d. Turquoize hydrogen

Turquoize hydrogen is a new form of hydrogen that is extracted from the thermal splitting of methane through pyrolysis. Solid carbon is produced as a by-product in this method instead of emitting CO2. Renewable energy can be used to supply energy for this process, and it can be categorized as a low-carbon emission hydrogen.

e. Red hydrogen

Red hydrogen is generated using nuclear energy and involves the high-temperature catalytic splitting of water. Oxygen is generated as a by-product in this method.

f. Purple hydrogen

Purple hydrogen, also identified as pink hydrogen, is also produced from nuclear power. Electrolysis-based water splitting is employed to produce hydrogen where oxygen is generated as a by-product.

g. Yellow hydrogen

Solar power is used to generate hydrogen by electrolysis of water to make yellow hydrogen, and oxygen is a by-product.

h. Green hydrogen

Green hydrogen means the hydrogen is produced using renewable energy for the water electrolysis technique. The name green hydrogen implies net zero emissions in this process. The world is gradually moving toward green hydrogen production, targeting a zero-emission future.

In the current context, green hydrogen is considered as a costly process, and as a result, mostly brown or gray hydrogen is used. However, with the advancement of technology and mass production, economists have estimated that the cost of green hydrogen will decline soon [22].

2.4. Conversion efficiency

Combustion is the only practicable and available method for fossil fuels to convert energy, whereas hydrogen can be easily converted through multiple mechanisms. Table 1.3 shows a convertibility comparison of fossil fuels and hydrogen.

Table 1.4 shows the comparison of the utilization efficiency factor, which is defined as below: (Utilization efficiency = fossil fuel efficiency/hydrogen efficiency.)

With the aforementioned highly sought-after characteristics, hydrogen has the potential to become the future source of energy in many sectors, including transport, electricity, heating, etc. Alongside the advancement of the technology related to renewable energy and clean hydrogen production, future prospects are clear for green hydrogen to entirely supply the global energy demand.

Table 1.3

Table 1.4

Around the world, a number of hydrogen pilot projects are under development in various sectors that include energy production, storage, transportation, electricity, heat, cooling for buildings and households, and the fabrication of feedstock:

• Haru Oni Project— the largest Latin American project producing green hydrogen using wind power [23].

• EU-supported large-scale green hydrogen underground storage demonstrator project [24].

• Hydrogen-powered mining truck project in South Africa [25].

• Microsoft uses hydrogen fuel cell backup power for data centers [26].

Currently, approximately 10 million metric tons of hydrogen are produced annually in the USA, which is 1% of the total energy consumption; however, 95% is gray hydrogen [27]. In Europe, around 2% of the energy demand is produced from hydrogen, and 96% is gray hydrogen [28]. Environmental friendliness is a major reason which attracts the world's attention toward hydrogen. Particularly with the usage of renewable energy, hydrogen can be produced using water, and water is again released as a by-product of hydrogen consumption; this is known as the water-to-water hydrogen life cycle, as illustrated in Fig. 1.4 [29].

3. Hydrogen economy

The concept of a hydrogen economy was proposed by John Bockris of the General Motors Technical Center in 1970. This is an economy that is dependent on hydrogen as the major source of commercial energy, including transport, electricity, heating, etc., which would help to achieve a carbon-neutral economy. As shown in Fig. 1.5, hydrogen becomes the dominant energy carrier in this concept with the below-mentioned capabilities [30]:

• Enabling large-scale renewable energy integration in power generation

• Distributing energy across sectors and regions

• Acting as a buffer to increase energy system resilience

• Decarbonizing transportation and industrial energy use

Many of the hydrogen and associated production technologies are already well-developed. However, the hydrogen economy concept is still in the early stages of implementation. This concept has an anticipated future in which hydrogen is used as a fuel for heat and hydrogen vehicles, for energy storage, and for long-distance transport of energy. However, realizing this hydrogen production and storage are the main issues that need to be solved at present.

Figure 1.4  Water to water hydrogen life cycle [29].

Figure 1.5  Concept of hydrogen economy.

4. Hydrogen global demands

To realize the hydrogen economy's vision and achieve its desired impact, a significant step-up across the supply value chain would be required. Deploying hydrogen infrastructure and scaling up manufacturing capacities to achieve competitive costs and mass market acceptance are important measures. As shown in Fig. 1.6, worldwide, hydrogen can play seven major roles in the transformations noted below:

1. Enabling large-scale renewable energy integration and power generation

2. Distributing energy across sectors and regions

3. Acting as a buffer to increase energy system resilience

4. Decarbonizing transportation

5. Decarbonizing industrial energy use

6. Helping to decarbonize building heat and power

7. Providing a clean feedstock for industry

In the current context, as noted in Fig. 1.7, the largest hydrogen consumer is oil refining. 33% of world hydrogen production is used in oil refining processes. 27% is consumed by ammonia production, whereas methanol and steel production consume 11% and 3%, respectively. The remaining 24% is consumed by several other industrial applications, including transportation and electricity generation [3].

Figure 1.6  Hydrogen: Seven major roles.

Figure 1.7  Global hydrogen usage.

The demand for hydrogen is projected to increase 8 times by 2050 compared to that for 2020, as shown in Fig. 1.8 [31]. According to these projections, the hydrogen global energy demand is predicted to reach 73 Mt (pessimistic case) to 568 Mt (optimistic case) by 2050 [32]. Electrolyzers and associated technologies are continuously evolving. Electrolyzer costs are projected to halve by 2040–2050, from USD840 per kilowatt (kW) as of today, while renewable electricity costs will continue to fall too. Most of the increased demand would be for the new sectors such as transportation and industrial energy, which consume negligible amounts of hydrogen energy at present. Future demand for hydrogen is expected to be supplied by green hydrogen, as that would significantly contribute to meeting the global emission targets.

Figure 1.8  Global energy demand (EJ) supplied by hydrogen (projected) [31].

5. Future hydrogen application scope

5.1. Oil refining

Hydrogen is mainly used for removing impurities in crude oil and upgrading heavier crudes. Even with the global scale agreements to limit fossil fuel usage, it is predicted that the demand for fossil fuels will continue to rise. As a result, by 2030, hydrogen demand for the oil refining is predicted to increase by 7% [3]. Furthermore, refining is more likely to be the main hydrogen consumer until 2050. Hydrogen production and usage in oil refineries are in a closed-loop system, which makes it very hard to replace with green hydrogen. Consequently, green hydrogen costs are comparatively expensive.

5.2. Chemical production

Hydrogen is part of the molecular structure of the most commonly used industrial chemicals and materials, such as plastics, fertilizers, solvents, and explosives. However, ammonia and methanol are the most commonly produced chemicals using hydrogen. Therefore, the demand in the chemical industry is predicted to increase from 44 Mt/yr to 57 Mt/yr by 2030 [3]. Currently, global ammonia and methanol production emits 630 Mt of carbon dioxide annually. Due to the high competitiveness of low-carbon hydrogen, it remains a challenge to integrate green hydrogen into chemical processes.

5.3. Iron and steel production

Direct reduction of iron is the method used to produce steel from iron. This is the third-largest hydrogen-consuming industry. With the high demand for infrastructure supplies, global steel demand is predicted to increase by 6% by 2030 [3]. In the steel production process, hydrogen is generated as a by-product, and a portion of that hydrogen is reconsumed within the production process. The hydrogen used for steel manufacturing is generated from either coal or other fossil fuels. In order to reduce carbon emission levels, new processes are being developed to use green hydrogen. The first very first commercialized plant is expected to be start production by the 2030s in Boden, northern Sweden [3].

5.4. Transportation

In recent years many global major vehicle manufacturers have introduced hydrogen-powered vehicles at the major motor shows. In transportation, hydrogen-powered vehicles/fuel cell electric vehicles (FCEVs) are commercially available now or will become available over the next 5 years in medium-sized and large cars, buses, trucks, vans, trains, and forklifts. FCEVs are a vital element to strengthen decarbonization in the transportation sector. Table 1.5 presents applications of hydrogen in various sectors of transportation. Currently, due to a lack of infrastructure and production, fuel cell-powered vehicles are expensive. However, with the development of infrastructure and associated hydrogen technologies, it is predicted that the cost of hydrogen powered vehicles will decline gradually in the future.

Table 1.5

FCEVs are convenient for consumers due to their long ranges and fast refueling times and are particularly competitive for heavy vehicles, as shown in Fig. 1.9. As capacity increases, however, the FCEV becomes cheaper, since adding hydrogen storage costs less than adding batteries. FCEVs meet performance and convenience requirements best. Costs are likely to drop with scale, allowing hydrogen to compete in more segments, such as smaller cars and minibuses. By 2030, 1 in 12 cars sold in California, Germany, Japan, and South Korea could be powered by hydrogen; more than 350,000 hydrogen trucks could be transporting goods; and thousands of trains and passenger ships could be transporting people without carbon emissions [33]. The global hydrogen market size was USD 1.14 billion in 2021 and is predicted to have a compound annual growth rate of 49.9% from 2021 to 2030 [34]. Especially the North America and Pacific regions are showing a high potential for hydrogen-powered vehicles due to the high level of environmental concern and policies in those regions [35]. Increasing population and environmental concerns about global warming are the main reasons for this high growth rate. 84.3% of the fuel cell market in 2021 will be for passenger vehicles. The Hyundai Motor Company is a leading hydrogen-based car manufacturer and recently announced a new hydrogen storage system technology that can reduce the number of manufacturing components by 75%, the weight of the system by 43%, and the cost of the entire system by 52% [36]. Many Asian automobile manufacturers such as Toyota, Honda, and Hyundai, and European manufacturers, such as Audi and BMW, are developing fuel cell vehicles with their early prototypes with the aim of releasing new fuel cell cars to the market in the coming years. As an example, Renault introduced a hydrogen powered electric SUV that has a power of 16 kW and can extend the range to 800 km without refilling. Compared to its battery-powered EV model, the new model has a 75% lower carbon footprint [34].

Figure 1.9  Hydrogen prospects in heavy vehicles [3].

Beyond 2030, hydrogen will increasingly be used to create renewable synthetic fuels to decarbonize commercial aviation and freight shipping, which are harder to decarbonize using only hydrogen fuel cells.

The deployment of transport solutions has begun around the world, with Japan, South Korea, California, and Germany leading the way. Activities in other European countries, in the Northeast US, and in China are also under way. Japan set itself the target of having 800,000 FCEVs on the road by 2030; China plans 1 million FCEVs by 2030 and is already investing in growing its manufacturing capabilities [3].

One important point is that large-scale deployment of hydrogen transport solutions would require major investments in hydrogen infrastructure. An important barrier to this infrastructure development is the synchronization of FCEV ramp-up and infrastructure development. Investments in refueling stations pay off only if vehicle numbers grow, but developing, building, and marketing vehicles is viable only with an adequate refueling infrastructure. The number of hydrogen refilling stations under development worldwide is shown in Fig. 1.10 [37].

Cost reduction is driven by three