A generic methodology to evaluate economics of hydrogen production using energy from nuclear power plants

Hydrogen, the deemed future transportation fuel can be produced from nuclear assisted energy sources. Assessment of economics of hydrogen production using energy from nuclear power plants is vital for asserting its competitiveness with competing technologies. A generic method is presented in this paper to evaluate Levelised Hydrogen Generation Cost, based on the discounted cash flow analysis. The method is illustrated by consideration of a typical case of hydrogen production via conventional electrolysis using electrical energy supplied from a pressure tube type boiling light water cooled heavy water moderated reactor concept.     

Comparison of sulfur–iodine and copper–chlorine thermochemical hydrogen production cycles

Sulfur–iodine and copper–chlorine water splitting cycles are promising methods of thermochemical hydrogen production. In this paper, these two cycles are compared from the perspectives of heat quantity, heat grade, thermal efficiency, related engineering challenges, and hydrogen production cost. The heat quantity and grade required by each step of the cycles are evaluated and the thermal efficiencies are approximated from the heat requirements. It is found that the overall heat requirements of the two cycles do not have significant differences and the overall efficiencies of the two cycles are similar, between 37 and 54%, depending on the portion of heat recovery. The copper–chlorine cycle has the advantage of a lower maximum temperature of 803 K, which is 300 K lower than the maximum temperature of 1123 K in the sulfur–iodine cycle. This indicates that the copper–chlorine cycle can link more readily with various heat sources, such as grade Generation IV nuclear and fossil fuel power stations. It is also reported that the copper–chlorine cycle can have fewer challenges of equipment materials and product separation. A cost analysis shows that the copper–chlorine and sulfur–iodine cycles have similar hydrogen production costs, which are lower than steam-methane reforming, and conventional and high temperature electrolysis, due to less use of electricity, no carbon related charges and no methane requirement in the thermochemical cycles.     

Recent Canadian advances in nuclear-based hydrogen production and the thermochemical Cu–Cl cycle

This paper presents recent Canadian advances in nuclear-based production of hydrogen by electrolysis and the thermochemical copper–chlorine (Cu–Cl) cycle. This includes individual process and reactor developments within the Cu–Cl cycle, thermochemical properties, advanced materials, controls, safety, reliability, economic analysis of electrolysis at off-peak hours, and integrating hydrogen plants with Canada's nuclear power plants. These enabling technologies are being developed by a Canadian consortium, as part of the Generation IV International Forum (GIF) for hydrogen production from the next generation of nuclear reactors.     

Life cycle assessment of nuclear-based hydrogen and ammonia production options: A comparative evaluation

In this study, nuclear energy based hydrogen and ammonia production options ranging from thermochemical cycles to high-temperature electrolysis are comparatively evaluated by means of the life cycle assessment (LCA) tool. Ammonia is produced by extracting nitrogen from air and hydrogen from water and reacting them through nuclear energy. Since production of ammonia contributes about 1% of global greenhouse gas (GHG) emissions, new methods with reduced environmental impacts are under close investigation. The selected ammonia production systems are (i) three step nuclear Cu–Cl thermochemical cycle, (ii) four step nuclear Cu–Cl thermochemical cycle, (iii) five step nuclear Cu–Cl thermochemical cycle, (iv) nuclear energy based electrolysis, and (v) nuclear high temperature electrolysis. The electrolysis units for hydrogen production and a Haber–Bosch process for ammonia synthesis are utilized for the electrolysis-based options while hydrogen is produced thermochemically by means of the process heat available from the nuclear power plants for thermochemical based hydrogen production systems. The LCA results for the selected ammonia production methods show that the nuclear electrolysis based ammonia production method yields lower global warming and climate change impacts while the thermochemical based options yield higher abiotic depletion and acidification values.     

Efficiency of hydrogen production systems using alternative nuclear energy technologies

Nuclear energy can be used as the primary energy source in centralized hydrogen production through high-temperature thermochemical processes, water electrolysis, or high-temperature steam electrolysis. Energy efficiency is important in providing hydrogen economically and in a climate friendly manner. High operating temperatures are needed for more efficient thermochemical and electrochemical hydrogen production using nuclear energy. Therefore, high-temperature reactors, such as the gas-cooled, molten-salt-cooled and liquid-metal-cooled reactor technologies, are the candidates for use in hydrogen production. Several candidate technologies that span the range from well developed to conceptual are compared in our analysis. Among these alternatives, high-temperature steam electrolysis (HTSE) coupled to an advanced gas reactor cooled by supercritical CO₂ (S-CO₂) and equipped with a supercritical CO₂ power conversion cycle has the potential to provide higher energy efficiency at a lower temperature range than the other alternatives.     

Comparison of thermochemical,electrolytic, photoelectrolytic and photochemical solar-to-hydrogen production technologies

Hydrogen produced from solar energy is one of the most promising solar energy technologies that can significantly contribute to a sustainable energy supply in the future. This paper discusses the unique advantages of using solar energy over other forms of energy to produce hydrogen. Then it examines the latest research and development progress of various solar-to-hydrogen production technologies based on thermal, electrical, and photon energy. Comparisons are made to include water splitting methods, solar energy forms, energy efficiency, basic components needed by the processes, and engineering systems, among others. The definitions of overall solar-to-hydrogen production efficiencies and the categorization criteria for various methods are examined and discussed. The examined methods include thermochemical water splitting, water electrolysis, photoelectrochemical, and photochemical methods, among others. It is concluded that large production scales are more suitable for thermochemical cycles in order to minimize the energy losses caused by high temperature requirements or multiple chemical reactions and auxiliary processes. Water electrolysis powered by solar generated electricity is currently more mature than other technologies. The solar-to-electricity conversion efficiency is the main limitation in the improvement of the overall hydrogen production efficiency. By comparison, solar powered electrolysis, photoelectrochemical and photochemical technologies can be more advantageous for hydrogen fueling stations because fewer processes are needed, external power sources can be avoided, and extra hydrogen distribution systems can be avoided as well. The narrow wavelength ranges of photosensitive materials limit the efficiencies of solar photovoltaic panels, photoelectrodes, and photocatalysts, hence limit the solar-to-hydrogen efficiencies of solar based water electrolysis, photoelectrochemical and photochemical technologies. Extension of the working wavelength of the materials is an important future research direction to improve the solar-to-hydrogen efficiency.     

Geothermal‐based hydrogen production using thermochemical and hybrid cycles: A review and analysis

Geothermal‐based hydrogen production, which basically uses geothermal energy for hydrogen production, appears to be an environmentally conscious and sustainable option for the countries with abundant geothermal energy resources. In this study, four potential methods are identified and proposed for geothermal‐based hydrogen production, namely: (i) direct production of hydrogen from the geothermal steam, (ii) through conventional water electrolysis using the electricity generated through geothermal power plant, (iii) by using both geothermal heat and electricity for high temperature steam electrolysis and/or hybrid processes, and (iv) by using the heat available from geothermal resource in thermochemical processes. Nowadays, most researches are focused on high‐temperature electrolysis and thermochemical processes. Here we essentially discuss some potential low‐temperature thermochemical and hybrid cycles for geothermal‐based hydrogen production, due to their wider practicality, and examine them as a sustainable option for hydrogen production using geothermal heat. We also assess their thermodynamic performance through energy and exergy efficiencies. The results show that these cycles have good potential and attractive overall system efficiencies over 50% based on a complete reaction approach. The copper‐chlorine cycle is identified as a highly promising cycle for geothermal‐hydrogen production. Copyright © 2009 John Wiley & Sons, Ltd.     

Life cycle assessment of nuclear hydrogen production processes based on high temperature gas-cooled reactor

Conventional hydrogen production technologies mostly fossil fuels as energy and material basis. The rapid development of nuclear energy in recent years offers a new opportunity. Clean electricity and process heat generated by nuclear reactors can provide energy for hydrogen production, effectively reducing the environmental burden. This study used life cycle assessment (LCA) method to sort out the inputs and outputs of the nuclear hydrogen production processes and analyze the environmental impacts based on local data in China. In this study, we constructed frameworks for two nuclear energy-based processes and created four different scenarios to compare the effect of energy efficiency. Six indicators were used to quantify the environmental impact. The results showed that: (1) electrolysis cell manufacturing and spent fuel disposal generate the largest emissions in hydrogen production. (2) S–I cycle is sensitive to heat transfer efficiency, while high-temperature electrolysis is more sensitive to power generation efficiency; (3) The environmental impact of high-temperature electrolysis (without carrier gas) is slightly lower than that of S–I cycle, but the advantage will disappear as energy efficiency increases. At present, high-temperature electrolysis offers a clean alternative to conventional technologies for hydrogen energy and hydrogen economy. The S–I cycle might have a better prospect in the future. Our study results will provide a scientific assessment of the possibilities of developing nuclear energy for hydrogen production in China and help to make some decisions and policies.     

Progress of international hydrogen production network for the thermochemical Cu–Cl cycle

This paper presents recent advances by an international team which is developing the thermochemical copper–chlorine (Cu–Cl) cycle for hydrogen production. Development of the Cu–Cl cycle has been pursued by several countries within the framework of the Generation IV International Forum (GIF) for hydrogen production with the next generation of nuclear reactors. Due to its lower temperature requirements in comparison with other thermochemical cycles, the Cu–Cl cycle is particularly well matched with Canada's Generation IV reactor, SCWR (Super-Critical Water Reactor), as well as other heat sources such as solar energy or industrial waste heat. In this paper, recent developments of the Cu–Cl cycle are presented, specifically involving unit operation experiments, corrosion resistant materials and system integration.     

Sustainable hydrogen production options and the role of IAHE

In this paper, some potential sustainable hydrogen production options are identified and discussed. There are natural resources from which hydrogen can be extracted such as water, fossil hydrocarbons, biomass and hydrogen sulphide. In addition, hydrogen can be extracted from a large palette of anthropogenic wastes starting with biomass residuals, municipal wastes, plastics, sewage waters etc. In order to extract hydrogen from these resources one needs to use sustainable energy sources like renewables and nuclear. A total of 24 options for sustainable hydrogen production are then identified. Sustainable water splitting is the most important method of hydrogen production. Five sustainable options are discussed to split water, which include electrolysis, high temperature electrolysis, pure and hybrid thermochemical cycles, and photochemical/radiochemical methods. Other 19 methods refer to extraction of hydrogen from other materials than water or in conjunction with water (e.g., coal gasification with CO₂ capture and sequestration). For each case the achievable energy and exergy efficiency of the method were estimated based on state of the art literature screening for each involved process. In addition, a range of hydrogen production capacity is determined for each of the option. For a transition period to hydrogen economy nuclear or solar assisted coal gasification and fossil fuel reforming technologies – with efficiencies of 10–55% including CO₂ sequestration – should be considered as a viable option. Other “ready to be implemented” technology is hydro-power coupled to alkaline electrolysers which shows the highest hydrogen generation efficiency amongst all electrical driven options with 60–65%. Next generation nuclear reactors as to be coupled with thermochemical cycles have the potential to generate hydrogen with 40–43% energy efficiency (based on LHV of hydrogen) and 35–37% exergy efficiency (based on chemical exergy of hydrogen). Furthermore, recycling anthropogenic waste, including waste heat, waste plastic materials, waste biomass and sewage waters, shows also good potential as a sustainable option for hydrogen production. Biomass conversion to hydrogen is found as potentially the most efficient amongst all studied options in this paper with up to 70% energy efficiency and 65% exergy efficiency.     

Synergistic roles of off-peak electrolysis and thermochemical production of hydrogen from nuclear energy in Canada

Hydrogen as a clean energy carrier is frequently identified as a major solution to the environmental problem of greenhouse gases, resulting from worldwide dependence on fossil fuels. However, most of the world's hydrogen (about 96%) is currently produced from fossil fuels, which does not address the issue of greenhouse gases. Although there is a large motivation of the “hydrogen economy”, for improvement of urban air quality, energy security, and integration of intermittent renewable energy sources, CO₂ free energy sources are critical to hydrogen becoming a significant energy carrier. Two technologies, applied in tandem, have a promising potential to generate hydrogen without leading to greenhouse gas emissions: 1) electrolysis and 2) thermochemical decomposition of water. This paper will investigate their unique complementary roles to reduce costs of hydrogen production. Together they have a unique potential to serve both de-centralized hydrogen needs in periods of low-demand electricity, and centralized base-load production from a nuclear station. Thermochemical methods have a significantly higher thermal efficiency, but electrolysis can take advantage of low electricity prices during off-peak hours, as well as intermittent and de-centralized supplies like wind, solar or tidal power. By effectively linking these systems, water-based production of hydrogen can become more competitive against the predominant existing technology, SMR (steam-methane reforming).     

Potential methods for geothermal-based hydrogen production

In this study, four potential methods are identified for geothermal-based hydrogen production, namely, (i) directly from the geothermal steam, (ii) through conventional water electrolysis using the electricity generated from geothermal power plant, (iii) using both geothermal heat and electricity for high temperature steam electrolysis and/or hybrid processes, (iv) using the heat available from geothermal resource in thermochemical processes to disassociate water into hydrogen and oxygen. Here we focus on relatively low-temperature thermochemical and hybrid cycles, due to their greater application possibility, and examine them as a potential option for hydrogen production using geothermal heat. We also present a brief thermodynamic analysis to assess their performance through energy and exergy efficiencies for comparison purposes. The results show that these cycles have good potential and become attractive due to the overall system efficiencies over 50%. The copper–chlorine cycle is identified as a highly promising cycle for geothermal hydrogen production. Furthermore, three types of industrial electrolysis methods, which are generally considered for hydrogen production currently, are also discussed and compared with the above mentioned cycles.     

Solar power tower as heat and electricity source for a solid oxide electrolyzer: a case study

High‐temperature steam electrolysis (HTSE) consists of the splitting of steam into hydrogen and oxygen at high temperature in solid oxide electrolyzers. Performing the electrolysis process at high temperatures offers the advantage of achieving higher efficiencies as compared to the conventional water electrolysis. Furthermore, this allows the direct use of process heat to generate steam. This paper is related to the FCH JU (Fuel Cells and Hydrogen Joint Undertaking) project ADEL (ADvanced ELectrolyser For hydrogen Production with Renewable Energy Sources), which investigates different carbon‐free energy sources to be coupled to the HTSE process. Renewable energy sources are able to provide the high‐temperature steam electrolysis (HTSE) process with heat and power. This paper investigates the capability of Concentrating Solar Power (CSP) technologies to provide the HTSE process with the necessary energy demand. The layout of the plant is shown in the following figure. The design of commercial‐scale high‐temperature steam electrolysis has been carried out. The HTSE plant is coupled to an air cooled solar tower. The configuration and the operating parameters of the solar tower are based on those of the solar tower of Jülich (Germany), which is operated by DLR. This paper presents the results of process analysis performed to evaluate the hydrogen production from a HTSE plant coupled to an 80MWth air solar tower. Additionally, the dynamic behavior of the system during energy fluctuations has been analyzed. The receiver‐to‐hydrogen efficiency (based on the Higher Heating Value of hydrogen) is 26% at a hydrogen production rate of 680 kg/h in steady‐state operation. The overall solar‐to‐hydrogen efficiency is calculated to be at 18%. Moreover, the analysis under transient conditions shows that a steady‐state operation of the plant is only possible for 8 h. Copyright © 2015 John Wiley & Sons, Ltd.     

Clean hydrogen production with the Cu-Cl cycle - Progress of international consortium, I: Experimental unit operations

Advancement of the thermochemical copper-chlorine (Cu-Cl) cycle for hydrogen production is reviewed and discussed in this paper. Individual unit operations and their linkage into an integrated cycle are being developed by a Canadian consortium, as part of the Generation IV International Forum (GIF) for hydrogen production with the next generation of nuclear reactors. This paper focuses on the consortium’s latest advances on the Cu-Cl cycle, particularly with respect to hydrogen production with Canada’s Generation IV reactor, called SCWR (Super-Critical Water Reactor). Other heat sources may also be utilized for the Cu-Cl cycle, such as solar energy or industrial waste heat. In this first of two companion papers, recent developments in Canada’s nuclear hydrogen program are reported, specifically unit operation experiments of the Cu-Cl cycle and system integration. The following second companion paper will present system modeling with Aspen Plus, corrosion resistant materials, thermochemistry, safety, and reliability aspects of the Cu-Cl cycle.     

Assessment of sustainable high temperature hydrogen production technologies

Apart from being a major feedstock for chemical production, hydrogen is also a very promising energy carrier for the future energy. Currently hydrogen is predominantly produced via fossil routes, but as green energy sources are gaining a larger role in the energy mix, novel and green production routes are emerging. The most abundant renewable hydrogen sources are water and biomass, which allow several possible processing routes, such as electrolysis, thermochemical cycles and gasification. By introducing heat to the process the required electricity demand can be reduced (high temperature electrolysis) or practically eliminated (thermochemical cycles). Each renewable hydrogen production route has its own strength and weaknesses; the choice of the most suitable method is always dependent on the economical potentials and the location. The aim of this paper is to evaluate the different high temperature, renewable hydrogen production technologies.     

Role of hydrogen in future North European power system in 2060

The Balmorel model has been used to calculate the economic optimal energy system configuration for the Scandinavian countries and Germany in 2060 assuming a nearly 100% coverage of the energy demands in the power, heat and transport sector with renewable energy sources. Different assumptions about the future success of fuel cell technologies have been investigated as well as different electricity and heat demand assumptions. The variability of wind power production was handled by varying the hydropower production and the production on CHP plants using biomass, by power transmission, by varying the heat production in heat pumps and electric heat boilers, and by varying the production of hydrogen in electrolysis plants in combination with hydrogen storage. Investment in hydrogen storage capacity corresponded to 1.2% of annual wind power production in the scenarios without a hydrogen demand from the transport sector, and approximately 4% in the scenarios with a hydrogen demand from the transport sector. Even the scenarios without a demand for hydrogen from the transport sector saw investments in hydrogen storage due to the need for flexibility provided by the ability to store hydrogen. The storage capacities of the electricity storages provided by plug-in hybrid electric vehicles were too small to make hydrogen storage superfluous.     

Turkey's industrial waste heat recovery potential with power and hydrogen conversion technologies: A techno-economic analysis

In this study an investigation of Turkey's overall industrial waste heat potential is conducted, and possible power and hydrogen conversion technologies are considered to produce useful energy such as power and hydrogen. The annual total industrial waste heat was has a 71 PJ in 2019 and is expected to double by 2050. The temperature range of the waste heat differs by sector at a large range of 50 °C–1000 °C. Absorption power cycle (APC), Organic Rankine Cycle (ORC), Steam Rankine cycle (SRC) and Gas Turbine (GT) systems are adapted for power production based on the waste heat temperature while electrochemical and electro-thermochemical hydrogen production systems are adapted for hydrogen generation. Proton Exchange Membrane, Alkaline, and high temperature steam electrolysis methods are selected for pure electrochemical conversion technologies and Hybrid Sulfur (HyS), Copper Chlorine (CuCl), Calcium–Bromine (CaBr), and Magnesium Chlorine (MgCl) cycles are utilized as hybrid thermochemical technologies. Many cases are formed, and best temperature matching power-hydrogen system couples are selected. It is possible to produce enough hydrogen to compensate up to 480 million m³ natural gas equivalents of hydrogen annually with selected technologies which corresponds to ~5% of residential natural gas consumption in Turkey. Economic analysis reveals that lowest hydrogen generation cost belongs to the GT-HyS system. When hydrogen is used for heating applications by a certain mixture fraction to NG pipelines, it may reduce more than 720 thousand tons of CO₂ reduction annually due to natural gas use.     

Optimized method for photovoltaic-water electrolyser direct coupling

Photovoltaics and electrolyser coupling is one of the most promising options for obtaining hydrogen from a renewable energy source. Both are well known technologies and direct coupling is possible; however, due to high variability of the solar radiation, an efficient relative sizing still presents some challenges. In fact, relative sizing is always a key issue when coupling renewable electric sources to water electrolysers. Few previous works addressed the relative sizing and an easy and efficient method is still missing. This work presents a new method for relative sizing between both components based on simple modelling of both polarisation curves. Modelling and simulation is used for extracting a cloud of maximum power points at all the radiation and temperature conditions for a normalised PV generator. Then, the ideal ratio between the size of components is obtained by fitting a normalised polarisation curve for the electrolyser to this cloud of maximum power points. PV generator and PEM electrolyser models are proposed and the method is applied, as example, to two different PEM water electrolysers. The method helps the relative sizing issue for designing solar hydrogen production systems based on water electrolysis, because it is derived from manufacturer parameters and the used of uncomplicated numerical methods.     

A techno-economic appraisal of hydrogen generation and the case for solid oxide electrolyser cells

There is significant interest in alternatives to fossil fuels in order to reduce carbon dioxide emissions. One option is the use of hydrogen in applications such as fuel cells. There are various routes to the production of hydrogen, one being via the electrolysis of water. Water electrolysers are already operational within industry on a small-scale, accounting for 4% of world hydrogen production. These electrolysers operate at low temperatures and require electrical power input that has been shown to be costly due to the limited efficiency of the electrolysis process. However, the use of high temperature solid oxide electrolyser cells (SOECs) has the potential to generate hydrogen with a higher electrical efficiency which may allow electrolysis to become cost competitive with steam methane reforming (SMR), depending on where the heat and electrical power to service the SOEC comes from.This paper examines the various routes to hydrogen production and, in particular electrolysis technologies. The cost of hydrogen production is examined in the context of the source of the electricity and the efficiency of the electrolysis process compared to SMR generation. It is found that to become cost competitive with SMR, the lowest cost electricity is required, sourced either from nuclear or combined cycle gas turbine plants with electrolysis efficiency as high as possible, meaning that SOEC technology is particularly attractive.     

Canada’s program on nuclear hydrogen production and the thermochemical Cu–Cl cycle

This paper presents an overview of the status of Canada’s program on nuclear hydrogen production and the thermochemical copper–chlorine (Cu–Cl) cycle. Enabling technologies for the Cu–Cl cycle are being developed by a Canadian consortium, as part of the Generation IV International Forum (GIF) for hydrogen production with the next generation of nuclear reactors. Particular emphasis in this paper is given to hydrogen production with Canada’s Super-Critical Water Reactor, SCWR. Recent advances towards an integrated lab-scale Cu–Cl cycle are discussed, including experimentation, modeling, simulation, advanced materials, thermochemistry, safety, reliability and economics. In addition, electrolysis during off-peak hours, and the processes of integrating hydrogen plants with Canada’s nuclear plants are presented.