Assessing techno-economic uncertainties in nuclear power-to-X processes: The case of nuclear hydrogen production via water electrolysis

Nuclear assisted low carbon hydrogen production by water electrolysis represents a potential application of nuclear cogeneration towards deep decarbonization of several fossil fuel-dependent industrial sectors. This work builds a probabilistic techno-commercial model of a water electrolysis plant coupled to an existing nuclear reactor for base load operations. The objective is to perform discounted cash flow (DCF) calculations for levelized nuclear hydrogen production cost under input parameter uncertainty. The probability distributions of inputs are used with the Monte Carlo-Latin Hypercube (MC-LH) sampling technique to generate 10⁵ input scenarios and corresponding distribution of the levelized or life cycle hydrogen production cost instead of deterministic point values. Based on current techno-economic conditions, the levelized production costs of electrolytic hydrogen using electricity from large water-cooled nuclear reactors are determined to be US $ 12.205 ± 1.342, 8.384 ± 1.148 and 6.385 ± 1.051/kg H₂ respectively at rated alkaline water electrolyser capacities of 1.25 MW(e), 2.5 MW(e) and 5 MW(e). The corresponding values for PEM water electrolysers are US $ 13.162 ± 1.356, 8.891 ± 1.141 and 6.663 ± 1.057/kg H₂. The potential for flexible nuclear reactor operation and management of power demand uncertainties through nuclear hydrogen cogeneration is also examined through a case study.     

A well to pump life cycle environmental impact assessment of some hydrogen production routes

In the present study, a comparative well to pump life cycle assessment is conducted on the hydrogen production routes of water electrolysis, biomass gasification, coal gasification, steam methane reforming, hydrogen production from ethanol and methanol. The CML 2001 impact assessment methodology is employed for assessment and comparison. Comparatively higher life cycle Carbon dioxide and Sulphur oxide emissions of 27.3 kg/kg H₂ and 50.0 g/kg H₂ respectively are determined for the water electrolysis hydrogen production route via U.S. electricity mix. In addition, the life cycle global warming potential of this route (28.6 kg CO_2eq/kg H₂) is found to be comparatively higher than other routes followed by coal gasification (23.7 kg CO_2eq/kg H₂)_. However, the ethanol based hydrogen production route is estimated to have comparatively higher life cycle emissions of nitrogen dioxide (19.6 g/kg H₂) and volatile organic compounds (10.3 g/kg H₂). Moreover, this route is determined to have a comparatively higher photochemical ozone creation potential of 0.0045 kg-ethene_eq/kg H₂ as well as eutrophication potential of 0.0043 kg PO_4eq/kg H_2. The results of this study are comparatively discussed to signify the importance of life cycle assessment in comparing the environmental sustainability of hydrogen production routes.     

The role of hydrogen in the road transportation sector for a sustainable energy system: A case study of Korea

This study analyzes the impact of the introduction of hydrogen as fuel in the road transportation sector of Korea. Since this sector is completely dependent on petroleum and alternative technologies such as fuel cell vehicles, hydrogen is one alternative fuel that could meet the challenges that Korea is facing due to rising oil prices. This study uses a scenarios-based energy economic model including the hydrogen path way as a sub-energy system to explore the energy system of Korea through 2044. This study also constructs six scenarios consisting of three government policies concerning carbon dioxide reduction and two oil price scenarios in order to assess the impact on hydrogen as fuel in the road transportation sector. The results of this study show that in a particular case (high Btu tax and oil prices) the share of hydrogen would reach 76% of the road transportation sector, and hydrogen would be produced mainly from renewable and nuclear resources via electrolysis facilities. It is also revealed that hydrogen is effective at reducing carbon dioxide, improving energy efficiency and contributing to the energy security of Korea.     

Development and techno-economic analyses of a novel hydrogen production process via chemical looping

In this work, a novel hydrogen production process (Integrated Chemical Looping Water Splitting “ICLWS”) has been developed. The modelled process has been optimised via heat integration between the main process units. The effects of the key process variables (i.e. the oxygen carrier-to-fuel ratio, steam flow rate and discharged gas temperature) on the behaviour of the reducer and oxidiser reactors were investigated. The thermal and exergy efficiencies of the process were studied and compared against a conventional steam-methane reforming (SMR) process. Finally, the economic feasibility of the process was evaluated based on the corresponding CAPEX, OPEX and first-year plant cost per kg of the hydrogen produced. The thermal efficiency of the ICLWS process was improved by 31.1% compared to the baseline (Chemical Looping Water Splitting without heat integration) process. The hydrogen efficiency and the effective efficiencies were also higher by 11.7% and 11.9%, respectively compared to the SMR process. The sensitivity analysis showed that the oxygen carrier–to-methane and -steam ratios enhanced the discharged gas and solid conversions from both the reducer and oxidiser. Unlike for the oxidiser, the temperature of the discharged gas and solids from the reducer had an impact on the gas and solid conversion. The economic evaluation of the process indicated hydrogen production costs of $1.41 and $1.62 per kilogram of hydrogen produced for Fe-based oxygen carriers supported by ZrO₂ and MgAl₂O₄, respectively - 14% and 1.2% lower for the SMR process H₂ production costs respectively.     

Tech-eco Efficiency Evaluation of hydrogen production industry under carbon dioxide Emissions regulation in China

This study introduces the concept of non-separable variables, and conducts a super-efficiency slack-based measure (SBM) model considered undesirable output variable to evaluate the economic and technical efficiencies of 15 hydrogen production methods in China. The results show that the average technical efficiency and scale efficiency values of hydrogen production industry are 0.438 and 0.352, respectively, which are relevantly low. The average pure technical efficiency value is 1.090. When the strong carbon constraint is introduced, the average technical efficiency and pure technical efficiency values of hydrogen production industry are increased by about 12.3% and 22.2%, respectively, but the average scale efficiency is reduced by 1.7%. The coal-to-hydrogen production with carbon capture, utilization and storage (CCUS) technology produces the highest technical efficiency, and the technical efficiency value and pure technical efficiency value are 1.435 and 1.679, respectively. The scale efficiency value of hydrogen production from chlor-alkali is 0.951, which is the most effective scale among all measured hydrogen production processes. The methanol-to-hydrogen production also performs great. However, hydrogen production by water electrolysis does not have the advantages of economic nor technical efficiencies. The results of the input-output slack of 15 hydrogen production methods show that the excessive production inputs and carbon dioxide emission are the main reasons for the poor efficiency evaluation results of most hydrogen production methods. The CO₂ emission regulation reduces the redundancy of the cost, comprehensive energy consumption and CO₂ emissions of 13 hydrogen production processes by more than four times, which affected the technical efficiency and the scale efficiency of hydrogen production industry. It indicates that CO₂ emission regulation has improved the economic and technical efficiency of hydrogen production processes in China.     

A techno-economic evaluation of the hydrogen production for energy generation using an ethanol fuel processor

The techno-economic analysis of a process to convert ethanol into H₂ to be used as a fuel for PEM fuel cells of H₂-powered cars was done. A plant for H₂ production was simulated using experimental results obtained on monolith reactors for ethanol steam reforming and WGS steps. The steam reforming (Rh/CeSiO₂) and WGS (Pt/ZrO₂) monolith catalysts remained quite stable during long-term startup/shut down cycles, with no carbon deposition. The H₂ production cost was significantly affected by the ethanol price. The monolith catalyst costs contribution was lower than that of conventional reactors. The H₂ production cost obtained using the expensive Brazilian ethanol price (0.81 US$/L ethanol) was US$ 8.87/kg H₂, which is lower than the current market prices (US$ 13.44/kg H₂) practiced at H₂ refueling stations in California. This result showed that this process is economically feasible to provide H₂ as a fuel for H₂-powered cars at competitive costs in refueling stations.     

Partial substitution of hydrogen for conventional fuel in an aircraft by utilizing unused cargo compartment space

Options are being actively sought in aviation to switch from petroleum-based fuels to alternative fuels, of which hydrogen is a promising candidate, despite challenges associated with its production and storage. The possibility is demonstrated in this study of using hydrogen in place of some mission fuel without making substantial aircraft modifications and while utilizing only available unused baggage space in the lower-deck cargo compartments of aircraft. The environmental impact reduction and weight increase are obtained accounting for a broad range of factors including aircraft model, seat capacity, passenger and baggage load factors, annual landing and take off cycles, container type, and costs of metal hydride and gaseous hydrogen storage units of various sizes. It is found that, while there may be a cost increase, CO₂ emissions are substantially reduced, by 25,000–570,000 tonnes annually in several cases and by up to 1.1 million tonnes annually for the 10 types of aircraft considered. It is also determined that with present technology, despite the low density of hydrogen, the weight of storage systems constitutes more of a challenge than their volume in aviation. Large-body aircraft are found to have more difficulties than the narrow-body aircraft regarding storage system weight. For the most frequently used narrow- and large-body aircraft considered, the number of the available containers within the required limits of weight and volume respectively are found to be 3 and 4 for the B 737-800 aircraft and 2 and 10 for the A 340-300 aircraft. Overall, the combined usage of hydrogen and kerosene investigated here may be feasible in the future, but is a challenging option with present technology and aircraft due to various factors.     

Analytical model for a techno-economic assessment of green hydrogen production in photovoltaic power station case study Salalah city-Oman

Hydrogen energy will play a credible role to reduce gas emissions in the transportation sector, the storage of energy, and other industrial applications. Moreover, the hydrogen produced from renewable energy sources allows to minimize greenhouse gas and increase the net profit of energy projects. This paper discusses the feasibility of the conversion of solar energy into hydrogen in a Photovoltaic Hydrogen Station (PVHS) in the south of Oman. Then, the sizing of different equipment and hydrogen production estimation in a 5 MWp PVHS is presented. The analysis of the investment cost (IC), the Net Profit (NP), and the Levelized Hydrogen Energy Cost (LHEC) are discussed to investigate the benefit of the project. The energy generated from the PV system and the produced hydrogen is calculated through an analytical model. The PVHS consists of 5 MWp PV panels connected to electrolyzers through maximum power point-controlled converters. The electrolyzers convert the electrical energy and the water into hydrogen. The hydrogen compressed and stored in special tanks can be used later in many industrial applications. The system produces about 90 910 kg of hydrogen per year with an IC of 5 301 760 €. The calculated LHEC is equal to 6.2 €/kg at an interest rate of 2%. The analysis has shown promising green hydrogen production projects in Oman.     

Production of hydrogen and carbon in the petrochemical industry by cracking of hydrocarbons in the process of heat utilization in steel production

Preliminary calculations suggest that 530 million tons of hydrogen can be obtained from the utilization of heat from blast-furnace and converter processes in the global steel production, which is approximately 8 times higher than the current annual production of hydrogen (75 million tons).Mankind, already now, by introducing everywhere the technology of utilizing the heat of cooling steel for the pyrolysis of methane, can achieve an 8-fold excess of world hydrogen production.To date, the use of heat from metallurgical processes (steel) for methane pyrolysis using all available possibilities for the maximum high-quality and relatively cheap separation of methane into soot and hydrogen is an important tactical task. In the process of globally organized petrochemical production of hydrogen by cracking methane in the steelmaking process, it is possible to arrange the production of high-purity hydrogen and high-purity carbon for further synthesis of tubulenes, graphene-like and fullerene-like materials. However, the following tasks stand in the way of this problem: 1) careful study of the behavior of saturated hydrocarbons, including methane at near-critical parameters and supercritical parameters, 2) organization of the optimal process for removing soot (carbon) from a catalytic cracking processor, 3) profiling the optimal design of catalytic cracking – processor.     

Solar hydrogen production from the thermal splitting of methane in a high temperature solar chemical reactor

This study addresses the single-step thermal decomposition (pyrolysis) of methane without catalysts. The process co-produces hydrogen-rich gas and high-grade carbon black (CB) from concentrated solar energy and methane. It is an unconventional route for potentially cost effective hydrogen production from solar energy without emitting carbon dioxide since solid carbon is sequestered.A high temperature solar chemical reactor has been designed to study the thermal splitting of methane for hydrogen generation. It features a nozzle-type graphite receiver which absorbs the solar power and transfers the heat to the flow of reactant at a temperature that allows dissociation. Theoretical and experimental investigations have been performed to study the performances of the solar reactor. The experimental set-up and effect of operating conditions are described in this paper. In addition, simulation results are presented to interpret the experimental results and to improve the solar reactor concept. The temperature, geometry of the graphite nozzle, gas flow rates, and CH₄ mole fraction have a strong effect on the final chemical conversion of methane. Numerical simulations have shown that a simple tubular receiver is not enough efficient to heat the bulk gas in the central zone, thus limiting the chemical conversion. In that case, the reaction takes place only within a thin region located near the hot graphite wall. The maximum CH₄ conversion (98%) was obtained with an improved nozzle, which allows a more efficient gas heating due to its higher heat exchange area.     

A comparison of two hydrogen storages in a fossil-free direct reduced iron process

Hydrogen direct reduction has been proposed as a means to decarbonize primary steelmaking. Preferably, the hydrogen necessary for this process is produced via water electrolysis. A downside to electrolysis is the large electricity demand. The electricity cost of water electrolysis may be reduced by using a hydrogen storage to exploit variations in electricity price, i.e., producing more hydrogen when the electricity price is low and vice versa. In this paper we compare two kinds of hydrogen storages in the context of a hydrogen direct reduction process via simulations based on historic Swedish electricity prices: the storage of gaseous hydrogen in an underground lined rock cavern and the storage of hydrogen chemically bound in methanol. We find the methanol-based storages to be economically advantageous to lined rock caverns in several scenarios. The main advantages of methanol-based storage are the low investment cost of storage capacity and the possibility to decouple storage capacity from rate capacity. Nevertheless, no storage option is found to be profitable for historic Swedish electricity prices. For the storages to be profitable, electricity prices must be volatile with relatively frequent high peaks, which has happened rarely in Sweden in recent years. However, such scenarios may become more common with the expected increase of intermittent renewable power in the Swedish electricity system.     

Application of gas-turbine exhaust gases for brackish water desalination: a techno-economic evaluation

During the last 20 years, the electricity generation system of Crete Island has been actually based on the operation of several gas-turbines, presenting an annual utilization factor higher than 50%. Despite the undeniable advantages of modern gas-turbines, one cannot disregard the huge quantities of hot exhausted gases produced, containing almost two thirds of the chemical energy of fuel consumed. On the other hand, the island faces serious water resources insufficiency problems, especially during hot periods of the year. In this context, the island electricity generation utility (Public Power Corporation (PPC)) is planning to allocate the so far unexploited exhausted gases of a recently installed gas-turbine (LM-6000) at the Linoperamata–Heraklion power station to the neighboring municipality of Gaziou. The main idea elaborated in the present study is the techno-economic evaluation of a new desalination plant, utilizing a thermal desalination process and taking advantage of the heat content of the above-mentioned gas-turbine. According to the results obtained, it is almost certain that the proposed desalination plant is able to produce an amount of clean water adequate to cover the local habitants' needs at a moderate cost, not only saving almost 15,000 tones of imported oil per year but also alleviating the local environment from several flue gases.     

Sustainable hydrogen production from steam reforming of bio-oil model compound based on carbon deposition/elimination

Steam reforming of crude bio-oil or some heavy component present in bio-oil is a great challenge for sustainable hydrogen production due to the extensive coke formation and catalyst deactivation. Catalyst regeneration will be an unavoidable operation in this process. In this paper, m-cresol (a model compound derived from bio-oil) was steam reformed on commercial Ni-based catalyst. Two conventional carbon elimination methods for coked catalyst were applied and the results showed that sustainable hydrogen production can be obtained based on carbon deposition/elimination. The carbon deposition can be gasified easily under certain temperature. The activity of regenerated catalyst samples can be nearly recovered as the fresh ones. Under the reaction conditions of 850 °C and steam to carbon ratio 5:1, >66% hydrogen mole fraction, >81% hydrogen yield, and >97% carbon conversion can be achieved based on regenerated catalyst. Catalyst characterization indicated that the loss of active metal can be considered as the main reason for tiny activity drop. Ni redispersion and Fe contamination may be another two factors that influence catalyst activity.     

Techno-economic analysis of a hybrid energy system for CCHP and hydrogen production based on solar energy

A typical problem in Northeast China is that a large amount of surplus electricity has arisen owing to the serious photovoltaic power curtailment phenomenon. To effectively utilize the excess photovoltaic power, a hybrid energy system is proposed that uses surplus electricity to produce hydrogen in this paper. It combines solar energy, hydrogen production system, and Combined Cooling Heating and Power (CCHP) system to realize cooling, heating, power, and hydrogen generation. The system supplies energy for three public buildings in Dalian City, Liaoning Province, China, and the system configuration with the lowest unit energy cost (0.0615$/kWh) was obtained via optimization. Two comparison strategies were used to evaluate the hybrid energy system in terms of unit energy cost, annual total cost, fossil energy consumption, and carbon dioxide emissions. Subsequently, the annual total energy supply, typical daily loads, and cost of the optimized system were analyzed. In conclusion, the system is feasible for small area public buildings, and provides a solution to solve the phenomenon of photovoltaic power curtailment.     

A techno-economic analysis of decentralized electrolytic hydrogen production for fuel cell vehicles

Hydrogen from decentralized water electrolysis is one of the main fuelling options considered for future fuel cell vehicles. In this study, a model is developed to determine the key technical and economic parameters influencing the competitive position of decentralized electrolytic hydrogen. This model incorporates the capital, maintenance and energy costs of water electrolysis, as well as a monetary valuation of the associated greenhouse gas (GHG) emissions. It is used to analyze the competitive position of electrolytic hydrogen in three specific locations with distinct electricity mix: Vancouver, Los Angeles and Paris. Using local electricity prices and fuel taxes, electrolytic hydrogen is found to be commercially viable in Vancouver and Paris. Hydrogen storage comes out as the most important technical issue. But more than any technical issue, electricity prices and fuel taxes emerge as the two dominant issues affecting the competitive position of electrolytic hydrogen. The monetary valuation of GHG emissions, based on a price of $20/ton of CO₂, is found to be generally insufficient to tilt the balance in favor of electrolytic hydrogen.     

Cost evaluation of two potential nuclear power plants for hydrogen production

Hydrogen is recognized as one of the most promising alternative fuels to meet the energy demand for the future by providing a carbon-free solution. In regards to hydrogen production, there has been increasing interest to develop, innovate and commercialize more efficient, effective and economic methods, systems and applications. Nuclear based hydrogen production options through electrolysis and thermochemical cycles appear to be potentially attractive and sustainable for the expanding hydrogen sector. In the current study, two potential nuclear power plants, which are planned to be built in Akkuyu and Sinop in Turkey, are evaluated for hydrogen production scenarios and cost aspects. These two plants will employ the pressurized water reactors with the electricity production capacities of 4800 MW (consisting of 4 units of 1200 MW) for Akkuyu nuclear power plant and 4480 MW (consisting of 4 units of 1120 MW) for Sinop nuclear power plant. Each of these plants are expected to cost about 20 billion US dollars. In the present study, these two plants are considered for hydrogen production and their cost evaluations by employing the special software entitled “Hydrogen Economic Evaluation Program (HEEP)” developed by International Atomic Energy Agency (IAEA) which includes numerous options for hydrogen generation, storage and transportation. The costs of capital, fuel, electricity, decommissioning and consumables are calculated and evaluated in detail for hydrogen generation, storage and transportation in Turkey. The results show that the amount of hydrogen cost varies from 3.18 $/kg H₂ to 6.17 $/kg H₂.     

Prospects of green hydrogen in Poland: A techno-economic analysis using a Monte Carlo approach

The European Commission's plan to decarbonize the economy using innovative energy carriers has brought into question whether the national targets for developing electrolysis technologies are sufficiently ambitious to establish a local hydrogen production industry. While several research works have explored the economic viability of individual green hydrogen production and storage facilities in the Western European Member States, only a few studies have examined the prospects of large-scale green hydrogen production units in Poland. In this study, a Monte Carlo-based model is proposed and developed to investigate the underlying economic and technical factors that may impact the success of the Polish green hydrogen strategy. Moreover, it analyzes the economics of renewable hydrogen at different stages of technological development and market adoption. This is achieved by characterizing the local meteorological conditions of Polish NUTS-2 regions and comparing the levelized cost of hydrogen in such regions in 2020, 2030, and 2050. The results show the geographical locations where the deployment of large-scale hydrogen production units will be most cost effective.     

Thermodynamic evaluation of hydrogen production from methane

Exergetic and energetic analysis has been utilized to estimate the effect of process design and conditions on the hydrogen purity and yield, exergetic efficiencies and CO₂ avoided. Methane was chosen as a model compound for evaluating single stage separation. Simple steam reforming was considered as the base – case system. The other chemical processes that were considered were steam reforming with CO₂ capture with and without chemical looping of a reactive carbon dioxide removal agent, and steam gasification with both the Boudouard reaction catalyst and the reactive carbon dioxide removal agent with and without the solids regeneration. The information presented clearly demonstrates the differences in efficiencies between the various chemical looping processes for hydrogen generation. The incremental changes in efficiencies as a function of process parameters such as temperature, steam amount, chemical type and amount were estimated. Energy and exergy losses associated with generation of syngas, separation of hydrogen from CO_x as well as exergetic loss associated with emissions are presented. The optimal conditions for each process by minimizing these losses are presented. The majority of the exergy destruction occurs due to the high irreversibility of chemical reactions. The results of this investigation demonstrate the utility of exergy analysis. The paper provides a procedure for the comparison of various technologies for the production of hydrogen from carbon based materials based on First and Second Law Analysis. In addition, two figures of merit, namely the comparative advantage factor and the sustainable advantage factor have been proposed to compare the various hydrogen production methods using carbonaceous fuels.     

Renewable hydrogen production: A techno-economic comparison of photoelectrochemical cells and photovoltaic-electrolysis

The present paper reports a techno-economic analysis of two solar assisted hydrogen production technologies: a photoelectrochemical (PEC) system and its major competitor, a photovoltaic system connected to a conventional water electrolyzer (PV-E system). A comparison between these two types was performed to identify the more promising technology based on the levelized cost of hydrogen (LCOH). The technical evaluation was carried out by considering proven designs and materials for the PV-E system, and a conceptually design for the PEC system extrapolated to future, commercial scale.The LCOH for the off-grid PV-E system was found to be 6.22 $/kg_H2, with a solar to hydrogen efficiency of 10.9%. For the PEC system, with a similar efficiency of 10%, the LCOH was calculated to be much higher, namely 8.43 $/kg_H2. A sensitivity analysis reveals a great uncertainty in the LCOH of the prospective PEC system. This implies that much effort would be needed for this technology to become competitive on the market.Therefore we conclude that the potential techno-economic benefits that PEC systems offer over PV-E are uncertain, and even in the best case, limited. While research into photoelectrochemical cells remains of interest, it presents a poor case for dedicated investment in the technology's development and scale-up.     

Comparative techno-economic assessment of a large-scale hydrogen transport via liquid transport media

A large-scale point to point hydrogen transport is one strategy for a prospective energy import scenario for certain countries. The case for a hydrogen transport from Australia to Japan has been addressed in several studies. However, most studies lack transparency and detailed insights into the made assumptions thus a fair evaluation of different transport pathways is challenging. To address this issue, we developed a model where a large-scale point to point hydrogen transport of liquid hydrogen is compared with the transport via liquid organic hydrogen carrier (LOHC), namely via methyl cyclohexane and hydrogenated dibenzyl toluene. We analyzed, where energy is required along the different pathways, where hydrogen losses do occur and how the costs are put together. Furthermore, the influence of hydrogen feed costs is also considered. For hydrogen production costs of 5 €₂₀₁₈/kg_H2 the total delivery costs are in the range of 6.40– 8.10 €₂₀₁₈/kg_H2.