High Temperature Steam Electrolysis Research Articles

Techno-Economic Analysis of Heat-Assisted Hydrogen Production from Nuclear Power

To play a full role in decarbonisation, hydrogen must be produced economically at scale; the role of nuclear power is interesting to national governments as it is capable of supplying both low-carbon electricity and high-quality heat. Depending on the hydrogen production technology choice, a plant may require electricity and/or heat input. This techno-economic evaluation considers not only the costs of the hydrogen plant itself but also the costs of the power supply it requires. This paper calculates cost estimates for HTSE (High Temperature Steam Electrolysis) coupled with nuclear heat and electricity, and a thermochemical SI (Sulphur Iodine) cycle coupled with nuclear heat, based on the predictions of technical process models. These estimates are then compared to estimates made elsewhere for the costs of using wind with low temperature liquid water electrolysis, and steam methane reformation with carbon capture. This analysis led to the identification of the conditions under which nuclear-heat-coupled hydrogen production would be competitively priced. Estimates for nuclear-coupled LCOH2 (levelised cost of hydrogen) in 2050 range from 2.14 to 1.24 £/kg for HTSE, and from 2.88 to 0.89 £/kg for the SI cycle. There is still a great deal of uncertainty around the efficiency of SI and how it may improve over time, and this limits the accuracy to which the LCOH2 can be predicted.

Design of an integrated system for electrofuels production through Fischer-tropsch process

There has been a growing recognition in recent years that Electrofules (e-fuels), also known as renewable and sustainable fuels, which are produced from hydrogen and carbon dioxide as the primary feedstocks, have great potential to reduce carbon footprint and address climate change. In the present study, contrary to most previous studies in which the sources of feedstock's preparation were considered as block boxes, two stand-alone processes are taken into account and incorporated into the e-fuels production system. H2 is obtained by a high-temperature electrolysis system having an overall efficiency nearly twice that of a low-temperature electrolysis system. CO2 is captured from a power plant flue gas stream with a purity of 99.81%. Investigating heat integration potential in such an integrated plant is an up-to-date and interesting topic and has not yet been well explored. Therefore, a heat integration within the three individual processes is implemented to reduce energy consumption. The design of the process-to-process heat transfer section is carried out using pinch design rules. By integrating individual units, approximately 42% of the required cold utility, traditionally supplied by chilled water and refrigerants, is allocated to generate high and medium-pressure steams. Having used the high-temperature steam electrolysis for H2 production, a process that requires less external electricity compared to low-temperature water electrolysis, a power-to-liquid efficiency of 70% is achieved. Furthermore, the results reveal a carbon conversion ratio of 98.6%, indicating the effective converting the carbon from the feedstock into liquid hydrocarbons.

Electrolysis-boosted substitute natural gas from biomass: Kinetic modeling of fluidized bed gasification and system integration

The present work deals with the modeling of electrolysis-boosted biomass gasification for the production of green synthetic methane (or substitute natural gas) with a composition that enables its potential injection into the natural gas distribution grid.A kinetic and hydrodynamic model has been built to simulate a bubbling fluidized bed reactor using a mixture of steam and oxygen as gasifying agent. The model was firstly validated by comparing it with experimental results available in the open literature. Outlet temperature spans from about 730 to 1060 °C depending on the used amount of oxygen and steam within the gasifying agent, expressed through parameters like equivalence ratio and steam-to-biomass ratio.Then, process modeling for the integration between biomass gasification and high-temperature steam electrolysis has been carried out. Electrolysis has been sized to enrich the hydrogen content of the syngas, enabling a stoichiometric composition in terms of hydrogen, carbon monoxide, and carbon dioxide for the subsequent catalytic methane synthesis via carbon oxides hydrogenation. Thermal integration has been carefully designed to improve the overall process efficiency up to about 71 % (based on lower heating value of both biomass and substitute natural gas).

Dynamic Modeling of a Solar-To-Hydrogen Flexible High Temperature Steam Electrolysis Plant

Sustainble hydrogen production for use as a renewable combustible fuel and clean chemical feedstock is an important objective as the world moves towards a renewable energy future. High temperature steam electrolysis is a promising hydrogen production technology due to its reduced electric input that is offset by heat input into steam generation and steam superheating. An option to provide this heat is to use concentrating solar thermal technology that can sustainably provide heat input while renewable electricity is used for the electrolysis reaction. In this work, a solar-to-hydrogen high temperature steam electrolysis plant is designed and dynamically modeled, showing continuous hydrogen production by utilizing supplemental heating and efficient recuperative heating from the electrolysis product streams. Through this design, over 90% of the required heat input for the process can by met by a combination of solar and recuperative heat. Additionally, the plant can flexibility operate by ramping down hydrogen production and through flexible heat integration, which intelligently integrates solar heat based on solar conditions. Smooth operation with flexible hydrogen production is demonstrated which decreases electrical input during on-peak grid times and also decreases the total supplemental heat load over the course of a day from 26.1% to 24.5%. In addition, by using flexible heat integration, the plant can increase its solar heat usage by 4.1% relative to a base case. Both options for flexibility show efficient use of solar thermal energy to sustainably and continuously produce hydrogen.

Hybrid systems design for blue and green hydrogen co-production: Integration of autothermal reforming with solid oxide electrolysis

Hydrogen is a clean and sustainable energy alternative to fossil fuels. Current hydrogen production methods are carbon intensive; hence, developing low-carbon hydrogen production methods is important. Among various production technologies, autothermal reforming (ATR) and solid oxide electrolysis (SOEC) are considered promising in terms of energy efficiency. However, there are several limitations: (i) ATR requires an air separation unit that consumes a large amount of energy, and (ii) SOEC, high-temperature steam electrolysis requires an electric resistance heater. To address these limitations, this study proposes a hybrid system of ATR integrated with SOEC. In the hybrid system, waste steam and heat in the ATR process are provided for the SOEC process, whereas the oxygen by-product in the SOEC process is supplied to the ATR process. In particular, the hybrid system where SOEC-generated oxygen completely satisfies the ATR reaction’s oxygen demand exhibits the best thermodynamic and economic performance. This system represents a 28.6% reduction in power consumption compared to a stand-alone system that independently produces blue and green hydrogen. In addition, it exhibits enhanced economic performance with a levelized cost of hydrogen of 5.28 $/kg, which is 1.22 $/kg lower than that of the stand-alone system.

Techno-economic analysis of direct air carbon capture and hydrogen production integrated with a small modular reactor

This study aims to explore the techno-economic potential of harnessing waste heat from a Small Modular Reactor (SMR) to fuel Direct Air Carbon Capture (DACC) and High Temperature Steam Electrolysis (HTSE) technologies. The proposed system's material flows, and energy demands are modelled via the ASPEN Plus v12.1 where results are utilised to provide estimates of the Levelised Cost of DACC (LCOD) and Levelised Cost of Hydrogen (LCOH). The majority of thermal energy and electrical utilities are assumed to be supplied directly by the SMR. A sensitivity analysis is then performed to investigate the effects of core operational parameters of the system. Key results indicate levelised costs of 4.66 $/kgH2 at energy demands of 34.37 kWh/kgH2 and 0.02 kWh/kgH2 thermal for HTSE hydrogen production, and 124.15 $/tCO2 at energy demands of 31.67 kWh/tCO2 and 126.33 kWh/tCO2 thermal for carbon capture; parameters with most impact on levelised costs are air intake and steam feed for LCOD and LCOH, respectively. Both levelised costs, i.e., LCOD and LCOH would decrease with the production scale. The study implies that an integrated system of DACC and HTSE provided the best cost-benefit results, however, the cost-benefit analysis is heavily subjective to geography, politics, and grid demand.

Hydrogen from solar? A rigorous analysis of solar energy integration concepts for a high temperature steam electrolysis plant

Hydrogen from solar? A rigorous analysis of solar energy integration concepts for a high temperature steam electrolysis plant

Economic evaluation of hydrogen production in second and third units of Bushehr nuclear power plant regarding future need of nuclear fission technology

Today, the most important challenge for hydrogen production is the use of suitable energy source for sustainable production. The dual use of nuclear power plants allows them to expand into other markets by eliminating greenhouse gas emissions from processes such as hydrogen production. The significance of this matter especially in countries with ongoing new nuclear power plants is high and shows the future need for nuclear fission technology. In this paper, an economic assessment of hydrogen production in the second and third units of the Bushehr nuclear power plant (BNPP) with the Hydrogen Economy Evaluation Program (HEEP) is carried out and a comparison of CO2 emission in nuclear and non-nuclear methods of hydrogen production is presented. Most nuclear reactors, including Advanced Pressurized WaterReactor (APWR), High Temperature Gas Reactor (HTGR), and Water-Water EnergeticReactor (WWER), can be used as a source of thermal and electrical energy for the process of hydrogen production. In this research, hydrogen production processes based on the Conventional Electrolysis (CE), High Temperature Steam Electrolysis (HTSE), and Sulfur-Iodine (SI) Process using different storage and transportation options are compared to choose the cost-effective method for coupling with the WWER1000 reactor. Hydrogen production, thermal energy, and electricity costs have been calculated and explained in detail. The results showed that the cost-effective option for hydrogen production is using the High Temperature Steam Electrolysis (HTSE) method, Compressed Gas (CG) storage, and pipeline transportation, by 2.88 $/kg. Also, applying this method to produce hydrogen, the nuclear power plant thermal efficiency, and the hydrogen plant efficiency are kept in the best possible conditions by 51.98% and 58.21%, respectively.

Engineering-Scale Integrated Energy System Data Projection Demonstration via the Dynamic Energy Transport and Integration Laboratory

The objective of this study is to demonstrate and validate the Dynamic Energy Transport and Integration Laboratory (DETAIL) preliminary scaling analysis using Modelica language system-code Dymola. The DETAIL preliminary scaling analysis includes a multisystem integral scaling package between thermal-storage and hydrogen-electrolysis systems. To construct the system of scaled equations, dynamical system scaling (DSS) was applied to all governing laws and closure relations associated with the selected integral system. The existing Dymola thermal-energy distribution system (TEDS) facility and high-temperature steam electrolysis (HTSE) facility models in the Idaho National Laboratory HYBRID repository were used to simulate a test case and a corresponding scaled case for integrated system HYBRID demonstration and validation. The DSS projected data based on the test-case simulations and determined scaling ratios were generated and compared with scaled case simulations. The preliminary scaling analysis performance was evaluated, and scaling distortions were investigated based on data magnitude, sequence, and similarity. The results indicated a necessity to change the normalization method for thermal storage generating optimal operating conditions of 261 kW power and mass flow rate of 6.42 kg/s and the possibility of reselecting governing laws for hydrogen electrolysis to improve scaling predictive properties. To enhance system-scaling similarity for TEDS and HTSE, the requirement for scaling validation via physical-facility demonstration was identified.

Electrochemical performance and stability of PrO1.833 as an oxygen electrode for solid oxide electrolysis cells

Significant efforts have recently been undertaken to develop highly efficient solid oxide cells for high-temperature steam electrolysis (SOEC). Implementing new materials and microstructures that would improve the performance and durability of this technology remains a major issue. For this purpose, a nano-structured PrO1.833 material coated by the electrostatic spray deposition (ESD) technique was studied as a promising active oxygen electrode for SOEC application. The study was performed considering the PrOx as the functional layer and strontium-doped lanthanum manganite (LSM) as the current collecting layer on a standard half-cell supported by a typical Ni-YSZ cermet, a YSZ electrolyte, and a gadolinium-doped ceria (GDC) barrier layer. The electrochemical characterizations showed promising initial performance at 700 °C in SOEC mode (− 1 A cm−2 at 1.4 V with H2O/H2 = 90 vol%/10 vol%). In addition, a reasonable degradation rate of ∼5.8% kh−1 was obtained at 700 °C within 1000 h of SOEC operation. The structural and elemental evolutions were analyzed with micrometer size resolution all along the functional layer thickness using synchrotron μ-X-ray diffraction and fluorescence. The electrode degradation was primarily attributed to the phase transitions of PrO1.833. In particular, the structural analyses of the sample aged under applied current revealed a small quantity of PrO1.5≤x≤1.7 phase at the GDC/AFL (active functional layer) interface which is expected to be less conductive than PrO1.833, along with PrO1.714 and GDC phases. Finally, additional structural characterizations were performed on samples annealed at different temperatures and dwell times: 700 °C for 1000 h and 800 °C for 700 h, respectively. The results are discussed to provide a better understanding of the stability of the praseodymium oxide.

Multiobjective optimization of a pressurized water reactor cogeneration plant for nuclear hydrogen production

In this paper, energy, exergy, economic analysis and multiobjective optimization of a pressurized water reactor (PWR) nuclear cogeneration plant for hydrogen production through high-temperature steam electrolysis (HTSE) are carried out. HTSE requires energy in the form of both heat and electrical work. A novel parameter, namely the heat/total energy ratio, is defined, and used as a decision variable in optimization. In addition to energy ratio, hydrogen production capacity, reactor thermal power, live steam temperature, reheating mass flow rate ratio, reheating temperature and steam extraction location are considered as the decision variables to simultaneously optimize the thermal efficiency, thermal-to-hydrogen efficiency, utilization factor, exergy efficiency and total revenue of the cogeneration plant. The analysis and optimization focus on the secondary cycle of the PWR and the effects of hydrogen and electricity prices and ambient conditions are also taken into account since these prices have a significant impact on the optimum design. For a hydrogen price of 4 $/kg and an electricity price of 0.1 $/kWh, when equal preference is given to all objective functions, the optimum production capacity is 6.778 kg/s. The energy ratio has an optimum value if the optimization focuses exclusively on the thermal efficiency and total revenue.

Realizing high-temperature steam electrolysis on tubular solid oxide electrolysis cells sufficing multiple and rapid start-up

Realizing high-temperature steam electrolysis on tubular solid oxide electrolysis cells sufficing multiple and rapid start-up

Integrated thermohydraulic transient testing of steam extraction loop system to support joint electricity-hydrogen production using generic boiling water reactor

The economic competitiveness of the current fleet of light water reactors may be improved by coupling nuclear reactors to industrial facilities. This will allow flexible use high-quality steam or electric power from the reactor when the cost of electricity is low compared to the generation cost. One promising application is hydrogen production. Understanding the nuclear plant response to steam offtake is important for safe operation of the reactor facility. Conceptual analysis has been performed for coupling pressurized water reactors (PWRs) to high temperature steam electrolysis hydrogen production; however, corresponding work done for boiling water reactors (BWRs) has not been published, even though BWRs make up 30% of the US operating fleet. This paper demonstrates the feasibility of coupling a generic BWR to a hydrogen production facility. The system response is analyzed for a 15% reduction in the electrical power output. This work shows that when steam is extracted from the main steam header without appropriate controls modifications, reactor power will increase beyond 100% rated power. We present addition analysis to maintain power below rated conditions by varying feedwater recirculation pump speeds.

Recent Advances in High-Temperature Steam Electrolysis with Solid Oxide Electrolysers for Green Hydrogen Production

Hydrogen is known to be the carbon-neutral alternative energy carrier with the highest energy density. Currently, more than 95% of hydrogen production technologies rely on fossil fuels, resulting in greenhouse gas emissions. Water electrolysis is one of the most widely used technologies for hydrogen generation. Nuclear power, a renewable energy source, can provide the heat needed for the process of steam electrolysis for clean hydrogen production. This review paper analyses the recent progress in hydrogen generation via high-temperature steam electrolysis through solid oxide electrolysis cells using nuclear thermal energy. Protons and oxygen-ions conducting solid oxide electrolysis processes are discussed in this paper. The scope of this review report covers a broad range, including the recent advances in material development for each component (i.e., hydrogen electrode, oxygen electrode, electrolyte, interconnect, and sealant), degradation mechanisms, and countermeasures to mitigate them.

Fabrication of anode supported solid oxide electrolysis cell with the co-tape casting technique and study on co-electrolysis characteristics

Solid Oxide Electrolysis Cell (SOEC) is an efficient green hydrogen production technology, which is a reverse of Solid Oxide Fuel Cell (SOFC). In this paper, an anode-supported SOEC produced via multi-layer organic co-tape casting with co-sintering process is investigated for high temperature steam electrolysis, carbon dioxide electrolysis, and co-electrolysis. SOEC cathode must maintain its electrocatalytic activity in a high temperature and humidity condition. La0.75Sr0.25Cr0.5Mn0.5O3-δ (LSCM) is one of the most promising cathode materials because of its superior electrocatalytic ability and redox stability. The anode-supported structure of electrolysis cell reduces ohmic resistance obviously and LSCM cathode exhibits good catalytic performance. To evaluate the performance of co-electrolysis, a continuous voltage of 1 V is applied for 256 h with 60% H2O and 40% CO2 at 750 °C. The anode-supported SOEC with LSM((La0.8Sr0.2)0.95Mn0.5O3-δ)/LSM-YSZ(Zr0.92Y0.08O2-δ)/YSZ/LSCM structure has good electrochemical performance and durability under co-electrolysis conditions combined with the distribution relaxation of time analysis of impedance spectra.

Comparative analysis of associated cost of nuclear hydrogen production using IAEA hydrogen cost estimation program

The interest in non-electric applications of nuclear energy is rising ranging from hydrogen production, district heating, seawater desalination, and various industrial applications to provide long-term answers for a variety of energy issues that both present and future generations will confront. Hydrogen is a dynamic fuel that can be used across all industrial sectors to lower carbon intensity. This study, therefore, aims at estimating the cost of nuclear hydrogen production from some light water reactors using International Atomic Energy Agency (IAEA) Hydrogen Calculator (HydCalc) program and comparing the result with similar existing studies conducted by other scholars using the Hydrogen Economic Evaluation Program (HEEP) program. The study employs six existing Light Water Reactors (LWRs) comprised of Korea Advanced Power Reactor 1400 MW electricity (APR1400), Russian VVER-1200, Davis-Besse Nuclear Power Plant in Ohio, Prairie Island NPP in Minnesota, Nine Mile Point NPP in New York, and Arizona Public Service's Palo Verde NPP to evaluate the Levelized cost of nuclear hydrogen production. Estimation of hydrogen demand was performed without carbon dioxide (CO2) tax since nuclear power has zero CO2 emission. The Levelized costs obtained using IAEA HydCalc and HEEP Programme were compared as follows; APR1400 cost are 2.6$/kg and 3.18$/kg, VVER1200 cost are 3.8$/kg and 3.44$/kg; Exelon cost are 1.7$/kg and 4.85$/kg; Davis Besse cost are 3.9$/kg and 3.09$/kg; Parlo Verde cost are 3.5$/kg and 4.77$/kg; Xcel Energy cost are 3.63$/kg and 0.69$/kg. The cost of hydrogen production using HEEP for Xcel Energy's Prairie Island NPP is 0.69 $/kg. This is because the reactor utilizes High Temperature Steam Electrolysis, method of hydrogen production, while the other methods employs Low Temperature Electrolysis. The results shows that the final price of the hydrogen for each reactor technology depends not only on the production method but also on the cost of the nuclear power plant and the production rate of the hydrogen plant.

Optimization of High-Temperature Electrolysis System for Hydrogen Production Considering High-Temperature Degradation

Solid oxide electrolysis cells (SOECs) have great application prospects because of their excellent performance, but the long-term applications of the stacks are restricted by the structural degradation under the high-temperature conditions. Therefore, an SOEC degradation model is developed and embedded in a process model of the high-temperature steam electrolysis (HTSE) system to investigate the influence of the stack degradation at the system level. The sensitivity analysis and optimization were carried out to study the influence factors of the stack degradation and system hydrogen production efficiency and search for the optimal operating conditions to improve the hydrogen production efficiency and mitigate the stack degradation. The analysis results show that the high temperature and large current density can accelerate the stack degradation but improve the hydrogen production efficiency, while the high temperature gradually becomes unfavorable in the late stage. The low air-to-fuel feed ratio is beneficial to both the degradation rate and hydrogen production efficiency. The results show that the optimization method can improve the hydrogen production efficiency and inhibit the stack degradation effectively. Moreover, part of the hydrogen production efficiency has to be sacrificed in order to obtain a lower stack degradation rate.

Fluorination Intensifying Oxygen Evolution Reaction for High-Temperature Steam Electrolysis

Solid oxide electrolysis cells (SOECs) have emerged as one of the most potent techniques for hydrogen production. As the restricted step for SOEC, as well as the most predominant obstacle to the scaled application, oxygen evolution reaction (OER) should be urgently accelerated by developing potent electrocatalysts. Despite inferior electrochemical activity to cobalt-based materials, perovskite ferrites exhibit great potential in the future with regard to good intrinsic stability and durability, abundant reserves, and good compatibility with other SOEC components. In this work, fluorination is introduced to the typical perovskite ferrite to further intensify the OER process. Ab initio calculations combined with physical–chemical characterizations are performed to reveal the mechanism. The doped F − leads to debilitating the strength of the metal–oxygen bond and then reduces the energy for oxygen vacancy formation and ion migration, which renders improvements to sub-processes of OER on the anode. The well-verified material, PrBaFe 2 O 5+δ F 0.1 (PBFOF), exhibited a low polarization resistance of 0.058 Ω cm −2 . Single cells based on PBFOF showed a high current density of 2.28 A cm −2 at 750 °C under 1.3 V. This work provides a clear insight into the mechanism of fluorination on perovskites and high-activity anode material for SOEC.

Evolution and effect on electrolysis performance of pores in YSZ electrolyte films prepared by screen-printing

Insights into the pore–matrix interactions in solid oxide electrolytes are necessary to develop high-efficiency solid oxide electrolytic cells. The role of particle size in ink and printed electrolyte films was analyzed in this study. This is distinct from solid electrolytes that are dense as a whole but have micropores. Herein, we demonstrate that the organic binder in the ink can significantly reduce the number of closed pores in the electrolyte by taking advantage of its thermal softening characteristics. Electron microscopic analysis provides evidence that the binder controls the pore generation and affects the pore distribution in the electrolyte films. The effect and mechanism of micropores in the electrolyte on the electrochemical process (when used for high-temperature steam electrolysis) are discussed.

Enhancing the catalytic activity and stability of the Pr2NiO4+δ Ruddlesden−Popper perovskite air electrode for high-temperature steam electrolysis with barium doping

Ruddlesden−Popper oxides Pr2NiO4+δ (PNO) as air electrode of solid oxide electrolysis cells (SOECs) have attracted considerable attention due to their excellent electrochemical performance. However, the thermal stability of PNO is poor at high temperatures (600–800 ℃). Thus, the long-term stability of SOECs with PNO air electrode may be affected. In this work, the structural stability, electrochemical performance, and durability of PNO are modified by substituting praseodymium with barium. Pr2−xBaxNiO4+δ (PBNO-x, x = 0, 0.1, 0.2, 0.3, and 0.4) samples are prepared using the solid-state method and evaluated for high-temperature steam electrolysis in SOECs. X-ray diffraction and thermal expansion coefficient results show that Ba-doped sample PBNO-0.2 has good chemical and thermal compatibility with GDC electrolyte. Electrochemical impedance measurement indicates that Ba doping can decrease the polarization resistance (Rp) of the samples. PBNO-0.2 electrode exhibits an Rp value of 0.06 Ω cm2 at 800 ℃, which is 66% lower than that of the sample without Ba-doped PNO. The PBNO-0.2 half-cell is extremely stable under a high current density of 1 A cm−2 for 126 h at 800 ℃. Furthermore, an electrolysis current density as high as − 723 mA cm−2 at 1.3 V is obtained for the full cell with PBNO-0.2 air electrode when the temperature and feed gas are 800 ℃ and 70% H2O− 30% H2, respectively. It indicates an increase of about 27% than that of the PNO electrode, which suggests that Ba doping can effectively enhance the electrochemical performance of the PNO air electrode. The high catalytic performance of the PBNO-0.2 air electrode can be attributed to its high oxygen vacancy concentration by X-ray photoelectron spectroscopy analysis. The results prove that PBNO-0.2 is an air electrode with high catalytic activity and stability for high-temperature steam electrolysis in SOECs.