Hydrogen System Research Articles

Copper-Catalyzed Continuous-Flow Transfer Hydrogenation of Nitroarenes to Anilines: A Scalable and Reliable Protocol.

A robust supported catalyst that is made up of copper nanoparticles on Celite has been successfully prepared for the selective transfer hydrogenation of aromatic nitrobenzenes to anilines under continuous flow. The method is efficient and environmentally benign thanks to the absence of hydrogen gas and precious metals. Long-term stability studies show that the catalytic system is able to achieve very high nitrobenzene conversion (>99%) when working for up to 145 h. The versatility of the transfer hydrogenation system has been tested using representative examples of nitroarenes, with moderate-to-excellent yields being obtained. The packed bed reactor (PBR) permits the use of a setup that can provide products via simple isolation by SPE without the need for further purification. The recovery and reuse of either EG or the ion-exchange resin leads to consistent waste reduction; therefore, E-factor distribution analysis has highlighted the environmental efficiency of this synthetic protocol.

A Resilience-Oriented Approach for Microgrid Energy Management with Hydrogen Integration during Extreme Events

This paper presents a resilience-oriented energy management approach (R-OEMA) designed to bolster the resilience of networked microgrids (NMGs) in the face of extreme events. The R-OEMA method strategically incorporates preventive scheduling techniques for hydrogen (H2) systems, renewable units, controllable distributed generators (DGs), and demand response programs (DRPs). It seeks to optimize the delicate balance between maximizing operating revenues and minimizing costs, catering to both normal and critical operational modes. The evaluation of the R-OEMA framework is conducted through numerical simulations on a test system comprising three microgrids (MGs). The simulations consider various disaster scenarios entailing the diverse durations of power outages. The results underscore the efficacy of the R-OEMA approach in augmenting NMG resilience and refining operational efficiency during extreme events. Specifically, the approach integrates hydrogen systems, demand response, and controllable DGs, orchestrating their collaborative operation with predictive insights. This ensures their preparedness for emergency operations in the event of disruptions, enabling the supply of critical loads to reach 82% in extreme disaster scenarios and 100% in milder scenarios. The proposed model is formulated as a mixed-integer linear programming (MILP) framework, seamlessly integrating predictive insights and pre-scheduling strategies. This novel approach contributes to advancing NMG resilience, as revealed by the outcomes of these simulations.

Electrification and hydrogenation on a PV-battery-hydrogen energy flexible community for carbon–neutral transformation with transient aging and collaboration operation

Considering the distinct differences in intrinsic characteristics (e.g., energy efficiency, power density, and response time), the synergy operation of combined hydrogen (H2) and battery systems within the source-grid-load-storage framework offers a promising solution to stabilize intermittent renewable energy supply, mitigate grid power fluctuations, and enhance system independence. However, the idling power of the H2 system (fuel cell and electrolyzer) poses significant limitations on H2 charging/discharging from intermittent renewable power sources, thereby affecting overall system performance. However, the current literature provides little progress on how to effectively self-consume onsite renewable energy and supply the electricity demand with high energy/power density in a fast response. To address these challenges, this study proposes and applies the H2-battery compensation operation in the hybrid H2-battery energy storage system to mitigate the adverse effects of idling power during low-carbon transformations. Additionally, transient degradation models for the battery and fuel cell (FC) are integrated into the system to dynamically quantify real-time aging, thereby avoiding performance overestimation. Moreover, the study also includes a comparative analysis of the pre-estimation on the H2 tank pressure level, and a parametrical analysis of the HV number and battery capacity. Results show that, compared to the isolated H2 energy storage system, the H2-battery synergy operation reduces the grid demand shortage coverage ratio from 91.01% to 57.8%. Furthermore, the proposed H2-battery compensation operation effectively overcomes the limitations of idling power during power charging/discharging of the H2 system, resulting in an increase of H2 demand shortage coverage ratio from 8.9% to 17.29%, and the decrease in battery degradation ratio from 1.73% to 1.65%. Afterward, a novel indicator, degradation cost per kWh energy, is proposed to quantify the techno-economic performance of the combined battery and H2 system. According to the results, the techno-economic feasibility is dependent on the proportion of battery and H2 capacities, with the FC ranging from 0.49 to 1.15 CNY/kWh and the battery ranging from 0.82 to 0.91 CNY/kWh. The research results provide valuable frontier guidelines for the design and operation of multi-energy systems, as well as innovative energy-sharing strategies, to achieve sustainable and carbon–neutral transformation.

Regime-driven niches and institutional entrepreneurs: Adding hydrogen to regional energy systems in Germany

In recent years, production and supply of hydrogen has gained significant attention within the German energy transition. This is due to increasingly urgent pressures to mitigate climate change and geopolitical imperatives to substitute natural gas. Hydrogen is seen as an important cross-sectoral energy carrier serving multiple functions including heat production for industry and households, fuel for transportation and energy storage for stabilization of electricity supply. In the context of various funding mechanisms on several administrative levels, regional value chains for green hydrogen supply are emerging. To date, however, few studies analyzing regional hydrogen systems exist. Due to its high projected demand of energy sources for heating, industrial processes and mobility, Germany appears to be a very relevant research area in this emerging field.Situated within the concept of the multi-level perspective, this article examines the way how regional “niches” of green hydrogen evolve and how they are organized. The study takes an evolutionary perspective in analyzing processes of embedding green hydrogen infrastructures in regional energy regimes which entered “re-configuration”-pathways. It argues that the congruence of available resources for renewable electricity, established networks of institutional entrepreneurs and access to higher level funding are conditions which put incumbent regime-actors in favorable positions to implement green hydrogen niches. Conversely, the embedding of green hydrogen infrastructures in regional energy systems is a case in point of how the attributes of niches in particular technological domains can be used to explain the transition pathway entered by a surrounding energy regime.

Hydrogenation of Alkynes and Olefins Catalyzed by Quaternary Ammonium Salts.

Catalytic hydrogenation of unsaturated hydrocarbons to alkenes and alkanes using molecular hydrogen is one of the most fundamental transformations in organic synthesis. While methodologies involving transition metals as catalysts in homogeneous and heterogeneous processes have been well developed, metal-free catalytic hydrogenation offers an ideal approach for future chemistry. Herein, the common and inexpensive quaternary ammonium salts are first introduced as catalysts in the catalytic hydrogenation system for the transformations from alkynes or olefins into the corresponding olefins or alkanes. Interestingly, the hydrogenation process of alkynes can be controlled to selectively produce alkenes or alkanes under different conditions. Moreover, the possible mechanism is discussed in new insights into the catalytic behavior of quaternary ammonium salts.

A novel zero carbon emission system based on the complementary utilization of solar energy and hydrogen

A novel zero carbon emission combined power and hydrogen system is developed in this paper, which integrates power generation, hydrogen production, and energy storage. The novel combined system is composed of solar power tower subsystem, supercritical carbon dioxide recompression Brayton cycle subsystem, hydrogen gas turbine subsystem, hydrogen production subsystem and thermoelectric generator subsystem. Considering the solar instability, three operating modes are set for the combined system: pure hydrogen mode, solar‑hydrogen hybrid mode and pure solar energy mode. Comprehensive energy, exergy and economic analyses are performed for the combined system. The effects of five key parameters on the system performance are investigated. Taking the maximum exergy efficiency and the minimum levelized cost of energy as the objective function, the key parameters are optimized by the genetic algorithm. Results show that in pure hydrogen mode, the thermal and exergy efficiency of the combined system are 44.79% and 45.49%, respectively. Compared with pure hydrogen mode, the levelized cost of energy is reduced by 44.76% and 75.16% in solar‑hydrogen hybrid and pure solar energy mode. There is an optimal compressor pressure ratio to make the combined system have better thermodynamic and economic performance. Parameter optimization results show that for pure solar mode, the levelized cost of energy of the combined system is 75.4% and 56.3% lower than that of pure hydrogen mode, solar‑hydrogen hybrid mode respectively in the levelized cost of energy optimal design. The derived significant contributions of this work highlight strong potentials for combined system based on solar energy‑hydrogen complementary utilization.

Multi-Timescale Trading Strategy for Renewable Power to Ammonia Virtual Power Plant in the Electricity, Hydrogen, and Ammonia Markets

Renewable power to ammonia (RePtA) is a prominent zero-carbon pathway for decarbonization. Due to the imbalance between renewables and production energy demand, the RePtA system relies on electricity exchange with the power grid. Participating in the electricity market as a virtual power plant (VPP) may help to reduce energy costs. However, the power profile of local photovoltaics and wind turbines is similar to those in the market, resulting in rising energy costs under the conventional strategy. Hence, we develop a multi-timescale trading strategy for the RePtA VPP in the electricity, hydrogen, and ammonia markets. By utilizing the hydrogen and ammonia buffer systems, the RePtA VPP can optimally coordinate production planning. Moreover, we find it possible to describe the trading of electricity, ammonia, and hydrogen in a unified timeframe. The two-stage robust optimization model of the electricity market is extended to multiple markets and solved by the column and constraint generation (CC&G) algorithm. The case is derived from an actual project in the Inner Mongolia Autonomous Region. Sensitivity analysis demonstrates the economic advantages of the RePtA VPP joining multiple markets over the conventional strategy and reveals the necessity of the hydrogen and ammonia buffer and reactor flexibility.

Study on integrated thermal management system of hydrogen fuel cell vehicles based on heat pump air conditioning

An integrated thermal management system (VITMS) of hydrogen fuel cell vehicle (FCV) is proposed to solve the issues of poor temperature control and high energy consumption in current dispersed TMS. The vehicle energy integration is realized by coupling the key subsystems of cabin, fuel cell, power battery and motor through the waste-heat source heat pump (WSHP). The temperature control capability under extreme working conditions are analyzed. The energy consumption of three heating modes under extreme cold conditions is evaluated. The results show that VITMS has excellent thermal control performance and can realize fourteen work modes such as cooling, heating, preheating, defrosting and energy recovery, ensuring the optimal temperature ranges and temperature uniformity of fuel cell, power battery, motor, and cabin. VITMS using WSHP offers superior energy saving effect in extreme cold conditions, which can reduce equivalent hydrogen consumption by 12.21% and 3.6%, and increase maximum driving range by 29.34% and 8% compared to PTC and air-source heat pump (ASHP). The cabin heating time using WSHP can be reduced by 34.5% compared to ASHP, ensuring all-weather ride comfort and extending the vehicle's driving range in low temperatures. Annual CO2 emission is 52.13% and 36.17% lower than diesel and electric buses.

Hybrid solar energy systems with hydrogen and electrical energy storage for a single house and a midrise apartment in North America

Allowing deeper penetration of renewable energy technologies through the adaptation of hybrid systems is unanimously considered critical for decarbonizing the building sector. The objective of this research is to analyze and contrast different renewable energy systems utilizing PV panels, an electrolyzer, and a fuel cell (FC) in a single-house and a midrise apartment located in North America. The study uses HOMER software to simulate and optimize three types of systems: PV/battery bank, PV/hydrogen, and PV/battery bank/hydrogen. The findings indicate that larger batteries can be utilized in place of the electrolyzer and fuel cell, but they incur a higher net present cost (NPC) due to their expensive initial investment. Therefore, a combination of PV arrays, hydrogen, and smaller battery banks can significantly reduce the net present cost of the system while also achieving efficient performance. After conducting an economic analysis of various setups for a single house, the research indicates that a configuration of 522 kW photovoltaic (PV) panels, 150 kW electrolyzer, 20 kW fuel cell, 200 kg hydrogen tank, 18.6 kW converter, and 159 batteries offers the most favorable results in Toronto, Canada. This configuration achieves lower NPC and levelized cost of energy (COE) than the PV/hydrogen system. In addition, according to the optimum design of the hydrogen system for the midrise apartment, the PV/battery bank/hydrogen configuration has a lower NPC and COE than the PV/hydrogen system, which shows that adding the battery to the system lowers the cost and offer short and long-term energy storage. The optimum design was then verified by implementing a sensitivity analysis to evaluate different solar radiation, electric load, derating factor and tilt angle of the PV array.

Design, optimization, and technical evaluation of coking dry gas chemical looping hydrogen generation systems coupled with solid oxide fuel cell

Coking dry gas from delayed coking processes is rich in light hydrocarbons, making it a comparative ideal feedstock for hydrogen production. Current steam reforming processes have the disadvantages of high energy consumption and carbon emissions, whereas chemical looping hydrogen generation produces high-purity hydrogen with inherent carbon capture and a low energy penalty. Therefore, this study proposes a coking dry gas chemical looping process for hydrogen production, considering two schemes (external-heating and self-heating) and optimizes key parameters of the systems in detail. The optimal molar ratios of the oxygen carrier, steam, and air to coking dry gas for the externally heated and self-heated schemes were 8.62, 4.90, 2.27 and 8.62, 3.78, 4.07, respectively. The energy efficiencies of the two systems can reach 76.55% and 77.93% with carbon capture rates of 76.29% and 100%, 3.26% and 5.13% higher than efficiency of the steam reforming system. The self-heated system had the highest hydrogen production of 2.67 kmol/kmol coking dry gas. Based on a self-heated hydrogen system, a chemical looping hydrogen generation system was coupled with a solid oxide fuel cell. This integrated system achieved the better power generation performance with an anode recycling ratio of about 0.7. The net electrical efficiency of the system was 58.79%, which is 3.34% higher than that of a steam reforming system coupled with a solid oxide fuel cell. The results reveal that the chemical looping systems are suitable for the clean utilization of dry gas and provide a strategy for efficient hydrogen production and power generation.

Safety Risk and Strategy Analysis of On-Board Hydrogen System of Hydrogen Fuel Cell Vehicles in China

Hydrogen fuel cell vehicles (HFCVs) represent an important breakthrough in the hydrogen energy industry. The safe utilization of hydrogen is critical for the sustainable and healthy development of hydrogen fuel cell vehicles. In this study, risk factors and preventive measures are proposed for on-board hydrogen systems during the process of transportation, storage, and use of fuel cell vehicles. The relevant hydrogen safety standards in China are also analyzed, and suggestions involving four safety strategies and three safety standards are proposed.

A distributed multi-objective optimization method for scheduling of integrated electricity and hydrogen systems

The growing diversity in energy demand has led to an increasingly intertwined relationship between the electric power system (EPS) and hydrogen energy system (HES). However, these systems are presently managed by entities with distinct interests, resulting in competition and privacy concerns during the scheduling of integrated electricity and hydrogen systems (IEHSs). To address this issue, this paper proposes a multi-objective IEHS scheduling model with the aim of minimizing costs for electricity and hydrogen suppliers, taking into account bi-directional energy transactions between EPS and HES. Furthermore, we present an innovative approach based on alternating direction multiplier method (ADMM) for distributed ξ-constraint optimization. This approach efficiently captures the optimal Pareto frontier while maintaining the privacy of EPS and HES. The proposed methodology is validated on an IEHS composed of an IEEE 33-bus EPS and a 20-node HES. The results demonstrate that no matter how many solution sets, a more uniform pareto front can be obtained than the traditional method. Furthermore, it simplifies the multi-objective optimization problem and effectively protects the privacy of participants at the expense of acceptable solution time.

Unravelling the trifunctional electrochemical properties of WSe2 nanosheets for self-powered hydrogen production

Two dimensional materials have received increasing recognition for their utility in electrochemical energy storage and conversion devices, as well as for self-powered systems. In this work, we are reporting the trifunctional electrochemical properties (such as energy-storage, hydrogen evolution reaction (HER) and oxygen evolution reaction (OER)) of WSe2 nanosheets (prepared by a solvothermal method) towards the development of a self-powered system for uninterrupted hydrogen (H2) production. First, we have examined the energy storage properties of the WSe2 nanosheets in the form of flexible solid-state supercapacitor (FSSC) that shows the presence of ion-intercalation pseudocapacitance in the WSe2 nanosheets. The fabricated WSe2 FSSC possess a high device capacitance, energy density, and power density with 119% capacitance retention over 5,000 cycles. Second, we explored the electrocatalytic properties of WSe2 nanosheets that indicated they possess effective HER and OER properties with low overpotential (115 mV for HER and 312 mV for OER), respectively. Finally, a proof-of-concept self-powered system comprising a solar cell, WSe2 FSSC, and lab-scale WSe2 electrolyzer (with a low overpotential of 1.604 V at 10 mA cm−2) was demonstrated to overcome the power fluctuation issues for effective and uninterrupted H2 production.

Comprehensive energy, exergy, and economic analyses of a geothermal and flue gas-based dual-source power, hydrogen, and freshwater trigeneration system

Designing a ploy-generation system to produce various products is an effective method to improve the common power plant’s performance. Hence, the current investigation proposes a green poly-generation system driven by geothermal and flue gas. The proposed scheme consists of an organic Rankine cycle, proton exchange membrane electrolyzer, saline water desalination unit, and Allam cycle to produce power, hydrogen, and freshwater. The produced oxygen in the electrolyzer feeds the Allam cycle to perform an oxyfuel process to achieve zero CO2 emission. Per the 4E analysis, the system produces 27,720 kW net power, 931 kmol/h hydrogen, and 616.7 kmol/h freshwater. In this way, the energy and exergy efficiencies are obtained at about 16.87% and 51.65%. The total exergy destruction rate is estimated at about 78,926 kW, in which the organic Rankine cycle and its vapor generator have the highest portions among the different parts and equipment by about 69% and 18.87%. The sensitivity analysis indicates that by the CO2 recycle ratio of 60%, the highest energy and exergy efficiencies reach 19.3% and 54.33%. Furthermore, the unit cost of hydrogen and electricity productions are 0.07$/kWh and 7.24 $/GJ, which is a considerable reduction compared to similar methods.

Cooperative scheduling and trading in sustainable water-integrated and networked energy systems incorporating power-to-gas

This paper presents a stochastic and cooperative approach for the operation of a cluster of interconnected multi-energy systems. The proposed model investigates the interaction among energy systems with the upstream grid and neighbor energy systems. In this model, the hydrogen systems (consisting of fuel cell, electrolyzer, and hydrogen storage tank) and water system (water well, desalination unit, and water storage tank) are integrated into the electrical, heating, and cooling systems to provide an efficient and reliable structure for the energy systems. The proposed model studies the performance of energy system agents in both decentralized and cooperative scheduling. In the decentralized framework, each agent is responsible for locally supplying different energy demands with their resources and trading energy with the main grid. In the decentralized framework, peer-to-peer energy trading between neighbor energy systems is impossible. Also, each agent can trade energy with the upstream grid and other neighbor energy systems in the cooperative framework. The simulation result shows that the proposed cooperative model decreases the operation cost of the system by $ 56.9. Also, the water storage system reduces the operation cost by 5.78 % (86.23 $) and 3.28 % (49.61 $) in the cooperative and decentralized modes, respectively.

Optimal scheduling and real-time control of a microgrid with an electrolyzer and a fuel cell systems using a reference governor approach

This paper proposes a novel approach for the optimal scheduling and control of a microgrid with an electrolyzer and fuel cell systems, both of proton exchange membrane (PEM) technology. It is based on a hierarchical procedure constituted of two levels of optimization: a higher level based on an economic optimization for the optimal scheduling of different components of the microgrid, and a lower level for the real-time control of the hydrogen systems: PEM electrolyzer (PEMEZ) and PEM fuel cell (PEMFC). The flexible operation imposed by the higher level leads to a violation of the limits designed by the manufacturer of the hydrogen components, specifically when switching from one power level to another. The current proportional-integral (PI) controllers integrated into those systems cannot handle this issue, which provokes a premature aging phenomenon of the materials and leads to poor performance of the systems. In the present paper, at the lower level, a reference governor (RG) real-time control approach has been added on top of the PI controller to ensure the respect of the operating limits and guarantee better performances. The focus has been given to the stack's temperature in both the electrolyzer and fuel cell systems as the control objective because of its direct influence on the material's durability and, by extension, on the efficiency. The bi-level optimization and control architecture has been applied and validated through simulations using data from a real-world case study, specifically the Savona Campus Smart Polygeneration Microgrid in Italy. The results showed a significant reduction in the overshoots of the stack's temperature compared to the PI controller.

Predicting the solubility of hydrogen in hydrocarbon fractions: Advanced data-driven machine learning approach and equation of state

BackgroundHydrogen is a free carbon source for energy that attracts massive interest to be utilized during energy transition period in the near future. Molecular hydrogen soon will be a key component in fuels productions. It can be produced through catalytic steam and natural gas. For such processes the accurate estimation of solubility of hydrogen in many alkanes’ solution can have a major impact on the design and optimization of such petrochemical processes. MethodsIn this study, advanced data-driven scheme consisting in a committee machine intelligent system (CMIS) model was proposed for predicting the solubility of hydrogen in many hydrocarbon liquids raging from light n-alkanes C1 to heavy n-alkanes of C46. The CMIS was gained by combining multilayer perceptron (MLP) and cascaded forward neural network (CFNN) beneath a sole model using gene expression programming (GEP). A wide range database of hydrogen solubility in a binary system of hydrogen and various n-alkanes types was considered for developing the intelligent model. Besides, the reliability of the physics-based models, namely the Peng–Robinson equations of state (PR EOS) was checked for predicting the solubility of H2 in n-alkanes. Significant findingsThe main results demonstrated that the developed CMIS scheme can estimate the solubility of hydrogen in n-alkanes with a quite low computational cost and excellent performance, where the yielded overall RMSE and R2 values were 0.0033 and 0.9972, respectively. Besides, the established machine learning based model is capable of providing a good match against a wide range of experiment data. Furthermore, it is found that the implemented CMIS paradigm is superior to the existing intelligent and physics-based models in terms of accuracy. Lastly, the result of this work is vital for increasing the accuracy of hydrogen solubility in various hydrocarbon solvents required for process optimization of the hydrogen production units.

Initial Quenching Efficiency Determines Light-Driven H2 Evolution of [Mo3 S13 ]2- in Lipid Bilayers.

Nature uses reactive components embedded in biological membranes to perform light-driven photosynthesis. Here, a model artificial photosynthetic system for light-driven hydrogen (H2 ) evolution is reported. The system is based on liposomes where amphiphilic ruthenium trisbipyridine based photosensitizer (RuC9 ) and the H2 evolution reaction (HER) catalyst [Mo3 S13 ]2- are embedded in biomimetic phospholipid membranes. When DMPC was used as the main lipid of these light-active liposomes, increased catalytic activity (TONCAT ~200) was observed compared to purely aqueous conditions. Although all tested lipid matrixes, including DMPC, DOPG, DPPC and DOPG liposomes provided similar liposomal structures according to TEM analysis, only DMPC yielded high H2 amounts. In situ scanning electrochemical microscopy (SECM) measurements using Pd microsensors revealed an induction period of around 26 minutes prior to H2 evolution, indicating an activation mechanism which might be induced by the fluid-gel phase transition of DMPC at room temperature. Stern-Volmer-type quenching studies revealed that electron transfer dynamics from the excited state photosensitizer are most efficient in the DMPC lipid environment giving insight for design of artificial photosynthetic systems using lipid bilayer membranes.

Performance analysis of a small lead-cooled fast reactor coupled with a copper-chloride cycle hydrogen production system

Hydrogen is widely acknowledged as a pivotal energy carrier in the global transition towards sustainable energy. One promising approach to hydrogen production is method copper-chlorine cycle powered by nuclear energy. This article presents an innovative integrated system for small lead-cooled fast reactors that are coupled with a copper-chlorine cycle. To assess the performance of the entire system with regards to energy, exergy, and economics, comprehensive modeling, simulation, and analysis are conducted using the simulation tool Simulink. Furthermore, a comprehensive examination of key operating parameters was conducted to explore their impact on the system. The obtained results demonstrate the energy efficiency of system is 21.3 % and the exergy efficiency of system is 40.9 %. The overall system based on the small LFR can produce high-pressure compressed hydrogen gas at a rate of 2.34 g/s and generate 53.9 kW of electricity. According to the study, the levelized cost of energy production is determined to be $0.04252/kW·h. The specific energy cost is primarily influenced by equipment investment, including the costs associated with operating and maintaining the system. Notably, the small lead-cooled fast reactor and the copper-chlorine cycle plant represent the major capital investments within the system. This study provides valuable insights and serves as a significant reference for the future engineering applications of lead-cooled fast reactors coupled with copper-chlorine cycle hydrogen systems.

Techno-economic analysis of solar powered green hydrogen system based on multi-objective optimization of economics and productivity

Green hydrogen, hydrogen produced from renewable sources, is emerging as clean energy carrier to combat climate change. In particular, on-site hydrogen production by solar power has the advantage of being simple to install with fewer regional limits. Cost and productivity of solar-based hydrogen, however, can be difficult to estimate and balance as the production is intermittent and unpredictable due to the volatility of renewable energy source. In this study, a multi-objective optimization-based framework for solar powered green hydrogen is presented for optimal system design that balances between economic cost and productivity. A system-wide model is developed that uses meteorological data to estimate how much solar power would be generated and how much hydrogen would be produced as a result. Then, using the model, a framework is suggested for calculating and simultaneously optimizing the amount of hydrogen produced and levelized cost of hydrogen (LCOH). The United States, China, Australia and Korea, all the major countries with interest in solar-based green hydrogen, are assessed using the framework. As a result, it is shown that an optimal system size exists for each different objective, and that a significant improvement in LCOH can be accomplished by enhancing the components’ cost and performance. More importantly, it is revealed that, for all the nations, the optimal electrolyser size to minimize LCOH is roughly 60% of the solar power capacity, and installing batteries is ineffective for boosting the economic viability, but can improve hydrogen production by utilizing unused electricity during peak period. Tradeoffs between economic viability and productivity vary depending on the size of the water electrolysis system and whether or not batteries are installed. An optimization study is carried out with an objective function combining the system’s economic viability and productivity, where key design variables such as the size and number of each unit system are determined. The results show that the consideration of multiple objective functions requires a trade-off and the multi-objective optimization framework allows for a customized design by simultaneously considering the hydrogen demand and economic viability with varying bias of preference.