Korea, Republic of
Proposal of Zero-Emission Tug in South Korea Using Fuel Cell/Energy Storage System: Economic and Environmental Long-Term Impacts
Mar 2023
Publication
This study presents the results of economic and environmental analysis for two types of zero-emission ships (ZESs) that are receiving more attention to meet strengthened environmental regulations. One of the two types of ZES is the ZES using only the energy storage system (All-ESS) and the other is the ZES with fuel cell and ESS hybrid system (FC–ESS). The target ship is a tug operating in South Korea and the main parameters are based on the specific circumstances of South Korea. The optimal capacity of the ESS for each proposed system is determined using an optimization tool. The total cost for a ship’s lifetime is calculated using economic analysis. The greenhouse gas (GHG) emission for the fuel’s lifecycle (well-to-wake) is calculated using environmental analysis. The results reveal that the proposed ZESs are 1.7–3.4 times more expensive than the conventional marine gas oil (MGO)-fueled ship; however it could be reduced by 1.3–2.4 times if the carbon price is considered. The proposed ZESs have 58.7–74.3% lower lifecycle GHG emissions than the one from the conventional ship. The results also highlight that the electricity- or hydrogen-based ZESs should reduce GHG emissions from the upstream phase (well-to-tank) to realize genuine ZESs.
Implementation of Formic Acid as a Liquid Organic Hydrogen Carrier (LOHC): Techno-Economic Analysis and Life Cycle Assessment of Formic Acid Produced via CO2 Utilization
Sep 2022
Publication
To meet the global climate goals agreed upon regarding the Paris Agreement governments and institutions around the world are investigating various technologies to reduce carbon emissions and achieve a net-negative energy system. To this end integrated solutions that incorporate carbon utilization processes as well as promote the transition of the fossil fuel-based energy system to carbon-free systems such as the hydrogen economy are required. One of the possible pathways is to utilize CO2 as the base chemical for producing a liquid organic hydrogen carrier (LOHC) using CO2 as a mediating chemical for delivering H2 to the site of usage since gaseous and liquid H2 retain transportation and storage problems. Formic acid is a probable candidate considering its high volumetric H2 capacity and low toxicity. While previous studies have shown that formic acid is less competitive as an LOHC candidate compared to other chemicals such as methanol or toluene the results were based on out-of-date process schemes. Recently advances have been made in the formic acid production and dehydrogenation processes and an analysis regarding the recent process configurations could deem formic acid as a feasible option for LOHC. In this study the potential for using formic acid as an LOHC is evaluated with respect to the state-of-the-art formic acid production schemes including the use of heterogeneous catalysts during thermocatalytic and electrochemical formic acid production from CO2 . Assuming a hydrogen distribution system using formic acid as the LOHC each of the production transportation dehydrogenation and CO2 recycle sections are separately modeled and evaluated by means of techno-economic analysis (TEA) and life cycle assessment (LCA). Realistic scenarios for hydrogen distribution are established considering the different transportation and CO2 recovery options; then the separate scenarios are compared to the results of a liquefied hydrogen distribution scenario. TEA results showed that while the LOHC system incorporating the thermocatalytic CO2 hydrogenation to formic acid is more expensive than liquefied H2 distribution the electrochemical CO2 reduction to formic acid system reduces the H2 distribution cost by 12%. Breakdown of the cost compositions revealed that reduction of steam usage for thermocatalytic processes in the future can make the LOHC system based on thermocatalytic CO2 hydrogenation to formic acid to be competitive with liquefied H2 distribution if the production cost could be reduced by 23% and 32% according to the dehydrogenation mode selected. Using formic acid as a LOHC was shown to be less competitive compared to liquefied H2 delivery in terms of LCA but producing formic acid via electrochemical CO2 reduction was shown to retain the lowest global warming potential among the considered options.
Process Design and Improvement for Hydrogen Production Based on Thermodynamic Analysis: Practical Application to Real-world On-site Hydrogen Refueling Stations
Sep 2023
Publication
An energy source transition is necessary to realize carbon neutrality emphasizing the importance of a hydrogen economy. The transportation sector accounted for 27% of annual carbon emissions in 2019 highlighting the increasing importance of transitioning to hydrogen vehicles and establishing hydrogen refueling stations (HRSs). In particular HRSs need to be prioritized for deploying hydrogen vehicles and developing hydrogen supply chains. Thus research on HRS is important for achieving carbon neutrality in the transportation sector. In this study we improved the efficiency and scaled up the capacity of an on-site HRS (based on steam methane reforming with a hydrogen production rate of 30 Nm3/h) in Seoul Korea. This HRS was a prototype with low efficiency and capacity. Its efficiency was increased through thermodynamic analysis and heat exchanger network synthesis. Furthermore the process was scaled up from 30 Nm3/h to 150 Nm3/h to meet future hydrogen demand. The results of exergy analysis indicated that the exergy destruction in the reforming reactor and heat exchanger accounted for 58.1% and 19.8% respectively of the total exergy destruction. Thus the process was improved by modifying the heat exchanger network to reduce the exergy losses in these units. Consequently the thermal and exergy efficiencies were increased from 75.7% to 78.6% and from 68.1% to 70.4% respectively. The improved process was constructed and operated to demonstrate its performance. The operational and simulation data were similar within the acceptable error ranges. This study provides guidelines for the design and installation of low-carbon on-site HRSs.
Preliminary Study for the Commercialization of a Electrochemical Hydrogen Compressor
Mar 2023
Publication
A global energy shift to a carbon‐neutral society requires clean energy. Hydrogen can accelerate the process of expanding clean and renewable energy sources. However conventional hydrogen compression and storage technology still suffers from inefficiencies high costs and safety concerns. An electrochemical hydrogen compressor (EHC) is a device similar in structure to a water electrolyzer. Its most significant advantage is that it can accomplish hydrogen separation and compression at the same time. With no mechanical motion and low energy consumption the EHC is the key to future hydrogen compression and purification technology breakthroughs. In this study the compression performance efficiency and other related parameters of EHC are investigated through experiments and simulation calculations. The experimental results show that under the same experimental conditions increasing the supply voltage and the pressure in the anode chamber can improve the reaction rate of EHC and balance the pressure difference between the cathode and anode. The presence of residual air in the anode can impede the interaction between hydrogen and the catalyst as well as the proton exchange membrane (PEM) resulting in a decrease in performance. In addition it was found that a single EHC has a better compression ratio and reaction rate than a double EHC. The experimental results were compatible with the theoretical calculations within less than a 7% deviation. Finally the conditions required to reach commercialization were evaluated using the theoretical model.
Pathways to the Hydrogen Economy: A Multidimensional Analysis of the Technological Innovation Systems of Germany and South Korea
Aug 2023
Publication
The global trend towards decarbonization and the demand for energy security have put hydrogen energy into the spotlight of industry politics and societies. Numerous governments worldwide are adopting policies and strategies to facilitate the transition towards hydrogen-based economies. To assess the determinants of such transition this study presents a comparative analysis of the technological innovation systems (TISs) for hydrogen technologies in Germany and South Korea both recognized as global front-runners in advancing and implementing hydrogen-based solutions. By providing a multi-dimensional assessment of pathways to the hydrogen economy our analysis introduces two novel and crucial elements to the TIS analysis: (i) We integrate the concept of ‘quality infrastructure’ given the relevance of safety and quality assurance for technology adoption and social acceptance and (ii) we emphasize the social perspective within the hydrogen TIS. To this end we conducted 24 semi-structured expert interviews applying qualitative open coding to analyze the data. Our results indicate that the hydrogen TISs in both countries have undergone significant developments across various dimensions. However several barriers still hinder the further realization of a hydrogen economy. Based on our findings we propose policy implications that can facilitate informed policy decisions for a successful hydrogen transition.
Economic and Environmental Potential of Green Hydrogen Carriers (GHCs) Produced via Reduction of Amine-capture CO2
Jun 2023
Publication
Hydrogen is deemed as a crucial component in the transition to a carbon-free energy system and researchers are actively working to realize the hydrogen economy. While hydrogen derived from renewable energy sources is a promising means of providing clean energy to households and industries its practical usage is currently hindered by difficulties in transportation and storage. Due to the extreme operating conditions required for liquefying hydrogen various hydrogen carriers are being considered which can be transported and stored at mild operating conditions and provide hydrogen at the site of usage. Among various candidates green hydrogen carriers obtained via carbon dioxide utilization have been proposed as an economically and environmentally feasible option. Herein the potential of using methanol and formic acid as green hydrogen carriers are evaluated regarding various production and dehydrogenation pathways within a hydrogen distribution system including the recycle of carbon dioxide. Recent progress in carbon dioxide utilization processes especially conversion of carbon dioxide captured in amine solutions have demonstrated promising results for methanol and formic acid production. This study analyzes seven scenarios that consider carbon dioxide utilization-based thermocatalytic and electrochemical methanol and formic acid production as well as different dehydrogenation pathways and compares them to the scenario of delivering liquefied hydrogen. The scenarios are thoroughly analyzed via techno-economic analysis and life cycle assessment methods. The results of the study indicate that methanol-based options are economically viable reducing the cost up to 43% compared to liquefied hydrogen delivery. As for formic acid only the electrochemical production method is profitable retaining 10% less cost compared to liquefied hydrogen delivery. In terms of environmental impact all of the scenarios show higher global warming impact values than liquefied hydrogen distribution. However results show that in an optimistic case where wind electricity is widely used electrochemical formic acid production is competitive with liquefied hydrogen distribution retaining 39% less global warming impact values. This is because high conversion can be achieved at mild operating conditions for the production and dehydrogenation reactions of formic acid reducing the input of utilities other than electricity. This study suggests that while methanol can be a shortterm solution for hydrogen distribution electrochemical formic acid production may be a viable long-term option.
Enhancing Safety through Optimal Placement of Components in Hydrogen Tractor: Rollover Angle Analysis
Feb 2024
Publication
Hydrogen tractors are being developed necessitating consideration of the variation in the center of gravity depending on the arrangement of components such as power packs and cooling modules that replace traditional engines. This study analyzes the effects of component arrangement on stability and rollover angle in hydrogen tractors through simulations and proposes an optimal configuration. Stability is evaluated by analyzing rollover angles in various directions with rotations around the tractor’s midpoint. Based on the analysis of rollover angles for Type 1 Type 2 and Type 3 hydrogen tractors Type 2 demonstrates superior stability compared to the other types. Specifically when comparing lateral rollover angles at 0◦ rotation Type 2 exhibits a 2% increase over Type 3. Upon rotations at 90◦ and 180◦ Type 2 consistently displays the highest rollover angles with differences ranging from approximately 6% to 12% compared to the other types. These results indicate that Type 2 with its specific component arrangement offers the most stable configuration among the three types of tractors. It is confirmed that the rollover angle changes based on component arrangement with a lower center of gravity resulting in greater stability. These findings serve as a crucial foundation for enhancing stability in the future design and manufacturing phases of hydrogen tractors.
Role of a Unitized Regenerative Fuel Cell in Remote Area Power Supply: A Review
Aug 2023
Publication
This manuscript presents a thorough review of unitized regenerative fuel cells (URFCs) and their importance in Remote Area Power Supply (RAPS). In RAPS systems that utilize solar and hydrogen power which typically include photovoltaic modules a proton exchange membrane (PEM) electrolyzer hydrogen gas storage and PEM fuel cells the cost of these systems is currently higher compared to conventional RAPS systems that employ diesel generators or batteries. URFCs offer a potential solution to reduce the expenses of solar hydrogen renewable energy systems in RAPS by combining the functionalities of the electrolyzer and fuel cell into a single unit thereby eliminating the need to purchase separate and costly electrolyzer and fuel cell units. URFCs are particularly well-suited for RAPS applications because the electrolyzer and fuel cell do not need to operate simultaneously. In electrolyzer mode URFCs function similarly to stand-alone electrolyzers. However in fuel cell mode the performance of URFCs is inferior to that of stand-alone fuel cells. The presented review summarizes the past present and future of URFCs with details on the operating modes of URFCs limitations and technical challenges and applications. Solar hydrogen renewable energy applications in RAPS and challenges facing solar hydrogen renewable energy in the RAPS is discussed in detail.
Techno‑Economic Comparative Analysis of Two Hybrid Renewable Energy Systems for Powering a Simulated House, including a Hydrogen Vehicle Load at Jeju Island
Nov 2023
Publication
This work undertakes a techno‑economic comparative analysis of the design of photo‑ voltaic panel/wind turbine/electrolyzer‑H2 tank–fuel cell/electrolyzer‑H2 tank (configuration 1) and photovoltaic panel/wind turbine/battery/electrolyzer‑H2 tank (configuration 2) to supply electricity to a simulated house and a hydrogen‑powered vehicle on Jeju Island. The aim is to find a system that will make optimum use of the excess energy produced by renewable energies to power the hydrogen vehicle while guaranteeing the reliability and cost‑effectiveness of the entire system. In addition to evaluating the Loss of Power Supply Probability (LPSP) and the Levelized Cost of Energy (LCOE) the search for achieving that objective leads to the evaluation of two new performance indicators: Loss of Hydrogen Supply Probability (LHSP) and Levelized Cost of Hydrogen (LCOH). After anal‑ ysis for 0 < LPSP < 1 and 0 < LHSP < 1 used as the constraints in a multi‑objective genetic algorithm configuration 1 turns out to be the most efficient loads feeder with an LCOE of 0.3322 USD/kWh an LPSP of 0% concerning the simulated house load an LCOH of 11.5671 USD/kg for a 5 kg hydrogen storage and an LHSP of 0.0043% regarding the hydrogen vehicle load.
A Computational Study of Hydrogen Dispersion and Explosion after Large-Scale Leakage of Liquid Hydrogen
Nov 2023
Publication
This study employs the FLACS code to analyze hydrogen leakage vapor dispersion and subsequent explosions. Utilizing pseudo-source models a liquid pool model and a hybrid model combining both we investigate dispersion processes for varying leak mass flow rates (0.225 kg/s and 0.73 kg/s) in a large open space. We also evaluate explosion hazards based on overpressure and impulse effects on humans. The computational results compared with experimental data demonstrated reasonable hydrogen vapor cloud concentration predictions especially aligned with the wind direction. For higher mass flow rate of 0.73 kg/s the pseudo-source model exhibited the most reasonable predictive performance for locations near the leak source despite the hybrid model yielded similar results to the pseudo-source model while the liquid pool model was more suitable for lower mass flow rate of 0.225 kg/s. Regarding explosion analyses using overpressure-impulse diagram higher mass flow rates leaded to potentially fatal overpressure and impulse effects on humans. However lower mass flow rates may cause severe eardrum damage at the maximum overpressure point.
H2 URESONIC: Design of a Solar-Hydrogen University Renewable Energy System for a New and Innovative Campus
Feb 2024
Publication
The necessity to move to sustainable energy solutions has inspired an investigation of innovative technologies for satisfying educational institutions’ sustainable energy needs. The possibility of a solar-hydrogen storage system and its integration into university energy management is investigated in this article. The study opens by providing context noting the growing relevance of renewable energy in universities as well as the necessity for effective energy storage systems. The goal is to delve into solar-hydrogen technology outlining its components operating mechanism and benefits over typical storage systems. The chapter on Integration Design examines current university energy infrastructure identifies problems and provides ways for integrating solar-hydrogen systems seamlessly. This integration relies heavily on technological and economic considerations such as a cost-benefit analysis and scalability studies. Case studies include real-world examples performance measurements and significant insights learned from successful implementations. The chapter Future Prospects investigates new trends in solar-hydrogen technology as well as the impact of government legislation providing a forward-looking viewpoint for colleges considering adoption. The report concludes with a summary of significant findings emphasizing the benefits of solar-hydrogen integration and making recommendations for future implementations. The limitation of this research is that it only focuses on design and simulation as a phase of preliminary study.
Development of Liquid Organic Hydrogen Carriers for Hydrogen Storage and Transport
Jan 2024
Publication
The storage and transfer of energy require a safe technology to mitigate the global environmental issues resulting from the massive application of fossil fuels. Fuel cells have used hydrogen as a clean and efficient energy source. Nevertheless the storage and transport of hydrogen have presented longstanding problems. Recently liquid organic hydrogen carriers (LOHCs) have emerged as a solution to these issues. The hydrogen storage technique in LOHCs is more attractive than those of conventional energy storage systems like liquefaction compression at high pressure and methods of adsorption and absorption. The release and acceptance of hydrogen should be reversible by LOHC molecules following favourable reaction kinetics. LOHCs comprise liquid and semi-liquid organic compounds that are hydrogenated to store hydrogen. These hydrogenated molecules are stored and transported and finally dehydrogenated to release the required hydrogen for supplying energy. Hydrogenation and dehydrogenation are conducted catalytically for multiple cycles. This review elaborates on the characteristics of different LOHC molecules based on their efficacy as energy generators. Additionally different catalysts used for both hydrogenation and dehydrogenation are discussed.
Recent Developments in Materials for Physical Hydrogen Storage: A Review
Jan 2024
Publication
The depletion of reliable energy sources and the environmental and climatic repercussions of polluting energy sources have become global challenges. Hence many countries have adopted various renewable energy sources including hydrogen. Hydrogen is a future energy carrier in the global energy system and has the potential to produce zero carbon emissions. For the non-fossil energy sources hydrogen and electricity are considered the dominant energy carriers for providing end-user services because they can satisfy most of the consumer requirements. Hence the development of both hydrogen production and storage is necessary to meet the standards of a “hydrogen economy”. The physical and chemical absorption of hydrogen in solid storage materials is a promising hydrogen storage method because of the high storage and transportation performance. In this paper physical hydrogen storage materials such as hollow spheres carbon-based materials zeolites and metal– organic frameworks are reviewed. We summarize and discuss the properties hydrogen storage densities at different temperatures and pressures and the fabrication and modification methods of these materials. The challenges associated with these physical hydrogen storage materials are also discussed.
Life Cycle Cost Analysis of an Autonomous Underwater Vehicle that Employs Hydrogen Fuel Cell
Feb 2024
Publication
The use of autonomous vehicles for marine and submarine work has risen considerably in the last decade. Developing new monitoring systems navigation and communications technologies allows a wide range of operational possibilities. Autonomous Underwater Vehicles (AUVs) are being used in offshore missions and applications with some innovative purposes by using sustainable and green energy sources. This paper considers an AUV that uses a hydrogen fuel cell achieving zero emissions. This paper analyses the life cycle cost of the UAV and compares it with a UAV powered by conventional energy. The EN 60300-3-3 guidelines have been employed to develop the cost models. The output results show estimations for the net present value under different scenarios and financial strategies. The study has been completed with the discount rate sensibility analysis in terms of financial viability.
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