• Transactions of the Korean hydrogen and new energy society
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• v.13 no.4
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• pp.330-338
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• 2002

A long-term energy system in the future is expected to be based on the ideal circulation system between water and hydrogen in the sense that the hydrogen prepared from water eventually returns to water again after its use. Currently, with respect to the hydrogen energy system, it is predicted that the turning-point at which the production cost of hydrogen will become to be lower than that of fossil fuels would be after 2010. However, fuel cell technology would be able to be practically used for the applications to the transportation vehicles and small-scale power sources from 2004, and therefore, an efficient construction of the infrastructure covering hydrogen production and supply systems would be required with short-/mid-term technologies for the $CO_2$ reduction associated with fossil fuel utilization. In this paper, the hydrogen quantity available in domestic market has been estimated focusing on the hydrogen by-produced from domestic industries, and also the infrastructure for hydrogen-driven vehicles like fuel cell cars has been reviewed.

• Transactions of the Korean hydrogen and new energy society
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• v.33 no.4
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• pp.309-317
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• 2022

There are 2,517 buses on 143 routes in Busan. One company is operating 36 hydrogen city buses (1.4%) and two hydrogen charging stations. By 2030, the number of hydrogen city buses will be increased to 500 and 40 hydrogen charging stations. In the survey of city bus companies, 61.5% of respondents answered 'not reviewing (at all)' and 23.0% of respondents '(actively) reviewing hydrogen buses'. And as for the level of help that hydrogen city buses give to bus companies, 23.5% answered 'helpful'. In order to promote the introduction of hydrogen city buses, first, it is necessary to stipulate support for hydrogen bus purchase cost and hydrogen charging station construction cost in related ordinances so that bus companies do not increase their burden of purchasing hydrogen buses in the future. Second, identify the number of new city buses introduced, convert about 50% to hydrogen city buses by the mid-term, and build 50% of the chargers in public garages with hydrogen chargers. Third, expand hydrogen refueling stations in city bus garages.

• Journal of Welding and Joining
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• v.34 no.6
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• pp.42-46
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• 2016

Hydrogen assisted cracking (HAC) is one of the most complicated problem in welding. Huge amount of studies have been done for decades. Based on them, various standards have been established to avoid HAC. But it is still a chronic problem in industrial field. It is well known that the main causes of the hydrogen crack are residual stress, crack susceptible micro structures and a certain critical level of hydrogen concentration. Even though the exact generating mechanism is unclear till today, it has been reported that the hydrogen level in the weld metal should be managed less than a certain amount to prevent it. Matsuda studied that the residual hydrogen level in the weld metal can be varied even if the initial hydrogen content is same. It is also insisted in this report that the residual hydrogen concentration is in stronger correlation with hydrogen crack than the initial hydrogen content. But, in practical point of view, the residual hydrogen is still hard to consider because measuring hydrogen level is time and cost consuming process. In this regard, numerical analysis is the only solution for considering the residual hydrogen content. Meanwhile, Takahashi showed the possibility of predicting the residual hydrogen by a rigorous FE analysis. But, few commercial software suitable for solving the weld metal hydrogen has been reported yet. In this study, two dimensional thermal - hydrogen coupled analysis was developed by using the commercial FE software MARC. Since the governing equation of the hydrogen diffusion is similar to the heat transfer, it is shown that the heat transfer FE analysis in association with hydrogen diffusion property can be used for hydrogen diffusion analysis. A series of simulation was performed to verify the accuracy of the model. For BOP (Bead-On-Plate) and the multi-pass butt welding simulations, remaining hydrogen contents in the weld metal is well matched with measurements which are referred from Kim and Masamitsu.

• Transactions of the Korean hydrogen and new energy society
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• v.21 no.4
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• pp.346-353
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• 2010

Hydrogen fueled vehicle was evaluated as one of the next-generation technology that will be able to solve the global warming, depletion of fossil fuel and etc. The practical use of hydrogen fueled vehicle, nevertheless, is being delayed more than expected schedule due to various causes. In order to promote the dissemination of hydrogen fueled vehicle, development status and obstacle factors of practical use for hydrogen fueled vehicles were reviewed and the strategy plans for dissemination promotion were proposed. Hydrogen fueled vehicles are included the hydrogen fuel cell, neat and enriched hydrogen fueled engines. The technicalness, economy, safety, cognizance, system, support and etc were considered in the strategy plans.

• Transactions of the Korean hydrogen and new energy society
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• v.31 no.5
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• pp.459-466
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• 2020

As the hydrogen industry grows, expansion of infrastructure for hydrogen supply is required, but the safety of hydrogen facilities is concerned due to the recent accidents at the Gangneung hydrogen tank and the Norwegian hydrogen fueling station. In this study, the damage range and impact analysis on the on-site hydrogen fueling station was conducted using Hy-KoRAM. This is a domestically developed program that adds functions based on HyRAM. Through this risk assessment, it was evaluated whether the on-site hydrogen fueling station meets international standards and suggested ways to improve safety.

• Transactions of the Korean hydrogen and new energy society
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• v.34 no.6
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• pp.562-574
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• 2023

Carbon neutrality has been suggested to overcome the global climate crisis caused by global climate change. Hydrogen energy is a major way to achieve carbon neutrality, and the developments and policies of hydrogen technology have been proposed to achieve this goal. To commercialize hydrogen energy resources, it is necessary to understand the overall value chain composed of hydrogen production, storage, and utilization and to present the direction of technological developments. In this paper the hydrogen strategies of major countries, including Europe, the United States, Japan, China, and South Korea will be analyzed, and hydrogen technologies by value chain will also be explain. This paper will contribute to understanding the overall hydrogen policy and technology, as both policy and technology are summarized.

• Transactions of the Korean hydrogen and new energy society
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• v.12 no.2
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• pp.75-86
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• 2001

In this paper it has been compared briefly the hydrogen storage using hydrogen storage alloys with other technologies and introduced the general properties of hydrogen storage alloys. The recent research trends and activities related to hydrogen storage alloys were given here.

• Transactions of the Korean hydrogen and new energy society
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• v.31 no.6
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• pp.605-613
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• 2020

In July and October of this year, the government announced the 'Green new deal plan within the Korean new deal policy' and 'Strategies for proliferation of future vehicles and market preoccupation'. And, in response to changes in the global climate agreement, it has decided to expand green mobility such as electric vehicles and hydrogen electric vehicles with the aim of a "net-zero" society. Accordingly, the goal is to build 310 hydrogen refueling stations along with the supply of 60,000 hydrogen vehicles in 2022, and the hydrogen infrastructure is being expanded. however, it is difficult to secure hydrogen infrastructure due to expensive construction costs and difficulty the selection of a site. In Korea, it is possible to build a mobile hydrogen station according to the safety standards covering special case of the Ministry of Industry. Since the mobile hydrogen station can be charged while moving between authorized place, it has the advantage of being able to meet a large number of demands with only one hydrogen refueling station, so it is proposed as a model suitable for the early market of hydrogen infrastructure. This study demonstrates the establishment of a hydrogen refueling station by deriving a virtual accident scenario for leakage and catastrupture for each facility for the risk factors in a mobile hydrogen station, and performing a quantitative risk assessment through the derived scenario. Through the virtual accident scenario, direction of demonstration and implications for the construction of a mobile hydrogen refueling station were derived.

• Transactions of the Korean hydrogen and new energy society
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• v.32 no.6
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• pp.565-572
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• 2021

Hydrogen is currently produced from natural gas reforming or industrial process of by-product over than 90%. Additionally, there are green hydrogens based on renewable energy generation, but the import of green hydrogen from other countries is being considered due to the output variability depending on the weather and climate. Due to low density of hydrogen, it is difficult to storage and import hydrogen of large capacity. For improving low density issue of hydrogen, the gaseous hydrogen is liquefied and stored in cryogenic tank. Density of hydrogen increase from 0.081 kg/m³ to 71 kg/m3 when gaseous hydrogen transfer to liquid hydrogen. Density of liquid hydrogen is higher about 800 times than gaseous. However, since density and boiling point of liquid hydrogen is too lower than liquefied natural gas approximately 1/6 and 90 K, to store liquid hydrogen for long-term is very difficult too. To overcome this weakness, this paper introduces storage method of hydrogen based on liquid/solid (slush) and facilities for producing slush hydrogen to improve low density issue of hydrogen. Slush hydrogen is higher density and heat capacity than liquid hydrogen, can be expected to improve these issues.

• Transactions of the Korean hydrogen and new energy society
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• v.19 no.2
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• pp.145-155
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• 2008

This paper deals with an economic evaluation of hydrogen production by fermentation. We evaluate the economic feasibility of domestic hydrogen production by fermentation utilizing glucose and waste water sludge in terms of hydrogen production prices. In addition, we make some sensitivity analysis of hydrogen prices by changing the values of input factors such as the price of glucose, the capital cost of the hydrogen production system, and the hydrogen production yields. The estimated hydrogen prices of the two-step dark-light hydrogen production by fermentation utilizing glucose was $5,347won/kgH_2$, and the single-step hydrogen production by anaerobic fermentation utilizing waste water sludge was $4,255won/kgH_2$, respectively. It is expected that the hydrogen production price by anaerobic fermentation can be reduced if we produce methane or hydrogen utilizing by-products such as alcohols and organic acids, or the government imposes some legal regulations on the treatment of waste water sludge.