• Journal of the Korea Convergence Society
• /
• v.9 no.11
• /
• pp.253-262
• /
• 2018

Recently, the energy industry is implementing renewable energy supply policy to reduce energy consumption. The purpose of this study is to build a database that can help promote the supply of geothermal energy system to prepare for the increase of renewable energy demand and to develop a method to evaluate the possibility of geothermal energy system installation by using database information. The data used in the study was reliable using open data provided by national agencies. We obtained information necessary for the possibility of geothermal energy system installation, constructed a dedicated database, and studied the method of calculating the geothermal well capacity by using the database information. In the future, this study will establish a local environmental evaluation standard and add information on other renewable energy to contribute to the activation of renewable energy supply.

• Journal of Advanced Marine Engineering and Technology
• /
• v.26 no.2
• /
• pp.256-263
• /
• 2002

The Boil-Off-Gases(BOG) in the LNG production terminal are continuously generated during the unloading, storage and supply processes by the heat penetration. In order to use these gases as useful fuel, the reliquefaction process should be installed to put the reliquefied BOG in the main LNG supply line before the secondary pump in terminal. The current reliquefaction method of BOG in LNG terminal is the direct contact one between LNG and BOG in the absorption column. But the system has severe disadvantage, which is the 10 times of LNG circulation needed for unit mass of BOG reliquefaction. It causes, therefore, high power consumption of LNG circulation pump and excessive city-gas supply, even if short demand of NG is needed in the summer time. In this paper, the new reliquefaction system of BOG by using LNG cold energy with indirect contact in precooler was suggested and analysed. The result showed new indirect contact method of BOG reliquefaction system between LNG cold energy and BOG is much more effective than the current direct contact one because of only about 1.3 times of LNG circulation needed and higher energy saving by pump power reduction.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.66 no.3
• /
• pp.486-492
• /
• 2017

In recent years, renewable energy sources have been mentioned as solution to environmental regulation and energy supply-demand. Energy storage systems are needed to mitigate the intermittent output characteristics of renewable energy sources and to operate micro grid efficiently using renewable energy generation systems. However, despite the necessity of energy storage system, this cannot secure the economical efficiency of the energy storage system by high initial cost. In this paper, a micro grid is constructed to supply electric power to industrial customers by using solar power generation system and energy storage system among renewable energy generation power sources and operated to improve energy independence. In the case study, we use photovoltaic system which is representative renewable energy generation system. Unlike conventional photovoltaic system, this system uses floating photovoltaic system with the advantage of having high output and no land area limitations. It is operated for the purpose of improving energy independence in the micro grid. In order to secure economical efficiency, the energy storage system operates a micro grid with a minimum capacity. Finally, this paper calculates the appropriate subsidy for the energy storage capacity.

• Journal of Energy Engineering
• /
• v.2 no.3
• /
• pp.239-250
• /
• 1993

아시아 북방국가중 에너지자원이 많아 수출의 가능성이 있는 나라들은 러시아, 중국, 베트남, 서남아시아 CIS 공화국 등이다. 이들은 경제발전단계가 우리나라의 중간재와 내구성 소비재를 수입하는 단계이기 때문에, 향후 우리나라와의 교역관계가 매우 증대할 전망이다. 그러나 이들 국가들은 경화의 지불능력이 약하기 때문에 이들이 가진 에너지를 수입할 수 있다면 교역은 더욱 확대될 수 있다. 여기에 이들 나라들의 에너지 수출가능성이 우리의 관심사가 된다.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.62 no.11
• /
• pp.1495-1504
• /
• 2013

Renewable energy integration and increased system complexities make system operator maintain supply and demand balance harder than before. To keep the grid frequency in a stable range, an appropriate spinning reserve margin should be procured with consideration of ever-changing system situation, such as demand, wind power output and generator failure. This paper propose a novel concept of dynamic reserve, which arrange different spinning reserve margin depending on time. To investigate the effectiveness of the proposed dynamic reserve, we developed a new short-term reliability criterion that estimates the probability of a spinning reserve shortage events, thus indicating grid frequency stability. Uncertainties of demand forecast error, wind generation forecast error and generator failure have been modeled in probabilistic terms, and the proposed spinning reserve has been applied to generation scheduling. This approach has been tested on the modified IEEE 118-bus system with a wind farm. The results show that the required spinning reserve margin changes depending on the system situation of demand, wind generation and generator failure. Moreover the proposed approach could be utilized even in case of system configuration change, such as wind generation extension.

• Journal of Advanced Marine Engineering and Technology
• /
• v.31 no.5
• /
• pp.514-521
• /
• 2007

There has been considerable interest recently in the topic of renewable energy. This is primarily due to concerns about environmental impacts. Moreover, fluctuating and rising oil prices, increases in demand, supply uncertainties and other factors have led to increased calls for alternative energy sources. Small hydropower, especially using water supply system, attracts high attentions because of relatively lower cost and smaller space requirements to construct the plant. Moreover. newly developed positive displacement turbine has high acceptability for the system. Therefore, the purpose of this study is focused on the examination of the performance characteristics and proposition of a optimum design method of the turbine for the improvement of the performance. The results show that newly proposed optimum design method for the turbine has high accuracy of performance prediction and good applicability for the performance improvement of the turbine.

• Resources Recycling
• /
• v.22 no.5
• /
• pp.3-12
• /
• 2013

It is necessary to manage risk of metals which are has rigid supply structures and expected demand expansion, considering to industry structure and resource securing capacity of each country. Countries conducted various criticality analyses and selected mainly rare metals as critical materials(or Critical metals or Critical raw materials). This study examined cases of metals risk evaluation and management which are based on technology changes and imbalance supply-demand. EU and U.S.A evaluated risk on metals needed as supply expansion of renewable energy. Japan forecasted demand of rare metals needed in Japan's growth engine industry. U.K analyzed criticality of metals, considering environmental burden occurred from mining to refining. Critical materials has features such as weak price signal, inelastic supply structure, demand volatility in technology change.

• Bulletin of the Korea Photovoltaic Society
• /
• v.3 no.2
• /
• pp.48-54
• /
• 2017

Nowadays Viet Nam's energy supply which is mainly produced by fossil fuels energy such as coal, gas, and oil. However, the operation of fossil fuel power plants is one of the major causes of environmental pollution and climate change as well. It has a serious impact on the survival of human beings in general. As can be seen, the manufacturing industry is strongly invested, the demand for energy is also increasing. As traditional fossil fuels are being depleted and to minimize environmental pollution, renewable energy is the solution widely used by many countries in the world. Therefore, renewable energy has a significant role in maintaining the sustainability of world economy. Renewable energy sources such as solar energy, wind energy, biomass energy, geothermal energy can supply clean and nature-sourced energy to replace fossil fuels. Encouraging development of renewables is a general trend in the world today, which is also a common goal of COP21 commitment on global GHG reduction. The objective of this study is to assess the opportunities and challenges for renewable energy development in Vietnam, particularly for solar power. This study also discusses policies to promote the development of solar energy in Vietnam. While solar power provides ecological, economic and social benefits, it is exploited very modestly in Vietnam, where there are many barriers to slow down the development of renewable energy.

• Transactions of the Korean hydrogen and new energy society
• /
• v.15 no.4
• /
• pp.324-332
• /
• 2004

According to the rapid depletion of the fossil fuels, the electricity and hydrogen will gradually take charge of the future energy supply. Especially, in order to control the supply and demand of electricity, energy storage medium is necessary and this could be solved by the combination of water electrolysis and fuel cell. Although electricity can be generated from such alternative energies as hydropower, nuclear, solar, and wind-power resources, alternative energy storage medium is also required since regenerative energies, solar and wind-powers, are intermittent energy resources. In this regard, hydrogen production from water electrolysis was recognized as a superb method for electricity storage. In this work, the current development and economic status of alkaline, solid polymer, and high temperature electrolysis were reviewed, and then the practical use of water electrolysis technology were discussed.

• Journal of Climate Change Research
• /
• v.8 no.3
• /
• pp.265-273
• /
• 2017

Recently the Paris Climate Change Accord has been officially put into effect, making global efforts to implement Greenhouse Gas (GHG) reductions, and also International environmental regulations in the automotive sector will be further strengthened. The electric vehicle, which minimizes the particulate matter generated by existing internal combustion engine automobiles, is evaluated as a representative eco-friendly automobile. However, charging the battery of an electric vehicle is not fully environment-friendly if it is fueled by electricity that is being generated by fossil fuels as an energy source. The energy generated by the photovoltaic power generation system, which is an infinite clean energy, can be used to charge an electric vehicle's battery. Currently, shortage of charging facilities, time of charging, and high battery prices are the problem of activating the supply of electric vehicles. This study is to build a conjunction between the EVBSS (Electric Vehicle Battery Supply System) and ESS (Energy Storage System), which can quickly supply the photovoltaic charged battery to the required demand. If the charged battery in the Battery Swapping Station (BSS) is swapped swiftly, it will dramatically shorten the waiting time for charging the battery. As a result, if the battery is rented when it is needed, electric vehicles can be sold without the cost of a battery, which accounts for a large portion of the total cost, then the supply of electric vehicles are expected to expand. Furthermore, it will be an important alternative to maneuver climate change by minimizing GHG emissions from internal combustion engine vehicles.