• Current Photovoltaic Research
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• v.8 no.4
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• pp.124-128
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• 2020

Output power of photovoltaic (PV) modules installed outdoors decreases every year due to environmental conditions such as temperature, humidity, and ultraviolet irradiations. In order to promote the installation of PV modules, the reliability must be guaranteed. One of the important factors affecting reliability is intermetallic compounds (IMC) layer formed in ribbon solder joint. For this reason, various studies on soldering properties between the ribbon and cell have been performed to solve the reliability deterioration caused by excessive growth of the IMC layer. However, the IMC layer of the PV module interconnected by multi-wires has been studied less than using the ribbon. It is necessary to study soldering characteristics of the multi-wire module for improvement of its reliability. In this study, we analyzed the growth of IMC layer of the PV module with multi-wire and the degradation of output power through damp-heat test. The fabricated modules were exposed to damp-heat conditions (85 ºC and 85 % relative humidity) for 1000 hours and the output powers of the modules before and after the damp-heat test were measured. Then, the process of dissolving ethylene vinyl acetate (EVA) as an encapsulant of the modules was performed to observe the IMC layer. The growth of IMC layer was evaluated using OM and FE-SEM for cross-sectional analysis and EDS for elemental mapping. Based on these results, we investigated the correlation between the IMC layer and output power of modules.

• Journal of the Korean Ceramic Society
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• v.51 no.4
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• pp.231-242
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• 2014

An interconnect in solid oxide fuel cells (SOFCs) electrically connects unit cells and separates fuel from oxidant in the adjoining cells. The interconnects can be divided broadly into two categories - ceramic and metallic interconnects. A thin and gastight ceramic layer is deposited onto a porous support, and metallic interconnects are coated with conductive ceramics to improve their surface stability. This paper provides a short review on ceramic materials for SOFC interconnects. After a brief discussion of the key requirements for interconnects, the article describes basic aspects of chromites and titanates with a perovskite structure for ceramic interconnects, followed by the introduction of dual-layer interconnects. Then, the paper presents protective coatings based on spinel-or perovskite-type oxides on metallic interconnects, which are capable of mitigating oxide scale growth and inhibiting Cr evaporation.

• New & Renewable Energy
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• v.8 no.3
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• pp.30-37
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• 2012

In this study, we studied solar cell and fuel cell. To estimate the technology competitiveness, we used patent analysis using patent information and delphi method. For patent analysis, PII indicating the impact of patent was used. Also to analysis PII, citations data of registered and published patent were used from 2001 through 2010 in the United States, Japan, South Korea and the European Patent Office. And the delphi method results of the 'International trend analysis on the Green Energy Technology and the establishment of international cooperation models(2009)' were cited to estimate the technology level. According to the analysis results, Korea's patent registration growth rate was fairly high, but the patent impact and technology levels were significantly lower than in the United States, Japan and Germany. Especially in the solar cell, United States's PII is 1.8, but Korea's PII is 0.2. And the technology level of United States is 7 to 8, but Korea's is 5 to 6. Therefore, to improve technology competitiveness, Korea need to enhance the core technology R&D, and set up the consumer-oriented R&D strategy for commercialization from R&D planning phase. In this study, we analysed competitiveness of renewable energy which is not actively discussed. But there are limitations of the study because we used the result of past research and patent data in the past 10 years. Therefore to accurate research the period of patent data should be extended. Finally diverse indicators for measuring the technology competitiveness should be researched and developed.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.5 no.2
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• pp.7-12
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• 2009

The fossil fuel has been used as the main resource of national development. Through this process, many environmental problems have happened. For example, we depend 97% energy on import for national spending and the exhaustion of the fossil fuel is at an important issue nowadays. So more people are interested in renewable energy which is more environmental and never be gone. However, the supply doesn't go on smoothly because of some problems such as capital condition, the limitation of geographical features and low technology, etc. In conclusion I'd like to check some policies and support systems about renewable energy first, and then to find problems for adapting other area through the comparison in this thesis.

• New & Renewable Energy
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• v.7 no.4
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• pp.10-17
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• 2011

Recently, electricity industry is facing high market uncertainty which has ever had and which increase risks in power market. In this study, we analyze risk factors such as discount rates, initial investment (overnight cost), plant factor, fuel cost, carbon price, etc, for the perspective of investor. For the analysis of risk factors, we used LCOE method. The results of this study show that renewable energy is more affected by plant factor and overnight cost than other risk factors. First, Renewable energy has higher proportion of overnight cost in the total investment than that of other technologies. Second, renewable energy is free of fuel cost and carbon price so plant factor is the most important factor, in other words, competitiveness of renewable energy depends on plant factor. Furthermore, we conducted economic feasibility of wind power and PV in domestic case study. The minimum requirement condition to get profitability is that plant factor 15% and overnight cost \6,000,000/kW and 26%, \2,200,000/kW for PV and Wind Power, respectively.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.109.1-109.1
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• 2011

KEPCO was operating power plants with diesel generators in 49 islands including Baekryeong-Do, and the generation capacity was about 66 MW in 2008. The cost of fuel is increasing by the international oil price inflation and continuous rise of oil price is predicted. For the stabilizing of electric power supply to the separate islands, renewable energy and fuel cell systems were considered. Hydrogen is made using renewable energy such as wind power and solar energy, and then a fuel cell system generates electricity with the stored hydrogen. Though the system efficiency is low, it is treated as the only way to secure the stable electric supply using renewable energy at this present. The analytic hierarchy process was used to select suitable candidate island for the system installation and 5 islands including Ulleung-Do were selected. Economic evaluation for the system composed of a kerosene generator, a wind power, an electrolysis, and a fuel cell system was conducted with levelized generation cost based on present value methode. As the result, the necessity of renewable energy combined generation system and micro grid composition in the candidated islands was confirmed. Henceforth, the development of an integration technology which connects micro grid to the total power grid will be needed.

• Transactions of the Korean hydrogen and new energy society
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• v.26 no.5
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• pp.484-492
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• 2015

As our government is actively introducing the RPS (Renewable Portfolio Standards) as a national renewable energy obligation policy, power producers are using the various renewable energy to meet the RPS supply quota since 2012. Recently, it is appling to use power bio-fuel oil in bio-fuel oil demonstration project with power companies. In general, power bio-fuel oils are composed of mixture products of vegetable oil, animal fat, fatty acid ester and waste oil. It is already developing for a power plant as a renewable energy abroad. In Korea, it is studying a 100% combustion and blended combustion of heavy fuel oil and bio-fuel oil. In this study, we investigated fuel characteristics of mixed power bio-fuel oil and its emission performance. Especially, it was reduced emissions of bio-oil in industrial boilers due to bio-fuel properties as compare with fuel oil.

• Journal of Energy Engineering
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• v.23 no.4
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• pp.31-40
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• 2014

The Korean government made the 2nd Energy Basic Plan to achieve 11% of new and renewable energies distribution rate until 2035 as a response to cope with international discussion about greenhouse gas emission reduction. Renewable energies include solar thermal, photovoltaic, bioenergy, wind power, small hydropower, geothermal energy, ocean energy, and waste energy. New energies contain fuel cells, coal gasification and liquefaction, and hydrogen. As public and private investment to enhance the distribution of new and renewable energies, it is necessary to clarify the economic effects of the new and renewable energies sector. To the end, this study attempts to apply an input-output analysis and analyze the economic effects of new and renewable energies sector using 2012 input-output table. Three topics are dealt with. First, production-inducing effect, value-added creation effect, and employment-inducing effect are quantified based on demand-driven model. Second, supply shortage effects are analyzed employing supply-driven model. Lastly, price pervasive effects are investigated applying Leontief price model. The results of this analysis are as follows. First, one won of production or investment in new and renewable energies sector induces 2.1776 won of production and 0.7080 won of value-added. Moreover, the employment-inducing effect of one billion won of production or investment in new and renewable energies sector is estimated to be 9.0337 persons. Second, production shortage cost from one won of supply failure in new and renewable energies sector is calculated to be 1.6314 won, which is not small. Third, the impact of the 10% increase in new and renewable energies rate on the general price level is computed to be 0.0123%, which is small. This information can be utilized in forecasting the economic effects of new and renewable energies sector.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.658-661
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• 2007

It was investigated on this paper that the status of biomass energy utilization in the registered CDM projects. The ratio of the case including the energy recovery among the registered biomass CDM projects is just about 57%. Direct thermal conversion technology is the most commonly applied for biomass energy recovery projects. Through the comparative study with world renewable energy outlook, the contribution of CDM to biomass energy supply in the world is not considerable yet.

• Transactions of the Korean hydrogen and new energy society
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• v.20 no.2
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• pp.116-124
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• 2009

We investigated the influences of cobalt coating deposited by DC electroplating on the ferritic stainless steel, STS 430, as a protective layer on a metallic interconnect for SOFC applications. Cobalt coated STS 430 revealed a uniform and denser-packing oxide surface and a reduced growth rate of $Cr_2O_3$ scales after oxidation at $800^{\circ}C$in air. Cobalt coating layer was oxidized to $CoCo_2O_4$ and Co containing mixed oxide spinels such as $Co_2CrO_4$, $CoCr_2O_4$, and $CoCrFeO_4$. The area specific resistance value of Co coated sample was $0.020\;{\Omega}cm^2$ lower than that of uncoated at $800^{\circ}C$ in air during 500 h. After 1000 h oxidation, cobalt oxide coating layer suppressed chromium outward diffusion.