• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.59 no.4
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• pp.354-361
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• 2023

In this study, the AHP (analytic hierarchy process) technique was used to analyze the risk of expected risk factors and fishing possibilities during gillnet fishing within the floating offshore wind farms (floating OWF). For this purpose, the risks that may occur during gillnet fishing within the floating offshore wind farms were defined as collisions, entanglements, and snags. In addition, the risk factors that cause these risks were classified into three upper risk factors and ten sub risk factors, and the three alternatives to gillnet fishing available within the floating OWF were classified and a hierarchy was established. Lastly, a survey was conducted targeting fisheries and marine experts and the response results were analyzed. As a result of the analysis, among the top risk factors, the risk was the greatest when laying fishing gear. The risk of the sub factors for each upper risk was found to be the highest at the berthing (mooring), the final hauling of fishing net, and the laying of the bottom layer net. Based on the alternatives, the average of the integrated risk rankings showed that allowing full navigation/fisheries had the highest risk. As a result of the final ranking analysis of the integrated risk, the overall ranking of allowing navigation/fisheries in areas where bottom layer nets were laid was ranked the first when moving vessels within the floating OWF was analyzed as the lowest integrated risk ranking of the 30th at the ban on navigation/fisheries. Through this, navigation was analyzed to be possible while it was analyzed that the possibility of gillnet fishing within the floating OWF was not high.

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.3
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• pp.286-293
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• 2020

In this study, we tried to verify the correlation of the amount of combustible industrial by-products, household waste used as fuels on cement sintering process and the amount of NOx, and CO, harmful components in the exhaust gas. The analysis uses coal as natural fuel, soft plastics (plastics with properties that tend to be scattered by wind, such as vinyls), hard plastics (plastics with properties that are not scattered by wind, such as PETs, wate rubbers), and reclaimed oils as alternative fuels. Utilizing the response surface analysis (RSM) technique using the process data of 2019, such as the fuel input and combustion temperature of a domestic A cement manufacturer's sintering facilities as independent variables, and the NOx, and CO emissions to the stack as dependent variables. Correlation was analyzed. As a result, it was confirmed that the impact on the emission material differs for each waste. In particular, it was analyzed that the hard plastics increase the CO emission but have an excellent effect of reducing NOx.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.1
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• pp.75-84
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• 2021

In this study, the correlation between cement quality(chemical composition, mineral composition, and compressive strength) and amount of waste alternative fuels used in the cement manufacturing process and was investigated. Cement manufacturing facility using coal, soft plastics(plastics that are easily scattered by wind power, such as vinyls), hard plastics(plastics that do not contain foreign substances, waste rubber, PP, etc.) and reclaimed oil was analised. Data was collected for 3 years from 2017 to 2019 and let the amount of fuels used as an independent variable and cement quality data as a dependent variable. As a result, depending on the type and quality of the alternative fuel has not a significant effect on the chemical composition(Cl and LSF) and mineral composition(f-CaO, C3S contents). Contrary to the concern that the compressive strength of cement would decrease, there was a significant positive correlation between amount of alternative fuel used and cement compressive strength.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.1
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• pp.85-91
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• 2021

Aggregate waste separator with rotating separating net was designed for applying classification process of construction waste. In order to evaluate the performance of the aggregate waste separator, according to the type of waste, standardized waste samples are prepared using acrylic. The appropriate operating point was evaluated by the classification efficiency and misclassification rate of recycled aggregate according to the control frequency of the blower operating and inlet position of the separating net. The classification efficiency at the operating point of the aggregate waste separator was evaluated through flow analysis assuming recycled aggregate and waste sample as particles. As a result of the performance test, when the distance. between the conveyor belt and the inlet was 0.2m, the classification efficiency was 95%, but the misclassification rate of recycled aggregate was 2% or more, which satisfies the classification efficiency and the misclassification rate of less than 2%. The operating point was shown at a control frequency of 58Hz at a suction distance of 0.254m. As a resu lt of flow analysis, there was no misclassification of recycled aggregate. In order to redu ce constru ction waste in the existing recycled aggregate production process, adsorption system using a rotating separating net that can be operated as an installation type was built.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.6
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• pp.129-134
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• 2021

Recently, the demand for electricity is gradually increasing due to the rapid industrial development and the improvement of living standards. In the case of Korea, which is highly dependent on fossil fuels due to such a surge in electricity demand, reduction and freezing of greenhouse gas emissions due to international environmental regulations will immediately lead to a contraction in industrial activities. Accordingly, there are many difficulties in competition with advanced countries that want to link the environment with the country's industrial production activities, and the development of alternative energy as a countermeasure is of great interest around the world. Among these new power generation methods, small-scale power generation facilities with relatively small capacity include photovoltaic generation, wind power generation, and fuel cell generation. Among them, the fuel cell attracts the most attention in consideration of continuous operation, high power generation efficiency, and long-term durability, which are important factors for practical use. Therefore, in this paper, the fuel cell power generation system was researched and constructed by designing the power conversion circuit necessary to finally obtain the AC power used in our daily life by using the DC power generated from the fuel cell as an input.

• JOURNAL OF ELECTRICAL WORLD
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• s.451
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• pp.22-31
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• 2014

온실가스 다량 배출로 인한 지구온난화 현상은 많은 분야에서의 변화를 요구하고 있다. 특히 온실가스 배출의 주원인으로 꼽히고 있는 발전 등 에너지산업 분야의 경우 그 요구는 매우 거세다. 과거에는 경제성장이라는 측면만 고려하면 됐지만, 지금은 기후변화 대응을 위해 환경을 최우선적으로 고려할 것을 주문하고 있기 때문이다. 문제는 현재 전 세계적으로 약 20%에 이르는 인구가 전기 에너지를 사용하지 못하고 있다는 점이다. 즉 향후 에너지를 사용하고자 하는 신규 소비자는 더욱 늘 것이고, 산업의 발전으로 인한 에너지 소비 역시 큰 폭으로 증가할 수밖에 없다. 문제가 굉장히 어렵지만 해결책도 분명 존재한다. 결론적으로 말해 온실가스 배출을 최소화하면서도 에너지 효율은 높인 기술을 개발하면 되는 것이다. 그리고 이미 세계 각국은 청정에너지 기술개발을 위해 다각도의 노력을 펼치고 있는 상황이다. 그렇다면 세계 각국은 미래 에너지시장을 선도할 청정에너지 기술로 어떤 것을 꼽고 있을까. 이 질문에 대한 대답은 지난 5월 서울에서 개최된 '제5차 클린에너지장관회의(CEM, Clean Energy Ministerial)'에서 제시된 바 있다. CEM은 한국, 미국, 영국, 독일, 중국, 일본 등 세계 에너지의 70%를 사용하는 주요 국가의 관계 장관들이 모여 클린에너지 공급 확대와 에너지효율 향상을 위한 구체적 액션플랜을 논의하는 자리다. 2010년 미국에서 첫 회의가 열렸고 아랍에미리트, 영국, 인도에 이어 한국은 5번째로 CEM을 개최했다. 특히 이번 CEM에서는 회원국들의 의견을 모아 10대 청정에너지 혁신기술을 최초로 선정, 발표했다. CEM은 "향후 10년 간 에너지 시장의 변화를 선도할 유망 기술을 선정한 것으로 IEA 등 국제기구와 주요국 기술 로드맵을 기준으로 해 23개 회원국 회람을 거쳐 최종 확정하게 됐다"고 배경을 설명했다. 이번에 선정된 10대 청정에너지 혁신기술은 ${\triangle}$초고압직류송전 ${\triangle}$에너지저장장치 ${\triangle}$바이오연료 ${\triangle}$마이크로 그리드 ${\triangle}$탄소포집 및 저장 ${\triangle}$초고효율 태양광 발전 ${\triangle}$해상풍력 ${\triangle}$신재생에너지 하이브리드시스템 ${\triangle}$빅데이터 에너지관리시스템 ${\triangle}$지열 시스템이다. 이와 관련해 산업통상자원부 윤상직 장관은 "이번에 선정된 10개의 기술은 최근의 기술적 정책적 추세가 잘 반영된 결과"라고 평가했다. 특히 윤 장관은 "중앙집중형 공급원에서 분산형 전원으로의 변화, 에너지 효율향상의 중요성, ICT와 융 복합 추세 등 우리나라의 상황에서 시사하는 바가 크다"며 "현재 수립하고 있는 '제3차 국가에너지기술 개발계획'에 이러한 기술적 추세를 반영하겠다"는 의사를 표명했다. 향후 10년 간 에너지시장의 변화를 선도할 10대 청정에너지 유망기술을 자세히 소개한다.

• Environmental and Resource Economics Review
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• v.22 no.1
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• pp.99-125
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• 2013

Renewable energy industry not only has a promising future but also has more risk than conventional energy industry because of its characteristics. Therefore, in this study, an analysis of domestic renewable energy company risk has been performed. The risk of domestic wind and photovoltaic energy companies has been analyzed by using time varying beta model. The model has been constructed based on risk factors like firm size, firm diversification index, domestic installation, and so on. The principal result of analysis can be summarized as follows. First, risk factors affect domestic renewable energy companies have been discovered. Variables like firm size, growth rate of debt ratio, firm diversification index are statistically significant. I found that large firms are less riskier than small firms. It is also confirmed that companies with high diversification index and high debt ratio have high risk. Second, I got the result that policy factors like domestic renewable energy installation and government R&D expenditure could decrease risk of domestic renewable energy company. Third, relative sensitivity of each risk factor have been discovered. The effect of each variable gets bigger in this order: growth rate of domestic installation, firm size or diversification index, growth rate of debt ratio, growth rate of government R&D expenditure.

• Journal of Energy Engineering
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• v.20 no.1
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• pp.8-12
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• 2011

For reducing greenhouse gas emissions, the short-term strategy is of existing energy-efficient appliances to facilitate the spread of energy efficiency improvements to improve energy efficiency, energy saving projects that will include investments to enable. R&D is at the core of the long-term strategy. To reduce energy demand, the equipments and processes improved energy efficiency should be developed. In terms of energy supply, the policies for greenhouse gas reduction is to replace fossil fuels by expanding the supply of renewable energy such as solar, wind, geothermal, biomass and nuclear power as nearly zero-emission of greenhouse gas. In terms of energy consumption, measures to reduce greenhouse gas emissions is in line with the policy for efficiency improvement. The buildings & work-site of high-energy consumption in the building & Industry sectors, should implement a policy to strengthening the voluntary agreement on energy-saving facilities and expand to invest in energy saving facilities.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.137-137
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• 2013

지속 가능한 발전을 위해, 한정된 자원인 석유의 고갈을 막기 위해 석유를 수송에너지로 주로 사용하는 자동차에서 바이오 디젤이나 연료전지, 전기자동차 등 다양한 대안이 제시되고 있다. 그러나 식량 가격 상승, 낮은 안정성, 인프라 확충 등의 문제의 해결이 필요할 뿐만 아니라, 석유의 소비를 감소시키는 대신, 지구에서 소비할 수 있는 다른 형태의 에너지를 소모한다는 측면에서 근본적인 에너지 문제의 해결책의 모색이 필요하다. 19세기 후반, 백열전구의 필라멘트 용도로 사용되기 시작한 탄소 섬유는, 철에 비해 5배 가볍고 강도는 10배가 높으며 내열성이 뛰어난 소재로서, 복합소재의 형태로 제조되어 비행기, 우주선, 풍력 발전 블레이드 등 다양한 산업 분야에서 소재의 장점을 발휘하는 재료로 적용 분야가 확대되고 있다. 특히 비행기 분야에서는 최근 비행기 몸체 구조에 기존 알루미늄 합금을 탄소섬유복합재가 대체하고 있으며, 최근에는 부피 기준 50% 가량까지 탄소섬유 복합재를 사용하여 비행기를 제작하고 있다. 이에 따라 기존에 비해 20% 가량 연료 소모가 감소하여, 비행기 한 대 당 연간 2,700톤의 이산화탄소 배출을 저감하고 있다. 이와 같이 탄소섬유 복합재를 다양한 분야에 적용함으로써, 에너지 문제에 대한 보다 근본적인 접근이 가능하다. 그러나 탄소섬유 복합소재는 금속 등 기존 재료에 비해 높은 가격으로 상용 자동차 등 에너지 소비량이 많은 분야에 널리 적용되는데 한계가 존재한다. 이와 같이 높은 탄소섬유의 가격은, 원가의 50% 가량을 차지하는 PAN 원사 가격과 나머지 반절에 해당하는 안정화/탄화 공정 비용에서 기인하는 것으로, 미국의 ORNL (Oak Ridge National Laboratory), 한국의 KIST 복합소재연구소 등에서는 원사, 안정화 공정, 탄화 공정 등 다양한 측면에서 탄소섬유 복합재의 가격을 절감할 수 있는 방안을 연구 중이다. 미국 ORNL에서는 마이크로웨이브 플라즈마를 이용하여 기존에 열을 이용해 수행하던 탄화 공정 비용을 크게 절감하고 있으며, KIST에서는 대기압 플라즈마를 이용하여 기존에 열을 이용해 2시간 가량이 소요되는 안정화 공정을, 대기압 플라즈마를 이용하여 30분여로 단축된 시간에 수행하는 공정을 개발 중이다. 본 발표에서는 탄소섬유 복합재의 개요와, 탄소섬유 가격 절감 방안으로서의 플라즈마에 대해 논의하며 대기압 플라즈마의 다양한 응용에 대해 소개할 예정이다.

• Environmental and Resource Economics Review
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• v.19 no.1
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• pp.159-198
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• 2010

The Korean government is planning to introduce the Renewable Portfolio Standard (RPS) system to replace the currently used Feed-in-Tariff (FIT) system which is a subsidy-based mechanism to foster the renewable energy industry. The RPS system is a market-oriented system in which the power companies are obliged to use renewable energy sources to produce electricity by a certain ratio of their production level. They can either produce for themselves or simply purchase the REC (renewable energy certificate) in the market to implement. The objective of this article is to compare the RPS system with the current FIT system in terms of the implementing cost to achieve the policy goal to expand the share of renewable energy m the total power generation. The analysis is conducted using Linear Programming models. The results of this study imply several policy suggestions to successfully introduce the RPS system.