• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.4
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• pp.653-660
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• 2021

Renewable energy resources are rapidly becoming an integral part of electricity generation portfolios around the world due to declining costs, government subsidies, and corporate sustainability goal. Interacting wind, solar, and load forecast errors can create significant unpredictable impacts on the distribution system, feeder congestion, voltage standard and reactive power stability margins. These impacts will be increasing with the increasing penetration levels of variable renewable generation in the power systems. There is a limit to the maximum amount of renewable energy sources that can be connected in a distribution feeder by the connection rule of transmission & distribution facility in Korea. This study represents the decision plans of hosting capacity for distribution feeders without the need for significant upgrades to the existing transmission infrastructure. Especially, the paper suggests and discusses the hosting capacity standard of feeder cables and minimum load calculation of distribution feeders.

• Atmosphere
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• v.31 no.1
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• pp.1-15
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• 2021

High-resolution wind resources maps (maps, here after) with spatial and temporal resolutions of 100 m and 3-hours, respectively, over South Korea have been produced and evaluated for the period from July 2016 to June 2017 using Korea Meteorological Administration (KMA) Post Processing (KMAPP). Evaluation of the 10 m- and 80 m-level wind speed in the new maps (KMAPP-Wind) and the 1.5 km-resolution KMA NWP model, Local Data Assimilation and Prediction System (LDAPS), shows that the new high-resolution maps improves of the LDAPS winds in estimating the 10m wind speed as the new data reduces the mean bias (MBE) and root-mean-square error (RMSE) by 33.3% and 14.3%, respectively. In particular, the result of evaluation of the wind at 80 m which is directly related with power turbine shows that the new maps has significantly smaller error compared to the LDAPS wind. Analyses of the new maps for the seasonal average, maximum wind speed, and the prevailing wind direction shows that the wind resources over South Korea are most abundant during winter, and that the prevailing wind direction is strongly affected by synoptic weather systems except over mountainous regions. Wind speed generally increases with altitude and the proximity to the coast. In conclusion, the evaluation results show that the new maps provides significantly more accurate wind speeds than the lower resolution NWP model output, especially over complex terrains, coastal areas, and the Jeju island where wind-energy resources are most abundant.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.1
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• pp.39-44
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• 2023

Renewable energy such as solar and wind power is a resource that is sensitive to weather conditions and environmental changes. Since the amount of power generated by a facility can vary depending on the installation location and structure, it is important to accurately predict the amount of power generation. Using meteorological data, a data preprocessing process based on principal component analysis was conducted to monitor the relationship between features that affect energy production prediction. In addition, in this study, the prediction was tested by reconstructing the dataset according to the sensitivity and applying it to the machine learning model. Using the proposed model, the performance of energy production prediction using random forest regression was confirmed by predicting energy production according to the meteorological environment for new and renewable energy, and comparing it with the actual production value at that time.

• 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 the Korean Institute of Gas
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• v.21 no.6
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• pp.23-29
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• 2017

Solar and wind energy among the renewable energy produce irregular power because resource is difficult to control. When connected to grid have unstable. However, when the fuel cell system is connected to grid more stable because regular frequency and output power based on controllable hydrogen energy. To using fuel cell system in the household, it is important that the safety performance of power conditioning system(PCS) and it is important that evaluation method of electromagnetic compatibility(EMC). In this study, we consider that introduce power-frequency magnetic field immunity test before analyzed that compare with the EMC of the international standards and KGS AB 934 PC53. Also, we conduct that actual assessment and study on available the quantitative analysis as using complementary indicator.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.4
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• pp.595-606
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• 2022

Korea has the characteristics of traditional power system such as large-scale power generation and large-scale power transmission systems, including 20 GW large-scale power generation complexes in several regions with unit generator capacity exceeding 1.4 GW, 2-3 ultra-high-voltage transmission lines that transport power from large-scale power generation complexes, and 6 ultra-high-voltage transmission lines that transport power from non-metropolitan areas to the metropolitan area. Due to the characteristics of the power system, the penetration level for renewable energy is low, but due to frequency stability issue, some generators are reducing the output of generators. In the future, the issue of maintaining the stability of the power system is expected to emerge as the most important issue in accordance with the policy of expanding renewable energy. When non-inertial inverter-based renewable energy, such as solar and wind power, surges rapidly, the means to improve the power system stability in an independent system is to install a natural inertial resource synchronous condenser (SC) and a virtual inertial resource BESS in the system. In this study, we analyzed the effect of renewable energy on power system stability and the BESS effect to maintain the minimum frequency through a power system simulation. It was confirmed that the BESS effect according to the power generation constraint capacity reached a maximum of 122.81 %.

• Environmental and Resource Economics Review
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• v.31 no.4
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• pp.865-885
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• 2022

Korean government updated her Nationally Determined Contribution (NDC) in 2021 and announced the target and various measures for reductions. Among the many issues, final energy demand and renewable energy power mix for 17 provinces to achieve the target are being analyzed using GCAM-Korea. Simulation results show that final energy demand of 2030 is approximated at the similar level to that of 2018. This is being enabled by the conservation of coal with higher electrification especially in industry sector. Higher power demand with lower coal consumption in final energy consumption is shown to be provided by 33.1% of renewable, 24.6% of gas, and 18.0% of nuclear power generation in 2030. Meanwhile, the share of coal-fired power generation is expected to be reduced to 12.8%. Major future power provider becomes Gyeongbuk (Nuclear), Gyeonggi (Gas), Jeonnam (Nuclear, Gas) and Gangwon (PV, Wind), compared to one of current major power provider Chungnam (Coal). This analysis is expected to provide a useful insight toward the national and provincial energy and climate change policy.

• 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.

• International Journal of Highway Engineering
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• v.13 no.4
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• pp.159-166
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• 2011

Green house gas emissions are increasing as development of the industrial economy of the international community. Many countries in the world are endeavoring to reduce green house gas emissions under severe climate change. In order to protect grobal warming, government is trying to reduce green gas emissions under "Low Carbon Green Growth Policy" and investing climiate-firendly industries such as renewable energy harvesting. Renewable energy has been rapidly developing as a result of investment for development technology of using natural energy such as solar, wind, tidal, etc. There are lots of waste energy in the road space. However, nobody is not interested in waste energy from the road space. This paper present a fundamentally experimental study of energy harvesting technique to use waste energy in the road. The waste energy in the road is covered a pressure and impact of vehicles on the road, the radiant heat from asphalt pavement, road noise and vibration etc. In this study, an energy harvesting device using piezoelectric element is proposed and various tests are conducted to investigate a characteristic of this device as function of impact loading based on piezoelectric effect behavior. This paper shows the energy harvesting results of the device using domestic piezoelectirc element as a function of impact load size and pavement types.

• Korean Business Review
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• v.22 no.2
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• pp.157-179
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• 2009

This papers aims to focus on the city marketing as the green growth policy strategies using a case study of Gangneung City, Republic of Korea. In the case study it was verified the fields of urban growth including ecology, culture, alternative and recycled energy, green transportation system. The implications of the study were as follows: First, the city government had regenerated the coastal pine forest through removing unlicensed buildings which were squatted down in decades. Secondly, the city government has recognized the value of culture that possessed various types of cultural asserts. Thirdly, it is possible to use and produce the ocean energy with the tidal power plant, wind power plant and green deep water because Gangneung City has the ocean-oriented image and is located the coastal region. Lastly, the city government has been utilizing the LED traffic light using solar heat and is going to apply the green car like an electric car. This paper indicates the importance of the alternatives of the green growth-oriented policy through city marketing using the concept of culture and ecology. The city government will strive after an advanced triple bottom line with the ecological sustainability, cultural diversity and economic effectiveness in the near future.