• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.4
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• pp.733-738
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• 2011

As increase of nonlinear loads and renewable energy generators (REGs) being connected to power distribution system via inverters, the concern on harmonic problems have increased. Recently, the harmonics evaluation method considering TDD (Total Demand Distortion) is used to analyze the effect of harmonics from inverters on power distribution quality. Harmonic current sources are typically used for simulation of nonlinear load. Most inverter type for REGs is voltage source inverter (VSI). So, harmonic voltage sources are more suitable to analyze impact of renewable energy generator on harmonics problem in power distribution system. In this paper, we presented the circuit model to analyze interaction between harmonics from nonlinear load and REGs. We verified that the harmonic analysis using the proposed circuit model is more appropriate than the harmonics evaluation method considering TDD through case study using PSCAD/EMTDC.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.11
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• pp.1401-1407
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• 2018

This paper proposed a method of energy storage system (ESS) operation to increase acceptable production of renewable energy (RE). We analyzed the rebound effect that does not show a demand increase even if the capacity of the ESS is increased and considered the charging time by analyzing the time when the output limit is most generated. The rebound effect was mitigated by adjusting the discharging time of the ESS, and the effect of the increase of acceptable production of the renewable energy was analyzed by adjusting the charging time.

• 한국태양에너지학회:학술대회논문집
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• 2012.03a
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• pp.529-533
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• 2012

By introducing RPS(Renewable Portfolio Standard) for reduction of greenhouse gas, Renewable energy sources have becoming widespread gradually. However, Renewable energy sources, such as wind power and PV are difficult to control the output and they have intermittent characteristics of the output. These characteristics would cause some problems when it is connected in the power system. In order to solve these problems, Energy Storage Systems(ESS) are considered to use. Although there are many different storage devices, the utilization of Secondary Battery is the one of the best ways to stabilize an output fluctuation of RES because of its fast responsibility. For that reason, it would better fit a large-capacity of Secondary battery for stabilization. However, batteries cannot be installed with a large capacity blindly because of its expensive cost. So to select proper capacity of the battery is an important consideration. This paper presented a methodology for the optimal capacity and operation of ESS in microgrids.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.285-288
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• 2009

정부는 최근 그린홈 100만호 사업을 중심으로 각종 신재생에너지 보급률 향상을 도모하는 많은 프로그램을 기획하여 현재 약 12개의 신재생 에너지 보급지원 프로그램과 R&D 프로그램을 운영하고 있다. 그러나 현재 국내 신재생에너지 정책 및 프로그램은 차후 개선 및 체계적인 운영을 위한 조직적인 프로그램 평가 체계를 갖추고 있지 않으며 평가 기관이나 평가 주기 등 평가에 필요한 기본적인 합의와 법제적 배경 역시 미비한 상황으로 신재생에너지 프로그램의 평가 제반 시스템에 대한 근본적 고민이 필요한 시점이라고 볼 수 있다. 이에 본 연구에서는 미국 DOE(Department of Energy)산하 EERE(Energy Efficiency & Renewable Energy)의 신재생에너지 보급사업평가체계를 분석하여 EERE 프로그램 평가 방법의 국내 적용 가능성을 검토해 보았다. EERE는 미국의 에너지 효율화 및 신재생에너지 전담 사무국으로 10개의 에너지효율화 및 신재생에너지 연방정부 프로그램을 운영하고 있으며 Strategic Management system을 통해 효율적인 프로그램 관리를 시도하고 있다. 특히 General program evaluation Guideline에서는 표준화된 세부 평가 방법론을 제시하여 정례적 혹은 일회적 평가를 시행하고 있는데 이 세부 평가 방법들은 프로그램의 특성에 따라 프로그램을 운영하고 프로그램의 존속 및 개선여부를 결정하는데 결정적인 도움을 주고 있어 차후 국내에서 시행되고 있는 신재생에너지 프로그램의 정성적/정량적인 평가를 시행하는 많은 시사점을 제공할 것으로 기대된다.

• Asian Journal of Innovation and Policy
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• v.11 no.3
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• pp.293-319
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• 2022

By analyzing the adaptive capacity, market formation and policy direction as functional areas of Technological Innovation System (TIS), the article evaluates the progress of renewable energy transition in the Maldives, with the inclusion of ideas from Mauritius and Cabo Verde. On the policy direction in the Maldives, technology roadmaps produced with assistance from International Renewable Energy Agency (IRENA) and Asian Development Bank (ADB) are evaluated. Although there are inducing factors such as the Solar Risk Management Initiative, the progress of energy transition is hindered by the lack of technical capacity and local value chain. The findings indicate the importance of facilitating and establishing industry and knowledge networks, incorporating innovation policies, greater involvement of the local private sector along with international investors, and taking water-energy nexus to achieve complementary targets. The study adds value to knowledge by offering a simplified TIS framework, with a current insight of the energy transition in Small Island Developing States with a focus on the Maldives.

• Journal of the Korean Solar Energy Society
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• v.39 no.6
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• pp.93-112
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• 2019

In this paper, a very new web-based software for renewable energy system (RES) design and economic evaluation was introduced. This solution would provide the precise RES estimation service including not only photovoltaic (PV), wind turbine (WT) and fuel cell (FC) individually but also energy storage system (ESS) as combined forms with PV or WT. The three reasons why we ought to develop it are: First, the standardized tool suitable to the domestic environment for estimating power generation from RES facilities and economic evaluation is required. Secondly, the standardized tool is needed to spread domestic RES supply policy and to promote the new industry in the micro-grid field. The last, the reliability of economic evaluation should be enhanced more for new facilities. To achieve those aims, the weather database of one hundred locations have established and the RES facility database has also constructed. For the energy management, mathematical models for PV, WT, ESS and FC were developed. As a final phase, the analytical process to evaluate economics has performed with field data verification.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.922-927
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• 2009

Due to the law of use of sustainable alternative energy recently legislated, many public institutions are ordered to use renewable energy. So it gets people's eyes on Geothermal energy system among other suggested renewable energy. Since there is hardly existence of a volcanic region, Geothermal heat pump system is generally used most in Korea. However, the important technology and materials are not localized and further, with only our technical skills it is arduous to popularize and develop Geothermal energy because of lack of revitalization related to the law and the regime for locally suitable Data-base. Moreover, an access of renewable energy is too much hard because of people's low interests about Geothermal energy. But fortunately, the well-studied about Geothermal heat system started to be adopted in many other provinces. Therefore, we study this with intend to popularize and develop Geothermal energy.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2005.11a
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• pp.315-318
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• 2005

One of the problems in using renewable energy sources is great difficulty of stable and sustainable supply. Because the fuel cell can provide stable and sustainable supply of energy sources without regard to external conditions, however, it will become one of the most useful renewable energy sources for buildings that need stable energy supply. For practical application of PEMFC system to common household, the data of household energy consumption are analyzed by electricity, cooking and heating. From the result of the data analysis, practical application methods of PEMFC system to household are designed to several models. The aim of this study is to establish a plan of practical application for applying Polymer Electrolyte Membrane Fuel Cell(PEMFC) system to the households.

• Nuclear Engineering and Technology
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• v.51 no.6
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• pp.1689-1695
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• 2019

This study suggests a simple economic model to analyze electricity grid that consists of different power sources. The substitutability of renewable energy for nuclear power in Korean electricity transmission network is investigated by suggested model. The monthly data from January 2006 to December 2013 reported by Electricity Power Statistics Information System (EPSIS) of Korea Power EXchange (KPX) are used. To estimate the elasticities of substitution among four power sources (i.e. coal, natural gas, nuclear power, and renewable energy), this paper uses the trans-log cost function model on which local concavity restrictions are imposed. The estimated Hicks-Allen and Morishima elasticity of substitution shows that renewable electricity and nuclear power are complementary. The results also evidenced that renewable electricity and fossil fueled thermal power generation are substitutes.

• Journal of the Korean Institute of Rural Architecture
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• v.24 no.4
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• pp.107-115
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• 2022

This study investigated the status of resident participation in the policy of supplying new and renewable energy in rural areas. According to the survey, most of the rural residents were well aware of the new and renewable energy supply project promoted by the government. However, it was found that participation in the project was difficult mainly for economic and social reasons. In order to activate the participation of rural residents who can't participate in the renewable energy power generation project for economic and social reasons, it is necessary to develop and promote business models and support policies for power generation projects in which village communities participate. Changes in residents' acceptability due to resident education and operation for solar power systems were analyzed. As a result of the survey, it was found that the satisfaction of rural residents was high when new and renewable energy power generation projects were introduced in rural areas. Therefore, it is thought that the government's goal of increasing farm household income and expanding the supply of new and renewable energy in rural area can be successfully achieved by the improvement of resident acceptability and the increase of the participation rate. Lastly, this study presented a plan to improve the resident acceptability of the renewable energy system by using the rural solar project and survey results.