• 한국태양에너지학회 논문집
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• 제39권4호
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• pp.41-54
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• 2019

The proportion of solar photovoltaic power generation has steadily increased in the power trade market. Solar energy forecast is highly important for the stable trade of volatile solar energy in the existing power trade market, and it is necessary to identify accurately any forecast error according to the forecast lead time. This paper analyzes the latest study trend in solar energy forecast overseas and presents a consistent comparative assessment by adopting a single statistical variable (nRMSE) for forecast errors according to lead time and forecast technology.

• 정보처리학회논문지A
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• 제10A권6호
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• pp.757-768
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• 2003

최근 환경 오염 및 자원 고갈 등의 이유로 대체에너지원은 미래의 에너지원으로 중요한 역할을 하고 있다. 국외에서는 대체에너지원에 관련된 정보 시스템의 개발 및 보급이 활발히 추진되고 있다. 그러나 국내에서는 대체에너지원 데이터의 효율적인 이력 관리 및 웹을 통한 검색 서비스가 제공되지 않고 있다. 따라서 이 논문에서는 대체에너지원 데이터의 방대한 이력 정보를 체계적으로 저장 및 관리하기 위한 대체에너지원 이력 데이터 관리 시스템을 제안한다. 이 시스템은 외부 관측 시스템으로부터 대체에너지원 데이터를 수집하여 이력 데이터베이스에 저장한다. 저장된 정보는 이력 질의 처리를 통해 검색되고 테이블, 그래프, 챠트, 등고선 등의 다양한 형태로 인터넷을 통해 제공된다. 특히, 제안 시스템은 실시간으로 이력 데이터를 관리하므로 사용자는 웹 인터페이스를 통해 항상 최신의 정보를 제공받을 수 있는 특징을 갖는다.

• 한국태양에너지학회 논문집
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• 제38권2호
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• pp.45-53
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• 2018

For the preliminary step for estimating the performance of roof-type photovoltaic system in urban areas, we analyzed the solar radiation reduction ratio by shadow effect by buildings using DSM (Digital Surface Model) and GIS (Geographical Information System) tools. An average loss by the shadow is about 19% in Seoul. The result was related to the building density and distribution. Monthly results show that the winter season (December and January) was more affected by the shading than during the summer season (June and July). It is expected that useful empirical formulas can be made if more detailed correlation studies are performed.

• 한국태양에너지학회 논문집
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• 제40권3호
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• pp.43-52
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• 2020

By blocking irradiance, shadows cast by high-rise buildings in urban areas can reduce the power generation efficiency of PV panels installed on low-rise buildings. As the conventionally installed PV panel is not suitable for the urban environment, which is unfavorable for power generating, a more radical solution is required. This study aims to help solve this problem by estimating the optimal PV panel angle. Using the proposed method, the optimal PV angle was calculated by considering shadows that could be cast by nearby buildings throughout the year, and the correlation between solar shading and elevation angle was discovered based on the calculated data.

• 한국태양에너지학회 논문집
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• 제38권6호
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• pp.27-36
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• 2018

Typical Meteorological Year Dataset is necessary for the renewable energy feasibility study. Since National Renewable Energy Laboratory has been built Typical Meteorological Year Dataset in 1978, gridded datasets taken from numerical weather prediction or satellite imagery are employed to produce Typical Meteorological Year Dataset. In general, Typical Meteorological Year Dataset is generated by using long-term in-situ observations. However, solar insolation is not usually measured at synoptic observing stations and therefore it is limited to build the Typical Meteorological Year Dataset with only in-situ observation. This study attempts to build the Typical Meteorological Year Dataset with satellite derived solar insolation as an alternative and then we evaluate the Typical Meteorological Year Dataset made by using satellite derived solar irradiance at Daejeon ground station. The solar irradiance is underestimated when satellite imagery is employed.

• 한국태양에너지학회 논문집
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• 제39권3호
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• pp.67-79
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• 2019

The reliable Typical Meteorological Year (TMY) data, sometimes called Test Reference Year (TRY) data, are necessary in the feasibility study of renewable energy installation as well as zero energy building. In Korea, there are available TMY data; TMY from Korea Institute of Energy Research (KIER), TRY from the Korean Solar Energy Society (KSES) and TRY from Passive House Institute Korea (PHIKO). This study aims at examining their characteristics by using Principle Component Analysis (PCA) at six ground observing stations. First step is to investigate the annual averages of meteorological elements from TMY data and their standard deviations. Then, PCA is done to find which principle components are derived from different TMY data. Temperature and solar irradiance are determined as the main principle component of TMY data produced by KIER and KSES at all stations whereas TRY data from PHIKO does not show similar result from those by KIER and KSES.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2008년도 추계학술발표대회 논문집
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• pp.306-309
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• 2008

Renewable energy information becomes one of the greatest issues, but it is difficult for a general user to manage and utilize new renewable energy information. Therefore we develop the utilization system of the resource map which aimed to provide the information for space analysis and vertification of the validity for development of each part of solar, wind, smallhydro, biomass, geothermal. But this system is needed to gather more supporting data and make resonable index to make various decisions.

• 대한공간정보학회지
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• 제22권4호
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• pp.13-19
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• 2014

한반도와 같은 산악지형에서 풍력단지를 조성할 경우, 인근 지형에 의한 차폐영향이 없기 때문에 상대적으로 풍력자원이 우수한 능선을 따라서 풍력터빈을 설치하는 것이 유리하다. 본 연구에서는 산악지형에서의 풍력단지 입지평가를 위하여 SRTM v4.1 3 arc-second 해상도의 수치고도 데이터베이스와 지형형태 분류 프로그램인 LandSerf v2.3을 이용하여 풍력터빈 설치 가능한 능선을 추출하였으며, 강원도에 건설된 강원풍력단지, 태기산풍력단지 및 매봉산풍력단지의 사례분석을 통하여 대부분의 풍력터빈이 상대적으로 풍력자원이 우수한 능선을 따라 배치되었음을 확인함으로써 이 방법의 유효성을 검증하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권5호
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• pp.2177-2193
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• 2018

This paper studies resource allocation schemes for the relay-aided cooperative system consisting of multiple source-destination pairs and decode-forward (DF) relays. Specially, relaying selection, multisubcarrier pairing and assignment, and power allocation are investigated jointly. We consider a combinatorial optimization problem on quality of experience (QoE) and energy consumption based on relay-aided cooperative system. For providing better QoE and lower energy consumption we formulate a multi-objective optimization problem to maximize the total mean opinion score (MOS) value and minimize the total power consumption. To this end, we employ the nondominated sorting genetic algorithm version II (NSGA-II) and obtain sets of Pareto optimal solutions. Specially, two formulas are devised for the optimal solutions of the multi-objective optimization problems with and without a service priority constraint. Moreover, simulation results show that the proposed schemes are superior to the existing ones.

• 한국태양에너지학회 논문집
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• 제39권6호
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• pp.113-125
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• 2019

With the opening of the small power brokerage business market in December 2018, the small power trading market has started in Korea. Operators must submit the day-ahead estimates of power output and receive incentives based on its accuracy. Therefore, the accuracy of power generation forecasts is directly affects profits of the operators. The forecasting process for power generation can be divided into two procedure. The first is to forecast solar irradiation and the second is to transform forecasted solar irradiation into power generation. There are two methods for transformation. One is to simulate with physical model, and another is to use regression model. In this study, we found the best-fit regression model by analyzing hourly data of PV output and solar irradiation data during three years for 242 PV plants in Korea. The best model was not a linear model, but a sigmoidal model and specifically a Gompertz model. The combined linear regression and Gompertz curve was proposed because a the curve has non-zero y-intercept. As the result, R² and RMSE between observed data and the curve was significantly reduced.