• 신재생에너지
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• 제2권3호
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• pp.23-30
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• 2006

Need developments of substitute energy to solve problem of global warming by excess use of fossil energy, excess discharge of carbon dioxide. wind power generation system is all-important energy in next generation as clean energy. Environmental pollution of wind power generation system is not exhausted entirely. And, electric-power generation system cost is cheap than other energy. Wind Generation system that is supplied much present is most horizontality style blade structure. But, Horizontal style structure is serious noise and there is problem in stability of blade. We designed special blade solve to this problem. And, manufactured vertical axis wind power generation system because using blade. Also, developed assistance power generator to increase driving efficiency ago wind power generation. We expect this devices that is such cover shortcoming of wind power generation system.

• Current Photovoltaic Research
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• 제8권3호
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• pp.86-93
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• 2020

The investment in solar and wind generation is rapidly increasing with government's renewable expansion policy and Renewable Portfolio Standard (RPS). Since the large penetration of solar and wind generation increases the variability and uncertainty of supply and demand balance in power system, the government is pursuing the policy of supplying energy storage system (ESS) linked to renewable energy. ESS contributes to the ease of transmission and distribution grid by shifting PV generation from daytime to evening hours. Recently, the declining market price of REC as ESS incentive, policies to cut down incentives and limited ESS storage due to fire events lead to the aggravation of long-term profitability, thus working as a barrier of ESS spreading. In this study, the factors affecting the profit of ESS are analyzed and brief indicators are derived. Based on the indicators, the profit changes are analyzed considering the variation of REC market price and REC incentive weights. Based on the profit change with respect to the increase of ESS capacity, economical ESS installation capacity is suggested.

• Journal of Platform Technology
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• 제6권3호
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• pp.38-46
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• 2018

스마트 그리드는 전력 생산자와 소비자 간의 양방향 통신을 통해 효율적으로 전력을 생산 및 소비하기 위한 지능형 전력망이다. 신재생 에너지가 발전하면서 신재생 에너지가 스마트 그리드에서 차지하는 비율이 점점 높아지고 있다. 신재생 에너지는 발전량이 실시간으로 변하기 때문에 발전량의 예측 및 조절이 가능한 기존의 발전 방식과는 다른 문제점이 있다. 스마트 그리드에 자가 적응 프레임워크를 적용하는 것은 실시간으로 변하는 신재생 에너지의 발전량에 적응함으로써 스마트 그리드의 효율적인 운영을 가능케 할 것이다. 본 논문에서는 태양광 발전 시설이 설치된 스마트 마을을 가정하고 이에 자가 적응 프레임워크인 AiTES 를 적용 하여 자가 적응 프레임워크를 통해 스마트 그리드의 효율적인 운영이 가능함을 보였다.

• Journal of Power Electronics
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• 제15권6호
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• pp.1446-1455
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• 2015

This paper illustrates resonant tank design considerations and the implementation of a LLC resonant converter with a wide battery voltage range based on the fundamental harmonic approximation (FHA) analysis. Unlike the conventional design at zero load, the parameter K (the ratio of the transformer magnetizing inductor L_m to the resonant inductor L_r) of the LLC converter in this paper is designed with two charging points, (V_{o_min}, I_{o_max1}) and (V_{o_max}, I_{o_max2}), according to the battery charging strategy. A 2.9kW prototype with an output voltage range of 36V to 72V dc is built to verify the design. It achieves a peak efficiency of 96%.

• 전기학회논문지
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• 제63권1호
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• pp.18-26
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• 2014

A microgrid can play a significant role for enlargement of renewable energy sources and emission reduction because it is a network of small, distributed electrical power generators operated as a collective unit. In this paper, an application of optimization method to economical operation of a microgrid is studied. The microgrid to be studied here is composed of distributed generation system(DGS), battery systems and loads. The distributed generation systems include combined heat and power(CHP) and small generators such as diesel generators and the renewable energy generators such as photovoltaic(PV) systems, wind power systems. Both of thermal loads and electrical loads are included here as loads. Also the emissions trading scheme to be applied in near future, the cost of unit start-up and the operational characteristics of battery systems are considered as well as the probabilistic characteristics of the renewable energy generation and load. A mathematical equation for optimal operation of this system is modeled based on the mixed integer programming. It is shown that this optimization methodology can be effectively used for economical operation of a microgrid by the case studies.

• 전기학회논문지
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• 제65권7호
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• pp.1135-1143
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• 2016

A private company's 1,000 MW coal-fired power plant will be the first coal-fired power plant that was included in the 5th 'Basic Plan on Electricity Demand and Supply' (2010). Now it is facing the task to abide by the RPS(Renewable Portfolio Standard) policy after commercial operation. If they fail to supply the necessary REC (Renewable Energy Certificate) mandated by the RPS policy, they are subject to be fined by the government and forced to modify the cost function to reflect the burden. Eventually the company's coal-fired power plant will be forced to reduce generation to maximize profit because the amount of electricity generated by the power plant and the REC obligation is positively correlated. This paper analyzed the change of cost function of private coal-fired power plant according to the introduction of RPS policy from the viewpoint of private company, and finally proposed the optimal generation to maximize the profit of private coal-fired power plant under the current RPS policy.

• International Journal of Precision Engineering and Manufacturing-Green Technology
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• 제5권5호
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• pp.623-630
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• 2018

The renewable energy systems have been in the spotlight as an alternative for environmental issues. Therefore, the governmental policies are being implemented to spread of promote power generation system using renewable energy in various countries around the world. In addition, Korea has also developed a policy called the power trading contract which can profit from electricity produced from renewable power generation system through Korea Electric Power Corporation (KEPCO) and Korea Power Exchange (KPX). As a result, the power trading contracts can trade power after self-consuming in-house by using small-scale renewable power system for residential customers as well as electricity retailers. The power trading contracts applicable as a small-scale power system have a 'Net metering (NM)' and a 'Power Purchase Agreement (PPA)', and these two types of power trading contracts trade surplus power, but payment method of each power trading is different. The microgrid proposed in this paper is based on grid connected microgrid using Photovoltaic (PV) system and Energy Storage System (ESS), that supplied power to residential demand, we evaluate the operation cost of microgrid by power demand in each power trading contracts and propose the appropriate power trading contracts according to electricity demand.

• 신재생에너지
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• 제19권4호
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• pp.98-107
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• 2023

A study was conducted to analyze data from 1981 to 2020 for understanding the impact of climate on solar energy generation. A significant increase of 104.6 kWhm^-2 was observed in the annual cumulative solar radiation over this period. Notably, the distribution of solar radiation shifted, with the solar radiation in Busan rising from the seventh place in 1981 to the second place in 2020 in South Korea. This study also examined the correlation between long-term temperature trends and solar radiation. Areas with the highest solar radiation in 2020, such as Busan, Gwangju, Daegu, and Jinju, exhibited strong positive correlations, suggesting that increased solar radiation contributed to higher temperatures. Conversely, regions like Seosan and Mokpo showed lower temperature increases due to factors such as reduced cloud cover. To evaluate the impact on solar energy production, simulations were conducted using climate data from both years. The results revealed that relying solely on historical data for solar energy predictions could lead to overestimations in some areas, including Seosan or Jinju, and underestimations in others such as Busan. Hence, considering long-term climate variability is vital for accurate solar energy forecasting and ensuring the economic feasibility of solar projects.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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• pp.87-90
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• 2008

Levelized generation cost(LGC) has been widely used in assessing feed-in tariffs(FiT) for electricity generating from new and renewable energies. Current FiTs for renewable electricity in Korea have been fixed and applied with realistic economic data by the efforts of KERI(Korea Electrotechnology Research Institute) since October 2006. Some critical issues on the estimation of LGC are, however, found in KERI's report. Major issues are the estimation of capital cost, the consideration of corporate tax, and the application of economic life cycle in the formulae for LGC. These critical issues are examined and interpreted in a correct way in this paper.

• Advances in Energy Research
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• 제4권1호
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• pp.47-68
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• 2016

A well designed hybrid power system (HPS) can deliver electrical energy in a cost effective way. In this paper, model for HPS consisting of photo voltaic (PV) module and wind mill as renewable energy sources (RES) and solar lead acid battery as storage device connected to unidirectional grid is developed for peak demand reduction. Life time energy cost of the system is evaluated. One year hourly site condition and load pattern are taken into account for analysing the HPS. The optimal HPS is determined for least life time energy cost subject to the constraints like state of charge of the battery bank, dump load, renewable energy (RE) generation etc. Optimal solutions are also found out individually for PV module and wind mill. These three systems are compared to find out the most feasible combination. The results show that the HPS can deliver energy in an acceptable cost with reduced peak consumption from the grid. The proposed optimization algorithm is suitable for determining optimal HPS for desired location and load with least energy cost.