• Journal of the Korean Solar Energy Society
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• v.28 no.5
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• pp.72-77
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• 2008

The purpose of this paper is to explain the real characteristics of generation system of large scale power system of high voltage the grid connected PV power system for electricity industry. Main system is made up PCS in the class 150kVA. and we studied commercial operation in Korea-Western Power Company,(Tae-An headquarter) with the capacity of module is 122.5 $kW_p$. On the average, power plant utilities' utilization is 12.71 percent and consumption rate is 6.66 percent. We operated normally since 25th, August 2005 without any other problems.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.402-405
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• 2008

SunPower's corporate mission is to reduce the installed cost of solar electricity 50% by 2012. As part of that mission, the company is continually exploring novel technologies that might enable progress towards the goal. This paper describes SunPower's efforts to decrease the levelized cost of electricity for solar power plants through the use of bifacial cell and system technology. The results of the first production run of SunPower bifacial cells and modules are presented. Future bifacial system development plans are reviewed.

• New & Renewable Energy
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• v.8 no.2
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• pp.33-43
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• 2012

Why solar companies preferred vertical integration of whole value chain? Major solar companies have built internally strong vertical integration of entire PV value chain. We raise a question whether such integration increases the corporate value and whether market situation affects the result. To test these questions, we conducted multi-variant analysis where characteristic factors mainly affect the corporate value measured in terms of Tobin'Q, based on the financial and non-financial data of PV companies listed in US stock market between 2005 and 2010. We hypothesize that since integration increases the overall efficiency but decreases the flexibility to adjust to various market situation, the combined effect of the efficiency gain and the flexibility loss ultimately determines the sign of integration effect on the corporate vale. We infer that the combined effect will be influenced heavily by business cycle, as in boom market (Seller's market) the efficiency gain may be larger than the flexibility loss and vice versa in bust market. We test whether the sign of combined effect changes after the year of 2009 and which factors influence most the sign. Year of 2009 is known as the year when market shifted from Seller's to Buyer's market. We show that 1) integration increases corporate value in general but after 2009 integration significantly decreases the value, 2) the ratios such as Production/Total Cost, Cash turnover period chosen for reversal of the flexibility measure are negatively affect Tobin's Q and especially stronger after 2009. This shows the flexibility improves corporate value and stronger in the recess period (Buyer's market). These results imply that solar company should set up integration strategy considering the tradeoff between efficiency and flexibility and the impact of the business cycle on both factors. Strategy only based on the price competitiveness determined in boom time can bring undesirable outcomes to the company. In addition, Strategic alliances in some value chains as a flexible bondage should be taken in account as complementary choice to the rigid integration.

• Journal of Environmental Policy
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• v.3 no.1
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• pp.71-94
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• 2004

The purpose of this study is to propose a way to develop and disseminate the renewable energy technologies and industries in the local community. Fundamentally, the renewable energy is able to reduce environmental pollution and diminish a use of fossil-fuel energy in the local area. And it will lead to promoting regional sustainable energy in the future, as well as making contributions to local economic development. Above all, based on the environmental conservation project, including greening of the city and improving water quality, Daegu metropolitan city has launched a series of renewable energy projects, such as solar city programs and local energy plan. But, some problems still exist, due to the technological, economic and socio-political barriers. Thus, to encourage and disseminate a renewable energy in Daegu city, we need to examine a present condition on renewable energy and analyze constraint elements to prevent its distribution. Based on the results, we have to set the feasible strategy to develop and disseminate renewable energy in Daegu city and help it systematically integrate renewable energy technologies and industries into environmental economics and city planning. Ultimately, to achieve this purpose, we need to adopt the following policy measures: (1) establishment of a master plan for renewable energy; (2) interconnection between local development project and energy industry; (3) promotion of technological development; (4) inducement of and assistance to renewable energy industry; (5) fostering venture companies; (6) specializing Daegu's public office by energy-specific education programs. In particular, local entities including local company, consumers, policy-makers and citizen's groups have to pay attention to local energy plan for the regional sustainable energy future. These measures will lead to establishing an environmentally friendly and sustainable city.

• Journal of the Korean Solar Energy Society
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• v.39 no.4
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• pp.69-77
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• 2019

Among the main functions of the grid-connected photovoltaic (PV) system, the anti-islanding operation function is a very important problem. Recently, due to the improvement in power generation efficiency and the maintenance advantages in PV system, the use of string inverter has increased so that the possibility of islanding operation has been raised. Generally, when a power system faults, the PV inverter must be disconnected from power system within 10 cycles by the anti-islanding operation function. However, in the real-time of power system, the output power of the PV system within 10cycles is effected. In this paper, we analyzed the effect of grid-connected PV system on power quality in a short time within 10 cycles on fault case of power system using the Matlab Simulink program.

• 한국태양에너지학회:학술대회논문집
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• 2012.03a
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• pp.286-292
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• 2012

In recent years, building energy has received much attention and there are many support system to reduce building energy consumption. In addition, It is clear that encouraging to energy efficiency investments can be beneficial to our society, because of the energy supply instability and higher energy price in Korea. Nevertheless, ESCO business, represent the existing building energy retrofit business, hardly has not expanded in Korea. besides, in the case of existing building, it is more difficult to achieve the energy retrofit measures than new building, due to the existing buildings have attributes such as a long life and a lots of energy factor, etc. Therefore, for activate ESCO business and expand ESCO bussiness target to small-to-medium building, it is needed to optimization of retrofitting methods for existing small-to medium buildings in Korea. this research was to derive energy retrofit methods through the energy audit and analysis performed for a small-to-medium building located in Suwon, Korea.

• Smart Media Journal
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• v.9 no.3
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• pp.18-24
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• 2020

Existing energy was a system produced by a specific company and sold to consumers, but it is expected that in the near future, producers will become consumers and consumers will become producers. Recently, the emergence of cloud systems, 5G network construction, and energy reuse, including solar energy, are changing the shape of the energy market. In order to share energy, there are various agent systems, energy networks, and structures that form markets. In this study, we defined the above three and proposed a strategy using the Secure Energy Model (SEM) by applying a blockchain for a safe and fair energy market. The analytical results showed that the trust between the energy producers and consumers participating in the energy trade was formed.

• Journal of the Korean Solar Energy Society
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• v.34 no.1
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• pp.81-90
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• 2014

The Jeju-Korea power system is a small-sized network with a system demand ranging from a autumn minimum of 350MW to a summer peak of 716MW. Because Jeju island is well exposed to north-east winds with high speed, applications to connect to Jeju power system are flooded. Considering physical/environmental constraints, Jeju Self-governing Province has also target for the wind power capacity of 1,350MW by 2020. It amounts to two or three times of Jeju average-demand power and wind power limit capacity announced by Korea Power Exchange (KPX) company. Wind farm connection agreements will be signed to maximize utilization of wind resource. In spite of submarine cable HVDC connected to Korea mainland, Jeju power system is independently operated by frequency and reserve control. This study reevaluates wind power limit based on the KPX criteria from 2016 to 2020. First of all wind power generation limit are affected by off-peak demand in Jeju power system. Also the possibility capacity rate of charging wind power output is evaluated by using energy storage system (ESS). As a result, in case of using 110MWh ESS, wind power limit increases 33~55MW(30~50% of ESS), wind power constraint energy decreases from 68,539MWh to 50,301MWh and wind farm capacity factor increases from 25.9 to 26.1% in 2020.

• Journal of the Korean Solar Energy Society
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• v.27 no.3
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• pp.169-174
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• 2007

Building integrated photovoltaic(BIPV) system operates as a multi-functional building construction material. They not only produce electricity, but also are building integral components such as facade, roof, window and shading device. As PV modules function like building envelope in BIPV, combined thermal and PV performance should be simultaneously evaluated. This study is to establish basic Information for designing effective BIPV by discovering relations between temperature and generation capability through experiment when the PV module is used as roof material for houses. To do so, we established 3kW full scale mock-up model with real size house and attached an PV array by cutting in half. This is to assess temperature influence depending on whether there is a ventilation on the rear side of PV module or not.

• Journal of the Korean Solar Energy Society
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• v.23 no.3
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• pp.37-44
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• 2003

This paper presents the modeling and analysis of V47-660 kW wind turbine generation system(WTGS) in Jeju wind farm using Psim program. Generally, WTGS is composed of complicated machinery. So it is very difficult to present the mathematic model. This means that WTGS has a nonlinear system. Using the real output data from V47 WTGS for one year, it is simply possible to express the rotor and gear coupling system as a torque generator according to wind speed. Also, the modeling of electrical system can be able to present using the data sheet from the company. To analyze the proposed method, results of computer simulation using Psim program are presented to support the discussion.