• Journal of Korean Society for Atmospheric Environment
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• v.33 no.4
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• pp.319-325
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• 2017

In this study, the new particulate matter emissions considering condensable PM (CPM) of stationary pollutant sources were calculated to modify the CAPSS emissions based on only filterable PMs in Seoul and Incheon. When the new calculated emissions were compared to the existing filterable PM based emissions of local governments, different contribution patterns of emission sources were found. For example, the proportion of mobile sources was high when the filterable PM was considered; however, the contribution of non-industrial sources was dominant in Seoul when the emissions of CPM were considered. Also, the proportion of energy industrial combustion and manufacturing combustion sources was significant in Incheon when CPM emissions considered. Therefore, it seems to be much desirable to consider CPM emissions for determining adequate locations of collective energy facilities and manufacturing combustion facilities in the future. In addition, CPM should be considered to solve the dust problem nationwide. The emission analysis, diagnosis, prediction and countermeasures using CPM emissions should be appropriately performed.

• KIEAE Journal
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• v.13 no.2
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• pp.27-32
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• 2013

For the past seven years, the increase in the energy consumption of universities in Korea has been 3.7 times higher than the overall increase in the energy consumption across Korea (22.5%). This is an example that shows that universities have been a massive source of greenhouse gases. Such an increase has been attributed to the new and expanded construction of architectural structures on campus. Many people argue that the increasing number of buildings may cause waste of energy and loss of efficiency. Therefore, this study was conducted as a preliminary study to derive energy efficiency measures for new university buildings. The two aspects of energy-saving as required by the eco-friendly structure certification standards have been applied to analyze the use of new/renewable energy and the energy consumption of new university buildings that have applied light density and light engineering methods. Based on these results, the major sources of energy of existing buildings and new university buildings were compared to comparatively discuss how effectively they improve energy performance.

• Journal of Power Electronics
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• v.17 no.3
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• pp.766-776
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• 2017

In modern power systems, high penetration of distributed generators (DGs) results in high stress on system stability. Apart from the intermittent nature of DGs, most DGs do not contribute inertia or damping to systems. As a result, a new control method named virtual synchronous machine (VSM) was proposed, which brought new characteristics to inverters such as synchronous machines (SMs). In addition, different active power droop controls for VSMs are being proposed in literatures. However, they are quite different in terms of their dynamic characteristics despite of the similar control laws. In this paper, mathematical models of a VSM adopting different active power droop controls are built and analyzed. The dynamic performance of the VSM output active power and virtual rotor angular frequency are presented for different models. The influences of the damping factor and droop coefficient on the VSM dynamic behaviors are also investigated in detail. Finally, the theoretical analysis is verified by simulations and experimental results.

• Journal of Electrical Engineering and Technology
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• v.8 no.6
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• pp.1605-1614
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• 2013

This paper presents a probabilistic methodology for small signal stability analysis of power system with correlated wind sources. The approach considers not only the stochastic characteristics of wind speeds which are treated as random variables with Weibull distributions, while also the wind speed spatial correlations which are characterized by a correlation matrix. The approach based on the 2m+1 point estimate method and Cornish Fisher expansion, the orthogonal transformation technique is used to deal with the correlation of wind farms. A case study is carried out on IEEE New England system and the probabilistic indexes for eigenvalue analysis are computed from the statistical processing of the obtained results. The accuracy and efficiency of the proposed method are confirmed by comparing with the results of Monte Carlo simulation. The numerical results indicate that the proposed method can actually capture the probabilistic characteristics of mode properties of the power systems with correlated wind sources and the consideration of spatial correlation has influence on the probability of system small signal stability.

• Land and Housing Review
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• v.9 no.2
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• pp.41-50
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• 2018

The purpose of this study is to review the U.S. renewable energy policies implemented by the federal government and the state governments to investigate potential barriers of renewable energy expansion and to develop policy implications for the successful renewable energy policy making in Korea. Recently, the restructuring in the energy supply chain has been being a new trend in many countries that shows a transition from traditional fossil fuels to sustainable renewable energy sources. The United States has enforced effective renewable energy policies (i.e., regulatory policies, financial incentives), which have led to the exploding growth of renewable energy facilities and productions over the last ten years. For example, many state governments in the U.S. are implementing Renewable Portfolio Standard (RPS) policies that require increased energy supply from renewable energy sources (i.e., solar, wind and geothermal). These RPS policies are expected to account for at least 10-50 percent of total electricity production in the next fifteen years. As part of results, in the recent three years, renewable energy in the U.S provided over 50 percent of total new power generation constructions. On the other hand, Korea initiated to develop climate change policies in 2008 for the Green Growth Policy that set up a target reduction of national Greenhouse Gas (GHG) emissions up to 37 percent by 2025. However, statistical data for accumulated renewable energy capacity refer that Korea is still in its early stage that contribute to only 7 percent of the total electricity production capacity and of which hydroelectric power occupied most of the production. Thus, new administration in Korea announced a new renewable energy policy (Renewable Energy 3020 Plan) in 2017 that will require over 95 percent of the total new generations as renewable energy facilities to achieve up to 20 percent of the total electricity production from renewable energy sources by 2030. However, to date, there have not been enough studies to figure out the barriers of the current policy environment and to develop implications about renewable energy policies to support the government plan in Korea. Therefore, this study reviewed the U.S. renewable energy policies compared with Korean policies that could show model cases to introduce related policies and to develop improved incentives to rapidly spread out renewable energy facilities in Korea.

• Transactions of the Korean hydrogen and new energy society
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• v.31 no.4
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• pp.337-344
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• 2020

Worldwide, there is a significant surge in the efforts for addressing the issue of global warming; the use of renewable energy is one of the solutions proposed to mitigate global warming. However, severe volatility is a critical disadvantage, and thus, power-to-gas technology is considered one of best solutions for energy storage. Hydrogen is a popular candidate from the perspective of both environment and economics. Accordingly, a hydrogen production system based on renewable energy sources is developed, and the economics of the system are assessed. The result of the base case shows that the unit cost of hydrogen production would be 6,415 won/kg H₂, with a hydrogen production plant based on a 100 MW akaline electrolyzer and 25% operation rate, considering renewable energy sources with no electricity cost payment. Sensitivity study results show that the range of hydrogen unit cost efficiency can be 2,293 to 6,984 Won/kg H₂, depending on the efficiency and unit cost of the electrolyzer. In case of electrolyzer operation rate and electricity unit cost, sensitivity study results show that hydrogen unit cost is in the range 934-26,180 won/kg H₂.

• Nuclear Engineering and Technology
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• v.52 no.6
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• pp.1327-1333
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• 2020

The global warming phenomenon emerges from the issue of climate change, which attracts the attention of intellectuals towards clean energy sources from dirty energy sources. Among clean sources, nuclear energy is getting immense attention among policymakers. However, the role of nuclear energy in pollution emissions reduction has remained inconclusive and demand for further investigation. Therefore, the current study contributes to extend knowledge by investigating the nexus between nuclear energy, economic growth, and CO₂ emissions in a developing country context such as Pakistan for the period between 1973 and 2017. The auto-regressive distributive lag model summarizes the nuclear energy has negative effect on environmental pollution as it releases carbon emission in the environment. Moreover, vector error correction Granger causality provides evidence for bidirectional causality between nuclear energy and carbon emissions. These interesting findings provide new insight, and policy guidelines provided based on these results.

• New & Renewable Energy
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• v.2 no.2 s.6
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• pp.108-117
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• 2006

This paper focus on power development options for remote islands. Recently, in accordance with progress in distributed generation technologies including renewable energy sources, many options are possible as power development option for island. At first we estimate generation cost by generation technology then recommend and suggest some countermeasures and implementation for institutional improvement.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.12
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• pp.2179-2185
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• 2008

This paper deals with the optimal investment method for distribution facilities, based on the analytical approach for the reliability assessment in distribution systems interconnected with new dispersed generations. The existing approach can estimate the expected reliability performance of distribution systems by a direct assessment of the configuration of the systems using the reliability indexes such as NDP(Non-Delivery Power) and NDE(Non-Delivery Energy). The indexes can only consider the number and configuration of the load, but can not consider the characteristics of the load which is the one of the most important factor in the investment cost for the distribution systems. Therefore, this paper presents the new performance indexes for the investment of the distribution facilities considering both the expected interruption cost for the load section and the operation characteristics of dispersed generations. The results from a case study show that the proposed methods can be a practical tool for the voltage management in distribution systems including dispersed sources.

• New & Renewable Energy
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• v.18 no.3
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• pp.72-84
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• 2022

As the threat of climate change escalates, 'net-zero' has become a priority for the international community, and the use of new and renewable energy sources is expected to play a significant role in reaching international carbon neutrality. Here, we evaluate technological competitiveness in terms of implementation and technology by analyzing scientific literature and patents in the new and renewable energy fields of five major countries. For the past 10 years (2009-2019), the most active areas of new and renewable energy research and development have been solar power, wind power, waste, and fuel cells. China is the forerunner in implementation, whereas the United States has the most advanced technology. Portfolio analysis revealed that Korea's fuel cell, the United States' bioenergy, China's waste, Japan's solar and fuel cell, and the European Union's wind power have shown to be in Star Field respectively. Technological competitiveness analysis found that Korea is lagging behind other countries in the new and renewable energy sector, and needs to set a new direction for future carbon-neutral research and development, investment, and policy.