• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.416-416
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• 2019

육상 담수는 대기중 이산화탄소($CO_2$) 배출의 중요한 발생원으로 주목되고 있다. 하천 및 강에서 대기중으로 배출되는 $CO_2$는 전 세계 탄소순환의 핵심요소이며, 대부분의 하천과 강은 $CO_2$로 과포화 되어있다. 세계적으로 하천 및 강의 $CO_2$ 배출량은 호수 및 저수지의 배출량보다 약 5배 많은 것으로 보고되고 있으나, 국내연구에서는 연구사례가 드물다. 따라서 본 연구의 목적은 낙동강 중하류에 위치해있는 강정고령보(GGW), 달성보(DSW), 합천창녕보(HCW), 창녕함안보(CHW)에서 발생되는 순 대기 배출 플럭스(Net Atmospheric Flux, NAF)의 동적 변동 특성을 분석하고, 데이터마이닝 기법을 적용하여 쉽게 수집할 수 있는 물리적 및 수질 변수로 $CO_2$ NAF를 추정하는데 사용할 수 있는 간략한 예측 모델을 개발하는데 있다. $CO_2$ NAF는 대기-수면 경계면에서의 $CO_2$ 부분압($pCO_2$)의 차에 기체전달속도를 곱하여 산정하였으며, 기체전달속도는 Cole and Caraco(1998)가 제안한 식을 사용하였다. 담수와 해수의 탄산염 시스템에서 열역학적 화학평형을 모두 고려한 $CO_2$SYS 프로그램을 사용하여 수중의 $pCO_2$를 산정하였고, $CO_2$ NAF는 Henry의 법칙과 Fick의 1차 확산법칙을 사용하여 계산하였다. $CO_2$ NAF의 시간적 변동성에 영향을 미치는 환경요인을 평가하기 위해서 상관분석, 주성분분석(Principal Component Analysis; PCA), 단계적다중회귀모델(Step-wise Multiple Linear Regression; SMLR), 랜덤포레스트(Random Forest; RF)방법을 사용하였다. SMLR 모델은 R package인 olsrr, RF 모델은 R package인 caret, randomForest를 이용하여 분석하였다. 연구 결과, 4개 보 상류 하천구간은 조류의 성장이 활발한 일부 기간을 제외한 대부분의 기간에서 $CO_2$를 대기로 배출하는 종속영양시스템(Heterotrophic system)을 보였다. $CO_2$ NAF의 중위값은 HCW에서 최소 $391.5mg-CO_2/m^2day$, DSW에서 최대 $1472.7mg-CO_2/m^2day$였다. 모든 보에서 NAF는 pH와 강한 음의 상관관계를 보였으며, $pCO_2$와 Chl-a도 음의 상관관계를 보였다. 이는 조류가 수중에서 $CO_2$를 소비하고 pH를 증가시키기 때문이다. PCA 분석 결과, NAF와 $pCO_2$가 높은 공분산을 보였으며, pH와 Chl-a는 반대 방향으로 군집되어 상관분석과 동일한 결과를 보였다. 이 연구를 통해 개발된 SMLR 모델과 RF 모델의 Adj. $R^2$ 값은 모든 보에서 0.77 이상으로 나왔으며, $pCO_2$ 측정 데이터가 없더라도 하천의 $CO_2$ NAF를 추정하는 방법으로 사용될 수 있을 것으로 평가된다.

• Proceedings of the KSEEG Conference
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• 1999.04a
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• pp.181-183
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• 1999

• Environmental and Resource Economics Review
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• v.30 no.3
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• pp.471-501
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• 2021

We measure Environmental Efficiency (EE) based on CO₂ in four income groups from 1998 to 2018, using the Meta Stochastic Frontier Analysis method by Input Distance Function. Our results showed that economic growth and energy consumption would increase carbon dioxide emissions, and increasing labor and capital input will reduce it. Moreover, we compared Group Environmental Efficiency (GEE), Meta Environmental Efficiency (MEE), and Environmental Gap Ratio (EGR). The results showed that GEEs were be overestimated. Furthermore, the MEE showed a downward trend during this period. The lower-middle-income group had the highest EGR performance. High-income and upper-middle-income groups showed less efficiency in MEE and EGR. To improve environmental efficiency, we must reduce fossil fuels and find more scientific and technological ways to solve existing environmental problems as soon as possible.

• Journal of the Korean Applied Science and Technology
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• v.31 no.3
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• pp.375-386
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• 2014

Carbon dioxide ($CO_2$) is a green-house gas which causes the global warming problems. Anthropogenic emissionspredominantly from the combustion of coal, oil, and natural gas in electricity generations are expected to increase continuously in the future, resulting in increased $CO_2$ concentration in the atmosphere. In this study, we investigated materials properties and process systems for $CO_2$ separation with an emphasis of the post-combustion process.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.1117-1121
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• 2008

Recently energy consumption and $CO_2$ emission issue are important problem on international society. The present study has been conducted economic analysis considering economical value of $CO_2$ reduction effect. We analyze annual energy cost and annual $CO_2$ emission of the cogeneration system and gas boiler system in hotel. The first results shows that annual energy cost of cogeneration system (751,740,126 won) is more profitable than gas boiler system (801,128,408 won) by 6.2% (49,388,281 won). The second results shows that annual $CO_2$ emission of cogeneration system (3,297 ton) is less than gas boiler system (3,536 ton) by 6.8% (239 ton). The Economical value of $CO_2$ reduction effect is 4,773,898 won. The cost effect according to the reduction of $CO_2$ is corresponding to 9.7% of reduction cost for total energy cost. The result of this study means that $CO_2$ reduction effect is essential item in introduction and change of facility for economic analysis.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.6
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• pp.115-131
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• 2022

Carbon dioxide (CO₂) emissions from the transportation sector in South Korea accounts for 16.5% of all CO₂ emissions, and road transportation accounts for 96.5% of this sector's emissions in South Korea. Hence, constant research is being carried out on methods to reduce CO₂ emissions from this sector. With the emerging use of smart crossings, attempts to monitor individual vehicles are increasing. Moreover, the potential commercial deployment of autonomous vehicles increases the possibility of obtaining individual vehicle data. As such, CO₂ emission research was conducted at five signalized intersections in the Gangnam District, Seoul, using data such as vehicle type, speed, acceleration, etc., obtained from image detectors located at each intersection. The collected data were then applied to the MOtor Vehicle Emission Simulator (MOVES)-Matrix model-which was developed to obtain second-by-second vehicle activity data and analyze daily CO₂ emissions from the studied intersections. After analyzing two large and three small intersections, the results indicated that 3.1 metric tons of CO₂ were emitted per day at each intersection. This study reveals a new possibility of analyzing CO₂ emissions using actual individual vehicle data using an improved analysis model. This study also emphasizes the importance of more accurate CO₂ emission analyses.

• Korean Chemical Engineering Research
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• v.55 no.3
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• pp.332-340
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• 2017

This study aims to propose a new optimization-based approach for design and analysis of the stand-alone hybrid energy supply system using renewable energy sources (RES). In the energy supply system, we include multiple energy production technologies such as Photovoltaics (PV), Wind turbine, and fossil-fuel-based AC generator along with different types of energy storage and conversion technologies such as battery and inverter. We then select six different regions of Korea to represent various characteristics of different RES potentials and demand profiles. We finally designed and analyzed the optimal RES stand-alone energy supply system in the selected regions using multiobjective optimization (MOOP) technique, which includes two objective functions: the minimum cost and the minimum $CO_2$ emission. In addition, we discussed the feasibility and expecting benefits of the systems by comparing to conventional systems of Korea. As a result, the region of the highest RES potential showed the possibility to remarkably reduce $CO_2$ emissions compared to the conventional system. Besides, the levelized cost of electricity (LCOE) of the RES-based energy system is identified to be slightly higher than conventional energy system: 0.35 and 0.46 $/kWh, respectively. However, the total life-cycle emission of $CO_2$ ($LCE_{CO2}$) can be reduced up to 470 g$CO_2$/kWh from 490 g$CO_2$/kWh of the conventional systems.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2000.04a
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• pp.206-207
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• 2000

지구환경문제 중 지구온난화는 에너지 사용과 상관 관계가 있기 때문에 국가간에 이해 관계가 완전히 해결되지 못한 상태이나, 1997년 쿄토 의정서가 체결됨으로써 우리나라에도 구체적 시행시기 및 감축의무에 대한 압력이 가중되고 있다. 지구 온난화에 가장 큰 영향을 미치는 $CO_2$에 대한 규제는 이미 유럽에서 자동차 규제, 탄소세 도입, 화력발전소 건설 규제 등의 형태로 나타나고 있다. 우리나라 전체 이산화탄소 배출량 중 에너지분야에서 배출되는 이산화탄소는 약 25% 정도인 것으로 알려져 있다. (중략)

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.536-538
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• 2005

본 논문은 우리나라 전력전송설비들의 현황에 기초하여 향후 전력수요 증가에 따른 설비확장 시 이산화탄소 배출권의 영향을 고려한 보다 효율적인 전력설비의 선택과 중장기 전력기술개발을 위한 방향을 제시하기 위한 개념적 모형을 제시하는 한편 기술의 투자비와 이득을 최적조류계산에 의해 상정하는 방법을 제시하고 간략한 계통에서 모의함으로써 새로운 전력설비 기술개발 선택의 방법론을 제시하였다.

• Journal of Environmental Policy
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• v.12 no.1
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• pp.101-123
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• 2013

This research aims to find out the existence of considerable induced effect that the conventional I-O model cannot. First, we construct an environmental Social Accounting Matrix for Korea by combining statistics on the Korean GDP and I-O with physical data on the fossil energy consumption and $CO_2$ emissions. The impacts of productive activities on fossil energy consumption and $CO_2$ emissions are evaluated by calculating the e-SAM multipliers. By applying decomposition technique further, we get direct, indirect, and induced effects of production activities by industry. The result of decomposing the e-SAM shows that while the direct effect of the electricity industry is large, its indirect effect is very small. In the case of the primary metal industry, both the direct and the indirect influence of this industry were very large. On the contrary, in case of the service industry, the induced effect of fossil energy consumption was as high as 50% of the gross effect. These results suggest that different energy policies should be established for different industries. Also, the findings show the e-SAM model is better than I-O model in analyzing implications of policies on energy use in the economy.