• JOURNAL OF ELECTRICAL WORLD
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• s.451
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• pp.22-31
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• 2014

온실가스 다량 배출로 인한 지구온난화 현상은 많은 분야에서의 변화를 요구하고 있다. 특히 온실가스 배출의 주원인으로 꼽히고 있는 발전 등 에너지산업 분야의 경우 그 요구는 매우 거세다. 과거에는 경제성장이라는 측면만 고려하면 됐지만, 지금은 기후변화 대응을 위해 환경을 최우선적으로 고려할 것을 주문하고 있기 때문이다. 문제는 현재 전 세계적으로 약 20%에 이르는 인구가 전기 에너지를 사용하지 못하고 있다는 점이다. 즉 향후 에너지를 사용하고자 하는 신규 소비자는 더욱 늘 것이고, 산업의 발전으로 인한 에너지 소비 역시 큰 폭으로 증가할 수밖에 없다. 문제가 굉장히 어렵지만 해결책도 분명 존재한다. 결론적으로 말해 온실가스 배출을 최소화하면서도 에너지 효율은 높인 기술을 개발하면 되는 것이다. 그리고 이미 세계 각국은 청정에너지 기술개발을 위해 다각도의 노력을 펼치고 있는 상황이다. 그렇다면 세계 각국은 미래 에너지시장을 선도할 청정에너지 기술로 어떤 것을 꼽고 있을까. 이 질문에 대한 대답은 지난 5월 서울에서 개최된 '제5차 클린에너지장관회의(CEM, Clean Energy Ministerial)'에서 제시된 바 있다. CEM은 한국, 미국, 영국, 독일, 중국, 일본 등 세계 에너지의 70%를 사용하는 주요 국가의 관계 장관들이 모여 클린에너지 공급 확대와 에너지효율 향상을 위한 구체적 액션플랜을 논의하는 자리다. 2010년 미국에서 첫 회의가 열렸고 아랍에미리트, 영국, 인도에 이어 한국은 5번째로 CEM을 개최했다. 특히 이번 CEM에서는 회원국들의 의견을 모아 10대 청정에너지 혁신기술을 최초로 선정, 발표했다. CEM은 "향후 10년 간 에너지 시장의 변화를 선도할 유망 기술을 선정한 것으로 IEA 등 국제기구와 주요국 기술 로드맵을 기준으로 해 23개 회원국 회람을 거쳐 최종 확정하게 됐다"고 배경을 설명했다. 이번에 선정된 10대 청정에너지 혁신기술은 ${\triangle}$초고압직류송전 ${\triangle}$에너지저장장치 ${\triangle}$바이오연료 ${\triangle}$마이크로 그리드 ${\triangle}$탄소포집 및 저장 ${\triangle}$초고효율 태양광 발전 ${\triangle}$해상풍력 ${\triangle}$신재생에너지 하이브리드시스템 ${\triangle}$빅데이터 에너지관리시스템 ${\triangle}$지열 시스템이다. 이와 관련해 산업통상자원부 윤상직 장관은 "이번에 선정된 10개의 기술은 최근의 기술적 정책적 추세가 잘 반영된 결과"라고 평가했다. 특히 윤 장관은 "중앙집중형 공급원에서 분산형 전원으로의 변화, 에너지 효율향상의 중요성, ICT와 융 복합 추세 등 우리나라의 상황에서 시사하는 바가 크다"며 "현재 수립하고 있는 '제3차 국가에너지기술 개발계획'에 이러한 기술적 추세를 반영하겠다"는 의사를 표명했다. 향후 10년 간 에너지시장의 변화를 선도할 10대 청정에너지 유망기술을 자세히 소개한다.

• Journal of the Korean earth science society
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• v.32 no.6
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• pp.602-612
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• 2011

Jeju Island, a volcanic island located in South Korea, has been one of the main targets of geophysical and/or geological studies because of its tectonic importance related to the volcanism and tectonic link to the southern part of the Korean Peninsula. Recently, as a number of broad-band magnetotelluric (MT) measurements were made, we have examined the deep part of the island. In such an insular setting, it is not easy to properly recover the deep structures such as the lower crust and the upper crust using MT data, because their low-frequency components are strongly affected by the surrounding sea of the island. In this study, we apply the sea-effect correction to the existing MT data collected at a total of 102 sites in Jeju Island. The sea-effect correction makes remarkable changes in the observed MT data at frequencies below 1 Hz, clearly indicating the existence of a conductive lower crust. The 2-D inversion results for both Jeju Southern Line (JSL) and Jeju Northern Line (JNL) show that the transition zone separating the resistive upper crust and conductive lower crust exists at a depth of 20 km on average.

• Journal of Plant Biotechnology
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• v.34 no.2
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• pp.111-118
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• 2007

Global warming crisis due primarily to continued green house gas emission requires impending change to renewable alternative energy than continuously depending on exhausting fossil fuels. Bioenergy including biodiesel and bioethanol are considered good alternatives because of their renewable and sustainable nature. Bioethanol is currently being produced by using sucrose from sugar beet, grain starches or lignocellulosic biomass as sources of ethanol fermentation. However, grain production requires significant amount of fossil fuel inputs during agricultural practices, which means less competitive in reducing the level of green house gas emission. By contrast, cellulosic bioethanol can use naturally-growing, not-for-food biomass as a source of ethanol fermentation. In this respect, cellulosic ethanol than grain starch ethanol is considered a more appropriate as a alternative renewable energy. However, commercialization of cellulosic ethanol depends heavily on technology development. Processes such as securing enough biomass optimized for economic processing, pretreatment technology for better access of polymer-hydrolyzing enzymes, saccharification of recalcitrant lignocellulosic materials, and simultaneous fermentation of different sugars including 6-carbon glucose as well as 5-carbon xylose or arabinose waits for greater improvement in technologies. Although it seems to be a long way to go until commercialization, it should broadly benefit farmers with novel source of income, environment with greener and reduced level of global warming, and national economy with increased energy security. Mission-oriented strategies for cellulosic ethanol development participated by government funding agency and different disciplines of sciences and technologies should certainly open up a new era of renewable energy.

• Journal of Wetlands Research
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• v.24 no.4
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• pp.268-287
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• 2022

This study reports newly discovered seven forest wetlands in the western part of the Korean Demilitarized Zone-Civilian Control Zone ecoregion. The wetland assessment criteria proposed by National Arboretum were adopted to evaluate four fields: vegetation and landscape, biogeochemical cycle, hydraulics and hydrology, and social-cultural-historical landscape and disturbances. Among seven wetlands located in Gimpo and Paju, five were of the fallow field type and two were of the natural type. A total of 474 plant species were recorded, including nine rare plants, such as the Carex capricornis Meinsh. ex Maxim. Three forest wetlands were sorted into A-grade, three into B-grade, and one into C-grade. Monitoring forest wetlands scattered across the border area ruled by military regulations can be challenging; still, as forest wetlands with high conservation value turned out, further investigations through remote sensing and cooperation by the relevant agencies will be required.

• Economic and Environmental Geology
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• v.46 no.4
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• pp.313-327
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• 2013

In the study, three-dimensional geostatistical simulations on McMurray Formation which is the largest oil sand reservoir in Athabasca area, Canada were performed, and the optimal site for steam assisted gravity drainage (SAGD) was selected based on the predictions. In the selection, the factors related to the vertical extendibility of steam chamber were considered as the criteria for an optimal site. For the predictions, 110 borehole data acquired from the study area were analyzed in the Markovian transition probability (TP) framework and three-dimensional distributions of the composing media were predicted stochastically through an existing TP based geostatistical model. The potential of a specific medium at a position within the prediction domain was estimated from the ensemble probability based on the multiple realizations. From the ensemble map, the cumulative thickness of the permeable media (i.e. Breccia and Sand) was analyzed and the locations with the highest potential for SAGD applications were delineated. As a supportive criterion for an optimal SAGD site, mean vertical extension of a unit permeable media was also delineated through transition rate based computations. The mean vertical extension of a permeable media show rough agreement with the cumulative thickness in their general distribution. However, the distributions show distinctive disagreement at a few locations where the cumulative thickness was higher due to highly alternating juxtaposition of the permeable and the less permeable media. This observation implies that the cumulative thickness alone may not be a sufficient criterion for an optimal SAGD site and the mean vertical extension of the permeable media needs to be jointly considered for the sound selections.

• Economic and Environmental Geology
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• v.38 no.6 s.175
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• pp.717-729
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• 2005

Peak cooling load of large buildings is generally greater than their peak heating load. Internal and solar heat gains are used fur selection of adquate equipment in large building in cold winter climate like Canada and even Korea. The cost of geothermal heat exchanger to meet the cooling loads can increase the initial cost of ground source heat pump system to the extend less costly conventional system often chosen. Thermal ice storage system has been used for many years in Korea to reduce chiller capacity and shift Peak electrical time and demand. A distribution system designed to take advantage of heat extracted from the ice, and use of geothermal loop (geothermal heat exchanger) to heat as an alternate heat source and sink is well known to provide many benifits. The use of thermal energy storage (TES) reduces the heat pump capacity and peak cooling load needed in large building by as much as 40 to $60\%$ with less mechanical equipment and less space for mechanical room. Additionally TES can reduce the size and cost of the geothermal loop by 1/3 to 1/4 compared to ground coupled heat pump system that is designed to meet the peak heating and cooling load and also can eliminate difficuties of geothermal loop installation such as space requirements and thermal conditions of soil and rock at the urban area.

• Journal of radiological science and technology
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• v.38 no.4
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• pp.337-345
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• 2015

After the Fukushima nuclear accident in 2011, concerns about radiation by people are increasing rapidly. If people could know how much they will be exposed by radiation, it may help them avoiding it and understand what exactly radiation is. By doing this, we were helping to reduce the anxiety of radiation contamination. In this study, we have researched figures of radioactivity with 'Captus-3000 thyroid uptake measurement systems' in well counter detector system. The materials were measured with Briquette, Shiitake, Pollock, Button type battery, Alkaline battery, Topsoil, Asphalt, Gasoline, Milk powder, Pine, Basalt stone, Pencil lead, Wasabi, Coarse salt, Tuna(can) Cigar, Beer, and then we categorized those samples into Land resources, Water resources, Foodstuff and Etc (Beer classified as a water resources has been categorized into Foodstuff). Also, we selected the standard radiation source linear 137Cs to measure the sensitivity of well counter detector. After that, we took cpm(counter per minute) for the well counter detector of thyroid uptake system's sensitivity. Then we compared the results of each material's cpm and converted those results to Bq/kg unit. There were a little limitation with the measurement equipment because it has less sensitivity than other professional equipment like 'High purity germanium radiation detector'. Moreover, We didn't have many choices to decide the materials. As a result, there are macroscopic differences among the rates of material's spectrum. Therefore, it had meaningful results that showed how much each material had emitted radiation. To compare the material's cpm with BKG, we've compounded their spectrums. By doing that, we were able to detect some differences among the spectrums at specific peak section. Lastly, Button type battery, Alkaline Battery, Briquette, Asphalt and Topsoil showed high value. There were classified emitting high radiation Group A and emitted lower radiation Group B. The Group A, alkaline battery showed higher rate of radiation by 7.67 %, and Button type battery was yield 4.65 % higher rate than BKG. Additionally, Asphalt (8.03 %), Topsoil (3.76 %), Briquette (7.46 %) were yield for higher values. Several samples of the daily supplies were yield little higher, but it seems safe to use in daily lives. In the case of the 'Foodstuff', all of the samples were safe and they were under the radiation limits of the Ministry of Food and Drug Safety for Food; thus, we highly recommend this study to you as a reference of common daily routine.

• Economic and Environmental Geology
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• v.51 no.1
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• pp.67-76
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• 2018

This study reviews three eco-friendly energy towns with hybrid thermal energy supply systems and borehole thermal energy storage (BTES) in Canada and Denmark. The district heating and cooling systems were designed by using multi-source energy for the higher efficiency and reliability as well as environment. ADEU (Alexandra District Energy Utility) located at the developing area in the city of Richmond, Canada was designed to supply district energy with the installation of 726 borehole heat exchangers (BHEs) and a backup boiler using natural gas. DLSC (Drake Landing Solar Community) located in the town of Okotoks, Canada is a district system to store solar thermal energy underground during the summer season by seasonal BTES with 144 BHEs. Brædstrup Solpark district heating system located in Denmark has been conducted energy supply from multiple energy sources of solar thermal, heat pump, boiler plants and seasonal BTES with 48 BHEs. These systems are designed based on social and economic benefits as well as nature-friendly living space according to the city based energy perspective. Each system has the energy center which distribute the stored thermal energy to each house for heating during the winter season. The BHE depth and ground thermal storage volume are designed by the heating and cooling load as well as the condition of ground water flow and thermophysical properties of the ground. These systems have been proved the reliance and economic benefits by providing consistent energy supply with competitive energy price for many years. In addition, the several expansions of the service area in ADEU and Brædstrup Solpark have been processed based on energy supply master plan. In order to implement this kind of project in our country, the regulation and policy support of government or related federal organization are required. As well as the government have to make a energy management agency associated with long-term supply energy plan.

• Economic and Environmental Geology
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• v.36 no.4
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• pp.257-268
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• 2003

The Cretaceous magmatism in the Gyeongsang Basin, Korea, led to the formation of two contrasting metallogenic provinces: the Haman-Gunbug-Goseong(-Changwon) (HGGC) and the Euiseong (EU). The mineralization in the HGGC metallogenic province represents copper, gold and iron of porphyry-related deposits that display close relationships in time and space with subvolcanic granitoids. Much of copper-gold-forming events in this province are consistently constrained to the period between ca. 89 and 81 Ma. The hydrothermal systems of copper-gold vein deposits in the HGGC province are associated with ore-forming fluids of high to intermediate temperature (300∼50$0^{\circ}C$) with high salinity (20∼55 equiv. wt. % NaCl). The ore-forming fluids become progressively more diluted by the incorporation of decreased quantities of magmatic water further from the nearby intrusion, suggesting significant input and fluid mixing of a meteoric water component to the magmatic fluids during the late stage of geothermal systems. In contrast, the EU metallogenic province is characterized by polymetallic vein deposits that are consistently constrained to a period of 78∼60 Ma. The geothermal systems of polymetallic vein deposits in the EU province are derived from a narrow range of intermediate temperature (200∼40$0^{\circ}C$) with relatively low salinity(1∼7 equiv. wt.% NaCl). It may represent a mixed fluid of magmatic and meteoric waters. The base-metal mineralization in the Gyeongsang Basin shows a close spatial and temporal distinction between the proximal environment derived from shallow-level granitoids in the southwestern HGGC province and the distal condition derived from volcanic environments in the northwestern EU province.

• Economic and Environmental Geology
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• v.31 no.3
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• pp.201-213
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• 1998

From the Jungwon and Munkyeong areas which are among the famous producers of the carbonate-type groundwaters in Korea, various kinds of natural waters (deep groundwater, shallow groundwater and surface water) were collected between 1996 and 1997 and were studied for hydrogeochemical and environmental isotope (${\delta}^{34}S_{so4}$, ${\delta}^{18}O$, ${\delta}D$)systematics. Two types of deep groundwaters (carbonate type and alkali type) occur together in the two areas, and each shows distinct hydrogeochemical and environmental isotope characteristics. The carbonate type waters show the hydrochemical feature of the 'calcium(-sodium)-bicarbonate(-sulfate) type', whereas the alkali type water of the 'sodium-bicarbonate type'. The former type waters are characterized by lower pH, higher Eh, and higher amounts of dissolved ions (especialJy, $Ca^{2+}$, $Na^{+}$, $Mg^{2+}$, $HCO_3{^-}$ and $SO_4{^{2-}}$). Two types of deep groundwaters are all saturated or supersaturated with respect to calcite. Two types of deep groundwaters were both derived from pre-thermonuclear (about more than 40 years old) meteoric waters (with lighter 0 and H isotope data than younger waters, i.e., shallow cold groundwaters and surface waters) which evolved through prolonged water-rock interaction. Based on the geologic setting, water chemistry, and environmental isotope data, however, each of these two different types of deep groundwaters represents distinct hydrologic and hydrogeochemical evolution at depths. The carbonate type groundwaters were formed through mixing with acidic waters that were derived from dissolution of pyrites in hydrothermal vein ores (for the Jungwon area water) or in anthracite coal beds (for the Munkyeong area water). If the deeply percolating meteoric waters did not meet pyrites during the circulation, only the alkali type groundwaters would form. This hydrologic and hydrogeochemical model may be successfully applied to the other carbonate type groundwaters in Korea.