• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.34 no.6
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• pp.454-460
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• 2021

In this work, we synthesized alloy-core InZnP quantum dots, which are more efficient than single-core InP quantum dots, using a solution process method. The effect of synthesis conditions of alloy core on optical properties was investigated. We also investigated the conditions that make up the gradient shell to minimize defects caused by lattice mismatch between the InZnP core and ZnS is 7.7%. The stable synthesis temperature of the InZnP alloy core was 200℃. Quantum dots consisting of three layered ZnSe gradient shell and single layered ZnS exhibited the best optical property. The properties of quantum dots synthesized in 100 ml and in 2,000 ml flasks were almost equal.

• Journal of Korean Society of Water and Wastewater
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• v.34 no.6
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• pp.403-410
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• 2020

The difficulty of securing freshwater sources is increasing with global climate change. On the other hand, seawater is less affected by climate change and regarded as a stable water source. For utilizing seawater as freshwater, seawater desalination technologies should be employed to reduce the concentration of salts. However, current desalination technologies might accelerate climate change and create problems for the ecosystem. The desalination technologies consume higher energy than conventional water treatment technologies, increase carbon footprint with high electricity use, and discharge high salinity of concentrate to the ocean. Thus, it is critical to developing green desalination technologies for sustainable desalination in the era of climate change. The energy consumption of desalination can be lowered by minimizing pump irreversibility, reducing feed salinity, and harvesting osmotic energy. Also, the carbon footprint can be reduced by employing renewable energy sources to the desalination system. Furthermore, the volume of concentrate discharge can be minimized by recovering valuable minerals from high-salinity concentrate. The future green seawater desalination can be achieved by the advancement of desalination technologies, the employment of renewable energy, and the utilization of concentrate.

• New & Renewable Energy
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• v.18 no.2
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• pp.60-72
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• 2022

The environmental, social, and governance (ESG) score is gaining recognition as important nonfinancial investment criteria. With climate change emerging as a global issue, energy companies must pay attention to the ESG impact on corporate performance. In this study, the ESG impact on the performance of energy companies was analyzed based on 23 companies selected from the S&P 500. The panel corrected standard error methodology was used. The Refinitiv ESG score was the independent variable, and financial performance metrics, such as Tobin's Q, return on assets, and return on equity, were the dependent variables. It was found that the ESG score is positively associated with long-term corporate value but not with short-term profitability in the electricity utility industry. Among the subcategories of ESG, the environmental and social scores also showed positive correlations with long-term corporate value. A direct incentive policy is recommended that can offset expenses for ESG activities to reduce carbon emission in the energy sector.

• Journal of Hydrogen and New Energy
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• v.35 no.1
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• pp.14-26
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• 2024

Global efforts continue with the goal of transition to a "carbon neutral (net zero)" society with zero carbon emissions by 2050. For this purpose, the technology of water electrolysis is being developed, which can store electricity generated from renewable energies in large quantities and over a long period of time as hydrogen. Recently, various research and large-scale projects on 'green hydrogen', which has no carbon emissions, are being conducted. In this paper, a comparison of water electrolysis technologies was carried out and, based on data provided by the International Energy Agency (IEA), large-scale water electrolysis demonstration projects were analyzed by classifying them by technology, power supply, country and end user. It is expected that through the analysis of large-scale water electrolysis demonstration projects, research directions and road maps can be provided for the development/implementation of commercial projects in the future.

• International Journal of Computer Science & Network Security
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• v.24 no.4
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• pp.87-106
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• 2024

Vehicle-to-Home (V2H) and Home Centralized Photovoltaic (HCPV) systems can address various energy storage issues and enhance demand response programs. Renewable energy, such as solar energy and wind turbines, address the energy gap. However, no energy management system is currently available to regulate the uncertainty of renewable energy sources, electric vehicles, and appliance consumption within a smart microgrid. Therefore, this study investigated the impact of solar photovoltaic (PV) panels, electric vehicles, and Micro-Grid (MG) storage on maximum solar radiation hours. Several Deep Learning (DL) algorithms were applied to account for the uncertainty. Moreover, a Reinforcement Learning HCPV (RL-HCPV) algorithm was created for efficient real-time energy scheduling decisions. The proposed algorithm managed the energy demand between PV solar energy generation and vehicle energy storage. RL-HCPV was modeled according to several constraints to meet household electricity demands in sunny and cloudy weather. Simulations demonstrated how the proposed RL-HCPV system could efficiently handle the demand response and how V2H can help to smooth the appliance load profile and reduce power consumption costs with sustainable power generation. The results demonstrated the advantages of utilizing RL and V2H as potential storage technology for smart buildings.

• Journal of the Korean Society of Industry Convergence
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• v.27 no.1
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• pp.173-182
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• 2024

While the current share of marine energy in South Korea is less than 1%, it is globally recognized as a resource approximately four times the annual electricity production. Considering the diverse geographical features of the East Sea, South Sea, and West Sea, marine energy development is crucial for South Korea and essential for achieving the 2050 carbon neutrality goal. Policy efforts for marine energy deployment focus on establishing an innovative, open, and integrated R&D system to respond flexibly. The construction of a scientific, economic, and social valid site selection system, along with a maritime spatial planning regime that considers environmental and socio-economic impacts, is emphasized. To expedite the early activation of marine energy, comprehensive policy endeavors, including discriminatory support policies and participation in international standardization, are anticipated to contribute to the sustainable development and dissemination of marine energy. Marine renewable energy plays a significant role in sustainability and addressing climate change, considered an essential component of South Korea's efforts toward carbon neutrality.

• New & Renewable Energy
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• v.20 no.1
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• pp.61-69
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• 2024

This study investigates the barriers to the deployment of solar thermal and ground source heat pump (GSHP) from the perspective of consumers and businesses, as well as evaluates priorities for improving the barriers via expert AHP evaluation. From a consumer's perspective, the overall satisfaction with solar thermal is significantly lower than that with PV and needs to be improved at the installation and use stages. GSHP needs to be improved at the prior-information search stage. From a business perspective, the non-distinction between heat and electricity in mandatory installations in public buildings, the difficulty in assessing the value of heat, and high initial costs impede the deployment. Based on the result of AHP analysis, the priorities for improving the barriers to the wide utilization of solar thermal are evaluated in the order of economic feasibility, policy, acceptability, and technology, where high installation cost is shown to be the greatest barrier. Barriers for GSHP are evaluated in the order of policy, acceptability, economic feasibility, and technology, where policy means improvement is evaluated as the most important factor in promoting the deployment of GSHP.

• New & Renewable Energy
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• v.20 no.1
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• pp.116-125
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• 2024

Ultra-low-head is an unexplored classification among the sites in which hydroelectric power can be produced. This is typically owing to the low power output and the economic value of the turbines available in this segment. A turbine capable of operating in an ultra-low-head condition without the need of a dam to produce electricity is developed in this study. A gate structure installed at a shallow water channel acting as a weir generates artificial head for the turbine mounted on the gate to produce power. The turbine and generator are designed to be compact and submersible for an efficient and silent operation. The gate angle is adjustable to operate the turbine at varying flow rates. The turbine is designed and tested using computational fluid dynamics tools prior to manufacturing and experimental studies. A parametric study of the runner blade parameters is conducted to obtain the most efficient blade design with minimal hydraulic losses. These parameters include the runner stagger and runner leading edge flow angles. The selected runner design showed improved hydraulic characteristics of the turbine to operate in an ultra-low-head site with minimal losses.

• International Journal of Aerospace System Engineering
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• v.11 no.1
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• pp.1-3
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• 2024

Around the world, fossil fuel energy is being replaced with renewable energy due to environmental problems and sharp price increases. Many countries are making a change in the direction of moving toward eco-friendliness by reducing carbon emissions. Among renewable energies, the wind energy is eco-friendly because it produces electricity by wind power without carbon emissions, and it attracts attention worldwide as a great alternative to the exhausted fuel energy. To improve the efficiency of wind turbines, large and extra-large wind turbines have been developed all over the world by increasing install and diameter. These wind turbines have difficulty in transport after manufacture because of their size and height. Since the height of wind turbine blades is higher than the existing tunnel height, it is impossible to transport them. In this study, therefore, a 5 MW class large blade was separated for transport easiness as wind power generators became larger globally. Aerodynamic design and analysis was carried out for the blade. After performing structural design and analysis with the model designed, the stress concentration of the analyzed model and the various factors for consideration when separating were considered to conduct the study of selecting the optimal blade separation positions.

• Nuclear Engineering and Technology
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• v.56 no.7
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• pp.2480-2488
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• 2024

Pakistan is a developing country whose maximum amount of mixed energy is provided by electricity, oil, coal, and gas. The study objective is to analyze the six major social factors to describe the significance of nuclear energy and CO₂ emissions at the decisive point coming from income, trade, energy, and urbanization. This study has tried to analyze the impact of different factors (i.e., fossil energy, GDP per capita, overall population, urban population, and merchandise trade) on Pakistan's CO₂ emissions using the extended STRIPAT model from 1986 to 2021. Ridge regression has been applied to analyze the parameters due to the multicollinearity problem in the data. The results show that (i) all the factors show significant results on carbon emissions; (ii) population and energy factors are the huge contributors to raising CO₂ emissions by 0.15% and 0.16%; however, merchandise and GDP per capita are the least contributing factors by 0.12% and 0.13% due to import/export and income level in Pakistan, and (iii) nuclear energy and substitute overall show a prominent and growing impact on CO₂ emissions by 0.16% and 0.15% in Pakistan. Finally, empirical results have wider applications for energy-saving, energy substitution, capital investment, and CO₂ emissions mitigation policies in developing countries. Moreover, by investigating renewable energy technologies and renewable energy sources, insights are provided on future CO₂ emissions reduction.