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Selected Papers from the 12th Asia-Pacific Forum on Renewable Energy (AFORE 2023)

A special issue of Energies (ISSN 1996-1073). This special issue belongs to the section "A: Sustainable Energy".

Deadline for manuscript submissions: 30 April 2024 | Viewed by 6786

Special Issue Editors


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Guest Editor
Faculty of Wind Energy Engineering, Graduate School of Jeju National University, 102, Jejudaehak-ro, Jeju-si 63243, Jeju-do, Republic of Korea
Interests: wind turbine system design; offshore wind power generation; aerodynamic blade design; integrated load analysis; prediction of wind power generation using machine learning techniques
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Guest Editor
Korea Institute of Energy Technology (KENTECH), 72, Ujeong-ro, Naju-si, Jeollanam-do, Republic of Korea
Interests: thin film solar cells; integrated PV modules and systems (BIPV, VIPV, RIPV)
Special Issues, Collections and Topics in MDPI journals

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Guest Editor
Principal Researcher, Carbon Neutral Technology R&D Department, Korea Institute of Industrial Technology (KITECH), 89 Yangdaegiro-gil, Ipjang-myeon, Seobuk-gu, Cheonan-si 31056, Chungcheongnam-do, Republic of Korea
Interests: design and optimization of fluid machinery; computational fluid dynamics (CFD); steady and unsteady numerical analyses; cavitation of hydraulic machines; flow measurements and experimental techniques
Special Issues, Collections and Topics in MDPI journals

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Guest Editor
Team Leader, Wind Energy Business Team, KR (Korean Register), 36, Myeongji Ocean City 9-ro, Gangseo-gu, Busan 46762, Republic of Korea
Interests: wind turbine and farm certification; wind turbine blade design; integrated load analysis; composite material; structural design and analysis

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Guest Editor
Department of Mechanical Engineering, Mokpo National University, 1666 Youngsan-ro, Cheonggye-myeon, Muan-gun 58554, Jeonnam, Republic of Korea
Interests: design of hydro turbine; pump turbine; wind turbine; wave and tidal turbines; design of pump, blower, compressor, etc.

Special Issue Information

Dear Colleagues,

The international climate action initiatives on sustainable environment goals aim to increase the share of renewable energy (RE) amongst world energy use. However, since RE resources are intermittent and variable in nature and require more efficient energy extraction to achieve these goal, there are many obstacles to be solved from technical and economical point of views. In this Special Issue, experts from academia and industry attending AFORE 2023 are invited to discuss practical measures and advanced technologies from technical and economic perspectives related to renewable energy and the pathway to carbon neutrality. This Special Issue covers all the topics related to RE technologies, including solar energy, wind energy, hydrogen and fuel cells, bioenergy, geothermal energy, hydro power, marine energy, energy storage and grid integration, resource assessment, policy and strategy, and low carbon technology.

Prof. Dr. Bum-Suk Kim
Prof. Dr. Jae-Ho Yun
Dr. Jin-Hyuk Kim
Dr. Sang-Lae Lee
Prof. Dr. Young-Do Choi
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Energies is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • solar energy
  • wind energy
  • hydrogen and fuel cells
  • bioenergy
  • geothermal energy
  • hydro power
  • marine energy
  • energy storage and grid integration
  • resource assessment
  • policy and strategy
  • low carbon technology

Published Papers (6 papers)

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Research

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18 pages, 38143 KiB  
Article
Application of 3D Digital Image Correlation Technique to Measurement of Wind Blade Properties from Coupon Test and Small-Sized-Blade Frequency Test
by Kwangtae Ha, Mingyu Kang, Daeyong Kwon, Sungmok Hwang and Cheol Yoo
Energies 2024, 17(4), 909; https://doi.org/10.3390/en17040909 - 15 Feb 2024
Viewed by 449
Abstract
As a wind blade is getting larger, its structural behavior becomes more complex and thus the risk of blade structural failure becomes higher. Generally, structural integrity is proved through blade testing with contact measurement devices such as strain gauges. However, contact measurement can [...] Read more.
As a wind blade is getting larger, its structural behavior becomes more complex and thus the risk of blade structural failure becomes higher. Generally, structural integrity is proved through blade testing with contact measurement devices such as strain gauges. However, contact measurement can only measure the physical quantities from installation points and requires lengthy cables to transmit the electrical signals to a data acquisition system, which can cause signal noise and add unnecessary weight. Recently, noncontact measurement techniques such as digital image correlation (DIC) have been widely used in various industries to process images captured from cameras and generate full-field strains and displacements without any mechanical connections such as cables. In this study, the application of three-dimensional DIC to wind blades was investigated; in addition, the material properties of glass-fiber-reinforced plastics used in blades for the measurement of the first frequency were also studied. Tensile testing was performed using coupons equipped with strain gauges and speckle patterns. In addition, a small blade from a 10 kW wind turbine was utilized to measure the first flapwise frequency using DIC and modal tests; the results showed a 2.1% difference between the two different measurements. This research showed that the DIC technique could be an alternative replacement for the traditional measurement technique upon further validation tests. Full article
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14 pages, 7148 KiB  
Article
Enhanced Cycle Performance of NiCo2O4/CNTs Composites in Lithium-Air Batteries
by Dae-Seon Hong, Yeon-Ji Choi, Chang-Su Jin, Kyoung-Hee Shin, Woo-Jin Song and Sun-Hwa Yeon
Energies 2024, 17(1), 58; https://doi.org/10.3390/en17010058 - 21 Dec 2023
Viewed by 553
Abstract
The lithium-air battery is a new type of secondary battery technology that is currently receiving a lot of attention in the field of power storage technology. These batteries are known to offer high energy densities and potentially longer driving ranges. In this study, [...] Read more.
The lithium-air battery is a new type of secondary battery technology that is currently receiving a lot of attention in the field of power storage technology. These batteries are known to offer high energy densities and potentially longer driving ranges. In this study, NiCo2O4 and CNTs were used to create a composite for use as the cathode of a Li-air battery. Improving the 3D needl-like structure that provides extensive transport channels for electrolyte infiltration and numerous sites facilitated charge transfer reactions and the synergistic effect of highly electrocatalytic NiCo2O4 with pronounced activity and high conductive CNTs, with the synthesized NiCo2O4@CNTs composites exhibiting active catalytic performance for both OER and ORR reactions. It also showed improved cycle performance at high current densities. NiCo2O4@CNTs composites were successfully fabricated using a hydrothermal method together with a sequential annealing treatment. The components of the completed composite were confirmed using TGA, XRD, and SEM, and the specific surface area was analyzed using BET. The composite was performed for over 120 cycles at a current density of 200 mA∙g−1, and 500 mA∙g−1 was achieved under the capacity limiting condition of 500 mAh∙g−1. The charging/discharging characteristics were compared under various current densities, exhibiting stable cyclability. The high catalytic activity of NiCo2O4 oxide supports its potential use as a cathode in Li-air batteries. Full article
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20 pages, 9416 KiB  
Article
Comparative Analysis of Estimated and Actual Power Self-Sufficiency Rates in Energy-Sharing Communities with Solar Power Systems
by Dawon Kim, Yonghae Jang and Yosoon Choi
Energies 2023, 16(24), 7941; https://doi.org/10.3390/en16247941 - 07 Dec 2023
Viewed by 743
Abstract
Amid the ongoing climate crisis, the international community is enacting policies to promote low-carbon energy-sharing communities. The primary objective of such communities is to enhance community-level energy self-sufficiency. Accurate energy self-sufficiency assessments are paramount in planning energy-efficient architectural designs, urban landscapes, and communal [...] Read more.
Amid the ongoing climate crisis, the international community is enacting policies to promote low-carbon energy-sharing communities. The primary objective of such communities is to enhance community-level energy self-sufficiency. Accurate energy self-sufficiency assessments are paramount in planning energy-efficient architectural designs, urban landscapes, and communal environments. In this study, the energy self-sufficiency rate of an energy-sharing community was estimated at the design stage and compared with the actual energy self-sufficiency rate calculated based on data collected over the following year (April 2022 to March 2023). The outcomes reveal that the estimated energy self-sufficiency rate is 171%, whereas the realized rate is 133%, underscoring the disparity between the projections and outcomes. An analysis of the seasonal variations in these discrepancies elucidated a correlation between the differences in the insolation levels between standard typical meteorological year (TMY) data that are conventionally used for energy generation projections and the actual meteorological conditions. Moreover, a notable incongruity surface exists between the monthly average electricity consumption of a standard four-person household, as stipulated by the Korean Electric Power Corporation (KEPCO) at 273 kWh, and the empirical power consumption at 430 kWh, resulting in a variance of approximately 157 kWh. This study illuminates the complex relationship between variables affecting energy self-sufficiency in energy-sharing communities. It serves as a crucial step towards informed decision making and precision in sustainable urban energy solutions. Full article
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16 pages, 6431 KiB  
Article
Techno-Economic Comparative Analysis of Two Hybrid Renewable Energy Systems for Powering a Simulated House, including a Hydrogen Vehicle Load at Jeju Island
by Christelle Arielle Mbouteu Megaptche, Hanki Kim, Peter Moses Musau, Sebastian Waita and Bernard Aduda
Energies 2023, 16(23), 7836; https://doi.org/10.3390/en16237836 - 29 Nov 2023
Viewed by 1094
Abstract
This work undertakes a techno-economic comparative analysis of the design of photovoltaic panel/wind turbine/electrolyzer-H2 tank–fuel cell/electrolyzer-H2 tank (configuration 1) and photovoltaic panel/wind turbine/battery/electrolyzer-H2 tank (configuration 2) to supply electricity to a simulated house and a hydrogen-powered vehicle on Jeju Island. [...] Read more.
This work undertakes a techno-economic comparative analysis of the design of photovoltaic panel/wind turbine/electrolyzer-H2 tank–fuel cell/electrolyzer-H2 tank (configuration 1) and photovoltaic panel/wind turbine/battery/electrolyzer-H2 tank (configuration 2) to supply electricity to a simulated house and a hydrogen-powered vehicle on Jeju Island. The aim is to find a system that will make optimum use of the excess energy produced by renewable energies to power the hydrogen vehicle while guaranteeing the reliability and cost-effectiveness of the entire system. In addition to evaluating the Loss of Power Supply Probability (LPSP) and the Levelized Cost of Energy (LCOE), the search for achieving that objective leads to the evaluation of two new performance indicators: Loss of Hydrogen Supply Probability (LHSP) and Levelized Cost of Hydrogen (LCOH). After analysis, for 0 < LPSP < 1 and 0 < LHSP < 1 used as the constraints in a multi-objective genetic algorithm, configuration 1 turns out to be the most efficient loads feeder with an LCOE of 0.3322 USD/kWh, an LPSP of 0% concerning the simulated house load, an LCOH of 11.5671 USD/kg for a 5 kg hydrogen storage, and an LHSP of 0.0043% regarding the hydrogen vehicle load. Full article
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15 pages, 15724 KiB  
Article
Refining the Selection of Historical Period in Analog Ensemble Technique
by Federico E. del Pozo, Jr., Chang Ki Kim and Hyun-Goo Kim
Energies 2023, 16(22), 7630; https://doi.org/10.3390/en16227630 - 17 Nov 2023
Viewed by 591
Abstract
A precise estimate of solar energy output is essential for its efficient integration into the power grid as solar energy becomes a more significant renewable energy source. Contrarily, the creation of solar energy involves fluctuation and uncertainty. The integration and operation of energy [...] Read more.
A precise estimate of solar energy output is essential for its efficient integration into the power grid as solar energy becomes a more significant renewable energy source. Contrarily, the creation of solar energy involves fluctuation and uncertainty. The integration and operation of energy systems are complicated by the uncertainty in solar energy projection. As a post-processing technique to lower systematic and random errors in the operational meteorological forecast model, the analog ensemble algorithm will be introduced in this study. When determining the appropriate historical and predictive data required to use the approach, an optimization is conducted for the historical period in order to further maximize the capabilities of the analog ensemble. To determine statistical consistency and spread skill, the model is evaluated against both the raw forecast model and observations. The outcome lowers the uncertainty in the predicted data by demonstrating that statistical findings improve significantly even with 1-month historical data. Nevertheless, the optimization with a year’s worth of historical data demonstrates a notable decrease in the outcomes, limiting overestimation and lowering uncertainty. Specifically, analog ensemble algorithms calibrate analog forecasts that are equivalent to the latest target forecasts within a set of previous deterministic forecasts. Overall, we conclude that analog ensembles assuming a 1-year historical period offer a comprehensive method to minimizing uncertainty and that they should be carefully assessed given the specific forecasting aims and limits. Full article
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Review

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20 pages, 3335 KiB  
Review
Energy Status in Africa: Challenges, Progress and Sustainable Pathways
by Maklewa Agoundedemba, Chang Ki Kim and Hyun-Goo Kim
Energies 2023, 16(23), 7708; https://doi.org/10.3390/en16237708 - 22 Nov 2023
Cited by 1 | Viewed by 2677
Abstract
Access to modern energy is essential for socioeconomic development, yet Africa faces significant challenges in this regard. For example, Sub-Saharan Africa (SSA) is marked by economic underdevelopment and poverty largely due to the non-environmentally friendly energy used (wood, charcoal) and limited access to [...] Read more.
Access to modern energy is essential for socioeconomic development, yet Africa faces significant challenges in this regard. For example, Sub-Saharan Africa (SSA) is marked by economic underdevelopment and poverty largely due to the non-environmentally friendly energy used (wood, charcoal) and limited access to modern energy resources. Indeed, this review provides an overview of the African energy landscape; it provides a comprehensive renewables-focused energy pathway for developing a cleaner and more sustainable African energy system. It explores end-use sector electrification in both rural and urban areas in Africa. It emphasizes the rapid expansion of renewable generation, the challenges facing and solutions for the implementation of renewable energy, and the role of emerging technologies. It also presents technological pathways and investment opportunities that will enrich the regional debate and help accelerate the energy transformation across Africa. The analysis demonstrated that the current trends of renewable energy used are hydropower, wind power, biomass, and geothermal energy. The electrification rate in West Africa is less than 58% in urban areas and less than 25% in rural areas. Results show that 65% of the SSA population does not have access to electricity and 81% rely on wood and charcoal. In West Africa, only Ghana (70% or so) and Cape Verde (95.9% or so) have equitable access to electricity between rural and urban areas. The potentiality of solar irradiance in Africa ranges between 3 and 7 KWh/m2/day. The wind speed ranges from 3 m/s to 10 m/s; the wave power can range from 7 to 25 kW/m per site in island regions. Egypt, Morocco, Ethiopia, Tunisia, and South Africa are, respectively, countries leading in wind power technology, and solar energy technology was more advanced in North Africa and South Africa. Finally, geothermal is only developed in Kenya and Tanzania and Kenya is the leader in that field. Although renewable energy in Africa is still growing year to year, it still faces power outages because most renewable energy potentialities are not yet exploited, the technologies used are weak, there is insufficient funding, there is ineffective infrastructure, and there are inadequate or no policies in that field. Full article
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