• Energy Research
• Open Access close
• Open Source close
• Embargo close
• TH close
• JP close
• Energy Reports close

Thailand has pledged to be carbon neutral by 2050 at the UN Climate Change Conference (COP26). Promoting all-new buildings to be net-zero energy consumption within 2030 is a strategy to achieve the goal. The previous works have revealed that policymakers and related stakeholders’ supportive strategies could significantly contribute to promoting the zero-energy buildings (ZEB) investment. Moreover, another big challenge in improving high-energy-efficient buildings is the high initial cost and uncertainties of the future costs. As far as we know, no studies have investigated an effect of such a change in economic and relevant costs on the financial benefits of the ZEB project in Thailand. Such parameters are a significant barrier to decision-making on ZEB investment. Consequently, the guidance for affordable financial feasibility and supportive measures could significantly promote ZEB projects. This study used sensitivity analysis to assess the variations of future costs, including initial cost, energy price, maintenance & operation cost, interest rate, and discount rate, influencing the project’s NPVs and the global costs of three representative office buildings. The analyses showed that the total cost was strongly sensitive to the investment cost, with a maximum reduction of 15.76% when the investment cost was reduced by 20%. The NPV was significantly influenced by energy price, with the variations ranging from 2.83% to 15.12%. ZEB development in large buildings provided more financial profitability than in small buildings. Finally, the key effective financial parameters and the key persons responsible for supporting financial measures were proposed to promote ZEB project investment in Thailand. The increase in energy prices and the decrease in initial cost, especially the cost of the air-conditioning systems, will increase investment returns. However, such increments in energy price also affect small and low-income enterprises. For future implementations of ZEB, policymakers should investigate suitable measures and financial incentives.

Sustainable energy transition is generally understood as a concept of developing robust, effective and efficient energy sectors in a particular country or region without compromising the present and future socio-environmental security. In view of this, several countries have made remarkable efforts towards achieving this all-important objective in compliance with modern energy needs and supply requirements. Over half of the reported impoverished people globally reside in the sub-Saharan Africa (SSA) region and a sizeable portion of these people (up to 400 million) live in Nigeria, being the most populated country in Africa. The economic growth and social development of any nation depend remarkably on the sufficiency of its energy sector. Thus, the realization of the Sustainable Development Goals (SDGs) comes the year 2030, as projected by the united nations, in Nigeria and the entire SSA region depends heavily on energy. In this study, the importance of an equitable right to sustainable energy adoption in Nigeria and other countries in Africa towards meeting United Nations SDG’s deadline has been succinctly discussed. The reform activities towards improving the energy sector of Nigeria are discussed and appropriate recommendations are made taking clues from other developing countries’ successful energy transition efforts.

In this study, two polymorphs of bismuth oxide were synthesized via the solution-based route for the aqueous phase glycerol transformation to high valuable compounds with low energy photocatalysis in the presence of hydrogen peroxide as the electron acceptor. The results showed that the hydrogen peroxide was deficient to produce OH•radicals in tetragonal bismuth oxide (β-Bi2O3) photocatalyst because it decomposed very fast to H2O and O2and unoxidized glycerol, resulting in a low glycerol conversion at almost 6.6 times comparing with that of monoclinic bismuth oxide (α-Bi2O3) photocatalyst. Also, more valuable products could be produced with α-Bi2O3 photocatalyst system. In addition, the possible mechanisms of hydrogen peroxide on the low energy photocatalytic performances of both bismuth oxide polymorphs were discussed.

PV power generation challenging in solar intermittency irradiance is a main problem in the system operation. Flexible Power Point Tracking (FPPT) algorithm for a PV and battery energy storage system (BESS) for storing surplus power or supplying lacking power are employed for smoothing the power. In contrast to Maximum Power Point Tracking (MPPT) algorithm that required a large BESS to regulate the dc-link voltage, the proposed FPPT can minimize the utilization of BESS. As a results, the operation of FPPT can reduce for the battery sizing while maintaining the benefit of power regulation under 10% of power ramp-rate. This paper presents a comparison of FPPT and without FPPT applying to the PV system to investigate the performance of the proposed control strategy focusing on the utilization of BESS. The real-time simulation HIL is simulated to verify the effectiveness of the system with an irradiance curve profiles.

Overvoltage is a critical problem of Thailand’ distribution system. The electrical protection device in the distribution system needs to be able to support this level of overvoltage. In the distribution system connecting the Chachoengsao2 substation and the Bang Khla substation, the overvoltage from a ferro resonance phenomenon affects the surge arrester directly. This research studies the effect of the drop-out fuse connection scheme on the voltage and surge arrester using the RMS/EMT Simulation mode in the DIgSILENT program. Normally, the surge arrester withstands a voltage of 1.9 p.u. of the phase voltage. If the overvoltage in the distribution system is higher than the voltage that the surge arrester can withstand, the surge arrester can be damaged. Therefore, it is necessary to study and analyze the drop out fuse insertion pattern that affects the overvoltage in the distribution system to understand the causes of overvoltage problems and their effects on each type of electrical protective equipment.

Today, the security of energy has become one of the primary concerns of all the countries around the world due to the limited energy sources, increasing population, energy prices fluctuations and limitations in energy supply. Japan is considered as one of the largest energy consumers and energy importers throughout the world which almost 96% of its primary energy supply in national level relies on the imports from other countries. After experiencing several harsh energy supply conditions over the last 40 years, Japan realized the sensitivity of its energy supply and decided to fundamentally restructure its energy supply and rely more on energy mix diversification, renewable energies, energy efficiency improvement, and carbon emissions reduction. In this article the energy security improvement and the government actions to boost diversification of energy by focusing more on renewable energies and reducing energy intensity, increasing energy efficiency and decreasing energy import dependency in Japan is studied. In addition, various renewable energy technologies as a substitute source of energy and promising ways of domestic energy supply as well as the factors to improve the security of energy supply are studied thoroughly. Moreover, it was realized that the most primary energy sources in Japan are biofuel and waste energy followed by hydropower and geothermal energy respectively.

Des structures liquides telles que des gouttelettes et des limaces existent à l'intérieur des canaux de gaz des piles à combustible à électrolyte polymère dans des applications à basse température. L'efficacité de ces dispositifs électrochimiques dépend de l'élimination efficace de l'eau produite. Les spécifications des canaux de gaz telles que la géométrie de la section, les angles d'angle et les propriétés de mouillabilité de la surface contrôlent sensiblement le processus d'élimination du liquide. Ici, cinq canaux avec différentes géométries de section sont modélisés et le processus de décharge liquide-slug est étudié en utilisant une méthode de volume transitoire de fluide. Le modèle numérique se compose d'un segment du canal de gaz côté cathode avec les conditions de fonctionnement d'une pile à combustible opérationnelle. Les simulations dynamiques d'écoulement en deux phases montrent que les canaux avec une largeur et une hauteur plus petites aboutissent à une distribution d'écoulement appropriée à l'alimentation en gaz. Un canal avec des dimensions de section de 0,5 mm × 0,5 mm entraîne un dégagement GDL (Gas-Diffusion Layer) 35,18 % plus rapide, une expulsion de liquide 29,32 % plus rapide par rapport à d'autres canaux ayant des dimensions 2 à 3 fois plus élevées. Par conséquent, ce canal est recommandé comme la meilleure conception pour améliorer les performances de la pile à combustible. Existen estructuras líquidas como gotitas y babosas dentro de los canales de gas de las celdas de combustible de electrolito polimérico en aplicaciones de baja temperatura. La eficiencia de estos dispositivos electroquímicos depende de la eliminación efectiva del agua producida. Las especificaciones de los canales de gas, como la geometría de la sección, los ángulos de las esquinas y las propiedades de humectabilidad de la superficie, controlan sustancialmente el proceso de eliminación de Aquí, se modelan cinco canales con varias geometrías de sección y se investiga el proceso de descarga de líquido-obstáculo utilizando un método de volumen transitorio de fluido. El modelo numérico consiste en un segmento del canal de gas del lado del cátodo con las condiciones de trabajo de una celda de combustible operativa. Las simulaciones dinámicas de flujo de dos fases muestran que los canales con menor ancho y altura resultan en una distribución adecuada del flujo en la alimentación de gas. Un canal con las dimensiones de sección de 0.5 mm × 0.5 mm da como resultado un aclaramiento de GDL (capa de difusión de gas) un 35.18% más rápido, una expulsión de líquido un 29.32% más rápida en comparación con otros canales que tienen dimensiones 2–3 veces más altas. Por lo tanto, este canal se recomienda como el mejor diseño para mejorar el rendimiento de la pila de combustible. Liquid structures such as droplets and slugs exist inside gas channels of polymer electrolyte fuel cells in low-temperature applications. The efficiency of these electrochemical devices depends on the effective removal of the produced water. The gas channels' specifications like section geometry, corner angles, and surface wettability properties substantially control the liquid removal process. Here, five channels with various section geometries are modeled and the liquid-slug discharge process is investigated using a transient volume of fluid method. The numerical model consists of a segment of the cathode-side gas channel with the working conditions of an operational fuel cell. The dynamic two-phase flow simulations show that channels with smaller width and height eventuate in proper flow distribution at the gas feed. A channel with the sectional dimensions of 0.5 mm × 0.5 mm results in. 35.18% faster GDL (Gas-Diffusion Layer) clearance, 29.32% faster liquid expulsion compared to other channels having 2–3 times higher dimensions. Therefore, this channel is recommended as the best design for improved fuel cell performance. توجد الهياكل السائلة مثل القطرات والرخويات داخل قنوات الغاز لخلايا وقود البوليمر المنحل بالكهرباء في تطبيقات درجات الحرارة المنخفضة. تعتمد كفاءة هذه الأجهزة الكهروكيميائية على الإزالة الفعالة للمياه المنتجة. تتحكم مواصفات قنوات الغاز مثل هندسة القسم وزوايا الزاوية وخصائص قابلية الترطيب السطحية بشكل كبير في عملية إزالة السائل. هنا، يتم نمذجة خمس قنوات ذات أشكال هندسية مختلفة ويتم فحص عملية تفريغ الشظية السائلة باستخدام حجم عابر من طريقة السوائل. يتكون النموذج العددي من جزء من قناة غاز جانب الكاثود مع ظروف عمل خلية وقود تشغيلية. تُظهر محاكاة التدفق الديناميكي ثنائي المرحلة أن القنوات ذات العرض والارتفاع الأصغر تحدث في توزيع التدفق المناسب عند تغذية الغاز. تؤدي القناة ذات الأبعاد المقطعية 0.5 مم × 0.5 مم إلى خلوص GDL (طبقة انتشار الغاز) أسرع بنسبة 35.18 ٪، وطرد سائل أسرع بنسبة 29.32 ٪ مقارنة بالقنوات الأخرى ذات الأبعاد الأعلى 2–3 مرات. لذلك، يوصى باستخدام هذه القناة كأفضل تصميم لتحسين أداء خلية الوقود.

An energy harvesting system requires a power converter with its compact size and high power efficiency. Following the trend, this study suggests a new switched capacitor converter (SCC). The proposed converter is designed by a parallel- and cross-connecting two Fibonacci topologies. This connection leads the proposed SCC to generate its multilevel outputs as well. The proposed SCC has the lowest output resistors under five times conversion ratios from the theoretical analysis and comparison of two different SCC topologies. Simulation results confirm that the proposed SCC can be operated over 90% power efficiencies under 100 mW.