Hasil untuk "Renewable energy sources"

D. Revel

Xiaodong Liang

M. Abdelkareem, M. Assad, E. Sayed et al.

Abstract Rapid population growth and industrial development have propelled water resources to the forefront of challenges facing modern societies. While water covers about two thirds of the surface of earth,

G. Notton, M. Nivet, Cyril Voyant et al.

Abstract Solar and wind energy are inherently time-varying sources of energy on scales from minutes to seasons. Thus, the incorporation of such intermittent and stochastic renewable energy systems (ISRES) into an electricity grid provides some new challenges in managing a stable and safe energy supply, in using energy storage and/or 'back-up' energy from other sources. In such cases, the ability to accurately forecast the output of “unpredictable” energy facilities is essential for ensuring an optimal management of the energy production means. This review syntheses the reasons to predict solar or wind fluctuations, it shows that variability and stochastic variation of renewable sources have a cost, sometimes high. It provides useful information on the intermittence cost and on the decreasing of this cost due to an efficient forecasting of the source fluctuation; this paper is for engineers and researchers who are not necessarily familiar with the issue of the notions of cost and economy and justify future investments in the ISRES production forecasting.

P. Brockway, A. Owen, Lina I. Brand-Correa et al.

Zeineb Abdmouleh, A. Gastli, L. Ben‐Brahim et al.

Mustafa Tevfik Kartal

Anco S. Blazev

Factors, both human and physical, including climatic conditions, hydrology, geomorphology and cropping practices are evaluated in terms of their contribution in desertification development. Particular emphasis is given on the effects of cultivation practices and the animal husbandry. The relation between local plants and desertification is also studied, emphasizing the role of the olive tree which is the dominant crop in the area. The main causes which are found to favor the occurrence of desertification include population increase, the extent of areas with low or without plant coverage, overgrazing combined or with the occurrence of fires, and the increased content in salts of water resources, especially at the eastern part of the island. With regard to agricultural practices and especially these applied for olive oil trees environmental compacts are either positive or negative depending on the physical circumstances and the used cultivating practices. What is important is the way weeds are combated, the type of the soil, irrigation applied and the conservation of plant cover. Vegetation restoration is considered one of the most effective ways to combat desertification. Native plant species suitable for such use include Ceratonia siliqua, Olea europea subsp.sylvestri and Pistacia lentiscus which are adapted to environmental conditions prevailing in the island of Crete. Additionally, findings from the international literature reveal an important role of AM fungi on the establishment of vegetation in degraded soils. Understanding the interrelationships between vegetation and soil microfauna is expected to contribute in the successful reestablishment of native shrub species in the degraded soils in Crete. Brief Biography of the Speaker: Vassilis Gekas son of Christos and Dimitra was born in Gallini of Larissa the year 1948. His studies were as follows: elementary school in the Gallini village (1954-1960) , secondary school in Larissa και(1960-1966). Chemical Engineering School in the National Technical University of Athens, (1966-1971). Military Service 1971-1973. In the Greek Industry worked as a Chemical Engineer (1973-1983) Ph D studies in the Technical Institute of Lund (1983-1987). Post doc studies on an ELF AQUITAINE sponsorship in the PAUL SABATIER University in Toulouse of France. Coming back to Sweden he obtained the degree of DOCENT (Asssociate Professor) in 1992. He taught in Lund and HELSINGBORG of Sweden, Oporto Portugal, Bahia Blanca and Rio Cuarto og Argentina, Celaya and Mexico City of Mexico and also he gave lectures in France, Italy, Spain and Germany. He speaks english, french, german, spanish, italian, portuguese and swedish. Since 1998 Professor of Transport Phenomana & Thermodynamics at the Environmental Department of the Technical University of Crete, Chania. He was the first Chairman of the Department (2000-2004). Author of several books and of chapters of books, in english and in greek. Author of >50 publications in cited journals with a Citation Index of approx. 1000. Know how in Membrane Technology, Food Engineering, Stirling cycles and active heliothermic systems. Current research topics: Desertification, Geometry & transport phenomena of biological structures such as the bronchic tree, sun-driven cars, BOLTZMANN equation. He participates in the Summer school of Delfi teaching on the connection between the modern knowledge with the Ancient Greek wisdom. 2nd WSEAS/IASME International Conference on RENEWABLE ENERGY SOURCES (RES'08) Corfu, Greece, October 26-28, 2008 ISSN: 1790-5095 11 ISBN: 978-960-474-015-4

Ramhari Poudyal, P. Loskot, Rabindra Nepal et al.

Abstract Nepal has been suffering from a serious energy crisis for decades. It has severely affected its economic, social and political developments. Owing to the continuously evolving energy situation in Nepal, and the recent progress in renewable energy technologies, this study aims to provide an up to date perspective on the current energy crisis in Nepal. In particular, the current energy production and consumption profiles are reviewed, and the main factors contributing to a widening gap between the energy supply and demand are identified. These factors concern delayed and overpriced hydropower projects, outdated and insufficient energy infrastructure, transmission and distribution losses, energy theft, deficient energy management, lack of energy conservation, low efficiency of equipment, unsustainable energy pricing strategies and unsatisfying energy market regulations. Other essential factors worsening the energy crisis can be attributed to specific geographical and geopolitical problems, the strong dependence on energy imports, and inadequate exploitation of the vast amounts of renewable energy resources. The status of existing and planned large hydropower projects is summarized. The recent policies and investment initiatives of the Nepalese government to support green and sustainable energy are discussed. Furthermore, a long-term outlook on the energy situation in Nepal is outlined using the energy modeling software LEAP in order to show how to exploit the tremendous renewable energy resources in Nepal. Our findings suggest that renewable resources are crucial not only for mitigating the present energy crisis, but also to ultimately provide energy independence for Nepal by establishing reliable and secure sources of energy.

P. Bórawski, A. Bełdycka-Bórawska, E. Szymańska et al.

Abstract The aim of the paper is to present renewable energy market development with particular regard paid to biofuels in the EU. The analysis included data on the share of renewables in Gross Island energy consumption, changes of renewable energy in the years 2004–2016 and the amount of liquid biofuels. The authors of the paper used descriptive and statistical methods to describe the changes in bioenergy development in the European Union (EU). The biggest share of biofuels and renewable waste can be seen in Latvia (31.2%), Finland (26.7%) and Sweden (24.8%). The highest percentage of wind energy in 2015 was found in: Denmark (7.2%), Portugal (4.3%), Ireland (4.0%) and Spain (3.5%). The highest share of solar energy in 2015 was found in Cyprus (3.5%), Spain (2.6%) and Greece (2.2%). The highest contribution of geothermal energy was found in 2015 in Italy (3.5%), Portugal (0.8%) and Slovenia (0,7%). Hydropower was the biggest in 2015 in Sweden (14.2%), Austria (9.6%) and Slovenia (5.0%). The highest coefficients of variation of the share of electricity from renewable energy sources were found in the years 2004–2017 in Malta (140.3%), Cyprus (101.1%) and United Kingdom (71.9%). In addition, the highest coefficients of variation of share of renewable energy sources in heating and cooling in the years 2004–2017 were found in Malta (72.4%), United Kingdom (69.81%) and Hungary (44.91%). Moreover, the highest coefficients of variation of share of renewable energy sources in transport in the years 2004–2017 were found in Finland (113.78%), Malta (115.52%) and Belgium (96.53%). The biggest producers of ethanol and biodiesel in EU were Germany, France and Poland. Cluster analysis data show that Germany and France are of key importance in the production of biodiesel and ethanol. The biodiesel production increased in the years 2003–2017 from 719,32 million liters to 13323 million liters (increase 1852.2%). However, in the years 2014–2017 a stagnation in biofuel production was observed from 13673 million liters to 13323 million liters (−2,56%). The situation on the market and the increasing demand for green energy suggest that the production of ethanol and esters of vegetable oils will increase by 2030, which will contribute to the development of this sector.

Mahdis Haddadi, Saman A. Gorji, Samson S. Yu

Inertia is a critical factor in maintaining the frequency stability of power systems. However, the growing integration of power electronics-based renewable energy sources (RESs) has significantly reduced system inertia. AC and dc microgrids have emerged as key solutions for integrating RESs. Unlike traditional synchronous generators, power electronic converters interfacing RESs lack inherent inertia and damping, posing challenges to the control and stability of these microgrids. To address these challenges, virtual inertia control strategies, which emulate the behavior of synchronous generators, have been widely adopted to enhance the stability of ac microgrids. Drawing on the analogies between ac and dc systems, similar virtual inertia concepts have been extended to dc microgrids, demonstrating their potential to improve system stability. This article provides a comprehensive review of inertia enhancement strategies for dc microgrids, examining their key features, benefits, and limitations. The analogy between synchronous generators/dc machines and energy storage systems is explored, with a particular focus on the implementation of virtual inertia and damping control in energy storage converters as a promising solution to mitigate power fluctuations. In addition, this article investigates the grid-forming and grid-following converter analogies in ac and dc microgrids. Various stability analysis methods applied to inertia enhancement strategies are also reviewed, offering readers a comprehensive understanding of the current state of research. By addressing the conceptual and technical analogies between ac and dc systems, this review aims to provide valuable insights for developing advanced control strategies for next-generation microgrids.

Arif Algifari, I. G. B. N. Makertihartha, Subagjo Subagjo et al.

The increasing demand for oil fuel and the decline of crude oil reserves highlight the need for alternative energy sources. Palm oil, as a renewable resource, has potential for biofuel production through catalytic cracking. This study aims to develop and evaluate modified zeolite-based catalysts, particularly ZSM-5/HY, to produce palm oil-derived gasoline that meets European fuel standards. The research involved catalyst preparation, modification with ZSM-5 and phosphorus, and activity testing in a fixed-bed reactor. Gasoline yield and catalyst performance were analyzed using gas chromatography. The results showed nearly 100% conversion of palm oil under optimal conditions, with gasoline yield meeting European standard. The addition of ZSM-5 improved conversion and RON, while phosphorus modification reduced catalyst acidity, affecting yield and coke formation. This study concludes that modifying zeolite catalysts with ZSM-5 and phosphorus enables efficient palm oil-derived gasoline production with high RON and reduced aromatic content, contributing to sustainable energy solutions. Copyright © 2025 by Authors, Published by BCREC Publishing Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Amal Herez, Hassan Jaber, Mohamad Ramadan et al.

The transition to renewable energy sources is expediting due to growing concerns about the harm that fossil fuels are causing to the environment. Because of its availability, affordability, and minimal environmental impact, solar energy stands out among them. However, conventional photovoltaic (PV) systems suffer from efficiency reduction due to high operating temperatures. This limitation has increased interest in hybrid photovoltaic/thermal (PVT) systems, which improve PV performance while producing thermal and electrical energy simultaneously. This study provides an extensive overview of recent advancements in PVT technologies, focusing on system configurations, innovative cooling strategies, and thermal storage materials. Studies published since 2021—including experimental, numerical, and simulation-based works—are examined and classified by climatic adaptability, working fluid, and application. The analysis of this literature concluded that compared to conventional PV, some PVT configurations achieve total efficiencies of up to 76 %, with numerical models showing electrical gains of 3–5 % when validated against experimental data. System performance and application versatility are further improved with the addition of nanofluids (NFs), phase change materials (PCMs), and thermoelectric generators (TEGs). In order to facilitate the design and implementation of PVT systems in a variety of settings, this document provides researchers and practitioners with an updated roadmap.

Henrik Zsiborács, N. Baranyai, A. Vincze et al.

Global electricity demand is constantly growing, making the utilization of solar and wind energy sources, which also reduces negative environmental effects, more and more important. These variable energy sources have an increasing role in the global energy mix, including generating capacity. Therefore, the need for energy storage in electricity networks is becoming increasingly important. This paper presents the challenges of European variable renewable energy integration in terms of the power capacity and energy capacity of stationary storage technologies. In this research, the sustainable transition, distributed generation, and global climate action scenarios of the European Network of Transmission System Operators for 2040 were examined. The article introduces and explains the feasibility of the European variable renewable energy electricity generation targets and the theoretical maximum related to the 2040 scenarios. It also explains the determination of the storage fractions and power capacity in a new context. The aim is to clarify whether it is possible to achieve the European variable renewable energy integration targets considering the technology-specific storage aspects. According to the results, energy storage market developments and regulations which motivate the increased use of stationary energy storage systems are of great importance for a successful European solar and wind energy integration. The paper also proves that not only the energy capacity but also the power capacity of storage systems is a key factor for the effective integration of variable renewable energy sources.

J. Benedek, Tihamér-Tibor Sebestyén, B. Bartók

The context and background of this study are based on the growing role of policy-driven renewable energy sources in improving energy security, protecting the climate, and encouraging economic development. In many cases, these high expectations are undermined by the lack of an integrated methodology for the measurement of renewable energy potential. Therefore, we assumed as the main hypothesis, the possibility of developing a complex and integrated evaluation methodology for renewable energy potential. Accordingly, we employed evaluation methods based on mapping techniques, simulation software for wind farms, and the analytical tools offered by the Geographical Information System. The main novelty of this study is related to the integration of three renewable energy sources (biomass, solar, and wind) and the respective measurement of their total renewable energy potential.

Mahbub Ul Islam Khan, Md. Ilius Hasan Pathan, Mohammad Mominur Rahman et al.

Electric vehicles (EVs) are commonly recognized as environmentally friendly modes of transportation. They function by converting electrical energy into mechanical energy using different types of motors, which aligns with the sustainable principles embraced by smart cities. The motors of EVs store and consume electrical power from renewable energy (RE) sources through interfacing connections using power electronics technology to provide mechanical power through rotation. The reliable operation of an EV mainly relies on the condition of interfacing connections in the EV, particularly the connection between the 3-<inline-formula> <tex-math notation="LaTeX">$\phi $ </tex-math></inline-formula> inverter output and the brushless DC (BLDC) motor. In this paper, machine learning (ML) tools are deployed for detecting and classifying the faults in the connecting lines from 3-<inline-formula> <tex-math notation="LaTeX">$\phi $ </tex-math></inline-formula> inverter output to the BLDC motor during operational mode in the EV platform, considering double-line and three-phase faults. Several machine learning-based fault identification and classification tools, namely the Decision Tree, Logistic Regression, Stochastic Gradient Descent, AdaBoost, XGBoost, K-Nearest Neighbour, and Voting Classifier, were tuned for identifying and categorizing faults to ensure robustness and reliability. The ML classifications were developed based on the datasets of healthy and faulty conditions considering the combination of six critical parameters that have significance in reliable EV operation, namely the current supplied to the BLDC motor from the inverter, the modulated DC voltage, output speed, and measured speed, as well as the output of the Hall-effect sensor. In addition, the superiority of the proposed fault detection and classification approaches using ML tools was assessed by comparing the detection and classification efficiency through some statistical performance parameter comparisons among the classifiers.

Babangida Modu, Md Pauzi Abdullah, Abdulrahman Alkassem et al.

The study addresses the integration of hybrid hydrogen (H2) and battery (BT) energy storage systems into a renewable energy microgrid comprising solar photovoltaic (PV) and wind turbine (WT) systems. The research problem focuses on improving the effectiveness and computational efficiency of energy management systems (EMS) while ensuring high system reliability. Despite the existing optimization methods for hybrid microgrids, challenges remain in optimizing energy storage and capacity planning in grid-connected microgrids. To solve this, we propose the use of the Levy Flight Algorithm (LFA) to optimize the capacities of PV, WT, H2 tanks, electrolyzers (EL), fuel cells (FC), and BT, which presents a complex nonlinear optimization challenge. The novelty of this study lies in integrating the LFA with a rule-based EMS, enhancing system reliability and efficiency. The proposed approach significantly reduces the annualized system cost (ASC) and the levelized cost of energy (LCOE). The result demonstrate that the LFA outperforms methods like the Salp Swarm Algorithm (SSA), Particle Swarm Optimization (PSO), Grey Wolf Optimization (GWO) and Genetic Algorithm (GA), yielding cost savings of $3,309, $5,297, $4,484, and $5,129 respectively. The LFA achieves the lowest LCOE at $0.275/kWh, compared to $0.278/kWh with SSA, $0.289/kWh with GA, $0.280/kWh with PSO and $0.283/kWh with GWO. This research contributes to the broader scientific community by providing a more efficient approach to optimizing renewable energy microgrids with hybrid storage systems, thus promoting eco-friendly and cost-effective energy solutions. The proposed system design offers a pathway to future energy systems with high renewable integration, especially as technology advances and costs continue to decrease.

D. Lawal, N. Qasem

Abstract Thermal-based renewable and low-grade energy sources to operate humidification-dehumidification (HDH) desalination systems are critically reviewed. The investigated renewable energy sources are solar energy and geothermal energy. The low-grade energy sources such as the waste heat of photovoltaic thermal (PV/T) panels, refrigeration and heat pump systems, and power plants are also investigated. For each hybrid HDH with another driving system, the details of HDH construction, performance, hybridization method, and general observations are summarized and compared in tabular forms. Most of the studies focused on using solar energy and refrigeration and heat pump systems to drive HDH systems. The best performance indices (i.e., gained output ratio (GOR), freshwater production, and freshwater cost) can be obtained by the integration of HDH systems with power plants and then by geothermal energy, especially when a large quantity of freshwater is needed (>200 kg/h). Refrigeration systems and solar collectors can lead to higher GOR, medium water production, and higher cost. The application of PV/T results in the lowest water production. Despite the high performance of HDH driven by power plants and vapor-compression refrigeration systems, geothermal energy, solar collectors, and PV/T panels could be the right choices for hybridization with HDH systems in off-grid regions.

Abrar Inayat, M. Raza

Abstract According to different studies, building sector consumes around 40% of the total energy produced and it is responsible for a major portion of the greenhouse gas (GHG) emissions. A significant share of this energy consumption is used for cooling and heating purposes. District cooling system (DCS) has been widely used to provide the necessary cooling comfort in residential, industrial and commercial buildings because of its low cost and high energy efficiency. DCS is a centralized system of supplying the thermal energy in form of chilled water for use in space cooling and dehumidification. In addition, DCS integrated with renewable energy is economically feasible when compared to conventional cooling systems. The purpose of this review is to present the possible potential of DCS with different renewable energy technologies. The most suitable renewable energy technologies that can be integrated with DCS are biomass energy, solar thermal energy, geothermal energy, surface water energy, solar photovoltaic energy, and waste heat energy. The conclusions obtained from the six contexts showed that the DCS has strong budding with these renewable energies to supply sustainable and clean cooling energy options in the future world.

Simon Jenniches

The transition of the global energy system is one of the main trends that offers opportunities as well as challenges for the economy. Most literature evaluates the impact of that transition at a national level. That view is broadened towards a regional scale. Due to the lower energy density of many renewable energy sources, renewable energy generation will be more decentralised, leading to potentially significant changes in the regional economy when transitioning to a renewable energy system. In this paper the current literature and methods of assessing regional economic impacts of a transition to renewable energy generation is reviewed. The findings suggest an overall need to clearly define the topics, such as technologies, that are assessed and the evaluated time period. A guideline for a regional impact assessment is provided, focusing on the suitability of applied impact assessment methods (employment ratios, supply chain analyses, input-output models, and computable general equilibrium models).