Renewable Energy Applications Research Articles

First-principles calculations to investigate structural, electronic, magnetic, thermodynamic, and thermoelectric properties of RbSrZ (Z = Ge and Sn) d0-d0 half-Heuslers for renewable energy applications

The aim of this study is to examine the thermoelectric properties alongside the structural, electronic, and magnetic properties of RbSrGe and RbSrSn d0-d0 half Heuslers. The full potential-linearized augment plane wave (FP-LAPW) system and Boltzmann transport equation are employed, utilizing classical Boltzmann approximation (CBA) in the background of density functional theory (DFT) as configured within WIEN2K. The structure optimization employed the PBE approximations and the Murnaghan equation of state, leading to a stable phase for RbSrGe and RbSrSn. The observed negative formation energy implies that the synthesis of RbSrGe and RbSrSn are possible. The half Heusler compounds under investigation were found to exhibit a narrow band gap in the majority spin direction and metallic character in the minority, which classifies these materials as half-metallic alloys based on the analysis of their electronic properties. The examination of elastic properties reveals that RbSrGe is brittle and RbSrSn is ductile. Critical analysis of thermoelectric properties demonstrates that RbSrGe and RbSrSn half Heuslers are possible materials for thermoelectrical applications.

Research on the application of renewable energy in power system based on adaptive hierarchical fuzzy logic maintenance

Condition-based maintenance is very desirable for minimizing the maintenance and failure costs of power systems without sacrificing reliability. A systematic approach including an adaptive maintenance advisor and a system maintenance optimizer is proposed here for effectively handling the operational variations and uncertainties for condition-based maintenance. First, the maintenance advisor receives and implements the maintenance plans for its key components from the system maintenance optimizer, which optimizes the maintenance schedules with multi-objective evolutionary algorithm, considering only major system variables and the overall system performance. During operation, the offshore substation will experience continuing ageing and shifts in control, weather and load factors, measurement and human judgment detected from the connected grid and all other equipments with uncertainties. Then, the advisor estimates the changes of reliability indices due to operational variations and uncertainties of its key components by hierarchical fuzzy logic and sends the changes back to the maintenance optimizer. The maintenance optimizer will upgrade the load-point reliability and report any drastic deterioration of reliability within each substation, which may lead to re-optimization of the substation's maintenance activities for meeting its desired reliability. The offshore substation connected to a medium-sized onshore grid will be studied here to demonstrate the ability of this proposed approach in dealing with uncertainties in the implementation of maintenance with significant reduction of computational complexity and rule base.

Unveiling the unique potential of MXene with and without graphene nanoplatelet for thermal energy storage applications.

Solar thermal energy storage (TES) is an outstanding innovation that can help solar technology remain relevant during nighttime and cloudy days. TES using phase change material (PCM) is an avant-garde solution for a clean and renewable energy transition. The present study unveils the unique potential of MXene as a performance enhancer in lauric acid (LA), which functions as a base PCM. The addition of graphene nanoplatelet (GNP) into the LA-MXene composite is prepared to comprehend and evaluate the benefits and detriments of adding carbon-based nanomaterial into the PCM via a two-step homogenizing method. A similar weight percentage of MXene and GNP at 0.75 was used for composite synthesis. The study found that the enthalpy of LA-MXene is comparable to LA at 169.87 J/kg and greater than LA-MXene/GNP, which has 137.53 J/kg. Regarding thermal storage performance, LA-MXene exhibited outstanding performance compared to LA-MXene/GNP in terms of enthalpy efficiency (λ) and relative enthalpy efficiency (η), achieving 95.4% and 96.1%, respectively. This is supported by the XPS spectra, which show that the crosslinking structure acted as a barrier, reinforcing the material and preventing further thermal degradation. This has resulted in robust and denser shells that significantly improved light absorption, enhancing both the photothermal conversion and thermal energy storage efficiency of LA/MXene. The present study reveals that LA-MXene is a promising and optimal candidate for the feasibility and reliability of TES in solar renewable energy applications. It was observed that the incorporation of exclusive MXene may effectively address the limitations of LA as a conventional PCM and surpass the traditional role of GNP. This study offers valuable insights into the superior performance of MXene alone, eliminating the need for doping with various nanomaterials and thereby reducing the complexity in synthesizing the PCM.

Comparative analysis of KXH3(X= Mg, be) hydride cubic perovskites for hydrogen storage properties: A computational approach

The burgeoning potential of hydrogen as a future clean energy source has spurred intense research into hydrogen storage solutions. Novel hydride perovskite materials aside metal hydride are at the forefront of this effort, engaging researchers worldwide. This study utilizes Ab-initio calculations based on density functional theory (DFT) implemented in VASP to compare the electrical, elastic, thermodynamic, and optical properties of cubic KXH3 (X = Mg, Be) compounds. Generalized gradient approximation (GGA) with the Perdew-Burke-Ernzrhof (PBE) scheme is employed for optimization. Our calculations agree well with previously reported results. However, the tolerance factor suggests KBeH3 may not be stable in the cubic form. The electronic structure reveals KMgH3 to be semiconductive, while KBeH3 exhibits metallic behavior. Both compounds exhibit mechanical stability within the study. Optical properties are also investigated, showing suitability for hydrogen storage in the low energy range. Additionally, the mechanical parameters satisfy the Born stability criterion, indicating good mechanical stability for both compounds. Finally, the gravimetric ratios for hydrogen storage are calculated as 5.86 wt% and 4.52 wt% for KMgH3 and KBeH3, respectively. These high values suggest both compounds hold significant promise for diverse renewable energy applications and long-term hydrogen fuel storage.

Theoretical investigations of double perovskites Rb2YCuX6 (X =Cl, F) for green energy applications: DFT study

Double perovskites, which have remarkable performance, great stability, environmental friendliness, and are Pb-free, are emerging materials for solar cells and thermoelectric generators. Herein, we present density functional theory (DFT) calculations on novel metal Pb-free double halide perovskites, Rb2YCuX6 (X = Cl, F), aiming to explore their potential for renewable energy applications. The compounds' negative formation energy confirms their thermodynamic stability, the Goldsmith tolerance factor (tG) provides evidence for their structural stability in the cubic crystalline form and the stable phonon dispersion spectrum confirm its dynamic stability. We found that the lattice constant increases noticeably as the halogen anions change (i.e replacing F by Cl). The mechanical stability of the compounds is validated by the relationships between elastic constants (ECs), namely C11–C12 > 0, C11 > 0, C11 + 2C12 > 0, and B > 0. Utilizing the TB-mBJ potential, it has been determined that the compound Rb2YCuCl6 exhibits an indirect bandgap semiconducting nature with a band gap of 2.31 eV. On the other hand, the compound Rb2YCuF6 demonstrates properties of a direct bandgap semiconductor with a band gap of 2.47 eV. In order to evaluate their suitability for applications in solar cells and optoelectronic devices, we analyze the dielectric function (ε(ω)), optical conductivity (σ(ω)), and reflectivity (R(ω)) of the compounds. Moreover, the thermoelectric performance has been elucidated through the analysis of the power factor (PF) and figure of merit (ZT). The presence of ultralow lattice thermal conductivity and a significant Seebeck coefficient (S) further enhance ZT, making these compounds suitable for thermoelectric applications. Our findings provide comprehensive insight in exploring the properties of Pb-free Rb2YCuX6 (X = Cl, F) double perovskites. It confirms their stability, suitable bandgaps, and impressive thermoelectric properties, highlighting their potential for solar cells and thermoelectric generators as environmentally friendly and sustainable energy solutions.

In‐situ polymerizable thermoplastic and bio‐epoxy based composites for offshore renewable energy applications

AbstractThis study evaluates various quasi‐static mechanical properties of an in‐situ polymerizable thermoplastic and a bio‐based thermosetting composite comprising of non‐crimp fabric reinforcement for potential use in the next generation of Offshore Wind and Tidal Power platforms. Mechanical properties are characterized under tensile, flexural, in‐plane shear and interlaminar shear loading. Results reveal that the evaluated properties differ based upon matrix type. Fractographic evidence from scanning electron microscopy is used to explain the differences observed and was generally consistent in terms of revealing cohesive failure at the fiber‐matrix interface for the thermoplastic composite and contrasting adhesive failure for the thermosetting composite. For glass fiber reinforcement, the thermoplastic composite is superior in terms of flexural 90° properties (+20%) while the thermosetting composite performed better in flexure 0° in terms of both strength (+15%) and modulus (+25%). In terms of interlaminar shear, the thermosetting composite exhibited higher strength (+14%) while Tensile and in‐plane shear properties are similar for composites of both resin systems. Overall, neither composite is superior in terms of overall mechanical properties and both matrices show promise as a stepping stone towards the use of more sustainable constituents in offshore structures.Highlights Quasi‐static mechanical performance and failure analysis of relatively sustainable composites are presented. Failure analysis indicate cohesive failure of the thermoplastic based composite and interfacial failure of the thermosetting based composite. Proposed composites are benchmarked against the composites manufactured using conventional resins. Overall, both matrices show promise as a stepping stone towards more sustainable offshore structures.

DFT calculations of new Li-based halides Li2AgAlY6 (Y = Cl, Br, I) for energy conversion applications

Recently, lead-free halide double perovskite (DP) materials have got scholarly attention owing to their environmentally sustainable characteristic, excellent stability and potential applications in solar cells and renewable energy. In this present article, we computationally examined the mechanical, optoelectronic and thermoelectric characteristics of a discernible compound Li2AgAlY6 (Y = Cl, Br, I) using the density functional theory (DFT). The evaluation of tolerance factor (tf), lattice constant (a0), and formation enthalpy (Hf) confirms the structural and thermodynamic stability of the investigated double DPs, also elastic constants further elaborate the mechanically stable nature. The studied compounds have direct band gap of 3.6 eV, 2.6 eV and 1.2 eV for Li2AgAlCl6, Li2AgAlBr6 and Li2AgAlI6 respectively, indicating the diverse energy absorption applications from ultraviolet to visible region. We used semi-classical Boltzman theory to determine the figure of merit (ZT) and corresponding Seebeck Coefficient (S), which validates the electrical and thermoelectric conductivity for the compounds under investigation. The current investigation establishes a theoretical foundation for the examined DPs, essential for comprehending and comparing forthcoming experimental inquiries aimed at exploring diverse optoelectronic and thermoelectric applications.

A single-phase grid-tied extendable-level inverter for renewable energy applications

The extraction of power from green energy sources (GES) has rapidly popularized owing to increasing energy demands, depletion of fossil fuels and growing concerns about climatic changes. Grid-tied multilevel inverters are critical components in the integration of green energy sources into the power grid and offer numerous benefits over standard two-level inverters. These benefits include superior power quality, diminished harmonic distortion, and the potential to utilize high power levels efficiently. A single-phase Grid-Tied Extendable-Level Inverter (GTELI) for green energy applications is demonstrated in this paper. The GTELI offers superior power quality and distortion-free output relative to existing grid-tied multilevel inverters and hence is an excellent choice for extracting power from sustainable energy sources. To ensure efficient utilization, the extracted power from GTELI is to be integrated into the supply grid. A new current control algorithm for the GTELI is also proposed in this paper. Using this current control technique a grid control technique is established to modulate the power flow to the grid. The proposed GTELI achieved sinusoidal grid voltage and injected current with minimised harmonic distortions of 1.6% and 2.7% respectively, which comply well with the tolerable range of the IEEE 519 standard.

A single DC source, seven-level switched capacitor tripple boost inverter with fewer switches for renewable energy applications

This article presents a new SSTB-MLI with 3 times voltage boosting capability for medium voltage applications with optimal efficiency. Single DC source MLI topologies are more appropriate for many applications, including grid applications and renewable energy (RE) conversion systems than multiple DC source MLI topologies. The ability of switched-capacitor multi-level inverters (SCMLIs) to raise voltage has made them more and more popular in recent years. LS-PWM technique is used for the switching scheme. Two capacitors are employed in SSTB topology to operate alternatively in charging and discharging states at the carrier frequency of this LS-PWM algorithm for making the levels of output voltage. Comparing this innovative topology to those documented in the literature. It can also minimise the number of switches and capacitors needed, their voltage stresses, and switching loss. Since the suggested topology includes built-in capacitor voltage balancing, no additional voltage balancing circuit is required. Applications requiring industrial drives as well as grid-connected and R, RL loads can employ the suggested architecture. Based on less TSV (total standing voltage), MSV (Maximum standing voltage), the number of components used, optimum efficiency 98.43%, and other factors, a comparative analysis is done between the existing topology and the proposed topology. Experimental data and thorough simulation are used to verify the suggested switched capacitor multilevel topology.

Study of optoelectronic, transport, and mechanical aspects of lead-free double perovskites Rb2AgTlX6 (X = Cl, Br) for green energy applications

The double perovskites are emerging candidates for renewable energy applications. This work uses the extensive density functional theory (DFT) method to investigate the structural, optoelectronic, transport, and mechanical properties of Rb2AgTlX6 (X = Cl, Br). The thermal and structural stabilities of Rb2AgTlX6 (X = Cl, Br) are investigated through formation energy and tolerance factorevaluation.The Rb2AgTlCl6 and Rb2AgTlBr6 have direct band gaps of 1.61 eV and 1.08 eV. The reported band gap reduction is associated with the p-d hybridization of cations and anions. Investigating optical characteristics yields important insights via the dielectric constant ε(ω), refractive index n(ω), absorption α(ω), and reflectivity R(ω). The ability to absorb light in visible and ultraviolet spectra as demonstrated by optical characteristics highlights the potentialof Rb2AgTlX6 for solar cell technology. In addition, the significant electrical conductivity and Seebeck coefficient led to a notable reduction in heat conductivity and figure of merit values of 0.68 and 0.67 at higher temperatures. Elastic parameters, Pugh’s, and Passion’s ratios are studied to confirm materials’ mechanical stability and nature. The studied materials have been found mechanically stable and brittle. Together, our findings demonstrate the distinctive and intriguing features of Rb2AgTlX6 (X = Cl, Br) are suitable for cost-effective energy conversion applications.

Comparative analysis of the predictive capabilities of some machine learning models: A case study using wind speed data

The widespread use of fossil fuels for global energy production significantly contributes to global warming. This study presents a comparative analysis of various machine learning models, which are the long short-term memory (LSTM) network, support vector regression (SVR), and gradient boosting method (GBM). Gaussian process regression (GPR) is a benchmark model across different forecasting horizons. The study uses South African wind speed data from 1 January 2018 to 31 December 2021, sourced from the Western Cape province. The dataset underwent preprocessing, and diverse feature selection techniques were implemented to enhance model accuracy. Performance evaluation of the models was done using mean absolute error (MAE), root mean squared error (RMSE), and mean absolute scaled error (MASE). Results indicate that SVR exhibits superior accuracy to other models for two distinct forecast horizons (h = 670 and h = 1339), respectively. Additionally, GPR surpasses other models for the forecasting horizon h = 224. This study provides insights into the comparative strengths and weaknesses of different machine learning models for wind speed prediction, which could be useful in selecting an appropriate model for future applications in renewable energy and weather forecasting. Potential areas for future research include improving prediction accuracy via ensemble deep learning algorithms and incorporating additional meteorological variables. Moreover, investigating temporal dynamics, broadening geographical coverage and integrating uncertainty quantification methods can improve wind speed prediction, thereby facilitating more effective renewable energy planning and decision-making processes

Unlocking renewable energy potential: Harnessing machine learning and intelligent algorithms

This review article examines the revolutionary possibilities of machine learning (ML) and intelligent algorithms for enabling renewable energy, with an emphasis on the energy domains of solar, wind, biofuel, and biomass. Critical problems such as data variability, system inefficiencies, and predictive maintenance are addressed by the integration of ML in renewable energy systems. Machine learning improves solar irradiance prediction accuracy and maximizes photovoltaic system performance in the solar energy sector. ML algorithms help to generate electricity more reliably by enhancing wind speed forecasts and wind turbine efficiency. ML improves the efficiency of biofuel production by optimizing feedstock selection, process parameters, and yield forecasts. Similarly, ML models in biomass energy provide effective thermal conversion procedures and real-time process management, guaranteeing increased energy production and operational stability. Even with the enormous advantages, problems such as data quality, interpretability of the models, computing requirements, and integration with current systems still remain. Resolving these issues calls for interdisciplinary cooperation, developments in computer technology, and encouraging legislative frameworks. This study emphasizes the vital role of ML in promoting sustainable and efficient renewable energy systems by giving a thorough review of present ML applications in renewable energy, highlighting continuing problems, and outlining future prospects

Design and Analysis of Modified Series–Parallel Quasiresonant Half-Bridge DC/DC Converter for Renewable Energy Applications

Design and Analysis of Modified Series–Parallel Quasiresonant Half-Bridge DC/DC Converter for Renewable Energy Applications

Improved high step-up converter with high efficiency for renewable energy applications

Improved high step-up converter with high efficiency for renewable energy applications

Processing and properties of Al–Si microcapsules with a biomimetic-corrugated structure and corundum-mullite composite shell

The encapsulation of metal-based phase change materials using ceramics can realize safe and effective storage of high-temperature thermal energy. However, the use of a low toughness ceramic shell around the microcapsules cannot ensure the provision of a high latent heat and thermal cyclic stability. Here, we provide a new and effective design strategy for preparing biomimetic Al–Si microcapsules that are based on a sea-shell corrugated structure and a nano-scale corundum-mullite composite shell. The latent heat of the microcapsules was over 400 J/g, much greater than other metal-based microcapsules reported to date. The unique biomimetic-corrugated structure microcapsules obtained by a heat treatment at 1000 °C exhibited excellent thermal stability, achieving near zero heat loss after 5000 thermal cycles, whose latent heat of absorption and release reached up to 448.3 J/g and 451.8 J/g respectively. Furthermore, the microcapsules possessed a giant heat storage density of 945.8 J/g within 300–700 °C, and the performance figure of merit was 6384.2 × 106 J2·K–1·s–1·m–4, approximately 15 times higher than that of commercial solar salt. This new approach provides a pathway the practical application of Al–Si alloys as thermal storage materials for renewable energy applications.

Novel high-gain boost converter with experimentally validated ADRC control technique for renewable energy applications

Novel high-gain boost converter with experimentally validated ADRC control technique for renewable energy applications

Ring-shaped cavity anchor Pt to derive Pt/WO3-x heterointerfaces for efficient hydrogen evolution in acidic water and seawater

Developing novelplatinum (Pt)-based hydrogen evolution reaction (HER) catalysts with high activity and stability is significant for the ever-broader applications of hydrogen energy. However, achieving precise modulation of the ultrafine Pt nanoparticles coordination environment in conventional catalysts is challenging. In this work, we developed a unique “ring-shaped cavity induced” strategy to anchor the Ptx through the ring-shaped cavity of polyoxometalates (POMs) Na33H7P8W48O184 (denoted as P8W48). The NayPtx[P8W48O184] (PtxP8W48) was in-situ converted into abundant Pt/WO3-x heterostructure with Pt (∼2 nm) and highly depressed Pt-O-W heterointerfaces. Pt/WO3-x nanoparticles supported on highly conductive rGO exhibit superior HER activity. The overpotentials of the catalyst are only 2.8 mV and 4.7 mV at 10 mA·cm−2 in acidic water and seawater, far superior to commercial 20 % Pt/C catalyst. Additionally, the catalyst can be stabilized at a current density of 30 mA·cm−2 for 180 h. This study provides a feasible strategy for rational design of Pt-based catalysts for renewable energy applications.

Modelling, design, control, and implementation of advanced isolated DC/DC converters for renewable energy applications

Modelling, design, control, and implementation of advanced isolated DC/DC converters for renewable energy applications

Research on geometry optimization of park office buildings with the goal of zero energy

At the conceptual design stage, the building geometry design can predict the building load demand and renewable energy application potential to some extent. Geometry design interventions are critical to efficiently achieving the goal of zero-energy buildings. In the existing studies, the typicality and representativeness of the object geometry in the practice project are not high, and the influence of different geometry indices on energy savings and photovoltaic (PV) utilization potential under the same type of plane shape is rarely considered. In addition, the surrounding building shading situations considered are single. There is still significant room for improvement in the typical geometries selection and optimization condition settings. This paper presents a study of three typical park office building geometries in hot summer and cold winter regions. An optimization method based on the genetic algorithm and energy consumption simulation is proposed that takes into account both building energy savings and PV utilization potential improvements. The geometry-related indices of each typical geometry are then optimized under different PV layout scenarios and surrounding shading situations, and suitable geometry design strategies for typical office buildings are proposed under each optimization scenario. Geometry optimization can significantly reduce building energy consumption (the building energy-saving rate is 1.3–10.7 %) and increase PV generation (enhancement of 13.37–66.67 % for PV generation potential), thus lowering the net energy consumption of buildings. The findings of this study can be used to guide the design of park office building geometries in hot summer and cold winter regions with the goal of zero energy, as well as to promote the practice of zero-energy office buildings at the regional and national levels.

EReaxFF force field development for BaZr0.8Y0.2O3-δ solid oxide electrolysis cells applications

The use of solid-oxide materials in electrocatalysis applications, especially in hydrogen-evolution reactions, is promising. However, further improvements are warranted to overcome the fundamental bottlenecks to enhancing the performance of solid-oxide electrolysis cells (SOECs), which is directly linked to the more-refined fundamental understanding of complex physical and chemical phenomena and mass exchanges that take place at the surfaces and in the bulk of electrocatalysis materials. Here, we developed an eReaxFF force field for barium zirconate doped with 20 mol% of yttrium, BaZr0.8Y0.2O3-δ (BZY20) to enable a systematic, large-length-scale, and longer-timescale atomistic simulation of solid-oxide electrocatalysis for hydrogen generation. All parameters for the eReaxFF were optimized to reproduce quantum-mechanical (QM) calculations on relevant condensed phase and cluster systems describing oxygen vacancies, vacancy migrations, electron localization, water adsorption, water splitting, and hydrogen generation on the surfaces of the BZY20 solid oxide. Using the developed force field, we performed both zero-voltage (excess electrons absent) and non-zero-voltage (excess electrons present) molecular dynamics simulations to observe water adsorption, water splitting, proton migration, oxygen-vacancy migrations, and eventual hydrogen-production reactions. Based on investigations offered in the present study, we conclude that the eReaxFF force field-based approach can enable computationally efficient simulations for electron conductivity, electron leakage, and other non-zero-voltage effects on the solid oxide materials using the explicit-electron concept. Moreover, we demonstrate how the eReaxFF force field-based atomistic-simulation approach can enhance our understanding of processes in SOEC applications and potentially other renewable-energy applications.