Green Energy Resources Research Articles

The Ecogeographical Impact of Air Pollution in the Azerbaijan Cities: Possible Plant/Synthetic‐Based Nanomaterial Solutions

The current paper deals with the major causes of air pollution in the big cities of Azerbaijan. In this context, industrial gas wastes and transport systems are the most important sources of air pollution. Also, relevant factors following the intensity of air pollution have recently been recognized. The motor transport system and its detrimental effects on human health are tightly connected with air pollution. Therefore, the use of ecological and geographical data could be an efficient approach to preventing air pollution in urban regions. Also, the advantage of nanotechnology in removing air contaminants has been introduced as a promising solution. Nanomaterials can serve as nano adsorbents, nanocatalysts, nano filters/membranes, and nanosensors in air pollution remediation. Moreover, the green synthesis of nanomaterials from plant‐based origins is promising in this context. Also, nanotechnology is a robust candidate for the production of green and sustainable energy resources. In a nutshell, recommendations on the prevention and alleviation of air pollution, as well as the methods of refining the urban environment and controlling polluting agents are represented.

A Low-Cost, Real-Time Rooftop IoT-Based Photovoltaic (PV) System for Energy Management and Home Automation

This work discusses the importance of monitoring and energy management of green energy resources in order to minimize the negative impacts of electricity generation by regular power plants. The paper introduces a highly efficient, low-cost rooftop photovoltaics (PV) solar panel system which can provide monitoring, controlling and automation. The proposed system is based on Internet of Things (IoT) and can be used to control different utilities in any premises automatically or set by the user-defined priority list, as compared to the existing IoT-based PV systems which can only perform monitoring and maintenance of the PV panels or only certain parameters, i.e., temperature, dust, etc. This is a new step in improving the efficiency of IoT-based PV system where the facility loads are automated by the IoT network. The proposed system can also provide a constant feedback about different parameters, i.e., voltage, dust, sun irradiance and humidity, etc., via low-cost open-source platforms for telemonitoring and controlling purposes. The simulation results show that the proposed system provides a high efficiency to energize the utilities and utilize the available energy as compared to the manual control.

Techno-Economic Analysis of Green Energy Resources for Power Generation & Direct Use

Techno-Economic Analysis of Green Energy Resources for Power Generation & Direct Use

A Phase Generation Shifting Algorithm for Prosumer Surplus Management in Microgrids Using Inverter Automated Control

Four-wire low-voltage microgrids supply one-phase consumers with electricity, responding to a continuously changing demand. For addressing climate change concerns, national governments have implemented incentive schemes for residential consumers, encouraging the installation of home PV panels for covering self-consumption needs. In the absence of adequate storage capacities, the surplus is sold back by these entities, called prosumers, to the grid operator or, in local markets, to other consumers. While these initiatives encourage the proliferation of green energy resources, and ample research is dedicated to local market designs for prosumer–consumer trading, the main concern of distribution network operators is the influence of power flows generated by prosumers’ surplus injection on the operating states of microgrids. The change in power flow amount and direction can greatly influence the economic and technical operating conditions of radial grids. This paper proposes a metaheuristic algorithm for prosumer surplus management that optimizes the power surplus injections using the automated control of three-phase inverters, with the aim of reducing the active power losses over a typical day of operation. A case study was performed on two real distribution networks with distinct layouts and load profiles, and the algorithm resulted efficient in both scenarios. By optimally distributing the prosumer generation surplus on the three phases of the network, significant loss reductions were obtained, with the best results when the generated power was injected in an unbalanced, three-phase flow.

A Review of Maximum Power Point Tracking Algorithms for Wind Energy Conversion Systems

Renewable energy resources are gaining a lot of popularity. Several researchers have worked on the tracking and extraction of energy from these sources. In the past few decades, among the available green energy resources, wind energy has been the most attractive option among the resources available. It is imperative to use the maximum power available in the wind to achieve the wind turbine (WT) operation at maximum power. The maximum power point tracking (MPPT) algorithms are a pioneer in this context. Many research papers are contributed in this domain which necessitates a thorough review while choosing an appropriate technique. This paper comprehensively focuses on reviewing different algorithms in the past and present for tracking maximum power point, and capturing maximized output power from the wind energy conversion system (WECS). In this paper, the algorithms are classified based on the direct and indirect power measurement, hybrid and smart algorithms for tracking maximum power point, and they are compared, considering the parameters like complexity, convergence speed, use of sensors, memory requirement, need for knowledge of system parameters, etc. The immense popularity of the different versions of perturb and observe (P&O) based algorithms due to their various features is evident from the literature. The review reveals that the hybrid maximum power point tracking algorithms can use the advantages of the conventional methods and eliminate their drawbacks.

Hierarchical twinning and light impurity doping enable high-performance GeTe thermoelectrics

Microstructure engineering fulfilled by phase transformation elicits the reduced thermal conductivity κ in thermoelectric materials. We demonstrate that the multiscale hierarchical twinning structure could exist in the GeTe alloys as the phase transformation from cubic β-GeTe to rhombohedral α-GeTe is manipulated by two-step cooling. The coexistence of nanoscale and microscale herringbone structures yields the low-lying κ, attributing to the reorientation of martensitic variants and pile-up of martensitic twinning. Dilute dopants of Cu and Bi/Sb further suppresses hole carrier concentration nH to the order of 1020 cm−3, leading to the enhanced power factor PF = S2ρ−1 of α-GeTe. Meanwhile, the phase diagram engineering probes the solubility limit of Cu in the single-phase GeTe, diminishing the formation of undesired impurity phases. These strategies boost the peak zT value to 1.5 at 698 K in the light-doped Bi0.01Cu0.01Ge0.98Te alloy. The multiscale twin hierarchy and carrier optimization synergistically enhance the thermoelectric performance of GeTe-based alloys that provide a new chapter in search of green energy resources out from phase change materials.

In Situ Grown CoMn2 O4 3D-Tetragons on Carbon Cloth: Flexible Electrodes for Efficient Rechargeable Zinc-Air Battery Powered Water Splitting Systems.

The integration of energy conversion and storage systems such as electrochemical water splitting (EWS) and rechargeable zinc-air battery (ZAB) is on the vision to provide a sustainable future with green energy resources. Herein, a unique strategy for decorating 3D tetragonal CoMn2 O4 on carbon cloth (CMO-U@CC) via a facile one-pot in situ hydrothermal process, is reported. The highly exposed morphology of 3D tetragons enhances the electrocatalytic activity of CMO-U@CC. This is the first demonstration of such a bifunctional activity of CMO-U@CC in an EWS system; it achieves a nominal cell voltage of 1.610V @ 10mA cm-2 . Similarly, the fabricated rechargeable ZAB delivers a specific capacity of 641.6 mAh gzn -1 , a power density of 135mW cm-2 , and excellent cyclic stability (50 h @ 10mA cm-2 ). Additionally, a series of flexible solid-state ZABs are fabricated and employed to power the assembled CMO-U@CC-based water electrolyzer. To the best of the authors' knowledge, this is the first demonstration of an in situ-grown binder-free CMO-U@CC as a flexible multifunctional electrocatalyst for a built-in integrated rechargeable ZAB-powered EWS system.

Fast fabrication of freestanding MXene-ZIF-8 dual-layered membranes for H2/CO2 separation

As one of the green, renewable, and clean energy resources, hydrogen is widely developed and utilized throughout the world. Highly efficient membrane separation for hydrogen production is required to give promising gas permeance with enough H2 selectivity. The membranes are desired to be produced in large-scale, fast and facile methods. Here we report for the first time a kind of freestanding MXene-ZIF-8 dual-layered membrane for hydrogen separation. Fast synthesis of such membranes is realized by combining electrophoretic deposition (EPD) and fast current-driven synthesis (FCDS), achieving the assemble of MXene layer and growth of ZIF-8 layer, respectively, overcoming the traditional time-consuming vacuum filtration methods and solvothermal synthesis. The MXene-ZIF-8 dual-layered membrane prepared within 20 min exhibits significantly improved gas separation performance, whose H2/CO2 selectivity increases from 44 for the pristine MXene membrane to 77 with H2 permeance of 5.97 × 10−8 mol m−2 s−1 Pa−1. This concept of structure design of membrane can also be extended to other dual-layered membranes, including various 2D nanosheet layers combined with different MOF layers.

Comprehensive ab-initio calculations of AlNiX (X = P, As and Sb) half-Heusler compounds: Stabilities and applications as green energy resources

The objective of this work is to explore structural, mechanical and thermal stability including electronic, optical and thermoelectric properties of state-of-the-art AlNiX (X = P, As and Sb) half-Heusler compounds having 18 valence electron count (VEC). Calculations have been carried out in the framework of density functional theory (DFT) implemented in WIEN2k code followed by the solution of the Boltzmann transport equation with constant relaxation time approximation. In the most energetically favorable structure, their lattice constants lie in the range of 5.501 Å – 5.983 Å and band gaps have been found to be 0 eV, which confirm the metallic behavior of these compounds. The different elastic and thermodynamic parameters confirm their mechanical and thermal stability with a mechanically anisotropic and ductile nature. Specific heat and entropy of these materials increase as the atomic number of X atom increases. The calculated optical parameters prove their candidature for promising photovoltaic devices and shields for UV radiation. The thermal conductivity has been computed using Slack's model. This detailed study shows that these compounds are promising for materials scientists due to their very high lattice thermal conductivity and low figure of merit. We deny recommending them as good thermoelectric applications.

Covalent‐Organic Frameworks (COFs) as Proton Conductors

AbstractProton conductivity is the paramount property of proton‐conducting materials that are playing significant roles in diverse electrochemical devices with applications in proton exchange membranes (PEMs) for fuel cells (PEMFCs). Considering the scarcity of fossil fuels, the development of clean and green renewable energy resources is in‐demand across the globe. Toward this direction, the development of solid‐state proton conductors is of significant interest. The higher structural tunability, lower density, good crystallinity, accessible well‐defined pores, excellent thermal and chemical stability of covalent‐organic frameworks (COFs) make them versatile platforms as proton conductors both under hydrous and anhydrous conditions. Taking advantage of such superior properties, the reports on proton‐conducting COFs have been increasing swiftly since 2014, which demands a summarization and comprehensive discussion for “at a glance” visualization and further development. In this review, the COFs are showcased as a newer class of solid‐state proton‐conducting material. A comprehensive discussion is presented by organizing the strategies taken to develop the proton‐conducting COFs. Establishment of structure–function relationships and the implementation of COFs as proton conductors are discussed as well. Moreover, challenges and future prospects are presented elaborately and are critically analyzed.

The effect of green energy, global environmental indexes, and stock markets in predicting oil price crashes: Evidence from explainable machine learning

This study aims to predict oil prices during the 2019 novel coronavirus (COVID-19) pandemic by looking into green energy resources, global environmental indexes (ESG), and stock markets. The study employs advanced machine learning, such as the LightGBM, CatBoost, XGBoost, Random Forest (RF), and neural network models. An accurate forecasting framework can effectively capture the trend of the changes in oil prices and reduce the impact of the COVID-19 pandemic on such prices. Additionally, a large dataset with different asset classes was used to investigate the crash period. The research also introduced SHapely Additive exPlanations (SHAP) values for model analysis and interpretability. The empirical results indicate the superiority of the RF and LightGBM over traditional models. Moreover, this new framework provides favorable explanations of the model performance using the efficient SHAP algorithm. It also highlights the core features of predicting oil prices. The study found that high values of GER and ESG lead to lower crude oil prices. Our results are crucial for investors and policymakers in promoting climate change mitigation and sustained economic prosperity through green energy resources.

Numerical Evaluation of the Flow around a New Vertical Axis Wind Turbine Concept

In order to develop a sustainable economy based on the efficient use of green energy resources, it is necessary to research and innovate systems such as wind turbines. In this paper, a new configuration for vertical axis wind turbines was proposed and numerically analyzed using CFD methods. The concept is based on solving the starting problem of lift-based vertical axis wind turbines. The new concept consists of three blades with different chords, arranged at different radii so that the interaction between the blades is reduced and the operation in the vortex wake is minimal, thus reducing the losses. Through comparing a classic case of an H-Darrieus wind turbine with the new concept, not only were satisfying results regarding the blade-to-blade interaction presented, but an increased efficiency of up to 10% was also observed. Among the presented results is the variation of the vorticity magnitude at different positions of the blades, thus, the concept’s blade-to-blade interaction is reduced. Conclusions drawn after the investigation are in favor of the proposed geometry and the concept should be pursued further.

Lollipop-shaped Co9S8/CdS nanocomposite derived from zeolitic imidazolate framework-67 for the photocatalytic hydrogen production

The unlimited consumption of traditional fossil fuels prompted an urgent need for the new H2 production strategies to provide green and sustainable energy resources. In this context, Co9S8 has emerged as a potent photocatalyst due to its narrow bandgap. Herein, we describe the synthesis of a recyclable lollipop-shaped Co9S8/CdS nanocomposite via direct annealing of zeolitic imidazolate framework-67 (ZIF-67) and CdS, as the template and sulfur source, respectively. The close contact of these two materials promotes the electron transfer and enhances the number of active sites toward the desired redox reaction. The special structure of Co9S8/CdS results in a high photocatalytic H2 production rate of 1852 μmol h−1 g−1 under visible-light illumination, which is ~200 times higher than that of pure ZIF-67 and Co9S8. Therefore, this study provides a new method for the preparation of Co9S8 that concomitantly improves the photocatalytic performance of pure ZIF-67 in the H2 production technology.

An OpenFOAM based study of Savonius turbine arrays in tunnels for power maximisation

There has been a significant disruption in the energy market because of the pandemic. Now the focus is shifting towards investing more in renewable energy to address the present health and energy crisis. Wind power has gained special prominence in our clean energy transition as wind energy is the easiest to harvest, most efficient resources, and lowest carbon emitter among the available technologies. The prime focus of this study is towards implementing an array configuration of Savonius turbines beside the train track to maximize the power production. A model is set up on OpenFOAM platform and studied for the different arrangements of turbine clusters. The effect of energy production by the series of turbines was assessed by varying distance among turbines in a staggered or inline manner and the location from the train as well. A systematic characterization of the optimum Savonius turbine cluster in a railway tunnel, which is relatively an unexplored area in the energy harvesting community, has been taken up in this study. It is exciting to note that our computer-oriented result matches well with the benchmark solution and proved to be a viable green energy resource that can possibly erase the energy crisis at remote places.

The role of fiscal measures in promoting renewable electricity in Spain

The sustainability of the environment implies a dire need to redesign electricity systems. The aim of this paper is to evaluate the role of alternative fiscal incentives to promote renewable electricity. To this end, a disaggregated, electricity-related Computable General Equilibrium model is developed, taking the current structure of the (renewable and non-renewable) electricity sector into account. The Computable General Equilibrium model developed presents at least two advantages: the changes are analyzed from a global perspective (including impacts on prices), and second, rebound effects are accounted for. The fiscal measures examine three scenarios of change in line with the decarbonization processes of economies. Specifically, the scenarios assess: (1) a 100% decrease in renewable electricity taxes; (2) a 23% increase in taxes paid by the non-renewable electricity sector; and, (3) both together. In addition, these fiscal measures are evaluated assuming improvements in electricity self-generation. The case study is the Spanish economy for 2016. The Computable General Equilibrium model is calibrated on a symmetric input–output table, constructed from supply and use tables. These tables disaggregate the energy and electricity sectors. Results reveal the role and strength of fiscal policy in boosting the production of electricity generation technologies using green energy resources, and reducing the production of electricity generated from brown sources. However, results suggest that these effects are limited to the energy chain sectors, with insignificant effects in the whole economy. This study also provides better information and guidance to politicians and decision-makers who wish to promote renewables, and the need to have a clear understanding of the influence price competitiveness has on the economy. Moreover, the results of this study have implications for rebound effects when electricity self-generation is implemented.

Renewable Green Energy Resources for Next-Generation Smart Cities Using Big Data Analytics

Energy is now seen as a significant resource that develops abundant on the world economy, with short supply and development. A study found that renewable energy systems are needed to prevent shortages. Hence, all the focus in this study to decrease electricity consumption and reduce the overall completion times for a regular console in green technology networks was an efficient and scalable production genomic solution. A Renewable green energy resources smart city (RGER-SC) framework is proposed that used a multi-target evolutionary algorithm was hybridized to be effective and calculated arithmetically in this study. This work deals with fostering renewable energy incorporation by adjusting federal charges to increase the energy accounting practitioners. Besides, this report analyses the timely generation of delay-tolerant demands and the maintenance of district heating at network infrastructure. In comparison, capacity differentials between consumers and information centres are considered and evaluated using the Renewable green energy resources smart city (RGER-SC) framework for energy conservation and controlled task management at an industrial level.

Pathways towards Boosting Solar-Driven Hydrogen Evolution of Conjugated Polymers.

Photocatalytic H2 evolution under solar illumination has been considered to be a promising technology for green energy resources. Developing highly efficient photocatalysts for photocatalytic water splitting is long-term desired but still challenging. Conjugated polymers (CPs) have attracted ongoing attention and have been considered to be promising alternatives for solar-driven H2 production due to the excellent merits of the large π-conjugated system, versatile structures, tunable photoelectric properties, and well-defined chemical composites. The excellent merits have offered numerous methods for boosting photocatalytic hydrogen evolution (PHE) of initial CP-based photocatalysts, whose apparent quantum yield is dramatically increased from <1to >20%in recent five years. According to the photocatalytic mechanism, this review herein systematically summarizes three major strategies for boosting photocatalytic H2 production of CPs: 1) enhancing visible light absorption, 2) suppressing recombination of electron-hole pairs, and 3) boosting surface catalytic reaction, mainly involving eleven methods, that is, copolymerization, modifying cross-linker, constructing a donor-acceptor structure, functionalization, fabricating organic heterojunction, loading cocatalyst, and surface modification. Finally, the perspectives towards the future development of PHE are proposed.

Energy efficiency financing and the role of green bond: policies for post-Covid period

PurposeOne of the major negative effects of the Coronavirus outbreak worldwide has been reduced investment in green energy projects and energy efficiency. The main purpose of this paper is to study the role of green bond proposed by the World Bank in 2008, as a reliable instrument to enhance the capital flow in energy efficiency financing and to develop green energy resources during and post the current challenging global time.Design/methodology/approachWe model energy efficiency for 37 members of OECD through a panel data framework and quarterly data over 2007Q1–2020Q4.FindingsThe major results reveal the positive impacts of issued green bonds and regulatory quality index on energy efficiency, while any increase in inflation rate and urbanization decelerates the progress of raising energy efficiency.Practical implicationsAs highlighted concluding remarks and policy implications, it can be expressed that the tool of green bond is a potential policy to drive-up energy efficiency financing and enhancing environmental quality during and post-COVID period. It is recommended to follow green bond policy with an efficient regulation framework and urbanization saving energy planning.Originality/valueTo the best of the authors' knowledge, although a few scholars have investigated the impacts of COVID-19 on green financing or examined the energy efficiency financing, the matter of modeling energy efficiency–green bond relationship has not been addressed by any academic study. The contributions of this paper to the existing literature are: (1) it is the first academic study to discover the relationship between energy efficiency and green bond in OECD countries, (2) since our empirical part provides estimation results based on quarterly data covering the year of 2019 and 2020, it may offer some new policy implications to enhance energy efficiency financing in and post-COVID period, (3) furthermore, we consider energy efficiency indicator (mix of industrial, residential, services and transport energy efficiency) as the dependent variable instead of using the simple energy intensity variable as a proxy for energy efficiency.

Implementation of DC voltage controllers on enhancing the stability of multi-terminal DC grids

Because of the increasing penetration of intermittent green energy resources like offshore wind farms, solar photovoltaic, the multi-terminal DC grid using VSC technology is considered a promising solution for interconnecting these future energies. To improve the stability of the multi-terminal direct current (MTDC) network, DC voltage control strategies based on voltage margin and voltage droop technique have been developed and investigated in this article. These two control strategies are implemented in the proposed model, a ±400 kV meshed multi-terminal MTDC network based on VSC technology with four terminals during the outage converter. The simulation results include the comparison and analysis of both techniques under the outage converter equipped with constant DC voltage control, then the outage converter equipped with constant active power control. The simulation results confirm that the DC voltage droop technique has a better dynamic performance of power sharing and DC voltage regulation.

Energy, exergy and environmental impact analysis on the novel indirect solar dryer with fins inserted phase change material

Solar energy is a widely used green energy resource that is used for drying processes. Through this assessment, the performance of an Indirect Solar Dryer (ISD) with three different cases, namely solar collector - without Thermal Energy Storage (TES), with TES unit having Phase Change Material (PCM) and with TES having fins inserted PCM have been experimentally analyzed during spring and summer seasons for drying Momordica charantia. Totally six experiments were undertaken to compare temperature, drying kinetics, and energy analyses. The initial moisture level of 2 kg of specimen decreased from 1.84 kg of water (92% w. b) to 0.24 kg of water (12% w. b) in 10.5 h utilizing ISD with TES having fins inserted PCM (Test 6). The maximum thermal efficiency achieved about 19.41% on Test 6. Exergy efficiency increased from 8.66% to 79.02% at Test 6. Environmental impacts assessment has revealed that the Energy Payback Time for the ISD was 1.42 years. The CO2 emission, mitigation, and carbon credit gained (Test 6) are 23.88 kg/year, 20.13 tons, and $100.642 to $402.569 for the 35 years’ intended lifespan. The assessment report showed that the device established was a potentially effective commercial drying technique, both in energy utilization and environmental sustainability.