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Abstract-: Partial shading deteriorates the overall performance of photovoltaic (PV) arrays by reducing the power output. Various shading mitigation strategies have been proposed in the literature with vulnerabilities of limited applications, switches, sensor counts, design, cost, and complexities. In this paper, a multi-string differential power processing (MS-DPP) based voltage equalizer is proposed for power output improvement in the PV arrays during shading. The equalizer is utilized for the series-parallel array which is equipped with a shading detection system achieved from the optimal placement of minimum sensor counts. The technique uses the concept of a switching capacitor that balances the voltage ratio between the modules of individual strings to ensure higher power generation and convex power curves during shading. The system is simulated and validated in MATLAB simulation and further verified on the OPAL-RT 4510 hardware-in-loop FPGA-based real-time platform. The technique is executed on three array sizes and compared with existing techniques under static and dynamic partial shading cases. The analysis shows that MS-DPP enhances the array power output with a conversion efficiency higher than 99 % during shading with lower system size and 98.38 % and 95.05 % reduced counts of switches and sensors than dynamic reconfigurations.

This study proposes a synergistic approach that aligns environmental sustainability with economic viability to meet the energy trilemma of energy security, affordability, and sustainability. Employing two qualitative methods-bibliometric analysis and systematic literature review- the research focused on Scopus-based articles related to renewable energy optimization using the VOSviewer software. The analysis revealed prevalent environmental tradeoffs in renewable energy schemes, including habitat loss, fragmentation, sediment transportation, and deforestation. Similarly, economic tradeoffs such as high initial costs, intermittency, reliability challenges, job security, resource scarcity, and supply chain risks were identified. Following a thorough examination, the study suggests solutions to manage these tradeoffs viz. strategic planning, continuous monitoring and adaptation, life cycle evaluation, policy and regulation implementation, and diversification of renewable energy sources. In conclusion, the study advocates a three-tiered recommendation for a smooth and predictable transition toward a secure energy future viz. integrated policy frameworks, and technological innovation.

The Water-Energy-Food (WEF) nexus is a paradigm that emphasises the interconnectedness and collaborative effects of water, energy, and food systems. This study presents a bibliometric analysis of South Africa's WEF nexus research landscape between 2011 and 2024 using the Scopus database. The article highlights the interconnectedness of sustainable development, resource management, sustainability challenges, and resilience strategies in the WEF Nexus in South Africa. The study also identifies critical research gaps in addressing socio-economic dimensions, policy and governance aspects, technological innovation, and human resource development within the WEF Nexus framework. The article reveals the transformative potential of blockchain technology in revolutionising resource management in South Africa. By leveraging blockchain's decentralised and transparent nature, the country can enhance efficiency, transparency, and sustainability in resource allocation and distribution.

To achieve carbon neutrality by 2050 and reduce greenhouse gas (GHG) emissions to a range of 350–420 megatons of carbon dioxide equivalent, South Africa, the largest emitter of GHG in Africa, introduced a carbon taxation system in June 2019. However, within just 3 years, it has become evident that the system faces significant challenges, with less than 6% of the estimated tax returns reaching the government. This issue raises concerns about potential corruption and manipulation within the system. To address these challenges, this study presents a comprehensive framework for a carbon trading and taxation system leveraging blockchain technology (BCT). Designing this framework from the government’s perspective ensures efficient monitoring and oversight. Notably, the proposed system operates automatically, eliminating the need for third-party intermediaries. This study also identifies a crucial research gap and lays the foundation for future studies. It empirically implements the system as a decentralised application) using the Hedera and Solana blockchain networks. Complemented by JavaScript for the user interface. Python, through Django, was used to handle the server-side system implementation. Thus, this research aims to address the shortcomings of Africa’s current carbon taxation system through a novel, government-centric approach powered by BCT. The proposed system’s potential to enhance transparency and efficiency justifies further exploration in future studies.

A stable power system is a desirable state for the optimal performance and delivery of electricity to the end-users. This study evaluates the effectiveness of grid contingency support devices in power system stability enhancement. The new voltage stability pointer (NVSP) was employed to optimally infer the flexible alternating current transmission systems devices through N − 1 contingency ranking. In this research, the static synchronous compensator (STATCOM) was considered as a grid support device. The effectiveness of this technique was validated in R2018a MATLAB with the IEEE 30-bus system using different combinable contingency cases to ascertain the critical lines and vulnerable buses to outages. Based on the results obtained through the NVSP, buses 30, 26, and 29 were cited as STATCOM candidate buses for overall optimal grid performance. The results obtained from the simulation revealed that the total real power loss was reduced by 90.21%. Similarly, the voltage magnitude of the buses was significantly improved to a minimum of 1.00 p.u. after placement of STATCOMs. Further investigation on single STATCOM placement in the IEEE 30-bus system revealed that the highest level of voltage improvement, minimum level of voltage deviation and maximum active power loss reduction was achieved when the STATCOM was placed at bus 30. The overall assessment of the proposed technique yielded better results compared with other methods on the same test system.

This research provides a comprehensive literature overview and bibliometric evaluation of multi-agent system (MAS) implementation in energy demand response (DR) to identify gaps. The review encompasses 39 relevant papers from searches in three academic databases, focusing on studies published from 2012 to the middle of 2023. The review includes MAS frameworks, optimization algorithms, communication protocols, market structures and evaluation methodologies. Bibliometric analysis of 587 documents from the search on the Scopus database identified prolific authors, influential articles and collaborative networks within the field. The findings reveal growing research interest in implementing an MAS for DR, focusing on integrating intelligent agents into electricity grids to enable effective load management and enhance grid stability. Additionally, the review outlines potential research directions, including exploring advanced MAS techniques, interoperability challenges, policy implications and the integration of renewable energy sources.

The rise in popularity of electric vehicles (EVs) is attributable to their economical maintenance, excellent performance, and environmentally-friendly nature due to zero carbon emissions. Nevertheless, the increased utilization of EVs poses challenges for the distribution system’s efficiency. The strategic placement of electric vehicle charging stations (EVCS) is crucial in maintaining the reliability of the radial distribution system (RDS). The improper allocation of EVCS can result in degradation and affect the distribution system. To overcome this issue, a potential solution involves integrating the charging stations with the RDS by utilizing distribution static compensators (DSTATCOMs) and distributed generation (DG) to mitigate the adverse effects of EVCS on the RDS. The appropriate sizing of DG/DSTATCOM depends on variations in load stages, as it impacts the stability of the RDS. Additionally, the uncertainty of distribution loads can lead to an underestimation of power within the system, posing a primary challenge. In this proposed work, two studies were examined: (i) DG and DSTATCOM allocation considering load uncertainty without EVCS impact, and (ii) DG and DSTATCOM allocation considering load uncertainty with EVCS impact. To address this multi-objective problem, an objective function was developed to reduce real power loss while adhering to system equality and inequality constraints. To tackle the challenge, the researchers used the bald eagle search algorithm (BESA), a revolutionary metaheuristic optimization methodology. The efficacy of the proposed approach was validated using two test systems: a 34-bus system and a 118-bus system. The results obtained from these test cases demonstrate that the BESA-based solution is highly exact in reducing real power loss, increasing bus voltage, and enhancing system stability with a significantly high convergence rate. Hence, the proposed approach presents a promising solution for optimizing RDS with multiple objectives.

This paper delves into the pivotal role of cleaner production in the pursuit of global water security. Leveraging Biblioshiny, a robust bibliometric analysis tool based on R-Software, the paper examined Scopus data, following PICO protocols and PRISM guidelines. The study's findings underscore the potential of cleaner production strategies on wastewater to underpin water security. To this end, the study proffers three policy interventions: an ''Industrial Cleaner Production Policy,'' a ''Water Eutrophication Prevention Policy,'' and an ''Environmental Sustainability Club Policy.'' These policies collectively constitute a comprehensive framework for ushering in an era of water security anchored in cleaner production principles. In conclusion, the study calls for the seamless integration of cleaner production into global discourse on water security, particularly within the United Nations framework, and its incorporation into various policy documents. This approach ensures cleaner production's central role as a multifaceted intervention tool, enhancing global commitment to water security.

Transparent conducting metal oxides (TCOs) are well known for their application in optoelectronic devices. However, the nonlinear optical (NLO) study of TCOs helps to understand the characteristic features which give insight into their practical utilization as well as device application in each optical spectrum. In this work, we studied the structural, electrical, optical, and nonlinear optical properties of Sn-doped CdO. The structural, electrical, optical, and nonlinear optical properties of Sn-doped CdO were studied by using an X-ray diffractometer (XRD), Hall measurement system, UV–vis spectrometer, and Z-scan measurement. The XRD analysis shows that Sn-doped CdO is a polycrystalline material with a preferential peak of a plane (111) shifting slightly toward the (200) plane as Sn doping suddenly increases. Sn-doped CdO proved good electrical properties with conductivity increase from 0.192 × 102 Ω−1 cm−1 to 2.03 × 102 Ω−1 cm−1 and decrease in resistivity from 52.1 × 10−3 Ωcm to 4.92 × 10−3 Ωcm as the molar dopant concentration increase from 0.0001 M to 0.0005 M. The obtained bandgap for undoped and 0.0005 M, 0.0004 M, 0.0003 M, 0.0002 M, 0.0001 M Sn-doped CdO are 2.37, 1.63, 1.70, 1.81, 1.86, and 2.09 respectively. The NLO absorption coefficient (β) for 0.0003 M, 0.0004 M and 0.0005 M are 6.31 × 10−3 m/W, 11.47 × 10−3 m/W and 10.6 × 10−3 m/W respectively.

Power flow reliability, voltage security and transmission congestion management are paramount operational issues in a power system. Flexible AC transmission system (FACTS) controllers are suitable technologies that can provide compensation and dynamic control of power system transmission parameters to enhance effective performance and reliability. The interline power flow controller (IPFC), if optimally placed, can regulate the impedance of multiple lines to improve active power transfer capacity and voltage profile. This study examines the performance of IPFCs for voltage enhancement by suppressing fluctuation. A modified Newton–Raphson load flow problem with an incorporated IPFC variable has been formulated with the objective to improve voltage stability and maintain active power flow. The effectiveness of the proposed method was tested on the Nigerian 41 bus transmission network. The obtained result of the system with an IPFC placed at the weakest bus of the network was compared with Newton–Raphson load flow analysis of the same network without an IPFC. The results of load flow analysis for Case 1 (the system without an IPFC) showed that the transmission network without an IPFC had a real power loss of 4.699488 p.u., and reactive power loss of 4.467413 p.u., whereas the integration of an IPFC to the power flow formation in Case 2 resulted in the reduction in the transmission network’s overall losses to 0.55297 p.u. and −38.3329 p.u. The modified method proves effective as the power system network with an IPFC returns a more stable voltage profile and improves active power flow. In addition, this method, similar to all other mathematical optimization approaches, returns a strong accurate result but may be a drawback in terms of longer computational time compared with metaheuristic methods which are preferred for a larger network system.

This paper performs a technoeconomic comparison of two hybrid renewable energy supplies (HRES) for a specific location in Ghana and suggests the optimal solution in terms of cost, energy generation capacity, and emissions. The two HRES considered in this paper were wind/hydrogen/fuel-cell and wind/battery storage, respectively. The necessity of this study was derived from the rise and expansion of hybrid renewable energy supply in a decentralised network. The readiness to embrace these new technologies is apparently high, but the best combination for a selected location that brings optimum benefits is not obvious and demands serious technical knowledge of their technical and economic models. In the methodology, an analytical model of energy generation by the various RE sources was first established, and data were collected about a rural-urban community in Doderkope, Ghana, to test the models. HOMER software was used to design the two hybrid systems based on the same load profiles, and results were compared. It turns out that the HRES 1 (wind/hydrogen/fuel-cell) had the lowest net present cost (NPC) and levelized cost of electricity (COE) over the project life span of 25 years. The energy reserve with the HRES 2 (wind/battery storage) was huge compared to that with the HRES 1, about 270% bigger. Furthermore, with respect to the emissions, the HRES 2 was environmentally friendlier than the HRES 1. Even though the battery storage seems to be more cost-effective than the hydrogen fuel-cell technology, the latter presents some merits regarding system capacity and emission that deserve greater attention as the world looks into more sustainable energy storage systems.

Power systems may encounter disturbances during operation as a result of switching of various components, etc. Such perturbations include transformer tap-changing action, load variations, and line outages due to various types of faults of which an earth fault is the most common. Stability analysis of a transmission system is necessary for us to determine the stability state of the system so that appropriate control measures can be implemented to guarantee system stability. This article presents the use of eigenvalue obtained from the system-linearized eigenvectors to analyze the stability state of the system. The choice of the eigenvalue principle is based on the strength of accuracy of the method to determine the actual state of the system providing adequate data for easy solution to the problem. The node admittance parameters computed from the line parameters is applied to the eigenvalue–eigenvector model to determine the system stability state. The state of the eigenvalue is used as an input to a control system, which utilized static volt-ampere reactive (VAR) compensators (SVC) to automatically stabilize the non-stable buses in the transmission network. The 6 × 6 nodal admittance matrix is formed and fed to the developed eigenvalue–eigenvector model via MATLAB in order to compute the right and left eigenvectors and the diagonal or eigenvalue of the network under steady-state and contingency condition. After this, the system stability state is determined, and necessary control actions by the SVC are implemented to guarantee system security. The developed model was tested on the 6 bus Eastern Grid Nigerian Transmission Network and validated using a 41 bus network of the same country. The compensated model showed considerable efficiency in improving the transient stability state of the transmission networks in terms of ease of operation, seamless integration into existing control system, and efficient utilization of SVS to compensate for reactive power imbalances. The results from the step response graph of the compensated model shows performance accuracy as the system regained stability in less than 0.5 s, which is a significant improvement over the uncompensated model.

In this paper, the Combined Heat and Power Dynamic Economic Emissions Dispatch (CHPDEED) problem formulation is considered. This problem is a complicated nonlinear mathematical formulation with multiple, conflicting objective functions. The aim of this mathematical problem is to obtain the optimal quantities of heat and power output for the committed generating units which includes power and heat only units. Heat and load demand are expected to be satisfied throughout the total dispatch interval. In this paper, Valve Point effects are considered in the fuel cost function of the units which lead to a non-convex cost function. Furthermore, an Incentive Based Demand Response Program formulation is also simultaneously considered with the CHPDEED problem further complicating the mathematical problem. The decision variables are thus the optimal power and heat output of the generating units and the optimal power curbed and monetary incentive for the participating demand response consumers. The resulting mathematical formulations are tested on four practical scenarios depicting different system operating conditions and obtained results show the efficacy of the developed mathematical optimization model. Obtained results indicate that, when the Incentive-Based Demand Response (IBDR) program’s operational hours is unrestricted with a residential load profile, the energy curtailed is highest (2680 MWh), the energy produced by the generators is lowest (38,008.53 MWh), power losses are lowest (840.5291 MW) and both fuel costs and emissions are lowest.