Search

Deployments of renewable energy technologies in the current century represent a critical approach to sustainable development. Renewable energy can be generated from sources with the backdrop to restock themselves based on timescale. The most important sources of renewable energy include solar photovoltaic conversion technologies, biomass and biofuel energy systems, wind energy turbines, geothermal energy technologies and hydroelectric power systems. Considerable investment in renewable energy in a country can lower the nation's dependency on imported fuels and purchase of energy from foreign market. It also drives technological innovation and generate employment scheme while enhancing clean development mechanism. Consequently, this paper presents the existing renewable energy technologies in the Nigeria and as well makes some critical recommendations to further induce development of renewable and sustainable energy systems based on autonomous energy systems and microgrid (µgrid) technologies. The recommendations are made based on varieties of energy technologies for solar power generation, biomass and bioenergy, wind energy, hydropower generation and the combined generation systems using hybrid energy mechanism. The structure of the study is concluded based on suggestions on how to pursue some impending socio-political, technological, investment policy and legislative issues for effective renewable energy development in the country. [ABSTRACT FROM AUTHOR]

Unit Commitment (UC) is an optimization problem used to determine the operation schedule of the generating units at every hour interval with varying loads and generations under different generational, environmental and technical constraints. With the significant increase of Renewable Energy Sources (RES) integration into the power networks, effects posed by these system changes to the UC are actively being studied and investigated by global researchers and operation engineers. To this end, this paper firstly provides a literature survey of UC concept, objectives and constraints. Different UC models developed for addressing RES impacts are also reviewed. Moreover, many algorithms have been proposed in the past few decades to optimize the UC problem. This work explores the necessity for alternative optimization approaches for UC solution. In doing that, the work uncovers the advantages and disadvantages of the existing methodologies so that future algorithms could be designed in retaining the advantages of the existing methodologies while avoiding the presented weaknesses. In addition, installation of energy storage devices to balance the fluctuation in power generation and their associated impacts on UC models are reviewed. The contents of this paper provide ready-to-refer and ready-to-use information for the researchers working in the field of UC. [ABSTRACT FROM AUTHOR]

Usually, consumers experience power failures due to problems in the distribution systems. Distribution systems have evolved to an extent where smart technologies are needed for their smooth operation. Network reconfiguration is one of the functions of distribution automation that improves the performance of the system by altering the structure of the distribution network. In literature, different network reconfiguration problems have been resolved with various methods. However, the active power loss minimisation problem is considered most of all, because if these losses are less than the standard, the distribution companies can benefit monetarily. In addition, during the last few decades, distribution system reliability has been developed to provide interruption free electricity services. With improved system reliability, power distribution companies can save the expenses that are spent on a distribution system's maintenance and operation after a power failure. This paper thus gives a general background, literature review and comparative analysis of methods used for network reconfiguration for reliability enhancement and loss minimisation in the distribution network, so that new researchers can easily read the literature, especially in this area. Moreover, this is the first effort to collect the previous and the most recent research works on the field of reliability of distribution system through network reconfiguration. Therefore, this work will serve as a one stop source for the guidance of the new researchers in this field. [ABSTRACT FROM AUTHOR]

Energy suppliers all over the world must expand energy in a way that is secure, clean, affordable, and environmentally responsible. Photovoltaic (PV) has been a competitive renewable-energy source for the power generation mix in the world. With the presence of solar PV technology, this paper proposes C4.5 approach for static security evaluation and classification (SSE). This paper proposes PV generators connected to the grid when bilateral energy transactions with the loads are implemented to see their impacts on the system security. To build a classifier in binary class, the process is divided into four components: data collection, pre-processing and feature selection, comparison of the techniques, best classifier selection and performance evaluation. A comprehensive comparison of four of Decision Tree׳s Algorithms for SSE is conducted. The study is (accomplished using) conducted on IEEE 30 bus system, which comprises 5 PV power generators deliver a total power of 40 MW. Data are generated on (30, 57, 118 and 300) bus IEEE test systems used to train and test the classifiers. Empirically, with the presence of PV power generators, the implementation results indicate that these classifiers have the capability for system security evaluation and classification. Lastly, C4.5 is an efficient and effective approach for real-time evaluation and classification classifier design. [ABSTRACT FROM AUTHOR]

Ever-increasing price of conventional energy resources and related environmental concern enforced to explore alternative energy sources. Inherent uncertainty of power generation and demand being strongly influenced by the electricity market has posed severe challenges for DRPs (Demand Response Programs). Definitely, the success of such uncertain energy systems under new market structures is critically decided by the advancement of innovative technical and financial tools. Recent exponential growth of DG (distributed generations) demanded both the grid reliability and financial cost–benefits analysis for deregulated electricity market stakeholders. Based on the SGT (signaling game theory), the paper presents a novel user-aware demand-management approach where the price are colligated with grid condition uncertainties to manage the peak residential loads. The degree of information disturbances are considered as a key factor for evaluating electricity bidding mechanisms in the presence of independent multi-generation resources and price-elastic demand. A correlation between the cost–benefit price and variable reliability of grid is established under uncertain generation and demand conditions. Impacts of the strategies on load shape, benefit of customers and the reduction of energy consumption are inspected and compared with Time-of-Used based DRPs. Simulation results show that the proposed DRP can significantly reduce or even eliminate peak-hour energy consumption, leading to a substantial raise of revenues with 18% increase in the load reduction and a considerable improvement in system reliability is evidenced. [ABSTRACT FROM AUTHOR]

Improving the transient response of power generation systems using automation control in a precise manner is the key issue. We design a fuzzy proportional integral derivative (PID) controller using Matlab and programmable logic controllers (PLCs) for a set point voltage control problem in the automatic voltage regulator (AVR) system. The controller objective is to maintain the terminal voltage all the time under any loads and operational conditions by attaining to the desired range via the regulation of the generator exciter voltage. The main voltage control system uses PLCs to implement the AVR action. The proposed fuzzy controller combines the genetic algorithm (GA), radial-basis function network (RBF-NN) identification and fuzzy logic control to determine the optimal PID controller parameters in AVR system. The RBF tuning for various operating conditions is further employed to develop the rule base of the Sugeno fuzzy system. The fuzzy PID controller (GNFPID) is further designed to transfer in PLCs (STEP 75.5) for implementing the AVR system with improved system response. An inherent interaction between two generator terminal voltage control and excitation current is revealed. The GNFPID controller configures the control signal based on interaction and there by reduces the voltage error and the oscillation in the terminal voltage control process. We achieve an excellent voltage control performance by testing the proposed fuzzy PID controller on a practical AVR system in synchronous generator for improve the transient response. [ABSTRACT FROM AUTHOR]

A hybrid model is designed by combining the genetic algorithm (GA), radial basis function neural network (RBF-NN) and Sugeno fuzzy logic to determine the optimal parameters of a proportional-integral-derivative (PID) controller. Our approach used the rule base of the Sugeno fuzzy system and fuzzy PID controller of the automatic voltage regulator (AVR) to improve the system sensitive response. The rule base is developed by proposing a feature extraction for genetic neural fuzzy PID controller through integrating the GA with radial basis function neural network. The GNFPID controller is found to possess excellent features of easy implementation, stable convergence characteristic, good computational efficiency and high-quality solution. Our simulation provides high sensitive response (∼0.005 s) of an AVR system compared to the real-code genetic algorithm (RGA), a linear-quadratic regulator (LQR) method and GA. We assert that GNFPID is highly efficient and robust in improving the sensitive response of an AVR system. [ABSTRACT FROM AUTHOR]

Abstract: A hybrid power system is an emerging power generation technique which involves a combination of different energy systems, mostly renewables for optimal output configuration. In modern pursuit for renewable energy (RE) development, optimum conditions for the production and utilization of energy system are considered to be an indispensable feature for economic load dispatch. This is a rationalizing fact taking into consideration the rising price of energy for socio-economic development. Therefore, this paper reviews primary issues regarding the drivers and specific benefits of hybrid renewable energy systems (HRES). Moreover, this paper presents discussions on the various renewable energy sources which can be explored for HRES implementation. Finally, the framework unfolds a vivid review on factors to be considered for designing and implementation of HRES in general including simulation and optimization software packages for making such analyses. [Copyright &y& Elsevier]

Abstract: Rising concerns about global energy security and climate change due to emissions of noxious gases resulting from the combustion of fossil fuels have strongly renewed interest in renewable energy development. These concerns have also coordinated a reaction towards the global focus on a clean development mechanism, which is a basic strategy endorsed in the framework of the Kyoto Protocol. The use of biomass for the sustainable distributed generation of power offers immense hope to rural dwellers, who have limited access to electricity from centralized grid systems. Like other renewable sources of energy, biomass distributed-generation systems will play a critical role in the future of electrical power demand outlooks and energy generation planning. This article presents the wide-ranging potential of bioenergy resources in Nigeria for bioelectric power generation. It explicates the poor energy situation of the country and highlights different categories of biomass that can be exploited to tackle the energy deficiency in many rural communities. The study concludes with a discussion on the significance of distributed-generation electricity using bioenergy resources for rural energy supply, including brief discussions on the technologies for bioelectric power utilization. [Copyright &y& Elsevier]

Highlights: [•] Optimal BSS placement reduces the impacts to distribution system performance. [•] The analytical method gave results similar to ABC for optimal BSS placement. [•] ABC gave faster solution in solving BSS sizing cases. [•] Simultaneous BSS and DG Sizing gave the lowest total DG capacity and power loss. [Copyright &y& Elsevier]

Abstract: Energy use is a prerequisite for physical and socio-economic development in both rural and urban communities. There is a need to promote and guarantee energy security, availability and reliability to preserve any existing level of development and further new developmental strides for human comfort. Access to modern energy is considered one of the foremost factors contributing to the disparity between developed and developing nations. Undisputedly, Sub-Saharan Africa (SSA) is the most physically and economically backward developing and poverty-stricken region in the world. The slower rate of development can be attributed to the low access to modern energy use in the region as a result of a high level of constraints ensuing from underprivileged energy policies, inadequate funding, ineffective energy infrastructures and the low pace of technological diffusion. These overlapping deficiencies are responsible for the looming scenario of energy crisis in the region, which has heightened the degree of dependency on combustible renewable energy sources for primary energy consumption. The application of modern renewable energy is a negligible component in the regional power sector compared with its naturally endowed potential. This review presents the current state of affairs of renewable energy application in SSA. From a focal point of view, wind energy, solar energy, hydropower, bioenergy and geothermal energy are fundamentally discussed within the framework of socioeconomic and technological developmental challenges in this review article. It was stressed that combustible bioenergy is excessively consumed in the region especially in the rural segment of society. It also pinpoints some prevailing challenges negatively influencing the development of renewable energy using modern technologies. Conclusively, this research highlights the need for effective international and cross-sector collaboration on inputs from financial, resource and technological development mechanisms for renewable energy exploitation. [Copyright &y& Elsevier]

Abstract: Fossil fuels-based conventional grid extension in developing countries from centralized power systems in urban centres to rural areas is usually capital intensive and in most cases not economically realistic. From a global perspective, more than a quarter of the human population experiences an energy crisis, especially those living in the rural areas of developing countries. Among these numerous victims of global energy shortage are the majority of people in sub-Saharan Africa, like Nigeria. More than 80% of Nigerians consistently rely on combustible biomass especially from forest wood and its charcoal derivatives for primary energy consumption amidst a serious shortage of access to modern energy sources. Nigeria has abundant renewable and non-renewable energy resources. While most attention is concentrated on tapping only the traditional bioenergy resources, other renewable energy resources are underexploited. This article reviews comprehensively the potential of four major kinds of renewable energy sources (biomass, solar, wind and hydro) in Nigeria. A total energy potential of 697.15TJ is estimated from crop residue, 455.80PJ from animal waste and 442MW from municipal solid waste in Lagos metropolis alone. The solar radiation in the country ranges from 4kWh/m2 in the south to 7kWh/m2 in the north, which is sufficiently above the threshold average value of 2.3kWh/m2 required for the operation of simple domestic load especially in rural communities. Wind speed in the country varies from 1m/s in the southern plain to 7.96m/s far northwest in Katsina State between June and September. Unexploitable hydropower potential of 12,954.2MW also exists as against the backdrop of 10,000MW required to raise the socio-economic growth level and alleviate poverty in the country. [Copyright &y& Elsevier]

Abstract: Unified power flow controller (UPFC) is used for controlling the real and reactive power in transmission line and bus voltage simultaneously and independently. An additional task of UPFC is to increase transmission capacity as result of power oscillation damping. The effectiveness of this controller depends on its optimal location and proper signal selection in the power system network. A residue factor has been proposed to find the optimal location of the UPFC controllers and eigenvalue analyses are used to assess the most appropriate input signals (stabilizing signal) for supplementary damping control of UPFC to damp out the inter-area mode of oscillations. The proposed residue factor is based on the relative participation of the parameters of UPFC controller to the critical mode. A simple approach of computing the residue factor has been proposed, which combines the linearized differential algebraic equation model of the power system and the UPFC output equations. While for signal selection a right-half plane zeros (RHP zeros) and Hankel singular value (HSV) is used as tools to select the most receptive signal to a mode of the inter-area oscillation. The placements of UPFC controllers have been obtained for the base case and for the dynamic critical contingences. The effectiveness of the proposed method of placement and selection of signals are demonstrated on practical network of TNB 25 bus system of south Malaysian network and New England 39 bus system. [Copyright &y& Elsevier]

Energy monitoring is one of the important aspects of the energy management, as such there is a need to monitor the power consumption of a premises before planning some of the technical measures to minimize the energy consumption. This paper presents the current state of art of appliances’ energy management through Intrusive Load Monitoring (ILM) and Non-intrusive Load Monitoring (NILM), ILM is referred to as distributive sensing and NILM is based on single point sensing. In an effort to explore the recent trend in Energy Management for researchers in the area, various techniques of Home Energy Management (HEM) using ILM and NILM have been analyzed and categorized. Different contributions made by the researchers have been highlighted together with some techniques of reducing power consumption of a building for cost saving and greener environment. This study reveal that there are issues concerning load monitoring and load management that need the attention; issues such as more accurate recognition and the need for monitoring system that can recognize as many kind of loads as possible. More efforts to apply NILM in appliances’ energy management is also required. Finally there is need for promoting the energy management culture among the electricity consumers whether in homes, offices or industries. The study will help the researchers in the area to have a clear vision of the recent trends in the area. [ABSTRACT FROM AUTHOR]

Abstract: Smart meter is an advanced energy meter that measures energy consumption in residential, commercial and industrial facilities with additional information related to the power system. This paper aims to review system functions of the latest smart meter technology which incorporates Advanced Metering Infrastructure (AMI). The paper also proposes future smart meter with some modification and improvement of AMI technology by introducing Artificial Intelligence Metering (AIM) techniques where the energy consumed by consumers' appliances is fully supervised by AIM. The AIM function is almost the same as AMI technology, but with some enhancement including schedule of various appliance usage by customers, PV integration and power quality monitoring. These modifications can facilitate consumers to manage their energy usage wisely, meanwhile promoting green technology to the community. [Copyright &y& Elsevier]

Abstract: This paper proposes a new method to allocate real power and real power loss of individual generators to system loads. Both allocation procedures are conducted independently and it is based on current operating point of the system, computed through AC load flow program. Based on solved load flow results, the method partitions the Y-bus matrix to decompose the current of the load buses as a function of the generators’ current and load voltage. Then it uses the modified admittance matrix to decompose the load voltage dependent terms into components of generator dependent terms. Finally using these two decompositions of current and voltage terms, the real power transfer between loads and generators are obtained. Similarly, by using the same concept, real power loss allocations caused by generators and loads are discussed and cost of real power loss due to generators and loads is carried out in this study. The advantage of the proposed methodology is demonstrated by using a simple 5-bus system and the modified IEEE 24-bus RTS system. The proposed methodology provides better reliability and minimizes the limitations of conventional power flow tracing methods. [Copyright &y& Elsevier]