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Bloemfontein, South Africa

Central University of Technology, Free State or Central University of Technology is a University of Technology in Bloemfontein in the Free State province of South Africa. It was established in 1981 as "Technikon Free State". As part of the South African government's restructuring of tertiary education for the new millennium it was promoted to university of technology status. Wikipedia.

The aim of this paper is to provide a survey of different innovative technologies that can be applied to the micro-hydropower system to make it cost effective for rural energy supply. Electrical, mechanical, civil or electronic technologies that can increase the viability of micro-hydropower as a cost-effective energy source for remote and isolated communities in rural South Africa are presented. The motivation behind this study is that there are a significant number of potential sites in South Africa where micro-hydropower is a viable energy option to provide reliable and low cost energy and where conventional schemes are not appropriate. © 2014 Elsevier Ltd. Source

Hydrokinetic power generation is a relatively recent type of hydropower that generates electricity from kinetic energy of flowing water making the conversion process more competitive compared to traditional micro-hydropower. Few authors have already analyzed the use of standalone hydrokinetic systems for rural electrification, however, there is no available literatures investigating the possibility of using this technology in combination with other renewable energy sources or diesel generator. Therefore, the aim of this paper is to investigate the potential use of hydrokinetic-based hybrid systems for low cost and sustainable electrical energy supply to isolated load in rural South Africa where adequate water resource is available. Different hybrid system configurations are modeled and simulated using the Hybrid Optimization Model for Electric Renewable (HOMER) and the results are analyzed to select the best supply option based on the net present cost and the cost of energy produced. The simulation results from two different case studies show that hybrid systems with hydrokinetic modules incorporated in their architectures have lower net present costs as well as lower costs of energy compared to all other supply options where the hydrokinetic modules are not included. © 2014 Elsevier Ltd. Source

Kusakana K.,Central University of Technology
IET Renewable Power Generation

In this study, two control strategies involving 'continuous' and 'ON/OFF' operation of the diesel generator in the solar photovoltaic (PV)-wind-diesel-battery hybrid systems are modelled. The main purpose of these developed models is to minimise the hybrid system's operation cost while finding the optimal power flow considering the intermittent solar and wind resources, the battery state of charge and the fluctuating load demand. The non-linearity of the load demand, the non-linearity of the diesel generator fuel consumption curve as well as the battery operation limits have been considered in the development of the models. The simulations have been performed using 'fmincon' for the continuous operation and 'intlinprog' for the ON/OFF operation strategy implemented in Matlab. These models have been applied to two test examples; the simulation results are analysed and compared with the case where the diesel generator is used alone to supply the given load demand. The results show that using the developed PV-diesel-battery optimal operation control models, significant fuel saving can be achieved compared with the case where the diesel is used alone to supply the same load requirements. © The Institution of Engineering and Technology 2015. Source

Kusakana K.,Central University of Technology
Energy Conversion and Management

The present paper develops a model to optimize the daily operation of a hybrid energy system consisting of a hydrokinetic, a pumped hydro storage system and diesel generator. The optimization approach is aimed at minimizing the cost function subject to the availability of water resource, the variable load requirements, and operational constraints of the hybrid system's components. The main purpose of the developed model is to minimize the daily amount of diesel fuel consumed to supply the load while maximizing the use of the hydrokinetic operating in conjunction with the pumped hydro storage. For simulation purposes, the hourly load demand, resource data for a selected rural area in South Africa have been collected and used as an input to the developed model. The economic analysis has resulted in the calculation of optimized daily operation cost of the proposed hybrid system in summer and winter conditions. The obtained results demonstrate that a substantial reduction in the daily operation cost can be achieved (88% in summer and 97% in winter) using the hybrid system compare to the case where the diesel generator is used alone. © 2015 Elsevier Ltd. All rights reserved. Source

Kusakana K.,Central University of Technology
Energy Conversion and Management

Hydrokinetic power generation is currently gaining interest as a cost effective way of supplying isolated areas where reasonable water resource is available. However the seasonal characteristic of the water resource as well as the intermittent fluctuating load demand prevents this power generation system from being entirely reliable without appropriate energy storage system. Few researchers have recently analyzed the use of hydrokinetic systems as standalone or combined with other energy source, however the authors of these researches did not explore other means of storing energy except for traditional battery storage systems. In this study, the most conventional and established storage technology, pumped hydro storage, is proposed to be used in conjunction with a standalone hydrokinetic system in off-grid power supply. The techno-economic feasibility of such combination is analyzed and compared to the option where batteries are considered as storage system. The operation principle of the system is presented; the mathematical model and simulation model are also developed. Simulations are performed using two different types of loads in rural South Africa as case studies to demonstrate the technical cost advantages as well as the cost effectiveness of the proposed supply option. The results reveal that the novel micro-pumped hydro storage based hydrokinetic system is a cost-effective, reliable and environmentally friendly solution to achieve 100% energy autonomy in remote and isolated communities. ©2015 Elsevier Ltd. All rights reserved. Source

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