A.B. Sebitosi

Design and Analysis of an Electromechanical Battery for Rural Electrification in Sub-Saharan Africa

This paper presents the design and analysis of an electromechanical flywheel energy storage system to enhance rural electrification in sub-Saharan Africa. The system consists of a flywheel rotor, an electrical machine, control system, bearings, and a containment structure. With the exception of the power electronics and magnets, local materials were used for the manufacture of the flywheel system. The flywheel rotor is made from glass fiber-epoxy composite, designed using novel shape profiles and utilizes a stress based solution by introducing a central hole for shaft inclusion. The system was accelerated to 6000 r/min storing up to 227 kJ. Numerical stress analyses were performed during the design stage to ensure that the maximum tensile strength is not exceeded. A lumped parameter thermal model is used to estimate the temperature distribution to ensure safe operating conditions of the flywheel system and environment. A life cycle cost analysis performed found that by integrating a flywheel system into a Solar Home System implies a cost savings of 35% per kilowatthour when compared with lead-acid batteries.

New Technologies for Rural Lighting in Developing Countries: White LEDs

Most of the third-world rural areas, especially in sub-Saharan Africa, are still without electricity. The few existing off-grid and upcoming installations are remote and characterized by limited resources that call for drastic conservation measures. For the majority of these emerging consumers, lighting is the priority load. Rural electrical lighting load models are characterized by inaccuracies due to technical omissions, highlighted in this paper, and result in energy wastage. Solutions to the third-world problems need not follow similar paths to those of the developed world. In fact, cutting-edge technologies like the cell phone have already leapfrogged rural communications where expensive infrastructure had been perennially cited as the impediment. In this paper, another futuristic technology, the white light emitting diode (LED), for general lighting, is poised to create yet another revolution in African rural electrification.

A concept of dynamic pricing for rural hybrid electric power mini-grid systems for sub-Saharan Africa

This paper presents a dynamic pricing concept that can be applied to hybrid electric power mini-grid systems to enable affordability of energy in these systems setup for the supply of energy to rural consumers. A location was identified in Eastern Uganda, resource assessment done, and a proposed hybrid electric power mini-grid system designed to supply electricity to this rural location. A theoretical deterministic demand profile was generated, and with it different supply configurations of the system were simulated to meet the daily load. The fluctuations in the demand and supply triggered a change in the cost of generating energy, due to the variations in the contributing electricity generating sources. Through communication, an intelligently designed and operated time-varying pricing scheme can be an effective tool for influencing the actions of price-responsive end-users such as rural consumers. A software program was used to simulate the hourly demand, supply, and corresponding cost of energy variations. This pricing model could potentially contribute to the ongoing search for the provision of affordable rural energy services.

Analytical sizing of an electrolyser for a small scale wind electrolysis plant

This paper presents an analytic way of sizing an electrolyser by considering the load requirements and efficiencies of the electrolyser, fuel cell and their ancillaries. Current density and the size of the active area of the membrane are optimised to ensure thermal self-sustaining mode of the electrolyser for stand-alone applications. This eliminates the need of heating the feed water. Correlations between the voltages and currents of the generator and the electrolyser are also established. Simulation results for electrolyser parameters are then presented. From these results it can be inferred that by maintaining the current density at 0.8A/cm2, the electrolyser can meet its hydrogen production rate and maintain the temperature in the operating range of 70–90°C.