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

• Published in: IEEE transactions on energy conversion Vol. 26; no. 4; pp. 1198 - 1209
• Main Authors: Okou, R., Sebitosi, A., Khan, M. A., Barendse, P., Pillay, P.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.12.2011; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Batteries; Cost control; Energy conversion; Energy storage; flywheels; Magnetic flux; permanent magnet machines; Permanent magnet motors; Rural areas; Stator cores; Stator windings; Studies
• ISSN: 0885-8969; 1558-0059
• DOI: 10.1109/TEC.2011.2160545

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.