Energy storage mechanisms for an African microgrid

Abstract

Due to the intermittent nature of renewable energy resources, storage mechanisms were modelled to support the power supply system. The main functions of the energy storage mechanism were to supply consumers with stored energy during periods when energy production was not able to meet the demands of consumers and to improve power quality by acting as a buffer between supply and demand. The energy stored was from periods when energy production exceeded energy consumption, i.e. off-peak hours, to supply consumers during periods where energy consumption exceeded the amount of energy produced i.e. peak hours. This report aimed to determine the ideal energy storage mechanism for an African microgrid, where the term “African microgrid” was defined as a microgrid which uses African resources to supply electrical energy to African communities. These resources included material resources and labour. It was determined that the GDP of a country is proportionate to the electrification rate. The country with the lowest electrification rate was, therefore, considered to be powered by a microgrid which that made use of renewable energy and possible surrounding resources (such as biomass) to generate electricity. The country selected for this study as an African country, was Burundi. The storage mechanisms modelled were to serve a community with an average energy consumption of 500 kWh per day. The storage mechanisms selected to be modelled were:  Pumped Hydro Storage Systems.  Battery Energy Storage Systems.  Supercapacitor Energy Storage Systems.  Flywheel Energy Storage.  Thermal Energy Storage. The energy storage systems were modelled using HOMER, with the following parameters modelled and compared: electrical specifications, energy storage specifications, emission volumes, and costs. The energy storage which had the most suitable results was then determined to be the best-suited energy storage mechanism for an African microgrid. The results of the models were then compared to each other, as well as to results from the literature.