I. Introduction
In recent times, there has been a significant increase in the utilisation of renewable energy resources such as solar and wind for electricity generation around the world as a result of climate change, environmental pollution as well as the quest to ensuring security of power supply. Also, the difficulties in extending electricity distribution network to remote locations due to bad terrain as well as poor load factor as a result of low and sparse population has made renewable energy generators popular for electrification of isolated rural communities. Renewable energy generators usually have high modular characteristics thereby giving opportunity for scalability and installation flexibility. However, one of the greatest challenges of renewable energy sources such as wind and solar is their intermittent nature which makes it difficult to supply electricity continuously to loads. This intermittent nature could affect the integrity of power supply in terms of system stability, power quality and system security. At any instant of time, there must be a balance between aggregated demand and continuous supply of electricity. However, renewable energy generators are not dispatchable rather they are controlled by nature, this could cause conventional generators to deviate from their operating curve since they must compensate for the shortages resulting from the renewable energy sources based generators [1]. Consequently, it has become a serious concern to the system planners and utility operators that integration of intermittent source of energy could increase the ancillary service cost. Traditionally, some of these ancillary services have been provided by gorvenor controls and system inertia. One of the ways to mitigate these intermittent characteristics and prevent associated challenges is the use of storage technologies [2].