Imbalance energy in Southern African power pool

Cross-border energy trading is one way of optimizing energy resources in interconnected electric power grids. Energy interchange is scheduled between electric power utilities through bilateral agreements or competitive electricity markets. Normally financial settlement of energy interchange is done based on agreed schedules, and not on actual metered energy. Yet, in a typical hour of delivery, a difference occurs between the agreed schedule and the actual metered energy. This difference is referred to as imbalance energy. If not properly managed, imbalance energy exposes electric power utilities to considerable technical and commercial risks. The objective of this study is to clarify relation between imbalance energy and other variables using long term quantitative data from operation of Southern African Power Pool (SAPP). Quantitative data from official archives such as Area Control Error and Frequency deviation are presented in this study. Although relation between these variables is theoretically well defined, each balancing authority is using slightly different regulations. This study shows operation of SAPP by analyzing statistic data covering 3.5 years.