Analysis of Battery Energy Storage System for power system load factor improvement – a case of Kenya’s power system

Abstract

The Load Factor is a key measure of an electrical power system’s efficiency. Load Factor is the ratio of average electrical demand over a period to the peak demand in that period. Kenya’s current load factor stands at approximately 73% as of March 2025, but there is room for improvement, mainly by adjusting electricity consumption patterns among domestic electricity consumers. Kenya’s power usage peaks between 6–7 AM and 6–10 PM, with off-peak periods, particularly between 11PM – 4AM, experiencing demand drops of up to 50%. To meet peak demand, significant investments in grid infrastructure are required, yet these assets remain underutilized during off-peak hours, creating economic inefficiencies and increased technical losses. This research explores using Battery Energy Storage Systems (BESS) to bridge the gap between peak and off-peak demand. By charging BESS units during low-demand periods and discharging them during peak hours, the study aimed to homogenise energy usage and create a more balanced consumption pattern. An action research design was employed to simulate the technical and economic viability of BESS. Results showed that through peak shaving, a properly sized BESS unit could reduce peak demand on a pilot distribution feeder from approximately 6000kW to 4000kW, aligning it with its normal average loading. This improved the feeder load factor from 51% to 77%. Although the BESS deployment involved a high initial cost, the return on investment achieved through improved efficiency justified its adoption. The study presents a viable and scalable model to enhance Kenya’s grid load factor, optimize infrastructure use, and reduce reliance on costly thermal power sources, which are mainly dispatched during peak demand periods.

Keywords: Load Factor, Electrical Power System Efficiency, Demand, Battery Energy Storage Systems (BESS), Peak Shaving, Distribution Feeder, Load Balancing