Techno-Economic Survey Analysis of UPS System as Backup Power Source during Load Shedding

The energy crises in Pakistan of the last two decades has forced electricity consumers to use backup power sources based on portable generator sets and Un-interrupted Power Supply (UPS) devices. In order to maintain continuity of supply to basic appliances such as lights and ceiling fans, the majority of consumers use UPS with battery backup due to its less initial cost compared to portable generator sets. Following the increased use of battery based UPS as backup power source, several technical and economic issues due to their use have not been addressed. The main component of UPS system is the battery, which is costly and has to be replaced after its useful service life. Failure to do so, the cost of utility bills increases since batteries operate charge at low efficiency, and have undesirable impact on consumer loads. In this work a survey highlighting the technical and economic issues with UPS system is described that allowed obtaining a cost model based on useful service life of battery, which have also been investigated with the local brands of batteries. The results showed the battery useful life as a function of charging/discharging cycles. In particular analysis shows that the operating cost of the battery increases with the number of cycles the battery undergoes. The work will form a platform for conducting studies related to UPS, for setting standards, policy and the areas where improvement is needed.