Estimation of cost of unserved electrical energy in Sri Lanka

Abstract

Quantitative reliability evaluation is an important aspect of power system planning and operation. The indices produced in these applications are utilised in a wide range of management decisions throughout a utility. One issue, which is often debated, is the cost associated with a particular level of reliability. In order to make this argument complete, it is necessary to examine the benefit of having a particular level of reliability. Estimates of the impacts of interruptions in service can be obtained by assessing the losses incurred by different customer types and categories. These data can then be used to calculate cost of energy not served in the selected utility service area. This report presents the results of an investigation of direct, short-term impacts and associated costs incurred by electrical consumers resulting from power failures. The analysis presented show that the average value of unserved electrical energy in Sri Lanka is Rs 140.72 per kWh considering all consumer groups and different interruption periods. As the interruption duration increases the cost of unserved energy stabilises at about Rs 50 per kWh which is likely to remain fixed after a period of about 8 hours of interruption duration.