Investigating the effect of pump availability on load shift performance

Due to the high electricity consumption of dewatering systems in the South African mining sector, numerous load-shifting projects have been implemented to reduce the peak electricity demand. In the past, a lack of maintenance on dewatering systems often caused deterioration in the load shift performance of these projects. Limited research has been published that evaluates the effect of pump availability on load shift performance. The purpose of this paper is to introduce a methodology that enables investigation and quantification of the effect that pump availability has on load shift performance. The methodology consists of four phases supported by eight individual steps. The methodology is applied to the dewatering systems on three different mines. The reduced availability correlated to poor load shift performance. Specifically, if hours of reduced availability directly preceded peak TOU periods. It is also found that reduced availability of pumps for more than one hour, further decreases load shift performance. The results proved that if the availability of one pump is reduced for one hour, the total operating cost can increase to a total of R1.4-million p.a. for the above mentioned three mines. If the availability of one pump is reduced for two hours, the operating cost can increase to a total of R4.6-million p.a. for the three mines.