Almost all palm oil mills have stand by diesel electricity generator sets (DGS). There are alternating views by mill managers on what criteria to adopt when choosing the capacities of these DGS. It is quite obvious that the mill managers did not spend enough time to analyse the requirements in more details when requesting for diesel sets for their mills. The selection of a steam power plant is relatively simple compared to DGS. Let us look at the mill requirements when the mill is not in operation. In the daytime, electricity is needed for the operation of office equipment, office and mill lighting. In the night time, the security lighting and domestic load will add on to the load. After midnight, the domestic load will drop until early morning.