Analysis of Coal Allocation on Steam Power Plants and The Effect of Multi-Suppliers, Demand and Time Variations on Coal-s Safety Stock
Andre Jason, Anna Maria Sri Asih*, Hari Agung Yuniarto
Industrial Engineering Program, Department of Mechanical and Industrial Engineering, Universitas Gadjah Mada (UGM)
*amsriasih[at]ugm.ac.id
Abstract
Fulfilling electricity needs which are mostly supplied by the coal steam power plants, such as Indonesia, has its own challenges. Therefore, the government is expected to provide a reliable coal supply to each power plant. The coal supply chain is a complex network in which various coal specifications can be supplied by more than one supplier, and also uncertainty in demand and lead time exist. Each supplier offers different price for the coal and also different transportation cost based on the location of the supplier which are scattered in several places in Indonesia. In order to find the set of suppliers and transportation route of coal, optimization model that minimizing the purchase and transportation cost of the coal to fulfil demand in the power plant was built. The output from the optimization was used as an input to find the effective safety stock, order quantity, and reorder point needed in each plant in order to prevent the occurrence of stock out. Furthermore, a sensitivity analysis was also carried out to understand the impact of variation in demand and lead time and also the impact of implementing multiple suppliers on safety stock level in each plant.
Keywords: Steam Power Plant, Coal Supply Chain, Stochastic Demand, Stochastic Lead Time, Multi-Supplier
Topic: Industrial Engineering