Delivery Cost Approximations for Inventory Routing Problems in a Rolling Horizon Framework

The inventory routing problem considered in this paper is concerned with the repeated distribution of a commodity, such as heating oil, over a long period of time to a large number of customers. The problem involves a central depot as well as various satellite facilities which the drivers can visit during their shift to refill their vehicles. The customers maintain a local inventory of the commodity. Their consumption varies daily and cannot be predicted deterministically. In case of a stockout, a direct delivery is made and a penalty cost is incurred. In this paper we present incremental cost approximations to be used in a rolling horizon framework for the problem of minimizing the total expected annual delivery costs.