Coal Logistics System (COLS)

The Coal Logistics System (COLS) is a comprehensive coal transportation and transshipment model that solves for coal flows on a network from supply nodes through transshipment nodes to steam and metallurgical demand nodes on the basis of systemwide cost minimization. The model is solved for a representative time period for the system of ports, and all decision variables are solved for simultaneously. COLS is a constrained optimization model formulated as a linear program with some integer variables. Its solution indicates the sources of the various types of coal, the routes and modes of transportation, and the locations, activity levels, and types of transshiment facilities that together minimize the systemwide costs. Effectively, the COLS model minimizes the cost per delivered British thermal unit of U.S. coal. COLS was designed specifically for the evaluation of coal flows in a competitive multiport framework. Additional aspects of the subject are discussed