A team from Sasol Synfuels, Jacobs Consultancy and Argonne National Laboratory has used results from a US industry-wide linear programming (LP) modeling study of individual US refineries to examine the impacts of a number of significant and looming changes—such as shifts in refinery crude slates; regional and seasonal variation; gasoline/diesel (G/D) production ratio; and GTL diesel blending—on US refinery, unit, and product efficiencies. (LP is the the primary tool for analysis and optimization in the refining industry.)