An MILP-based formulation for minimizing pumping energy costs of oil pipelines: Beneficial to both the environment and pipeline companies

Optimal scheduling of pumps operation in fluid distribution networks (e.g., oil or water) is an important optimization problem. This is due to the fact that the dollar cost and also global carbon footprints of such a major transportation are in mega scales. For example, one of our industrial partners, a Canadian oil pipeline operator, spent more than $18.11 million dollars in 2008 for pumping costs. According to our calculations, this would lead to up to 182,460 tons of CO₂ emissions annually. Therefore, even slight improvements in operation of a pipeline system can lead to considerable savings in costs and also reducing carbon footprints emitted to the environment (by introducing air pollutions needed to generate those huge amounts of electricity). In this paper, a methodology for determining optimal pump operation schedule for a fluid distribution pipeline system with multi-tariff electricity supply is presented. The optimization problem at hand is a complex task as it includes the extended period hydraulic model represented by algebraic equations as well as mixed-integer decision variables. Obtaining a strictly optimal solution involves excessive computational effort; however, a near optimal solution can be found at significantly reduced effort using heuristic simplifications. The problem is efficiently formulated in this paper based on Mixed-Integer Linear Programming. The proposed model is evaluated on a typical oil pipeline network. The numerical results indicate the effectiveness and computationally efficient performance of the proposed formulation.