Well Drainage Optimization in Abandoned Mines Under Electricity Price Uncertainty

摘要

In this pit drainage study, we investigate how pump control optimized with respect to the prevailing electricity prices impacts the operating costs. The optimization of the well operation takes the dependency of the electrical power on the water volume lifted and the changing water levels into account. The nonlinear dependency is transformed into a linear optimization problem in multiple stages. First, a superstructure optimization is used. Second, the characteristic pump profiles are linearized piecewise, resulting in a simplified problem where only the multiplication of a binary and a positive real variable remains. The multiplication of the two variables is replaced by a new variable, transforming the optimization problem into a mixed integer linear optimization (MILP) problem. The results of the superstructure optimization yield the optimal pump size and the minimal costs incurred, which are then used to optimize the maintenance strategy. We find that well costs can be reduced markedly by the optimization proposed.