Combining Dantzig-Wolfe and Benders decompositions to solve a large-scale nuclear outage planning problem

Optimizing nuclear unit outages is of significant economic importance for the French electricity company EDF, as these outages induce a substitute production by other more expensive means to fulfill electricity demand. This problem is quite challenging given the specific operating constraints of nuclear units, the stochasticity of both the demand and non-nuclear units availability, and the scale of the instances. To tackle these difficulties we use a combined decomposition approach. The operating constraints of the nuclear units are built into a Dantzig-Wolfe pricing subproblem whose solutions define the columns of a demand covering formulation. The scenarios of demand and non-nuclear units availability are handled in a Benders decomposition. Our approach is shown to scale up to the real-life instances of the French nuclear fleet. (c) 2021 Elsevier B.V. All rights reserved.

Automated summary

Optimizing nuclear unit outages is crucial for the economic performance of French electricity company EDF, as it involves substituting more expensive means to meet electricity demand. This study proposes a combined decomposition approach to tackle the challenges posed by the specific operating constraints of nuclear units, stochastic demand and non-nuclear unit availability, and the scale of the problem. The approach incorporates the operating constraints into a Dantzig-Wolfe pricing subproblem and handles demand and non-nuclear unit availability using Benders decomposition. The scalability of the approach is demonstrated on real-life instances of the French nuclear fleet.