Optimal Power Flow with Storage

Solution algorithms for the optimal power flow (OPF) problem are well established for traditional electricity networks. However, there is an increasing need for integrating renewable sources and energy storage into electricity networks. These newer devices have physical characteristics that require modification of standard OPF algorithms. In particular, energy storage devices introduce temporal coupling over the optimization horizon. Also, the modeling of non-unity storage efficiency requires complementarity conditions. This paper explores two algorithms that extend OPF methods to incorporate energy storage devices and wind generation. The first method is based on the well-known AC-LP OPF method, while the second is a quadratic program with DC power flow constraints. The algorithms are demonstrated using several test cases that consider a modified RTS-96 system. The performance of the two algorithms is compared in terms of convergence properties and quality/optimality of their respective solutions.