Optimal Power Flow With Large-Scale Storage Integration

Restructuring of the electric power industry along with mandates to integrate renewable energy sources is introducing new challenges for the electric power system. Intermittent power sources, in particular, require mitigation strategies in order to maintain consistent power on the electric grid. We investigate distributed energy storage as one such strategy. Our model for optimal power flow with storage augments the usual formulation by adding simple charge/discharge dynamics for energy storage collocated with load and/or generation buses cast as a finite-time optimal control problem. We first propose a solution strategy that uses a convex optimization based relaxation to solve the optimal control problem. We then use this framework to illustrate the effects of various levels of energy storage using the topology of IEEE benchmark systems along with both time-invariant and demand-based cost functions. The addition of energy storage and demand-based cost functions significantly reduces the generation costs and flattens the generation profiles.