A Lagrangian Decomposition Approach to Energy Storage Transportation Scheduling in Power Systems

In this paper, we propose a security-constrained unit commitment (SCUC) model which considers the impact of mobility of Battery-based Energy Storage Transportation (BEST) system. The BEST technology considers the transmission of electricity via rails (in the form of storage) rather than utilizing transmission lines, which allows transmission grid operators to focus on certain geographical regions of the grid and provides the grid with more flexibility to relieve the congestion. To solve the resulting large-scale MILP model, a Lagrangian decomposition-based technology is presented, which uses a modified sub-gradient method to accelerate the convergence of the BEST algorithm. The IEEE 118-bus system integrated with a railway network composed of 8 railway stations and 10 rail lines is used to illustrate the applicability of the BEST model and the performance of the algorithm. The results show that the BEST solution can reduce the overall cost of power delivery by transporting the electricity from low locational marginal price (LMP) areas to high LMP areas, relieve transmission congestion, reduce the need for acquiring additional transmission right-of-ways, and optimize the use of existing space on freight trains which is already vacated by the closure of coal power plants throughout the country.