PNNL

Abstract

Modern day energy systems are evolving to be complex, interconnected and transactive systems, without clear demarcation between energy “producers” and “consumers”. This is aided by largescale proliferation of renewables (both at a centralized scale as well as in more distributed settings such as rooftop solar) and the growing potential for energy usage flexibility, which subsumes the increasingly widespread use of energy storage. In this paper, we propose a mathematical framework which considers the interaction of energy flexibility (e.g., storage functionality) and renewable generation in a transactive power system, where a grid operator can secure both generation and flexibility (storage) resources from centralized and/or distributed assets. Our results, derived under network-abstracted settings, mathematically relate the system operating cost to the available storage capacity. In addition, our proposed framework also characterizes the inflection point beyond which further addition of storage capacity do not affect cost of system operation. Furthermore, the relationship between the price spread in the grid, i.e., difference between maximum and minimum prices over the time horizon under consideration, and the available storage capacity, is also commented upon. Finally, we demonstrate our findings on a modified IEEE 30 bus test network.