Role of grid and bulk storage in the integration of variable renewable energy resources: Framework for optimal operation-driven multi-period infrastructure planning

Abstract

This paper presents a unified framework for quantifying the techno-economic value of various technologies in systems with high levels of variable renewables, which is of utter importance in evaluating roadmaps towards an affordable and sustainable future for various energy industry stakeholders. The optimal planning framework is based on integrating the solution of a transmission and generation/storage expansion problem with the solution of unit commitment, with the objective to minimize the total capital and operational expenditures over a selected horizon. The formulation includes, but is not limited to, traditional thermal units, pumped-hydro storage, batteries and transmission technologies. The decision variables include new cross-zonal transmission capacity, bulk energy storage and generation capacity, which are computed over the selected horizon while accounting for the impact of wind and solar variability on hourly (or sub-hourly) basis. A reduced representative version of the European system is used to demonstrate the value of transmission and bulk energy storage for a selected set of future scenarios, including scenarios corresponding to high proliferation of distributed energy storage and e-mobility. Comparative results are presented with emphasis on the renewable energy shares, investment costs, average cost of electricity, and carbon emission targets. Sensitivity analysis is performed considering technology and fuel costs.