Multi-Temporal Analysis and Techno-Economic Evaluation of Offshore Wind Energy Integration to the Western Interconnection

The intermittent nature of renewable energy generation introduces distinctive capacity challenges that hinge on various weather events occurring at different time intervals, ranging from rapid sub-hourly ramping to prolonged decadal droughts. To address these challenges, it becomes increasingly crucial to incorporate geographic and technological diversity into the energy mix. This diversity can be facilitated by transmission planning that takes into account operational considerations like frequency response, regulation, ramping capabilities, and contingency reserves, while also quantifying the broader system-wide advantages and drawbacks. This research builds upon an approach that evaluates these operational elements and extends its application to the planning of electricity transmission systems in the context of the emergence of offshore wind (OSW) energy projects in Northern California and Southern Oregon. Three generation and transmission scenarios across two future representations of the Western Interconnection (WI) are modeled, and detailed production cost modeling (PCM) and power flow (PF) models of each topology were constructed. A novel multi-terminal high voltage direct current (MTDC) model was developed and utilized, and its performance is compared with conventional high voltage direct current (HVDC) radial topology. The case studies show how OSW changes the energy flow on three major paths in WI with PCM, as well as contingency analysis, transient stability, and voltage stability in PF. Through an iterative manner, the proposed approach identifies necessary upgrades to the transmission system based on PF results, builds the upgrades in the PCM, and re-runs. Significant potential benefits of West Coast OSW in interregional energy coordination and resilience to extreme weather conditions from using different generation and transmission scenarios are observed.