PNNL

Abstract

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 and power flow models of each topology were constructed. A novel multi-terminal high voltage direct current (MTDC) model was developed and utilized, and its benefit is compared with conventional high voltage direct current (HVDC) radial topology.