October 1, 2024
Journal Article

Capacity Contributions of Southern Oregon Offshore Wind to the Pacific Northwest and California

Abstract

Variable renewable energy generation poses unique capacity challenges, which increasingly depend on weather events at varying timescales. Facilitated by transmission planning, geographic and technological diversity of the generation fleet may provide a mitigation to capacity shortfalls. In this work, offshore wind (OSW) energy is sited in the areas off the West Coast between Coos Bay, Oregon, and Crescent City, California. Three generation and transmission scenarios across two future representations of the Western Interconnection are modeled: (i) 3.4 gigawatts (GW) of installed OSW capacity connected to Southern Oregon through a 2030 High Voltage Alternating Current (HVAC); (ii) 12.9 GW of installed OSW capacity connected to Washington, Oregon, and California through a 2030+ High Voltage Direct Current (HVDC) Radial Topology, and (iii) the same 12.9 GW connected to the same locations through a 2030+ Multi-terminal DC (MTDC) Backbone Topology. Zonal dispatch assuming coincident wind, solar, and hydropower production and loads over 18 meteorological years, accounting for temperature-dependent equipment derating and forced outages, informed capacity value through the Associated System Capacity Contribution (ASCC) metric. As assessed through ASCC, capacity contribution is 33%, 25% and 34% for the 2030 HVAC Radial Topology, 2030+ HVDC Radial Topology, and 2030+ MTDC Backbone Topology, respectively. Transmission design is shown to mitigate the typical erosion of marginal capacity contribution as more OSW is developed. Without changing the OSW generation or points of interconnection, the MTDC backbone allows for interregional transmission and increases the ASCC by 28% to the Pacific Northwest over the 2030+ HVDC Radial topology, underscoring the opportunity for grid modernization while decarbonizing the generation mix.

Published: October 1, 2024

Citation

Douville T.C., S. Zhou, J. Zhu, and M. Severy. 2024. Capacity Contributions of Southern Oregon Offshore Wind to the Pacific Northwest and California. The Electricity Journal 37, no. 4-5:107407. PNNL-SA-194455. doi:10.1016/j.tej.2024.107407