Hourly Power System Operation in the Western U.S. under Varying Water Availability for Hydropower

Abstract:

Hydropower plays a significant role in balancing the Western U.S. power system. We explore how hourly operations of the power system are impacted under a range of hydropower availability scenarios according to three different climate models under historical (1981-2010) and future (2011-2095, RCP 4.5 and RCP 8.5) conditions. We use an hourly production cost model that represents individual power plants and aggregates transmission to county level to understand the spatial impacts at over 400 counties in the Western U.S. in a historical power system which relies largely on hydropower, coal, and natural gas. This provides the most comprehensive set of hourly simulations of the power system under varying hydropower availability to date, from which we can observe a wide range of drought conditions. We explore the hourly variability of dispatch by generator type and location in order to understand how the simulated power system relies on hourly hydro variability. This work informs the improvement of hydropower representation in production cost models, as it highlights the assumed flexibility of hydropower and the importance of that flexibility under drought scenarios. We highlight counties and generator types most important in responding to drought conditions in the historical system, informing resilience planning for future power systems.