The wholesale price of electricity is a key driver in resource decision making and captures the dynamics of supply of and demand for electricity throughout the Western power grid (WECC[1] footprint). To forecast prices into the future the Council uses a model, AURORA[2], that can both estimate the buildout of future resources throughout the western grid and generate wholesale power prices via production cost modeling.

For the 2021 Power Plan, the Council’s price forecasts are primarily focused on capturing the effects on market prices and avoided CO2e emissions rates[3] due to the changing policy landscapes. These effects are explored via scenario work where different policy outcomes are tested over a number of different hydro runoff conditions, which continue to be a major component of price variability in the Pacific Northwest due to the regional reliance on hydropower generation. Sometimes results from multiple model configurations are used to inform the analysis for the 2021 Power Plan policy scenarios.

Throughout the advisory committee and plan development process were many modifications to the modeling techniques and revised input assumptions for the studies supporting the power plan analysis. These changes are catalogued in the subsections described below, and the timeline of the changes is covered in more detail on the System Analysis Advisory Committee webpage.

The Sections 3.1 discusses the analytical results of the WECC-wide capital expansion of the power system, and Section 3.2, the corresponding price forecast results over many different hydro runoff conditions.  Sections 3.3 and 3.4 discuss how those results are used to support the analysis using the Council’s other models, Regional Portfolio Model and GENESYS.

[1] WECC stands for Western Electric Coordinating Council which is the not for profit corporation that exists to ensure a reliable bulk power system throughout the Western Interconnection, which includes the following: British Columbia, Alberta, Washington, Oregon, Idaho, Wyoming, California, Nevada, Utah, Arizona; most of New Mexico, Montana, Colorado; and some of the Dakotas, Nevbraska and North Baja California.

[2] AURORA is a commercial production cost model licensed from Energy Exemplar

[3] CO2e refers to carbon dioxide equivalent emissions