WECC’s Transmission Expansion Planning work requires data from various resources and for various future study horizons, depending on the Interconnection-wide Transmission Plan being developed. Data is the foundation on which the WECC planning analysis is built. Current data describes the grid as it is today, as well as aspects of how the grid will look in 10 years, i.e., data about projects under construction. Historical data provides benchmarks for comparison. Data can come from stakeholders, study requestors, national laboratories, WECC committees or other sources.
When necessary data are unavailable, assumptions are made. These educated or informed assumptions help to fill in data gaps. As planning looks to the future, and the future is not certain, assumptions also help define the “what-ifs” in the study cases.
The procurement of data and defining of assumptions is a preparatory step in running a study case. The data and assumptions are used as inputs to the tools and models WECC uses in its analyses.