Based on presentation given by DOE National Transmission Planning study, the load electrification assumptions have most significant impact on power and energy demand and load shapes.

PNW is experiencing significant growth in new large industrial loads, re-shoring, hyper scale data centers. Make sure your study models reflect the projected load growth.

Electrification transportation and buildings can increase load demand significantly, e.g. Seattle City Light study: https://powerlines.seattle.gov/wp-content/uploads/sites/17/2022/01/Seattle-City-Light-Electrification-Assessment.pdf

What methodology are you planning to use to develop load forecasting scenarios?

For the PCM part of the study, we recommend consideration of low, medium, and high load growth scenarios that incorporate uncertainties related to the variables listed above.  Methods to translate from an LSE level to a nodal level of granularity for the simulation models