The Western Transmission Expansion Coalition (WestTEC) is on track to publish the first phase of its transmission planning study this summer despite some delays in finalizing the models that will underpin the study, coalition members said during a May 27 webinar.
The goal of the study is to produce transmission portfolios for 10- and 20-year planning horizons. Models related to both planning horizons have been delayed by a few months, Keegan Moyer, a partner at Energy Strategies and consultant for WestTEC, said during the presentation.
Moyer said the delays are not to be “totally unexpected” given the study’s “scope and ambition.”
“We were going to have results around now from the preliminary analysis,” Moyer said. “The models are still being finalized, so we are expecting to have a better understanding of what we’re seeing in the 10-year time frame in the next two to three months. We still think we’re going to be roughly on time for the report focused on that 10-year horizon, which will be issued in the late summer, kind of early fall, time frame.”
The 20-year horizon is similarly delayed but “overall on track for the project as a whole,” he added.
The 10-year plan originally was scheduled to be published in August 2025 and the 20-year horizon study in September 2027.
The WestTEC study, jointly facilitated by the Western Power Pool and WECC, will address long-term interregional transmission needs across the Western Interconnection. The WestTEC Steering Committee unanimously approved the project’s study plan in September 2024. (See WestTEC Committee OKs Plan for ‘Actionable’ Tx Study.)
The study will include a reference case based on anticipated trends in load growth, technology and policy in transmission planning. The reference case assumes a 2.2% annual load growth between 2024 and 2045.
The scenario planning subcommittee also is developing two separate cases, labeled “flux” and “core,” to be included in the 20-year horizon, according to the study plan.
The flux case represents a high-growth scenario that reflects rapid changes in power demand and technology innovation in areas like artificial intelligence, wind, solar and energy storage. The annual load growth under the flux case is 3%.
The core case, meanwhile, includes a moderate-growth scenario with select technology breakthroughs and a 2% annual load growth, according to the May 27 presentation.
The technologies in the core case “are sort of advanced geothermal, nuclear, [small modular reactors], carbon capture, these types of technologies with a lower level of load growth and an assumption that there’s some statutory delays,” Moyer said.
“The goal with these two scenarios and the reference case is to create divergent futures,” Moyer said. He added that “there are a wide range of futures that should definitely produce some interesting modeling results.”
