Do You Have Any Recommendations On How The Study Should Evaluate Various Solutions (new transmission, new resources, non-wires, etc.)?

This study is informational in its nature. To quote CAISO 20-year transmission outlook “the objective of the 20-Year Transmission Outlook is to provide a long-term conceptual plan of the transmission grid in 20 years, meeting the resource and electric load needs aligned with state agency input on integrated load forecasting and resource planning”

We recommend the study done in several phases

• WPP engineers to perform initial reliability studies and to identify the transmission constraints
• WPP work with regional Transmission Planners to validate the initial study results, and whether there are projects currently planned to address the identified transmission constraints

As far as solutions, we propose to consider other objectives beyond Reliability Standards

• Minimizing environmental impact, e.g. through optimization of existing transmission corridors
• Maximizing resiliency to extreme events, such as temperature extremes, wild fires, and particularly earthquakes

What Load Forecasting Questions and Recommendations Do You Have?

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

What Modeling and Data Questions and Recommendations Do You Have?

Engage regional Transmission Planners early and often in base case review

Coordinate with other regions to see what their plans are for the similar time horizons

Any “unserved load” in an all lines in service optimized PCM simulation should be closely scrutinized as an indicator that the modeled system was insufficient for that scenario.

Additional comments with respect to demand response (DR):  This is not a full load or resource issue.  It is in-between.  The integration of the distribution and transmission systems is an important variable as more solar and storage develops at the distribution level. Some of these may be smart, meaning they may be dispatched by the transmission operator (e.g., virtual power plants).  In the future, some of these distribution networks may be integrated into transmission operations to some extent.   How to model that effect is challenging from a modeling perspective, but a post-processing adjustment may be justified. 

What Resource Forecast Questions and Recommendations Do You Have?

IRPs can be used to estimate the amount of resources needed in the next 20 years to meet the forecasted loads.

Existing Generation Interconnection requests can be used as an indicator of potential resource locations.  Historically, less than 25% of the requests will be energized (see LBNL Queued Up study https://emp.lbl.gov/publications/queued-characteristics-power-plants )

Resources where transmission is already available or will soon be available following completion of committed upgrades are more likely

The uncertain availability of emerging technologies could be addressed with sensitivity cases. 

Since hydro is the largest part of the regional resource mix, consider sensitivities with low, median, and high runoff.

 

Energy Storage

Energy storage will play increasingly greater role in decarbonized power system.

What is your strategy on placement of energy storage (load centers or co-located with solar plants) ? It’s likely that some combination of both applications with be needed.

How to model operation of energy storage – charging and discharging ? 

Do you see application for long duration energy storage ?  Simulation of long duration storage in PCM scenarios may require revised methods due to the “look ahead” logic in existing software.

General Comment

Comments Provided by BPA:
We recommend reliability studies to include 

• Summer
  • Peak load
  • Peak day sunset 
  • Peak day energy with storage charging
• Winter
  • Peak evening load
  • Peak day energy storage changing
  • Light load high renewable scenario

We recommend that the production cost modeling study start by developing a reference case that is based on a current vintage WECC Anchor Data Set (ADS) with any additional modeling updates or refinements that study team members wish to provide.  Then, scenario cases including test years further in the future could be developed.  The reliability studies could inform assumptions about additional constraints to monitor in the PCM study.