Transmission Planning for Long-term Reliability
In this report, Brattle Principal Johannes Pfeifenberger, Managing Energy Associate Joe DeLosa III, and Senior Energy Associate Aniruddh Mohan explore the resource adequacy value of regional and interregional electric transmission.
Coauthored with PNNL and Telos Energy experts, the report examines how transmission makes power grids across the United States more reliable and affordable. It documents gaps in how contributions of transmission to resource adequacy are considered in planning, which leads to higher generation investments and increased costs for end users.
Three gaps stand out in the alignment of regional transmission planning processes with supply planning to address resource adequacy needs:
- Differences in planning horizons and objectives: While resource planning typically uses a 20-year planning horizon, transmission planning is focused on reliability needs over only the next 5–10 years.
- Differences in modeling methods: While transmission planning models focus on grid reliability without considering resource adequacy, resource adequacy models mostly ignore or only consider zonal transmission constraints.
- Differences in the input data: The input data used in these planning processes differ, preventing better integration or co-optimization of these planning processes.
For interregional planning, additional gaps include:
- Existing planning processes generally do not explore how interregional transmission expansion can reduce total system costs.
- There is no established best practice for assessing transmission’s resource adequacy valuation through planning reserve margin (PRM) reduction, accreditation, or other mechanisms.
- Assumed caps modeling external assistance during resource adequacy events prevents recognizing the full value of new interregional transmission in most areas.
- Where the resource adequacy value of additional interregional transmission is recognized, the benefits are commonly socialized, failing to incentivize participant-funded or merchant business models.
The full report is available below.
