New ESIG report presents an “integrate, broaden, deepen” approach that connects siloed transmission planning tracks that run in parallel, and supports the coordinated development and selection of transmission upgrades to deliver multi-driver, multi-value transmission portfolios aligned with FERC Order 1920.

The Energy Systems Integration Group (ESIG) today released Modernizing Transmission Planning: Integrating Silos to Deliver Multi-Driver, Multi-Value Outcomes, a report addressing a central challenge: U.S. transmission planning remains fragmented across several planning areas including generator interconnection, load interconnection, reliability, economic, asset replacement, and public policy, tracks that have separate mandates and operate on misaligned timelines and with different assumptions. This siloed approach produces piecemeal fixes, repeated mitigations in the same transmission corridors, and slower, less predictable interconnection of generation and load just as demand rises, large loads concentrate, resources shift, and extreme weather increases system stress.

The report sets out an integrate, broaden, deepen approach, which connects formerly siloed transmission planning tracks, uses shared planning futures, and makes possible the coordinated development and selection of projects to deliver multi-need, multi-value transmission portfolios aligned with FERC Order 1920. Accompanying the report is a link to an interactive data explorer showing how transmission projects are approved and categorized across regions, with trends by voltage, project type, and in-service year, as of mid-2025.

“Planning teams are being asked to do more and do it faster, amid rising demand, new load centers, evolving resource mixes, and more frequent extreme weather,” said Ahmed Rashwan, senior director at Electric Power Engineers, and the task force lead. “The guidance given in this report connects studies that utilities and system operators already run, so projects are scoped once to meet multiple needs. This delivers clear gains: less congestion, faster interconnection, coordinated portfolios, and right-sized replacements.”

Near-term integration priorities recommended in this report

• Integrating interconnection with long-range planning. Planners should use common futures and constraints across studies, group compatible requests, convert recurring bottlenecks into shared corridor upgrades tied to the long-range plan, and use high-interest queue areas and load-interconnection zones in expansion plans.

• Integrating asset replacement with long-term needs. Planners should make right-sizing the default and bundle overlapping rebuilds with nearby system constraints, so that a single corridor upgrade avoids repeated construction and delivers durable transfer capability.
• Integrating operations with planning. Study teams should bring ramping, stability, inertia, voltage, and weak-grid conditions into screening and design; formalize operator input; use production-cost-derived stress periods; and apply transient analysis when warranted.

“Aligning interconnection with the long-range plan gives generators and large loads a clearer, more predictable path to interconnection and delivery,” said Drew Siebenaler, senior manager, Electric Power Engineers. “It reduces restudies and withdrawals, minimizes planning uncertainty, and targets appropriately sized upgrades where they deliver the most value.”

Why it matters:

• Planning studies produce coordinated portfolios and documented decisions by using shared assumptions, common benefits, and portfolio-level scoring.
• Interconnection of generation and load moves faster and becomes more predictable as shared corridor upgrades address recurring constraints and align with the long-range plan.
• The grid expands steadily at higher voltages, with a consistent pipeline of high-voltage, multi-benefit lines complemented by targeted lower-voltage projects designed for the same scenarios.
• Near-term fixes and asset replacements are right-sized for long-term needs, reducing serial mitigations and rework.

“Modernization is not about discarding methods that work; it is about linking them,” said James Okullo, Director of System Planning at ESIG. “The integrate, broaden, deepen approach described in this report ensures that the transmission we build reflects how the grid will actually run.”

###