ESIG Report Calls for Integrated Transmission Planning as Grid Pressures Mount

The Energy Systems Integration Group (ESIG) has released a new report examining how fragmented transmission planning practices are slowing grid development at a time of rising demand and increasing system stress.

Titled Modernizing Transmission Planning: Integrating Silos to Deliver Multi-Driver, Multi-Value Outcomes, the report finds that U.S. transmission planning remains divided across multiple tracks — including generator interconnection, load interconnection, reliability, economic, asset replacement, and public policy planning. These tracks operate under different mandates, timelines, and assumptions, resulting in piecemeal solutions, repeated mitigation work in the same corridors, and slower, less predictable interconnection of new generation and load.

According to the report, these challenges are becoming more acute as electricity demand grows, large loads concentrate in specific areas, generation resources shift, and extreme weather places additional strain on the grid.

The report outlines an “integrate, broaden, deepen” framework designed to connect traditionally siloed planning processes, align them around shared planning futures, and enable coordinated development of transmission projects that address multiple needs. The approach is intended to support the development of multi-value transmission portfolios aligned with Federal Energy Regulatory Commission Order 1920.

An interactive data explorer accompanies the report, showing how transmission projects are approved and categorized across regions. The tool includes trends by voltage level, project type, and in-service year, reflecting data current through 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 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.”

The report identifies several near-term integration priorities, including closer alignment between interconnection studies and long-range planning. Recommended actions include using common assumptions across studies, grouping compatible interconnection requests, converting recurring bottlenecks into shared corridor upgrades tied to long-range plans, and incorporating high-interest queue areas and load-interconnection zones into expansion planning.

Another priority is integrating asset replacement planning with long-term system needs. The report recommends making right-sizing the default approach and bundling overlapping rebuilds with nearby system constraints to avoid repeated construction in the same corridors while delivering durable transfer capability.

The report also calls for stronger integration between operations and planning, including incorporating ramping, stability, inertia, voltage, and weak-grid conditions into planning studies; formalizing operator input; using production-cost-derived stress periods; and applying transient analysis when appropriate.

“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 at Electric Power Engineers. “It reduces restudies and withdrawals, minimizes planning uncertainty, and targets appropriately sized upgrades where they deliver the most value.”

According to ESIG, a more integrated planning approach can lead to coordinated transmission portfolios built on shared assumptions and documented decision-making. The report states that such coordination can speed interconnection timelines, support a steady expansion of higher-voltage infrastructure complemented by targeted lower-voltage projects, and ensure that near-term fixes and asset replacements are designed to meet long-term system needs.

“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.”