Queued Up: 2026 Edition, Characteristics of Power Plants Seeking Transmission Interconnection As of the End of 2025

Electric transmission system operators (ISOs, RTOs, or utilities) require proposed power plants seeking to connect to the transmission grid to undergo a series of impact studies before they can be built. This process establishes what new transmission equipment or upgrades may be needed before a project can connect to the system and assigns the costs of that equipment. The lists of projects in this process are known as “interconnection queues”. 

In collaboration with https://www.interconnection.fyi. Berkeley Lab compiled, aggregated, and cleaned interconnection queue data from >50 transmission grid operators (7 ISO/RTOs and 50 non-ISO balancing areas), which collectively represent ~98% of currently installed U.S. electric generating capacity. The dataset includes requests submitted to queues through the end of 2025, and only includes generation requests seeking to connect to the transmission grid (i.e., does not include load interconnection requests nor distribution-connected or behind-the-meter projects).

The files below include both a PDF slide deck and an Excel data file. The PDF slide deck analyzes interconnection data and metrics through the end of 2025. The Excel data file includes (a) the full project-level interconnection queue dataset through 2025, (b) a codebook (data dictionary) describing each data field, and (c) 36 additional tabs featuring tables summarizing a range of interconnection metrics.

Key highlights from the Queued Up: 2026 Edition (featuring data through 2025) include:

• As of the end of 2025, there were ~8,200 projects actively seeking grid interconnection in the U.S., representing 1,312 GW of generation and approximately 749 GW of storage.
• High withdrawal rates alongside relatively fewer new requests resulted in a 10% decrease in total active queue volume compared to the prior year.
• Active natural gas capacity (253 GW, +86%) increased in 2025, while solar (773 GW, -19%), storage (749 GW, -16%) and wind (220 GW, -19%) capacity decreased.
• 549 GW of capacity already has a draft or executed interconnection agreement (IA) but has not yet reached commercial operations, including 256 GW of solar, 161 GW of storage, 76 GW of wind, and 45 GW of gas. 
• The time projects spend in queues before reaching COD is increasing. For the regions with available data, the median duration from IR to COD was over 5 years for projects built in 2025.
• Ultimately, most of this proposed capacity will not be built. Only 13% of capacity that submitted interconnection requests from 2000-2020 had reached commercial operations by the end of 2025; 75% of that capacity had been withdrawn and 10% was still active. 
• FERC Order 2023 and various other reforms are being implemented. These are important measures to reduce interconnection bottlenecks and enhance grid system reliability, but it is too early to measure and assess their full impact.