Wait Times Remain Long: Berkeley Lab's Queued Up 2026 on Power Plants Seeking Interconnection

A proposed power plant that wants to connect to the transmission grid must go through a series of studies before it can be built. Transmission providers require proposed generation and storage plants "to undergo a series of studies before they can be built," and the lists of projects in that process are known as interconnection queues. Lawrence Berkeley National Laboratory presents "an annual snapshot of trends in requests for generator interconnection," and its deck "Queued Up: 2026 Edition," dated June 2026, covers requests "As of the End of 2025."

The deck "summarizes empirical data from transmission providers’ (i.e., ISO/RTOs and utilities) publicly-available interconnection queues," and "In some cases, the analysis leverages additional (non-public) data provided to LBNL directly from transmission providers to fill in gaps from the public data." It counts only what supplies power. "The data presented here only include resources that supply electricity to the transmission grid (i.e., generation and storage); there are separate queues for large loads and those are not included in this report." And it "neither directly comments on nor recommends any specific policies." The work was funded by the U.S. Department of Energy.

A data center's own request to connect sits in a separate queue that this deck does not count. What the deck measures is the supply side of the line a new campus depends on.

What is waiting

Under the heading "Overall queue volume decreased year-over-year, but gas increased," the deck finds roughly 2,061 gigawatts of capacity "actively seeking interconnection" at the end of 2025, 1,312 GW of it generation and 749 GW storage. Gas rose while the others it names fell. Natural gas capacity in the queues increased by 86% in 2025, while solar fell by 19%, storage by 16% and wind by 19%.

Wait times remain long

The deck calls completion rates "generally low." "About 19% of projects (13% of capacity) requesting interconnection from 2000-2020 reached commercial operations by the end of 2025."

"The average time projects spent in queues remains high in most, but not all, regions," the deck says, and the median wait has lengthened. "The median project built in 2025 took 61 months from the interconnection request to commercial operations," it says, "compared to 36 months in 2015 and 22 months in 2008." A note at the foot of the page limits that count. "Valid in-service date was only available for 73% of all operational projects." The same box adds that "These trends raise concerns for meeting growing electricity demand and meeting resource adequacy requirements."

That wait is measured for the plants that did reach operation. For a campus that needs new supply by a date, a project still in the queue is a risk to that date until it reaches operation too.

Capacity withdrawn, and agreements processed

For the second year running, more capacity left the queues than joined them. The deck says "Over 750 GW" of capacity "withdrew in 2025, while about 600 GW submitted new requests." Its note limits that count too. "Withdrawn year was only available for 63% all withdrawn requests, so the chart illustrates less than the total withdrawn capacity in each year." The deck names possible reasons, with a "may." "Interconnection process reforms, alongside market conditions, transmission constraints, permitting barriers, and other factors may be contributing to this trend."

CAISO, ERCOT, SPP and MISO processed more interconnection agreements "than any prior year," and in CAISO and ERCOT the agreements processed in 2025 each summed to more than 50% of their peak load capacity.