The U.S. grid interconnection queue reached 2,600 gigawatts (GW) of proposed generation and storage capacity in 2023, according to Lawrence Berkeley National Laboratory (LBNL), exposing a structural mismatch between the pace of battery storage development and the transmission system's capacity to absorb it. Policy tools-including Inflation Reduction Act (IRA) tax incentives, FERC process reforms, and fast-track procurement approvals-are taking effect, but developers and analysts say systemic gaps remain.
Background
The interconnection queue is the mandatory review process through which new power projects apply to connect to the transmission grid. All seven U.S. independent system operators (ISOs) and regional transmission organizations (RTOs), along with roughly 50 non-ISO utilities, maintain queues that have historically operated on a first-come, first-served basis. The nationwide backlog has delayed new generation interconnection, with wind, solar, and battery storage projects-incentivized by IRA tax benefits-comprising much of the pileup.
Time spent in queues before commercial operation continues to grow. For regions with available data, median duration from interconnection request to commercial operation has doubled-from under two years for projects built in 2000-2007 to over four years for those built in 2018-2024. The typical project reaching commercial operation in 2024 spent 55 months, or 4.5 years, in the queue.
FERC's Order No. 2023, issued July 28, 2023, represented the first major reform to the commission's interconnection procedures in twenty years. The reforms implement a "first-ready, first-served" cluster study process, increase processing speed, and incorporate technological advancements into interconnection procedures. FERC issued a clarifying rehearing order, Order 2023-A, in March 2024.
Queue Dynamics: Decline in Volume Does Not Signal Relief
Total interconnection queue capacity dropped from 2,600 GW in 2023 to 2,300 GW in 2024-the first decline in queue size in at least a decade. LBNL's 2025 edition of its annual Queued Up report confirmed that as of the end of 2024, approximately 2,290 GW of capacity remained active across U.S. queues-nearly twice the capacity of the current U.S. power plant fleet.
Analysts caution that the volume reduction does not indicate improved processing. Solar and battery storage capacity entering the queue declined 47% and 32%, respectively, and a record 112 GW of combined solar and storage capacity withdrew in 2024, driven by political uncertainty, high interest rates, tariffs, and local permitting challenges. Over 700 GW of capacity withdrew from queues in 2024, significantly outpacing roughly 500 GW of new submissions. While this may reduce speculative projects, high withdrawal rates-particularly the one-third of 2024 withdrawals occurring at the facility study or interconnection agreement phases-trigger costly re-studies for remaining projects.
Some long-stalled projects finally cleared the process: large-scale solar (31 GW) and grid-scale battery storage (11 GW) both saw record backlogged capacity come online in 2024. Yet historical data show only about 19% of projects entering U.S. queues between 2000 and 2018 reached commercial operation.
Regional Hotspots
Regional concentration remains pronounced. Active queue capacity is highest in the Western Interconnection at 706 GW, followed by CAISO at 523 GW. Roughly half of all active solar (47%) and storage (48%) capacity in the queues consists of hybrid configurations such as solar-plus-battery. In CAISO specifically, hybrids account for 93% of all active solar capacity in the queue, adding integration complexity.
In MISO, over 170 GW of solar, wind, and storage await interconnection, with many projects facing delays of four or more years. MISO proposed an Expedited Resource Addition Study (ERAS) process in mid-March 2025, and FERC approved the proposal on July 22, 2025, underscoring the urgency of bringing more generation onto the grid. In February 2025, FERC also approved PJM Interconnection's Reliability Resource Initiative, a fast-track review covering fifty generating projects to address shortfalls in load growth, premature plant closures, and new generation delays.
In ERCOT, which falls outside FERC jurisdiction, the interconnection surge has created its own bottlenecks, with nearly 100 GW of renewables and storage queued.
Policy Gaps Persist for Storage Developers
The IRA's standalone storage investment tax credit (ITC) under Sections 48 and 48E has provided a strong demand signal for utility-scale battery projects. The energy storage industry has benefited significantly from the IRA's federal income tax provisions, with storage among the law's major beneficiaries on both deployment and manufacturing sides-including the long-sought ITC for standalone energy storage facilities.
Yet the queue bottleneck is eroding those incentives in practice. In the first half of 2025 alone, over $22 billion in renewable projects were canceled, eliminating 16,500 jobs and stranding billions in tax-equity capital. Developers with projects missing 2026-2028 start dates for Section 45Y and 48E clean-energy credits face significant cost increases, according to industry analysts.
FERC Order 2023 does not adequately address comprehensive regional transmission planning and funding, according to the Solar and Storage Industries Institute (SI2). Experts stress that proactive planning, enhanced data transparency, queue automation, better coordination of affected-system studies, and refined network upgrade cost allocation are needed to meaningfully reduce the backlog.
Outlook
Clean energy deployment will be essential to meeting the historic electricity demand surge, forecast to require more than 150 GW of additional capacity by 2030, according to Grid Strategies' November 2025 report. The fast-track approvals granted to PJM and MISO do not advance wider system transformation; they are localized, one-time processes that expedite projects meeting specific qualifications. Stakeholders across the industry continue to call for structural transmission planning reform linked directly to the interconnection process to prevent the backlog from reconstituting as demand-driven applications resume.
