Interconnection queues for U.S. power plants have grown steadily for years, largely due to the strength of wind, solar, and more recently, battery storage. At one point, the queue held enough clean energy capacity to meet all U.S. electricity demand. But joining the queue does not guarantee a project will get built. High interconnection costs and sometimes coordinated local opposition routinely thin the list.
An analysis by Interconnection.fyi shows that total capacity in the queues fell 12%, sliding from 2,596 GW in 2023 to 2,290 GW in 2024. However, this decline was not uniform, as some regions logged increases, and proposed natural gas capacity rose sharply.
Solar posted the largest decline in interconnection queue capacity, dropping 11.9% from 1,086 GW to 956 GW. That 130 GW reduction accounted for 43% of the 306 GW nationwide contraction. Stand-alone battery storage fell 7.2%, hybrid projects (wind or solar paired with storage) dropped 19.2%, and offshore wind lost more than half its queued volume, amid policy and market headwinds.
Natural-gas proposals moved in the opposite direction, rising 72% from 79.2 GW to 136.2 GW, led by projects in ERCOT, MISO, the Southeast, and SPP.
Interconnection.fyi attributes much of the shift to tighter interconnection rules at regional grid operators. PJM, MISO, and CAISO now require higher deposits, clearer site control, and milestone-based study processes—changes that mirror FERC Order 2023. Although the order is not yet fully in force, the analysts believe the stricter standards appear to be here to stay.
The updated rules aim to trim the overwhelming backlog of interconnection requests that, among other effects, forced PJM to pause new applications several years ago.
- CAISO posted the largest decline, shedding roughly 200 GW (about two-thirds of the national total), largely from the “Cluster 15” study group.
- ISO-NE recorded sizable reductions in offshore wind and utility-scale solar.
- NYISO lost more than 43 GW in offshore wind, along with significant drops in solar and storage.
- PJM saw a sharp fall in solar capacity.
Some markets moved in the opposite direction. ERCOT added about 15% in proposed solar and more than 50% in storage. MISO reported gains across all major resources, though analysts note that the jump is partly a timing artifact: the region was closed to new applications for most of 2023, opening to a surge in early 2024.
The analysis shows that most projects withdrawing from the queue had already waited years, many with deposits on file for four to five years. In CAISO, withdrawn projects had an average wait of about 5.5 years, while other regions averaged three to four years.
Tax credits under the Inflation Reduction Act are now scheduled to fall by roughly 60% for projects beginning construction in 2026, and to expire after 2027. Those deadlines are expected to thin the queue further as developers reassess timelines.
To gauge which projects are most likely to advance, the study examined those with signed generator interconnection agreements. Nationwide, about 386 GW of capacity has reached that stage, which is nearly 17% of the total queue. Texas tops the list with more than 100 GW, while utilities in the Western Interconnection (excluding CAISO) account for another 83 GW.
Nationwide, roughly 150 GW AC (about 200 GW DC) of solar projects now hold signed, active interconnection agreements. The queue also includes about 70 GW of stand-alone battery storage and another 70 GW of hybrid wind- or solar-plus-storage capacity with active approvals.
For context, the U.S. Energy Information Administration expects developers to install about 50 GW DC of new solar capacity in 2025.
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