US grid connection backlog, dominated by solar, grows to 2.6TW in 2023

Solar accounted for the majority of generation capacity in the queues with a combined capacity of 1,080GW, followed by wind (366GW). A total of 571GW of solar capacity in the queues were proposed as hybrid plants due to falling battery prices, accounting for 53% of all solar projects in the queues. Over half of all storage capacity (525GW) in the queues was proposed in hybrid configurations with generation.

The overall growth in the interconnection queue in 2023 came in spite of slowdowns in the queues in the Midcontinent Independent System Operator (MISO) and PJM Interconnection. Due to the influx of new interconnection requests in 2022, MISO did not accept new requests last year as they sought approval for sweeping procedural reforms. Also, PJM announced that they would not review new requests until at least 2025, resulting in few new requests in 2023.

The slowdowns in MISO and PJM Interconnection were offset by the growth in other regions, such as CAISO, which received a record-breaking capacity of new requests (523GW) in 2023.

Additionally, the Inflation Reduction Act (IRA) incentivised some clean energy capacity entering the queues last year. Over 1,200GW of capacity, including more than 500GW of solar, over 540GW of storage and 125GW of wind, has requested interconnection since the passage of the IRA.

“The IRA supercharged the already-vigorous market for clean energy and storage development. But while the IRA improved economic certainty for projects, other uncertainties, including grid interconnection and permitting, remain challenging,” said Nick Manderlink, co-author of the study.

Withdrawal of interconnection requests

According to the study, over 70% of interconnection requests were withdrawn in previous years. Only 19% of the projects, and just 14% of the capacity, that submitted interconnection requests from 2000-2018 reached commercial operations by the end of 2023.

Solar projects had an even lower percentage in terms of connecting to the grid. Only 13% of solar projects and 10% of the capacity were operational after submitting requests between 2000-2018.

The report also found that the waiting time for interconnections rose last year. Interconnection requests typically took more than three years to complete requisite grid impact studies in most regions. The timeline from the initial connection request to having a fully built and operational plant has increased from less than two years for projects built between 2000-2007 to more than four years for projects built in 2018-2023.