The United States has more generation capacity in its interconnection queue than installed nationwide. If all the power projects that are seeking to connect to the grid were to come online right now, we would solve power demand problems for years to come.
According to a new report from Lawrence Berkeley National Lab, there are “nearly 11,600 projects representing 1,570 gigawatts of generator capacity and 1,030 GW of storage actively seeking interconnection,” or 2,600 GW in total. That’s more than double the 1,279 GW of installed capacity currently available in the country.
The bulk of the capacity that is waiting for connection is renewable energy; 95% of the queuing generation capacity is from solar, storage, and wind projects, with 3% coming from gas.
Solar and storage, in particular, make up over 80% of the interconnection queue, with most of the capacity in the increasing number of hybrid plants. Most hybrid plants couple renewable generation with batteries. Over half of all active solar and storage capacity in the queue is found in hybrid plants that together could add 1,100 GW to the grid.
And wait times are only increasing.
The average renewable energy project that came online in 2023 languished for five years in the grid interconnection queue, the report found. That same process took only three years in 2015, and less than two years in 2008.
Dropping completion rates
However, a shrinking share of projects is actually graduating from the queue. Of all the projects that requested interconnection over the span of nearly a decade, from 2000 to 2018, only 20% were operational by the end of 2023, representing 14% of capacity.
“Completion rates are even lower for solar (14%) and battery (11%) projects,” according to the report. And the longer a project is left in limbo, the authors found, the more likely it is to be withdrawn.
The issue is happening all over the world, caused in part by the failure of the expanding grid to keep up with the rapid speed of renewable energy development. And it’s being exacerbated by the skyrocketing power demand spearheaded by electrification, onshoring (especially in the United States), and a boom in data center development. In a report last year, the Department of Energy highlighted the importance of grid modernization, noting that new projects alone won’t be able to meet rising load growth.
Of course, the longer a project waits in the interconnection queue, the more expensive it becomes. According to another LBNL study released last year, interconnection costs reported between 2019 and 2023 ”were 44% greater than during the preceding 5 years.”
Even withdrawn projects had costs that were 23% greater. That’s a group that makes up the bulk of the queue; around 70% of projects get withdrawn sometime during the wait.
More than 1,250 requests, representing over 200 GW of potential capacity, were withdrawn in 2023, according to the report.
While most withdrawals occur early during the development of a project, “later-stage withdrawals… may be increasing.” The potential consequences include both increasing costs and delays by disrupting assumptions built into other projects’ interconnection studies — which require a redo in some cases.
Size matters
However, it’s not just that more requests are being made — the projects are bigger than ever before.
The size and capacity of renewable plants has steadily climbed since 2015. The mean solar plant requesting grid interconnection in 2023 was over 250% larger than in 2015; standalone battery plants grew 330% bigger in the same time period. Though wind plant growth was less significant, the mean wind capacity also jumped 66%.
The bigger a project is, the more likely it is to stall in the queue — and to stay there longer. The average time between making an interconnection request and coming online increases monotonically by project size, meaning that connection time always grows, no matter how large a project gets.
Image credit: LBNL
20 MW is essentially the cutoff point; anything smaller than 20 MW takes 11 – 18 months on average to go from start to finish. Anything larger than 20 MW jumps to 30 months or more, the report found. Over 100 MW? You’re looking at a median of 4+ years from request to commercial operations. The average 200+ MW project takes over 55 months.
The report also notes that 49% of the total capacity in grid interconnection queues — or 1,271 GW — has a proposed commercial operations date by the end of 2026. Only 311 GW, representing 12% of the total capacity, already has a finalized interconnection agreement. Though withdrawals of projects in the interconnection agreement phase are less common, they appear to be on the rise.
“[These] late-stage withdrawals can be more costly for developers (sunk costs, deposits) and can trigger re-studies for other projects in the queue, increasing delays,” the report said.
Still, policy can help ease developer worries.
The Inflation Reduction Act and other favorable policies for renewable deployment are spurring a jump in grid interconnection requests. Since the passage of the IRA, over 1,200 GW have requested interconnection to the grid. Fewer than one hundred have been withdrawn.
The report authors note that “although not all of the post-IRA interconnection requests can be attributed to the IRA, these provisions increased developer interest in clean energy and the queues are one indicator of this.”
Editor’s note: This story was updated on March 6, 2025 to reflect additional analysis from Bianca Giacobone. The introduction section was updated, and the section titled “Dropping completion rates” was added, as well as the first and third charts. The title was updated (from “Large solar hybrid projects are surging — and so are wait times for grid connection” to “The US interconnection queue is twice its installed capacity”) and Bianca was added as a co-author.
