Large solar hybrid projects are surging — and so are wait times for grid connection

The average renewable energy project that came online in 2023 languished for five years in the grid interconnection queue, a new report from the Lawrence Berkeley National Laboratory found. 

And that wait time is still rising. 

• The top line: An influx of clean electricity is on the way, but a congested interconnection queue means it’s taking longer and longer to get that power to the grid. Compared to 2008, renewable energy projects are spending more than twice as much time waiting to connect to the grid. Despite strong development activity in solar, storage, and wind –  which together make up 95% of the active queue capacity – project completion rates are falling fast nationwide. 
• The market grounding: The active generation and storage capacity in the queue (2,600 gigawatts) is more than double the installed capacity of the entire United States power grid, or 1,280 GW. Nearly 12,000 projects are actively seeking interconnection; the longer a project is left in limbo, the authors found, the more likely it is to be withdrawn. In 2023 alone, over 1,250 interconnection requests were pulled out of line. And, with only 19% of interconnection requests submitted between 2000 - 2018 being built by the end of last year, the odds are stacked against developers. 

Given that each of the nation’s seven RTOs uses a different interconnection process, pushing a project from start to finish can take much more time than initially expected. 

Annual interconnection requests have been on the rise since 2013. Over 900 GW joined the queue in 2023 alone. And, it’s not just that more requests are being made – the projects are bigger than ever before. 

An increasing number of hybrid plants — those that combine two or more types of power generation or storage — is likely also bumping up the wait time. 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. 

Hybrid plants do have greater dispatch flexibility. Still, hybridization can decrease interconnection capacity limits and can be subject to stricter permitting and regulatory review. 

Nationwide, 20% of all proposed solar plants are hybrids, with 98% of solar in CAISO’s queue and 81% of solar in the non-ISO West queue being hybridized. Compared to wind or gas projects, which historically have ranged from 20-31% average completion rates, solar and battery projects have lower rates of 13 and 11% respectively.

Size matters

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. 

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.”