Nearly 1TW of renewables in US interconnection queues as wait times continue to grow

Facebook
Twitter
LinkedIn
Reddit
Email
Solar and storage have some of the worst interconnection rates, while wait times for all forms of power generations are on the rise. Image: Unsplash.

There was almost 1TW of renewable energy capacity and an estimated 427GW of storage active in US interconnection queues at the end of 2021 according to a Lawrence Berkeley National Laboratory (LBNL) analysis, which also showed that queues were growing year-on-year.

In total, over 930GW of zero-carbon generating capacity is currently seeking transmission access. Solar accounts for a record 676GW of this generation – beating the previous record of 462GW at the end of 2020 – and wind power makes up 247GW. Fossil fuels looking to connect are on the decline, however, with 75GW of natural gas and less than 1GW of coal currently proposed.  

This article requires Premium SubscriptionBasic (FREE) Subscription

Unlock unlimited access for 12 whole months of distinctive global analysis

Photovoltaics International is now included.

  • Regular insight and analysis of the industry’s biggest developments
  • In-depth interviews with the industry’s leading figures
  • Unlimited digital access to the PV Tech Power journal catalogue
  • Unlimited digital access to the Photovoltaics International journal catalogue
  • Access to more than 1,000 technical papers
  • Discounts on Solar Media’s portfolio of events, in-person and virtual

Or continue reading this article for free

Solar and battery storage are by far the fastest growing resources in the queues – together accounting for 85% of new capacity entries in 2021 –  but have some of the lowest completion rates, LBNL said. Clean energy organisations have long been calling for system reform to help more solar and storage get connected.

Meanwhile, hybrid projects comprise a large and growing share of proposed capacity, particularly in CAISO and the non-ISO West, LBNL said, adding that 286GW of solar hybrids (primarily solar-plus-battery storage) and 19GW of wind hybrids are currently active in the queues.

“Nearly half of the battery storage capacity in the queues is paired with some form of generation (mostly solar),” LBNL said.

Interconnection queues indicate that commercial interest in solar and storage has grown significantly. Source: LBNL.

Much of this proposed capacity will ultimately not be built, however, with only 23% of projects seeking connection from 2000 to 2016 having subsequently been built based on a LBNL analysis of a subset of queues. Only ISO-NE and ERCOT exceeded 30% completion rates, with CAISO performing the worst at 13%.  

LBNL found that interconnection wait times are also on the rise. In the regions with available data, the typical duration from connection request to commercial operation increased from around 2.1 years for projects built in 2000-2010 to roughly 3.7 years for those built in 2011-2021.

In February, a coalition of three clean energy trade associations called on the US Federal Energy Regulatory Commission (FERC) to make interconnection reform a top priority to reduce the backlog of projects waiting to connect to the country’s grid.

“Interconnection backlogs are one of the biggest impediments to our ability to quickly and efficiently decarbonise our electricity grid in the near term,” Sean Gallagher, vice president of state and regulatory affairs at SEIA said in February.

Proposed capacity by generation source varies across US regions, although solar is the dominant form in most areas. Source: LBNL.

Furthermore, ‘completion percentages’ of projects looking to connect appear to be declining and are even lower for wind and solar than other resources, LBNL said.

LBNL analysed interconnection queue data from all seven ISOs/RTOs in concert with 35 non-ISO utilities, representing over 85% of the total US electricity load.

In the US, electric transmission system operators (ISOs, RTOs or utilities) require projects seeking to connect to the grid to undergo a series of impact studies before they can be built. 

Most projects that apply for interconnection are ultimately withdrawn and those that are built are taking longer on average to complete the required studies and become operational, LBNL said.

Earlier this week, the North American Electric Reliability Corporation (NERC) wrote for PV Tech Premium about the key considerations – and difficult balance – of managing grid connection from a transmission operators point of view.

7 October 2025
San Francisco Bay Area, USA
PV Tech has been running an annual PV CellTech Conference since 2016. PV CellTech USA, on 7-8 October 2025 is our third PV CellTech conference dedicated to the U.S. manufacturing sector. The events in 2023 and 2024 were a sell out success and 2025 will once again gather the key stakeholders from PV manufacturing, equipment/materials, policy-making and strategy, capital equipment investment and all interested downstream channels and third-party entities. The goal is simple: to map out PV manufacturing in the U.S. out to 2030 and beyond.
21 October 2025
New York, USA
Returning for its 12th edition, Solar and Storage Finance USA Summit remains the annual event where decision-makers at the forefront of solar and storage projects across the United States and capital converge. Featuring the most active solar and storage transactors, join us for a packed two-days of deal-making, learning and networking.
16 June 2026
Napa, USA
PV Tech has been running PV ModuleTech Conferences since 2017. PV ModuleTech USA, on 16-17 June 2026, will be our fifth PV ModulelTech conference dedicated to the U.S. utility scale solar sector. The event will gather the key stakeholders from solar developers, solar asset owners and investors, PV manufacturing, policy-making and and all interested downstream channels and third-party entities. The goal is simple: to map out the PV module supply channels to the U.S. out to 2027 and beyond.

Read Next

June 30, 2025
Australian module manufacturer Tindo Solar has secured a 30MW solar module supply agreement to power Australia's first "net zero pipeline”.
June 27, 2025
Renewables investment platform Nexwell Power has signed a round of power purchase agreements (PPAs) with “one of the largest” US tech companies for solar PV capacity to be built in Spain.
June 26, 2025
A round-up of news from the US solar sector this week, including Akuo, Meta and RWE.
June 26, 2025
A group of minority shareholders in Norwegian silicon firm REC Silicon has triggered an investigation into the circumstances surrounding the closure of the company’s US polysilicon production site.
June 26, 2025
Nextracker will supply solar tracker systems to a 550MW solar PV project in the Greek province of Western Macedonia, owned by Greek renewables developer PPC Renewables.
June 26, 2025
Adapture Renewables and Meta have signed two EAPAs that will see the latter acquire power from a 360MW Texas solar portfolio.

Subscribe to Newsletter

Upcoming Events

Upcoming Webinars
June 30, 2025
10am PST / 6pm BST
Solar Media Events
July 1, 2025
London, UK
Solar Media Events
July 1, 2025
London, UK
Media Partners, Solar Media Events
July 2, 2025
Bangkok, Thailand
Media Partners, Solar Media Events
September 2, 2025
Mexico City, Mexico