Gridlock: Visualizing the U.S. Clean Energy Backlog

The U.S. has almost 2 million megawatts (MW) of solar, wind, and storage capacity on hold in interconnection queues, seeking connection to the electrical grid.

However, the lack of transmission infrastructure, in addition to a lengthy permitting process, has resulted in a bottleneck of clean energy projects awaiting approval before they can be plugged into the grid.

This infographic sponsored by the National Public Utilities Council maps U.S. clean energy capacity in interconnection queues by transmission region, based on data from the Berkeley Lab.

But before we dive into the data, let’s fully understand what interconnection queues mean.

What are Interconnection Queues?

Before new power plants can be built and connected to the grid, they go through a series of impact assessments to ensure safety and reliability. The projects in this process form grid interconnection queues, which are essentially waitlists of proposed power plants seeking grid connection.

Here are some of the problems associated with U.S. interconnection queues:

• Wait times: The average time projects spend in the queue is up from 2.1 years in 2000 to 3.7 years in 2021, according to the Energy Transitions Commission. 
• Withdrawal rates: Historically, most projects have withdrawn from the queue, with just 21% of projects seeking connection from 2000–2017 reaching commercial operation.
• Aging transmission: The U.S. grid is aging, and queued-up projects can end up facing large fees from the updates required to transmission infrastructure.

Although the backlog is alarming, the interconnection queues also show that project developers are invested in the clean energy transition. In fact, the amount of clean energy capacity in interconnection queues exceeds the amount needed to get to 90% zero-carbon electricity by 2035, according to Berkeley Lab.

U.S. Clean Energy in Queues

Solar and battery storage projects account for the majority of capacity in interconnection queues, followed by wind.

Data as of the end of 2022.

Notably, 48% of all solar capacity in the queues is proposed as a “hybrid plant” that combines generation with battery storage. Similarly, over half of all battery storage capacity is proposed with some amount of generation.

The large number of hybrid and storage configurations show that project developers are addressing the intermittent nature of renewables by combining generation with storage.

Interconnection queues are managed by Independent System Operators (ISOs) and Regional Transmission Organizations (RTOs) that operate the grid and wholesale electricity markets in different regions. Here’s a look at the clean energy capacity in queues grouped by major transmission regions and ISOs:

Data as of the end of 2022. Percentages may not add up to 100 due to rounding. 

Overall, the West (non-ISO) region has the most solar (254 GW), battery (262 GW), and onshore wind (63 GW) capacity in interconnection queues. Offshore wind capacity is highest in New York (63 GW), managed by the NYISO.

In 2022, California ISO did not accept any new interconnection requests due to the backlog from 2021. Meanwhile, the PJM announced that it would not review any new requests until 2025. Despite these slowdowns, over 700 GW of capacity was added to U.S. interconnection queues in 2022.

Unlocking the Gridlock

Given the current backlog, along with the incentives for new clean energy projects in the Inflation Reduction Act, clearing the gridlock is now more important than ever.

The large backlog, long wait times, and high withdrawal rates highlight the growing challenges in interconnection and transmission. Among other longer-term solutions, there are two ways to alleviate the gridlock:

• Expanding high-voltage transmission lines: Many solar and wind projects are located in remote areas and require high-voltage transmission lines to carry electricity to cities. Expanding the transmission network can allow more projects to connect to the grid.
• Streamlined permitting: Interconnection processes and the reviews involved are long and costly for project developers. Reforming processes and streamlining permits can help in shortening the wait times for projects in queues.

To address this problem, some grid operators have already made changes to their interconnection processes. Additionally, the Department of Energy has launched the Interconnection Innovation Exchange (i2X) in an effort to improve collaboration and transparency in interconnection.

History shows that most of the projects in interconnection queues will ultimately not be built. However, what’s clear is that the U.S. is on the road to decarbonization, and energy project developers are focusing on clean energy sources for the future.

The 2022 Energy Crisis: A Tipping Point for Clean Energy

The global energy crisis of 2022 sent shockwaves in the energy markets.

The crisis acted as a double-edged sword—on one hand, consumers felt the pinch of rising energy prices, but on the other hand, it became a turning point for clean energy, spurring action from governments to cut dependence on fossil fuels.

This infographic from the National Public Utilities Council explores how the energy crisis accelerated the growth of clean energy and nuclear power.

Shockwaves From the Energy Crisis

Although the consequences of the crisis were felt in 2022, its roots go back to 2020 when energy demand dipped during the pandemic.

Following the unprecedented fall in demand, energy markets tightened in 2021 as the global economy rebounded to grow at the fastest pace since 1973. Russia’s invasion of Ukraine escalated the situation, creating a full-scale energy crisis.

As a result, energy prices soared to their highest levels in decades, resulting in rampant inflation worldwide. This highlighted how many nations remained dependent on fossil fuels for energy, in turn creating a tipping point for clean energy.

Clean Energy Turns the Corner

Countries including the United States, the UK, and many EU member states have supercharged clean energy investment over the last two years, partly in response to the energy crisis.

Here’s how global government spending for clean energy has grown since July 2021, as tracked by the IEA:

• $380 billion as of July 2021
• $470 billion as of October 2021
• $714 billion as of March 2022
• $1,215 billion as of November 2022

European countries deployed funding for energy efficiency and low-carbon power generation (through REPowerEU) in response to natural gas supply disruptions from Russia. In August of 2022, the U.S. signed the Inflation Reduction Act into law, providing over $390 billion in clean energy and climate funding.

Consequently, clean energy technologies are growing at an unprecedented rate. The IEA forecasts that global renewable electricity capacity additions from 2022 to 2027 (2,383 GW) will nearly equal all the renewable capacity added between 2001 and 2021 (2,409 GW).

Nuclear Turnaround

Besides renewables, nuclear power has seen a resurgence as governments look for a reliable energy source to replace fossil generation.

Here’s a look at the top 10 countries by the number of prospective nuclear reactors based on the Global Nuclear Power Tracker. This includes announced, pre-construction, and under-construction reactors.

Besides the countries building and planning reactors, others have reversed their plans to phase out nuclear power:

• Germany extended the lifetime of three plants that were set to shut down in 2022.
• France reversed course to reduce reliance on nuclear, with a plan to build six new reactors.
• Japan accelerated the restarts of nine reactors by winter 2022 and a further seven by summer 2023.

The impact of this accelerated clean energy deployment is already evident.

In 2022, the growth of clean energy technologies helped avoid 550 million tonnes of CO₂ emissions, according to the IEA. On the other hand, a decline in nuclear power generation led to an additional 55 million tonnes in CO₂ emissions, highlighting the importance of nuclear in reducing emissions.

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