Clean Energy
Gridlock: Visualizing the U.S. Clean Energy Backlog
The following content is sponsored by the National Public Utilities Council
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- Withdrawal rates: Historically, most projects have withdrawn from the queue, with just 21% of projects seeking connection from 2000–2017 reaching commercial operation.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.
| Energy Source | Capacity in Interconnection Queues (MW) | % of Total |
|---|---|---|
| Solar | 947,452 | 49% |
| Battery Storage | 682,782 | 35% |
| Wind | 186,144 | 10% |
| Offshore Wind | 114,006 | 6% |
| Total | 1,930,384 | 100% |
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:
| ISO/Transmission Region | Clean Energy Capacity in Interconnection Queues (MW) | % of Total |
|---|---|---|
| West (non-ISO) | 578,937 | 30% |
| Midcontinent ISO (MISO) | 321,723 | 17% |
| PJM (RTO) | 284,384 | 15% |
| Electric Reliability Council Of Texas (ERCOT) | 207,808 | 11% |
| California ISO (CAISO) | 196,792 | 10% |
| New York ISO (NYISO) | 108,163 | 6% |
| Southern Power Pool (SPP) | 105,398 | 5% |
| Southeast (Non-ISO) | 92,956 | 5% |
| New England ISO (ISO-NE) | 34,223 | 2% |
| Total | 1,930,384 | 100% |
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.
Learn more about how electric utilities and the power sector can lead on the path toward decarbonization here.
Clean Energy
Which U.S. Utilities Are Investing in Clean Energy the Most?
In this graphic, we show which U.S investor-owned utilities have allocated the most capital expenditure toward clean energy.
Which U.S. Utilities Are Investing in Clean Energy the Most?
Decarbonizing the power sector will require significant investments in clean energy as utilities replace existing fossil fuel infrastructure.
In this graphic, we show which U.S investor-owned utilities (IOUs) have allocated the most capital expenditure (CAPEX) toward carbon-free sources of electricity.
The data comes from the latest edition of the Annual Utility Decarbonization Index, created in partnership with the National Public Utilities Council, which quantifies and compares the status of decarbonization among the largest U.S. IOUs.
The Carbon-Free Investment Ranking
The Utility Decarbonization Index ranks companies on six metrics based on the latest available data, specifically those that pertain to their fuel mix, carbon emissions, and decarbonization goals.
The sixth and final metric measures the share of each utility’s planned CAPEX for carbon-free electricity generation, such as nuclear power and renewables.
Here are the top scorers out of the 47 IOUs included in the report.
| Rank | Company | Share of Planned Generation CAPEX Allocated To Nuclear & Renewables |
|---|---|---|
| #1 | NextEra Energy | 100% |
| #2 | Public Service Enterprise Group | 100% |
| #3 | Avangrid | 100% |
| #4 | Pacific Gas and Electric* | 96% |
| #5 | Alliant Energy | 94% |
| #6 | National Grid | 93% |
| #7 | AES Corporation | 92% |
| #8 | Constellation Energy | 90% |
| #9 | WEC Energy | 90% |
| #10 | Emera | 86% |
| #11 | Dominion Energy* | 84% |
| #12 | American Electric Power | 83% |
| #13 | TransAlta | 81% |
| #14 | MGE Energy | 78% |
| #15 | Duke Energy | 68% |
| #16 | Evergy | 68% |
| #17 | DTE Energy Company | 67% |
| #18 | Fortis Inc. | 67% |
| #19 | Consumers Energy | 66% |
| #20 | Southern Company | 63% |
*Planned CAPEX unreported, shows 2022 realized CAPEX
Avangrid climbed to first place in 2022, tying with NextEra and PSEG, who both maintained their 100% carbon-free investment plans from 2021. This marks an improvement from Avangrid’s 98% the year prior.
Meanwhile, National Grid pulled off the most significant percentage increase, from 3% to 93% from 2021 to 2022.
Overall, carbon-free investment is up 3 percentage points year-over-year from 63% to 66% for the top 47 IOUs.
Which Utilities Are Included in the Decarbonization Index?
The IOUs ranked in this year’s Utility Decarbonization Index are the 47 largest in the U.S. by their 2022 net owned and purchased electricity generations.
U.S. IOUs that had fewer than 2 million megawatt-hours (MWh) of owned generation were excluded from the report.
The 47 IOUs featured in the Index accounted for over two-thirds of the nation’s electricity generation in 2022. As a result, these utilities’ decarbonization efforts will significantly impact the 33% of U.S. emissions that come from the power sector.
Download the 2024 Annual Utility Decarbonization Report
In addition to the Decarbonization Index, there’s much more to explore in the 2024 report, including:
- Inflation Reduction Act impacts
- Market trends
- Year-to-year progressions
- Fuel mix rankings for the largest public utilities
- Gas utility emissions rankings
Are you interested in seeing the rest of the rankings? Download the 2024 NPUC Annual Utility Decarbonization Report now.
Clean Energy
Visualized: Renewable Energy Capacity Through Time (2000–2023)
This streamgraph shows the growth in renewable energy capacity by country and region since 2000.
Visualized: Renewable Energy Capacity Through Time (2000–2023)
Global renewable energy capacity has grown by 415% since 2000, or a compound annual growth rate (CAGR) of 7.4%.
However, many large and wealthy regions, including the United States and Europe, maintain a lower average annual renewable capacity growth.
This chart, created in partnership with the National Public Utilities Council, shows how each world region has contributed to the growth in renewable energy capacity since 2000, using the latest data release from the International Renewable Energy Agency (IRENA).
Renewable Energy Trends in Developed Economies
Between 2000 and 2023, global renewable capacity increased from 0.8 to 3.9 TW. This was led by China, which added 1.4 TW, more than Africa, Europe, and North America combined. Renewable energy here includes solar, wind, hydro (excluding pumped storage), bioenergy, geothermal, and marine energy.
During this period, capacity growth in the U.S. has been slightly faster than what’s been seen in Europe, but much slower than in China. However, U.S. renewable growth is expected to accelerate due to the recent implementation of the Inflation Reduction Act.
Overall, Asia has shown the greatest regional growth, with China being the standout country in the continent.
| Region | 2000–2023 Growth | 10-Year Growth (2013–2023) | 1-Year Growth (2022–2023) |
|---|---|---|---|
| Europe | 313% | 88% | 10% |
| China | 1,817% | 304% | 26% |
| United States | 322% | 126% | 9% |
| Canada | 57% | 25% | 2% |
It’s worth noting that Canada has fared significantly worse than the rest of the developed world since 2000 when it comes to renewable capacity additions. Between 2000 and 2023, the country’s renewable capacity grew only by 57%.
Trends in Developing Economies
Africa’s renewable capacity has grown by 184% since 2000 with a CAGR of 4%.
India is now the most populous country on the planet, and its renewable capacity is also rapidly growing. From 2000–2023, it grew by 604%, or a CAGR of 8%.
It is worth remembering that energy capacity is not always equivalent to power generation. This is especially the case for intermittent sources of energy, such as solar and wind, which depend on natural phenomena.
Despite the widespread growth of renewable energy worldwide, IRENA emphasizes that global renewable generation capacity must triple from its 2023 levels by 2030 to meet the ambitious targets set by the Paris Agreement.
Learn how the National Public Utilities Council is working toward the future of sustainable electricity.
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