Chart: The US clean energy backlog is getting bigger and bigger

Energy developers are more eager than ever to build new solar, wind, and battery projects in the U.S.

As of December 2023, proposed projects encompassing nearly 2,600 gigawatts (GW) — or 2.6 terawatts — were making their way through the series of studies and steps required to plug into the power grid, according to a new report from Lawrence Berkeley National Laboratory. Almost all of this backlog, known as the interconnection queue, consists of clean energy — and it’s mostly from solar and batteries.

At 2.6 terawatts, the interconnection queue is now about double the size of the entire existing U.S. electrical grid. The problem has swelled in recent years as emissions reduction goals, clean energy subsidies, and falling costs have spurred unprecedented interest in building renewable power. In 2023, a typical project took nearly five years to make it through the queue. In 2015, that figure was just three years.

To be clear, the vast majority of these power plants will never get built; the project completion rate between 2000 and 2018 was just 19 percent. But even at that rate, we’re talking about hundreds of gigawatts’ worth of solar, wind, and grid battery projects that are plodding through the interconnection queue when the country needs the exact opposite — a rapid expansion of clean energy — to hit its goal of building a completely carbon-free grid by 2035. Meeting that goal requires adding between 43 and 90 gigawatts of solar and 70 to 145 gigawatts of wind each year between now and 2030, according to a study from the National Renewable Energy Laboratory — a fourfold increase over today’s pace.

Last July, the Federal Regulatory Energy Commission approved a broad set of reforms aimed at modernizing and speeding up the interconnection process, a move then chair Willie Phillips described as the ​“largest and most significant set of interconnection reforms” in the past two decades. Clean energy groups applauded the new rules but noted that the country still needs to fix the biggest issue causing the interconnection bottleneck: The U.S. just isn’t building enough power lines to carry all that new electricity. Most recently, the Department of Energy released a sprawling roadmap that sketches out the pathway to fixing the interconnection backlog.

Despite the backlog, clean energy is still the fastest-growing source of electricity in the U.S. by a long shot. But imagine, given the terawatts’ worth of pent-up demand, how much more rapidly it could grow — and how much more gas and coal it could displace — if the interconnection queue could be made to move faster.

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