Fusion Power Might Not Get Cheap as Quickly as You Think

Fusion power has been the holy grail of clean energy for decades—limitless, zero-emissions electricity, no meltdowns, no long-lived radioactive waste. But a new study in Nature Energy throws a bucket of cold water on the idea that fusion will get cheap fast, even if we finally get plants built.

Technologies tend to follow a learning curve: as you deploy more of them, costs fall. Lithium-ion batteries are roughly 90% cheaper than they were in 2013. Solar modules have seen similar dramatic drops. But not everything follows that path. Nuclear fission, for example, has an experience rate of just 2%—meaning every time installed capacity doubles, costs only fall by 2%. That’s glacial.

The researchers behind this new paper wanted to figure out where fusion might land on that spectrum. They interviewed fusion experts—both from public labs and private companies—and asked them to rate fusion power plants on three factors that correlate with experience rates: unit size, design complexity, and how much customization each plant needs.

Fusion plants are going to be big. They generate heat, so they’ll resemble coal or fission plants in scale. They’ll likely need less customization than fission plants (simpler regulations, fewer safety headaches), but far more than something like a solar panel. And complexity? Almost unanimous agreement that fusion is “incredibly complex.” One expert literally said it was off the scale the researchers gave them.

Putting all that together, the researchers landed on an experience rate between 2% and 8%. That’s faster than fission, but way slower than solar (23%) or batteries (20%). It’s also significantly lower than the 8% to 20% that many energy modeling studies currently assume for fusion.

What does that mean in practice? It means that even if fusion works, it would take a lot of deployment—and probably a lot of time—for the cost of building reactors to drop meaningfully. Electricity from fusion could stay expensive for a long while.

Lingxi Tang, a PhD candidate at ETH Zurich and one of the study’s authors, raises a pointed question: “If you’re talking about decarbonization of the energy system, is this really the best use of public money?” The US allocated over $1 billion to fusion in fiscal 2024, and private-sector funding hit $2.2 billion between July 2024 and July 2025. That’s a lot of cash for a technology that might not deliver cheap power anytime soon.

But I’ve been around long enough to know that predicting technology costs is a fool’s game. Egemen Kolemen, a professor at the Princeton Plasma Physics Laboratory, makes exactly that point: in 2000, most analysts thought solar would stay expensive, and then China went all in and prices crashed. “People weren’t exactly wrong then,” he says. “They were just extrapolating what they saw into the future.”

He’s right. How fast fusion costs drop depends on regulations, geopolitics, labor costs, and a dozen other things we can’t foresee. We haven’t built the thing yet. We don’t know.

Still, this study is a useful reality check. Fusion advocates often talk about it as if it’s destined to follow solar’s trajectory, but the physics and engineering are fundamentally different. A fusion reactor isn’t a silicon wafer you can stamp out by the millions. It’s a complex, bespoke machine that needs to contain a star. That’s not a recipe for rapid cost decline.

None of this means fusion is a dead end. It could still play a role in a decarbonized grid, especially if we need baseload power that renewables can’t provide. But if you’re betting on fusion to save us from climate change at a reasonable price, you might want to hedge your bets.