Fusion Power Probably Won’t Get Cheap Fast—Here’s Why

Fusion power has been the great “maybe” of clean energy for decades. Steady, zero-emissions electricity, no meltdown risk, fuel from seawater. The pitch writes itself. But a new study from researchers at ETH Zurich throws cold water on one of the core assumptions: that fusion will get cheap quickly.

The problem is a metric called the experience rate. It measures how much costs drop every time installed capacity doubles. Solar modules have an experience rate around 23%. Lithium-ion batteries sit at about 20%. Onshore wind is at 12%. These technologies have gotten dramatically cheaper as we’ve built more of them.

Fission nuclear power? Its experience rate is just 2%. That’s essentially flat. More plants, same price. The new study, published in Nature Energy, suggests fusion will land somewhere between 2% and 8%. Better than fission, but nowhere near solar or batteries.

The researchers arrived at this by having fusion experts evaluate three characteristics that historically correlate with slow cost declines: unit size, design complexity, and need for customization. Fusion plants will be large—think coal or fission plant scale. They’ll need less customization than fission because regulations should be simpler, but more than solar panels. And on complexity, the experts were nearly unanimous: fusion is brutally hard. Some literally said it was off the scale the researchers gave them.

That 2-8% range is sobering because many energy modeling studies currently assume fusion will have an experience rate of 8% to 20%. The difference matters when you’re talking about billions in investment. The US government allocated over $1 billion to fusion in fiscal 2024. Private funding hit $2.2 billion between July 2024 and July 2025.

Lingxi Tang, one of the study’s authors, puts it bluntly: “If you’re talking about decarbonization of the energy system, is this really the best use of public money?”

I get the appeal of fusion. It’s elegant. It’s the literal power of the sun. But the history of energy is littered with technologies that looked great on paper and never got cheap. The study doesn’t say fusion won’t work. It says that even if it works, it might not be cheap enough to matter much.

Of course, there’s a counterargument. Egemen Kolemen from Princeton Plasma Physics Lab points out that in 2000, analysts thought solar would stay expensive. Then China ramped up production and prices collapsed. “People weren’t exactly wrong then,” he says. “They were just extrapolating what they saw into the future.”

Fair point. But solar had advantages fusion doesn’t: small unit size, modular design, relatively simple manufacturing. Fusion reactors are bespoke engineering projects. They don’t scale the same way.

The honest answer is we don’t know. We haven’t built a working fusion plant yet. But the smart money probably shouldn’t assume fusion will save us from hard decarbonization choices. It might help eventually. It might not. Betting the farm on it seems reckless.