Fusion: where it really stands
Fusion is how the sun makes energy: light atoms join and release enormous energy. It has made real progress, but no machine has yet put net electricity on the grid. Here is what is proven, what isn't, and when to expect it.
Plain-English explainer by Joe Miller, a nuclear engineer. Not investment advice. Figures are the latest public numbers we could find and change fast; sources are at the bottom of each page.
10. Fusion
How it works: Joins light atoms, forms of hydrogen, at over 100 million degrees, the way the sun does, instead of splitting heavy ones.
Strengths: No chain reaction to run away, no meltdown, and no long-lived high-level waste; fuel from seawater and lithium.
Weak spots: No machine has yet made more electricity than it uses. Materials, tritium supply and cost are unsolved.
Where you'll find it: Lawrence Livermore's NIF reached ignition in 2022 (8.6 MJ record in 2025); Commonwealth Fusion's SPARC is about 80% built, aiming at first plasma in 2027; Helion is building a plant for Microsoft with a 2028 target; ITER in France plans research operations around 2034.
| Project | Who | Status (late 2026) |
|---|---|---|
| NIF (laser fusion) | Lawrence Livermore National Laboratory | Ignition in December 2022: more fusion energy out than laser energy in at the target; record 8.6 MJ in April 2025. Not a power plant. |
| SPARC (tokamak) | Commonwealth Fusion Systems | About 80% built in August 2026; first plasma targeted for 2027. A test machine aiming to show net fusion gain. |
| Polaris and Orion | Helion (Microsoft deal) | Polaris reported about 150 million °C and deuterium-tritium fusion in 2026. Orion plant under construction in Malaga, Washington, with a 50-MW target in 2028, a contract goal, not yet demonstrated. |
| ITER (tokamak) | 35 nations, France | Research operations around 2034; deuterium-tritium from 2035. Aims at 500 MW of fusion from 50 MW of heating, but will not make electricity. |
My take
Fusion has gone from "always 30 years away" to real hardware and real milestones. But making net electricity, reliably, for decades, at a competitive price is a much harder engineering problem than reaching ignition once. I'd watch SPARC in 2027 and Helion in 2028, and plan on fusion at scale in the 2040s. In the meantime, fission carries the load. See the other nine reactor types.
Sources
Checked November 15, 2026.