Scientists and Startups Close to Demonstrating Practical Nuclear Fusion — Major Hurdles Remain

Startups Near Public Fusion Demonstrations, But Challenges Persist

Startups and research teams are approaching the point where they can publicly demonstrate nuclear fusion that resembles the thermonuclear reactions that power stars. The idea of "creating a working star on Earth" may sound fantastical, but recent experiments and heavy private investment have pushed the concept closer to reality.

What Fusion Is And Why It Matters

Nuclear fusion merges light atomic nuclei to form heavier nuclei, releasing large amounts of energy — the same process that powers the sun. The International Atomic Energy Agency (IAEA) says that if fusion can be replicated at industrial scale, it could become a virtually limitless, low‑carbon source of electricity.

Recent Milestones

In December 2022, researchers reported an experiment that briefly produced more energy from fusion reactions than the energy delivered to the fuel capsule — a milestone often described as an important scientific breakthrough. However, that result did not mean a commercial power plant was imminent: the overall energy input to the facility and plant‑level economics remain far from demonstrated.

Why It's So Difficult

Fusion requires heating a small volume of gas to extreme temperatures — typically above 100 million °C on Earth — so the gas becomes a plasma (electrons stripped from atoms) and nuclei can overcome their mutual repulsion and fuse. Because the plasma is fragile, it must be confined at high temperature and pressure for sufficient time to produce net energy. As The New York Times put it, the plasma is so delicate "you could snuff it out by blowing on it," which is why researchers use enormous magnets, lasers, or other confinement approaches.

"First you need to heat a puff of gas to unimaginable temperatures, over 100 million degrees Celsius... Make your plasma hold onto this heat for long enough, and at high enough pressure, and more energy comes out than you put in to heat it up."

Approaches Under Development

Most large demonstrations use tokamaks — torus‑shaped magnetic confinement devices — which are proven scientifically but complex and costly to build and operate. Private companies are exploring a variety of alternative approaches: stellarators (twisted magnetic geometries designed for steadier confinement), sheared plasma filaments driven by electric currents, and mechanical compression of plasma with pistons and shock waves. Each approach carries different technical tradeoffs and development risks.

Economic And Materials Challenges

Critics caution that even if the physics is solved, the path to commercial fusion plants faces substantial obstacles: timelines that could still span decades, very high capital costs, and engineering challenges such as materials that must tolerate intense neutron flux and heat loads. While fusion generally produces far less of the long‑lived radioactive waste associated with fission, component activation and materials longevity remain important issues for designers and regulators.

Investment And The Road Ahead

High‑profile investors including Bill Gates and Jeff Bezos have backed fusion startups with hundreds of millions of dollars, accelerating private R&D. Still, experts emphasize that demonstration of a sustained, net‑positive, economically viable power plant is the next critical step. As Richard Magee of TAE Technologies put it, "It's kind of the wild west right now. It's going to be really interesting to see who's still standing in 10 years."

Fusion offers an attractive long‑term possibility for low‑carbon energy, but policymakers, investors and the public should weigh realistic timelines, costs and engineering challenges against urgent climate and energy needs.