Artificial Sun Hits Key Milestone, Heating Up Race for Clean Energy

A commercial “artificial sun,” or tokamak, has achieved a world-first for a private company, generating plasma at 180 million degrees Fahrenheit, which is the temperature at which fusion can take place.

UK-based Tokamak Energy announced that its privately funded ST40 spherical tokamak had achieved an important temperature milestone on Thursday, calling it “the threshold required for commercial fusion energy.”

World-first “artificial sun” hits key milestone, heating up race for clean energy

Even though several government-funded fusion experiments, such as the Korea Superconducting Tokamak Advanced Research, have hit this temperature milestone, this is the first time a private fusion company has done the same.

“We are proud to have achieved this breakthrough which puts us one step closer to providing the world with a new, secure, and carbon-free energy source,” said Tokamak Energy CEO Chris Kelsall in a statement.

The process is almost the opposite of nuclear fission, which powers current nuclear plants and takes heavy elements and splits them into smaller atoms. The current process uses precursors to the these reactions, such as uranium, but they are expensive — and, with the by-products being radioactive, it makes them difficult to dispose of and not practical on a large scale, for global use.

Fusion, on the other hand, uses heavy hydrogen or deuterium as a precursor to reactions, something that can be extracted from seawater. And, with the by-product of the fission reaction being helium, it is a clean process as well.

Tokamaks must be hotter than the Sun

At the heart of stars, the immense gravitational pressure of these massive stellar bodies overcomes the repulsion between hydrogen ions — atoms that have been stripped of electrons leaving them with a positive charge — forcing them together, resulting in the fusion of hydrogen atoms thus creating helium, with the difference in mass released as energy.

The immense gravitational forces generated by stars cannot be replicated on Earth, meaning higher temperatures are required to drive together hydrogen in the plasma generated in tokamaks.

The center of the Sun, where hydrogen fusion takes place, has an estimated temperature of around 27 million degrees Fahrenheit, meaning that the optimal temperature for fusion to take place in tokamaks is about seven times greater than those at the heart of the Sun — roughly 180 million degrees Fahrenheit.

Tokamaks need more than superheated temperatures, as they also depend on powerful magnets to constrain and contain this plasma. Tokamak Energy says that their machine, the ST40 spherical tokamak, will now be upgraded to include high-temperature superconducting (HTS) magnets.

“When combined with HTS magnets, spherical tokamaks represent the optimal route to achieving clean and low-cost commercial fusion energy,” Kelsall said. “Our next device will combine these two world-leading technologies for the first time and is central to our mission to deliver low-cost energy with compact fusion modules.”

The device will serve as a template for the development of future fusion technology and advancements that Tokamak Energy said will form the basis of the design of a world-first fusion pilot plant, set to be commissioned in the early 2030s.