A private start-up called Helion aims to have a working fusion reactor by 2028

Building a working nuclear fusion reactor has proven to be a daunting challenge even for multiple wealthy nations, as we’ve seen with the much-delayed ITER project. However, a private start-up called Helion thinks it can build one and start supplying energy by 2028 by taking a different approach than other reactors.

Founded in 2013, Helion is in the news thanks to a $425 million funding round, backed by billionaires like Sam Altman and Peter Thiel. With more than $1 billion raised, the company is now valued at $5.4 billion.

Nuclear fusion, which combines hydrogen atoms to form helium, is the holy grail for green energy. It’s carbon free, and unlike current nuclear plants, produces no long-term radioactive waste. At the same time, reactors could produce enough electricity to power small cities.

Sustained fusion reaction that produces more energy that it consumes has never happened, though. The largest project, ITER (International Thermonuclear Experimental Reactor), is projected to cost up to $22 billion and won’t go online until at least 2034 — and still hasn’t produced a sustained reaction. The longest fusion reaction is 1,066 seconds (17 minutes and 43 seconds), set just recently by the EAST reactor in China.

So how does Helion think it can succeed? Most experimental reactors compress plasma using magnetic or inertial confinement, which heats it enough to spark a fusion reaction. Once that happens, the fusion-generated heat powers a steam turbine to generate electricity.

Helion is using a different approach by dispensing with the steam turbine. Fuel (deuterium and helium-3) is injected into both ends of the hourglass shaped reactor, then heated to form a plasma. Magnets form the plasma into a donut shape and fire them at each other at speeds up to 1 million MPH. They collide in the narrow middle section of the reactor and are further compressed by magnets there. That heats them up to the magic 100 million degrees Celcius, creating fusion.

“As the plasma expands, it pushes back on the magnetic field from the machine’s magnets,” Helion explains on its website. “By Faraday’s Law, the change in field induces current, which is directly recaptured as electricity, allowing Helion’s fusion generator to skip the steam cycle.”

This system is simpler and potentially more efficient than a steam turbine. However, while the company has achieved fast enough pulse rates to achieve fusion, it has only done so on a small scale to date. “There [are] some big engineering challenges to get to those high repetition rates at the kind of big pulse powers where we talk about millions of amps,” CEO David Kirtley told TechCrunch.

And that’s the rub with every other reactor. Fusion produces a huge surge of energy all at once and so far no one has been able to control and harness that. Helion thinks its simpler system will help, but has yet to prove it can do it experimentally, let alone commercially. Still, the company says its seventh-generation reactor, Polaris, is now “in operation” but has declined to share any results to date.