Helion brings in $500M for its novel approach to nuclear fusion

Despite its theoretical promise, fusion has never been harnessed. Are VCs throwing billions at science fiction?
By Eric Wesoff

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Helion co-founders Chris Pihl and David Kirtley (Helion)

Fusion startup Helion Energy just announced the close of an astonishing Series E fundraising round that brought in $500 million, adding to the $78 million it had already raised.

Helion plans to build the first fusion device capable of demonstrating net electricity production by 2024, David Kirtley, founder and CEO of the company, told Canary Media in an interview.

It’s a bold claim, even in an industry built on bold claims.

Sam Altman, CEO of OpenAI and former president of Y Combinator, led the funding round and in a press release called Helion’s technology by far the most promising approach to fusion I’ve ever seen.”

Altman serves as Helion’s executive chair and has been involved with the firm since 2015. Existing investors Dustin Moskovitz, Mithril Capital and Capricorn Investment Group also participated in the round. An additional $1.7 billion of funding is being held in reserve by the investors, to be released as Helion reaches certain objectives.

Fusion fundamentals

Our sun performs the fusion trick by confining hydrogen and other nuclides with its own gargantuan gravity. Humans attempting to recreate the physics of the sun on Earth have to rely on massive magnets, mammoth laser arrays or other extreme means to compress and control the plasma.

Here are some fusion basics.

When heated to tens of millions of degrees Celsius, hydrogen changes from a gas to a plasma in which negatively charged electrons are separated from positively charged atomic nuclei. Plasma is considered to be a fourth state of matter, and it’s the medium in which fusion occurs.

Fusion machines compress and confine the plasma in order to bring nuclei so close as to overcome repellant electrostatic forces and allow the nuclei to fuse. Fusion occurs by virtue of the nuclear strong force and yields helium and energy in the form of neutrons.

Neutrons generated from a fusion reaction would be absorbed in a molten salt or metal surrounding the reaction vessel. Heat energy collected from the molten material could be used to drive a conventional turbine.

The fundamental challenge is to achieve a rate of heat emitted by a fusion plasma that exceeds the rate of energy injected into the plasma,” according to the World Nuclear Association.

Proponents claim that fusion energy, if harnessed, would have none of the proliferation or meltdown risks of nuclear fission. But while fusion does pose less of a radioactive waste problem than fission, it certainly comes with its own set of radioactive materials, as well as proliferation and societal health risks.

Boiling water

Despite all of humanity’s scientific progress, enlightenments and renaissances, we still produce a lot of our power by boiling water to generate steam and power turbines. Too often, we boil the water by burning oil, gas, wood or dung. Commercial nuclear power plants boil water with the fission reaction. Most of the fusion startups we’ve profiled plan to use the results of the fusion reaction to boil water.

Helion’s intent is to skip the boiling-water step and convert fusion energy directly into electricity. 

We came from the traditional fusion field, and we sort of abandoned the past approaches to be focused on what matters, which is electricity,” Kirtley said.

Our approach to fusion, direct energy recovery,’ was proposed by some brilliant scientists in the 1950s. Since fusion is already electromagnetic and all the energy is in charged particles, you have to hold it with a magnetic field anyway. So why don’t we figure out how to directly harness that electricity?”

In other words, stay in the electromagnetic realm and don’t make a thermal conversion. 

Kirtley explained the process and Helion’s unique take further:

When you use a pulsed electromagnet rather than big cryogenic superconductors — just a regular aluminum magnet — and pulse it with a large electric current, that generates a magnetic field. Like two magnets that when you push on them repel each other, that induces a magnetic force that compresses a fusion fuel up to these 100-million-degree temperatures. That fuses, and as that pressure pushes back on the magnetic field, you can extract electricity directly just with Faraday’s law, with the same fundamental technology as regenerative braking in an EV or an alternator in a conventional car.

All of this action takes place inside a 40-foot-long dumbbell-shaped vessel.

A cutaway diagram showing the interior and exterior of a white dumbbell-shaped device
Helion claims its plasma accelerator can raise fusion fuel to 100 million degrees Celsius. (Helion)

It’s the power electronics

Dipender Saluja of Capricorn Investment Group is an investor in Helion. It’s the electrical engineer in me that was attracted to Helion because of the role that power electronics are playing,” he said.

Instead of being scared of nuclear energy, what we’re saying is, how do we get an unfair advantage? The way you get Moore’s law to work on your side is with smart power electronics because power electronics do benefit from Moore’s law.”

Why did we invest in Tesla in 2006?” he continued. It was because we saw what was happening with the curves of lithium-ion batteries and the curves of power electronics.”

Helion’s CEO also cites power electronics and modern gigahertz fiber optics as key enablers of the company’s fusion system.

Nuclear fusion firm TAE Technologies has touted its own power electronics, going so far as to spin out a new business unit targeting electric vehicle charging.

A decade ago, investor Vinod Khosla called for better power electronics in terms of enabling the widespread deployment of a smart grid. If we invest in new power electronics devices, things will change radically,” he said. The design of existing systems will change based on these new components.”

Billions invested

Canary covered a number of VC-funded fusion startups and their technologies back in June.

For more than 70 years, nuclear fusion’s massive energy-generation potential has attracted physicists, governments, oil and gas giants, and entrepreneurs. But while nuclear fission plants have been providing electricity around the world since the 1950s, nuclear fusion has never become viable.

The billionaire class and once-sane venture capitalists are now enthusiastically embracing deep-tech fusion physics. More than $2.5 billion from scores of private capital sources has been aimed toward commercializing nuclear fusion over just the last few years.

Fusion science is real, but there’s been nothing resembling practical, controlled, earth-based fusion energy despite the billions spent.

Innovation drives progress, and we must explore new energy avenues like fusion, but we have to deploy our money and our human capital with common sense. If we’re putting tens of billions of dollars into chasing a fusion solution that won’t be producing grid-coupled energy for decades to come, we need to assess whether that money would be better spent on commercial solutions that can be deployed today or research that can yield a more immediate payback. 

Eric Wesoff is editorial director at Canary Media.