Helion, a highly scrutinised fusion startup, has gained attention for its ambitious goals. Established 12 years ago, the company is backed by Sam Altman, who is reportedly in discussions with OpenAI, and it is set to provide Microsoft with electricity by 2028, ahead of its competitors.
The company’s unconventional approach to fusion energy and its low profile have garnered a mix of supporters and detractors. However, its investors remain confident in Helion’s vision.
Helion announced a Series F funding round on Tuesday, raising $425 million, which has increased its valuation to $5.245 billion. The startup recently activated its latest prototype, Polaris, aiming to be the first fusion reactor to successfully generate electricity.
Polaris, the seventh prototype from Helion, is situated in a 27,000-square-foot facility in Everett, Washington. It took over three years to construct, which is relatively quick in the fusion sector. To meet its ambitious target of providing power to Microsoft by 2028, Helion will need to accelerate the development of its commercial power plant.
The challenges faced by Helion mirror those encountered in other pioneering industries.
CEO David Kirtley explained that supply chain issues are critical: “In AI, obtaining the chips is a significant obstacle. In fusion, it is the same.” He noted that Polaris requires 50,000 large-scale, pulse-power semiconductors, which significantly impacts the timeline.
The funding will be directed toward in-sourcing a considerable amount of specialised manufacturing. For instance,Helion placed orders for capacitors—essential short-term energy storage devices—three years in advance.
Kirtley stated, “Our objective is to transition from waiting three years for a supplier to delivering our own capacitors, enabling us to produce them in a year or less.”
Despite the challenges of establishing a supply chain from the ground up, Kirtley is optimistic about Helion’s ability to deliver electricity to Microsoft within the next few years.
According to Kirtley, siting for the Microsoft facility has been underway for several years now. Although he refrained from disclosing the location, he mentioned that efforts are focused on securing permits and establishing grid connections, a process that typically requires a significant amount of time.
Helion’s unique approach to fusion energy is both its appeal and a source of criticism.
In general, there are two dominant methodologies for fusion: Magnetic confinement utilises intense magnetic fields to compress plasma to the necessary heat and density to trigger fusion, designed for continuous burning to produce steam for turbines. Inertial confinement employs high-powered lasers directed at fuel pellets, compressing them to achieve fusion. For efficient steam generation for turbines, a reactor needs to achieve multiple firings per second.
Helion is developing a distinctive reactor known as a field-reversed configuration reactor. Visually, it resembles an hourglass with a bulging centre, encircled by powerful magnets that guide and compress the plasma throughout each reaction, termed a “pulse” by Helion.
During the initiation of a pulse, Helion introduces a mixture of deuterium and helium-3 into either end and heats the mixture until it transitions into plasma. The magnets then shape the plasma into a toroidal form, accelerating them towards each other at speeds exceeding 1 million miles per hour.
Upon reaching the fusion chamber—the bulging centre of the hourglass—the plasmas collide and are further compressed by additional magnets. This process raises the plasma temperature to over 100 million degrees Celsius, resulting in a series of nuclear fusions. This sequence is comparable to how a spark plug ignites fuel in an internal combustion engine.
The energy released from the fusion reactions produces an increase in magnetic force, which counteracts the reactor’s magnets. This enhanced magnetic force is subsequently converted directly into electrical energy. Ideally, Helion’s reactor will generate more electricity from this magnetic surge than the energy required to activate the magnets. Since the system relies on magnetic energy rather than steam-driven turbines, it aims to achieve greater efficiency and reduce the threshold for breakeven.
The design for a commercial Helion reactor is expected to pulse several times per second, with a single reactor capable of producing 50 megawatts of electricity. A power plant could be composed of numerous reactors.
In laboratory conditions, the company has smaller systems that can pulse over 100 times per second, suggesting that future reactors may reach a firing rate of 60 pulses per second, aligning with grid frequency. Kirtley acknowledged that significant engineering hurdles remain to achieve these high repetition rates at the substantial pulse powers necessary for millions of amps to flow.
To expedite the development of the power plant, Helion has secured new funding to enhance its machining capabilities and capacitor production. Kirtley stated, “The timeline for Polaris was significantly influenced by the need to manufacture all the magnetic coils, and my aim is to produce these components internally.”
This latest funding round is smaller than the previous $500 million raised by the startup. New participants in this round include Lightspeed Venture Partners, SoftBank Vision Fund 2, and a prominent university endowment. Current investors such as Sam Altman, Capricorn Investment Group, Mithril Capital, Dustin Moskovitz, and Nucor also contributed.
