Helion’s Fusion Startup Aims for 2028 Electricity Deadline

Table of Contents

  • Helion says plasmas in its Polaris prototype have reached 150 million°C, about three-quarters of what it expects a commercial plant will need.
  • CEO David Kirtley says Polaris is running deuterium-tritium (D-T) fuel, which he described to TechCrunch as a first for a fusion company.
  • Helion’s business deadline is anchored by a contract to sell electricity to Microsoft starting in 2028, expected to come from a larger reactor called Orion.
  • The company is pursuing direct electricity generation from fusion pulses, rather than capturing heat to run steam turbines.

Helion Achieves 150 Million Degrees Celsius in Polaris Reactor

Helion, the Everett, Washington-based fusion startup, calls the Polaris result a key step toward commercial fusion electricity.

In the reporting cited, the milestone is specifically about plasma temperature inside Polaris; Helion’s electricity-delivery commitment is tied to the larger Orion reactor planned for the Microsoft contract. Helion’s CEO and co-founder, David Kirtley, told TechCrunch the company is “really excited” to reach this point, describing it as roughly three-quarters of the way to the operating temperature Helion believes it will need for a power plant.

The number matters because Helion’s approach demands unusually hot plasmas. While some other designs aim for temperatures on the order of 100 million°C, Helion says its reactor needs plasmas that are about twice as hot to work as intended. The company’s stated target is 200 million°C, which Kirtley described as an “optimal sweet spot” for operating a power plant.

Polaris is built around a field-reversed configuration (FRC), a design that differs from the tokamak approach used by some better-known fusion efforts. Helion describes an hourglass-shaped chamber: fuel is injected at the wide ends and turned into plasma, then magnets accelerate the plasmas toward each other. When they merge, Helion says the plasma is around 10 million to 20 million°C. A subsequent magnetic compression step drives the temperature higher—up to the reported 150 million°C—and the entire sequence happens in less than a millisecond.

Helion’s 150 Million°C Pulse
What the 150 million°C milestone is / isn’t (as described in the reporting)
1) Inject fuel at both ends of the hourglass chamber and ionize it into plasma.
2) Accelerate the two plasmas toward each other using magnets.
3) Merge the plasmas (Helion says this is where the combined plasma is ~10–20 million°C).
4) Magnetically compress the merged plasma to raise temperature (reported peak: 150 million°C).
5) Do it fast: Helion says the full sequence occurs in < 1 millisecond.
Checkpoint to keep in mind: this is a peak temperature inside a pulse. It’s a meaningful physics/engineering step, but it’s not the same thing as demonstrating a power plant that can run repeatably, recover electricity pulse-after-pulse, and operate with the reliability a grid customer expects.
Freshness cue: this milestone was announced in the cited reporting as a recent update from Helion about Polaris.

That pulse-based, magnet-driven architecture is central to Helion’s commercial pitch. Instead of treating fusion primarily as a heat source, Helion aims to turn the physics of the pulse into electricity more directly. Over the last year, Kirtley said the company refined circuits in the reactor to increase how much electricity it can recover—an engineering detail that underscores how Helion is trying to translate plasma milestones into power-plant performance.

Helion has also been careful about which milestones it emphasizes.

In fusion discussions, “scientific breakeven” typically refers to whether the reaction produces more energy than is required to initiate it; in the TechCrunch interview, Kirtley did not claim Helion has reached that point. When asked whether the company had reached scientific breakeven—the point where a fusion reaction produces more energy than it takes to start it—Kirtley did not claim it. He said Helion focuses on “the electricity piece,” reflecting a strategy that prioritizes end-to-end power delivery over headline scientific thresholds.

First Fusion Company to Utilize Deuterium-Tritium Fuel

Alongside the temperature milestone, Helion says Polaris is operating with deuterium-tritium (D-T) fuel, a mixture of two hydrogen isotopes. Kirtley said this makes Helion the first fusion company to use D-T fuel in this way, and that the company observed fusion power output rise “dramatically as expected,” showing up as heat.

D-T is widely discussed in fusion because it is a comparatively “easier” fusion reaction to ignite than many alternatives—one reason many fusion concepts plan to start with it. Helion’s longer-term plan, however, is different from the mainstream: it ultimately wants to run on deuterium–helium-3 (D–He3). The company’s reasoning is tied to its direct electricity approach. D–He3 produces more charged particles, which Helion says push forcefully against the magnetic fields that confine the plasma—making that fuel better suited to a system designed to harvest electricity from electromagnetic effects rather than from heat.

Fuel Strategy: D–T to D–He3
Why D–T now, and D–He3 later (in Helion’s framing)
– D–T in Polaris (now): used to increase fusion output in the near term; Kirtley said the fusion power output rose “dramatically as expected,” observed as heat.
– D–He3 (later): Helion’s preferred long-term fuel because it produces more charged particles, which the company says interact strongly with magnetic fields—supporting its goal of direct electricity recovery rather than turning heat into steam.
– What changes for direct electricity recovery: the more the reaction products are charged (as Helion describes for D–He3), the more the pulse can “push” on magnetic fields in a way that’s aligned with Helion’s electricity-harvesting concept.
– Practical constraint: helium-3 is rare on Earth, so Helion says it must produce, purify, and recycle it as part of the system.

That fuel roadmap introduces a practical constraint: helium-3 is rare on Earth. Helion acknowledges the challenge directly. While helium-3 is often described as common on the Moon, Helion’s plan is to make its own. The company says it will initially fuse deuterium nuclei to produce early batches of helium-3. In regular operation, Helion expects that even while the main power comes from D–He3 fusion, some reactions will still be deuterium-on-deuterium, producing helium-3 that Helion can purify and reuse.

Kirtley said work is already underway to refine that fuel cycle, and described progress as “a pleasant surprise,” adding that Helion has been able to produce helium-3 at “very high efficiencies” in both throughput and purity. Those statements are important because they position helium-3 not just as a theoretical future fuel, but as an engineering program Helion says it is actively advancing.

Helion also hinted at a potential role beyond its own reactors. Kirtley suggested other companies may eventually adopt helium-3 if they pursue direct electricity recovery and its efficiency gains, and he indicated he would be open to selling helium-3 to them. In a sector where many startups are racing toward similar commercial timelines, control over a scarce fuel cycle could become a strategic advantage—if Helion’s production and purification claims hold up at scale.

Contract with Microsoft for Electricity Sales by 2028

Helion’s most concrete commercial pressure point is its Microsoft deal. In an industry where many companies talk in decades, a dated commitment—especially one tied to a major buyer—stands out. Helion says the electricity would come not from Polaris, but from a larger commercial reactor called Orion, which the company is currently building.

The distinction between Polaris and Orion is central to understanding Helion’s timeline. Polaris is a prototype meant to prove key physics and engineering steps—temperature, fuel behavior, and the pulse system Helion uses to recover electricity. Orion, by contrast, is described as a 50-megawatt fusion reactor intended to deliver power under the Microsoft deal. Kirtley framed Polaris as a step toward “scaled power plants,” emphasizing that the company’s goal is not to “build and deliver Polaris” as an end product.

External reporting around the Microsoft agreement has highlighted that the deal includes financial penalties if Helion fails to meet the deadline, raising the stakes beyond reputational risk. In practice, that makes the 2028 target a commercial delivery obligation, not just an R&D aspiration. That structure matters because it turns a technology milestone into an operational one: Helion must not only achieve fusion conditions, but also deliver a product—electricity—on a schedule that a customer can plan around.

Prototype Milestones vs Power Delivery

What’s being compared Polaris (prototype) Orion (commercial reactor for Microsoft) Why it matters for 2028
Primary purpose Prove key physics/engineering steps (temperature, pulse behavior, electricity recovery circuits) Deliver 50 MW under a customer contract A prototype milestone doesn’t automatically translate into a deliverable power product
Output expectation (as described here) Peak plasma temperature and experimental pulses Usable electricity sales to a buyer The contract is judged on delivered electricity, not just lab metrics
Timeline pressure Iteration-driven R&D cadence Commissioning + operations on a fixed date 2028 compresses build, test, reliability, and grid integration into one schedule
Key execution risks implied by the reporting Reaching 200 million°C target; demonstrating repeatable pulses and recovery Scaling hardware, commissioning, and reliable operation; penalties if late The biggest risk is the “prototype → plant” translation under a deadline
What success looks like Credible stepping stone toward scaled plants Power delivered on time and repeatedly The milestone that matters to Microsoft is operational performance

The Microsoft contract also illustrates why Helion’s focus on “the electricity piece” is more than messaging. For a buyer, the relevant question is not whether a plasma briefly hits a target temperature, but whether a system can repeatedly produce usable power and integrate with real-world infrastructure. Helion’s approach—direct electricity recovery from the fusion pulse—aims to simplify the conversion chain compared with heat-based systems that rely on steam turbines. In theory, fewer conversion steps could mean fewer losses and potentially a more compact plant design, though Helion has not publicly tied the Microsoft delivery to specific efficiency numbers in the reporting cited.

Still, the gap between a prototype pulse and a contracted power delivery remains large. Helion’s own comments underscore that it is still climbing toward its stated 200 million°C target, and it has not claimed scientific breakeven. The Microsoft timeline therefore compresses multiple layers of risk—physics, engineering, manufacturing, and commissioning—into a single date on the calendar.

Significant Funding Boost for Helion’s Fusion Ambitions

Helion is not pursuing its 2028 goal on a shoestring. The company raised $425 million last year from a group that included Sam Altman, Mithril, Lightspeed, and SoftBank, according to TechCrunch. That financing sits within a broader surge of investor interest across fusion, driven by the promise of potentially abundant, clean energy.

The funding matters because Helion is simultaneously running a prototype program (Polaris) and building toward a commercial-scale system (Orion). Fusion hardware is capital-intensive: high-powered magnets, specialized chambers, pulse power electronics, and the broader infrastructure required to test and iterate quickly. Helion’s CEO also pointed to circuit refinements over the last year that increased electricity recovery—an example of the kind of iterative engineering that requires sustained capital and specialized talent.

The broader research around Helion’s financing has described the company as having raised over $1 billion in total funding, including the $425 million Series F round reported in early 2025 by Helion itself. Totals can differ across reports depending on what’s included, but the cited coverage consistently places Helion among the better-capitalized private fusion efforts. While totals can vary depending on how rounds are counted, the key point is that Helion is among the better-capitalized private fusion efforts—an important factor when the company is attempting to beat the industry’s typical timeline by several years.

Recent Fusion Funding Highlights

Company (as cited in reporting) Reported funding figure Timing / round (as described) Source context
Helion $425M “last year” raise Reported by TechCrunch; investors listed include Sam Altman, Mithril, Lightspeed, SoftBank
Commonwealth Fusion Systems (CFS) $863M “last summer” raise Reported by TechCrunch; investors mentioned include Google and Nvidia
Inertia Enterprises $450M Series A Reported by TechCrunch; investors mentioned include Bessemer and GV
Type One Energy $250M “in the midst of raising” Reported by TechCrunch as an in-progress raise
Helion (total, various reports) “over $1B” cumulative total Reported in broader coverage; totals can vary by what’s counted (equity vs other instruments, timing, and inclusion rules)

Investor enthusiasm is not unique to Helion, and that context cuts both ways. On one hand, abundant capital can accelerate development, attract experienced engineers, and support parallel workstreams (prototype validation, fuel cycle development, plant construction). On the other, the influx of money can amplify expectations and compress timelines—especially when paired with a high-profile customer commitment like Microsoft’s.

Helion’s funding also arrives amid a wave of large rounds for other fusion startups, suggesting that investors are treating fusion less as a single moonshot and more as a portfolio of competing technical bets. In that environment, Helion’s differentiators—field-reversed configuration, direct electricity recovery, and a future helium-3 fuel cycle—become part of the narrative investors use to justify why one approach might reach commercial viability sooner than another.

Competition Among Fusion Startups Targeting the 2030s

Helion is racing in a crowded field, but its timeline is unusually aggressive. TechCrunch notes that most other fusion startups are targeting the early 2030s to put electricity on the grid, while Helion is aiming for 2028 under its Microsoft contract. That gap—years, not months—helps explain why Helion’s milestones are being watched closely.

Competitors are pursuing different reactor designs and therefore different milestone ladders. TechCrunch points to Commonwealth Fusion Systems (CFS) as an example: CFS is building a tokamak, a doughnut-shaped device that uses powerful magnets to contain plasma, and it needs to heat plasmas to more than 100 million°C inside that system. Helion’s design, by contrast, is an FRC that the company says requires plasmas about twice as hot to function as intended, with a stated goal of 200 million°C.

The competitive landscape is also being shaped by capital flows. In the same week as Helion’s temperature announcement, Inertia Enterprises disclosed a $450 million Series A that included Bessemer and GV, according to TechCrunch. Type One Energy told TechCrunch it was raising $250 million, and Commonwealth Fusion Systems raised $863 million last summer from investors including Google and Nvidia. Those numbers underscore that fusion is no longer a niche research topic; it is a venture-backed hardware race with multiple well-funded contenders.

Fusion Companies and Timelines

Company (mentioned in the reporting) Approach (as described here) Target grid timeframe (as described here) Notable milestone / signal cited
Helion Field-reversed configuration (FRC); direct electricity recovery 2028 (Microsoft contract) Polaris reported 150M°C; Orion described as 50 MW
Commonwealth Fusion Systems (CFS) Tokamak with powerful magnets Early 2030s (industry context) Needs plasma >100M°C inside tokamak
Type One Energy (Not specified in this article) Early 2030s (industry context) Reported to be raising $250M
Inertia Enterprises (Not specified in this article) Early 2030s (industry context) Reported $450M Series A

Yet the industry’s caution remains visible in timelines. Even as startups raise large rounds, many still point to the 2030s as the period when grid electricity becomes realistic. That caution reflects the complexity of moving from a physics demonstration to a power plant: repeated operation, component lifetime under extreme conditions, and the practicalities of building and commissioning large machines.

Helion’s strategy—direct electricity recovery and a future shift to helium-3—adds another axis of differentiation. If it works, it could offer efficiency advantages compared with heat-based approaches. But it also introduces unique dependencies, including the need to produce and recycle helium-3 at scale. In a competitive market, those trade-offs will likely determine whether Helion’s speed is a durable advantage or simply a higher-wire act.

The Future of Fusion Energy: Helion’s Path Forward

Innovative Approaches to Energy Generation

Helion’s core bet is that fusion can be engineered into a power product faster by rethinking how electricity is extracted. Helion aims to generate electricity directly from the fusion pulse. In its description, each pulse creates a magnetic field that pushes back against the reactor’s magnets, inducing an electrical current that can be harvested.

That approach is tightly coupled to Helion’s preferred long-term fuel: deuterium–helium-3. Helion argues that D–He3 produces more charged particles, which interact more strongly with magnetic fields—making it better suited to direct electricity recovery. The company says it is already working on the helium-3 fuel cycle and has achieved high efficiencies in throughput and purity, while also acknowledging that helium-3 is scarce on Earth and must be produced.

On the reactor side, Helion’s field-reversed configuration and rapid pulse cycle—fuel injection, plasma acceleration, merging, and magnetic compression in less than a millisecond—reflect a philosophy of compact, repeatable bursts rather than long-duration plasma confinement. Polaris reaching 150 million°C is framed as a step toward the 200 million°C operating point Helion believes is optimal for a power plant.

Helion’s path forward is defined as much by what it has not yet claimed as by what it has. The company has not said it has reached scientific breakeven, and Kirtley has explicitly emphasized electricity delivery over traditional scientific milestones. That stance may make sense for a commercial company, but it also means outside observers have fewer familiar benchmarks for judging progress.

The 2028 deadline adds additional pressure. Delivering electricity to Microsoft implies not only achieving fusion conditions, but also building and commissioning Orion, a 50-megawatt reactor, and operating it reliably enough to sell power. Helion’s own framing—Polaris as a step toward scaled plants—suggests the company sees the remaining work as a scale-up challenge, not just a lab demonstration.

Finally, Helion is operating in a sector where competitors are well-funded and where many timelines cluster in the early 2030s. That creates a dual challenge: Helion must prove its approach is technically sound, and it must do so on a schedule that is meaningfully faster than the rest of the field. If it succeeds, it could reset expectations for commercial fusion. If it slips, it will join a long history of ambitious fusion timelines colliding with the realities of building extreme hardware.

From Plasma to Grid Power
A practical roadmap from “hot plasma” to “sold electricity” (aligned to what’s described in this article)
1) Physics milestone (pulse performance): hit target temperatures (150M°C → aiming for 200M°C) and validate behavior with chosen fuels.
2) Energy conversion milestone (electricity recovery): demonstrate that the pulse reliably induces recoverable current, and that circuit refinements translate into repeatable gains.
3) Scale-up milestone (Orion build): turn the prototype architecture into a 50 MW machine with manufacturable components and maintainable subsystems.
4) Commissioning milestone (plant reality): prove stable, repeatable operation over many pulses, with downtime, maintenance, and component wear managed.
5) Delivery milestone (customer + grid): deliver electricity on schedule under the Microsoft contract terms (including the implied consequences of missing the date).
Where Polaris fits: primarily stages 1–2. Where Orion must succeed: stages 3–5.

This piece is written from a product-and-systems delivery lens shaped by Martin Weidemann’s experience building and scaling complex, regulated technology businesses—focusing on what reported milestones imply for execution, commissioning, and repeatable operations.

This article reflects publicly available information at the time of writing about reported claims and milestones for Helion’s Polaris and Orion reactors and their implications for a 2028 electricity-delivery goal. Some figures and timelines come from company statements and media coverage and may change as projects evolve. Where sources disagree (for example on cumulative funding), the uncertainty is noted rather than treating any single number as definitive.

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