Thea-retical fusion

Hey there,

Today, we’re going “back to our roots,” as it were, keeping things “laser”-focused (calling lasers to mind via pun is actually kind of antithetical to the company this piece is about, but not the subject matter overall, as you’ll see) on energy technologies and a startup I’ve had the pleasure of getting to know recently.

I speak with a baker’s dozen of climate and energy tech startups weekly. Often, it happens virtually. I won’t go into a long digression on how disorienting that can feel at times; after all, I’ve made close friends, both professionally and not, whom I first met online and cultivated relationships with for years before we ever met in person.

Still, it’s quite a different experience to be on-site with companies, particularly those building some of the most ambitious tech imaginable. A few months ago, I had the opportunity to take a walking tour of Thea Energy’s facilities in Kearny, New Jersey, with the company’s CEO, Brian Berzin. Turns out, (surprise!) shaking a founder and CEO’s hand and palpably feeling his conviction and passion for his and his team’s work does make a difference, the day-to-day time-saving benefits of handling most meetings virtually from the comfort of my apartment or coffee shops nearby notwithstanding.

♡ If you find this work valuable, you can support it here. I put a lot of heart into it. ♡

DEEP DIVE

As I type this, in the sun, which is slowly setting over my right shoulder as I sit in my North Brooklyn apartment, billions of metric tons of hydrogen and helium are fusing together (the rate of fusion reactions constantly happening in our solar system’s sun is ~600 million metric tons of hydrogen and helium atoms per second). These are not quantities or magnitudes worth trying to wrap my head around. If you can, kudos!

So no, fusion energy is not some “novel” thing. Absent the sun’s ongoing, unfathomably massive release of energy from fusion reactions, the Earth would never have miraculously spawned single cellular organisms, let alone complex, let alone conscious, complex beings. It probably wouldn’t even be a cohesive, rocky mass still. So fortunately, fusion exists!

Still, as much miraculous progress as we’ve made as a species, we have not come close to producing sustained fusion reactions on Earth that create a comprehensive net energy gain. And that’s despite a century’s worth of awareness, starting with proposals and measurement from scientists like Francis William Aston and Arthur Eddington about what could allow the sun that all planets in our solar system orbit (rest in peace, Pluto) to produce and give off so much energy that said energy can traverse 90 millions of miles of space and create the conditions for life and sustain life on our planet.

That said, in another sense, plants generate 10x more energy via photosynthesis and other processes than all of humanity does across all generation sources. In a way, they’re harnessing fusion.

Further, solar panels are basically a way of turning the sun’s fusion reactions and light into electricity, too. h/t to Jesse Peltan for long preaching that “rebrand.”

So the benefits of fusion are abundantly clear. But, quick record scratch. I digress. In service of getting less lost in the weeds, let’s get back to discussion of creating actual, sustained fusion reactions on Earth and some discussion of Thea Energy, which, after all, is headquartered mere miles from where I live, as opposed to the 90 million-plus miles that separate me from the sun.

Thea Energy’s ambition is relatively simple, though accomplishing it will be far from straightforward. The company wants to commercialize nuclear fusion to generate more abundant, emissions-free electricity. Not an usual mission these days, for good reason. Let’s get to the specifics shortly. But first, we’ll start with some recent news for context.

First, the news

If you missed this news, I don’t blame you, because it fell off my writing radar for some time, even if the announcement itself was abundantly at the front of my inbox half a dozen times (and even though, again, I physically have shaken the CEO’s hand).

Last month, Thea Energy, a nuclear fusion company based out of New Jersey that bills itself as reinventing the stellarator, demonstrated something many fusion enthusiasts have long, well, longed for. There are many approaches to trying to sustain fusion reactors on Earth and to then harness energy from those reactions in a functional, controllable fashion to produce electricity or heat. We’ll get to those. First, let’s focus on this news:

Thea Energy focuses on simplifying the notoriously complex magnetic systems that are often built to control fusion reactions, at least in systems that employ magnetic confinement techniques to create ideal conditions for plasma and fusion reactions (we’ll bifurcate different fusion approaches later on). Specifically, Thea makes superconducting planar coil magnet arrays. I’ve seen them in person. Here’s what they look like:

First key differentiator? As you can see, the magnets aren’t massive; holding one in your hand is a visceral departure from the mental images some of us might call to mind when we think of nuclear fusion machines. ITER, an international nuclear fusion research and engineering megaproject in France, for instance, sprawls 1 kilometer long and 400 meters wide (think hundreds of football fields). That’s not all magnets, but you get the idea.

Using its core IP, namely smaller, more modular magnets in the world’s first superconducting magnet array, in late March, Thea announced it successfully created and controlled stellarator-relevant magnetic fields, a key step in proving the company is making meaningful progress towards commercial fusion energy production (which is not to say that many, many more steps aren’t still required before the company gets to that stage of development).

What’s particularly compelling to me and others about Thea’s approach? Again, it's the focus on modularity, ease of iteration and prototyping, reorientation towards a software-led focus, and aims for scalability and vertical integration. Thea’s magnets should be easier to mass produce and more “stackable” than other twisted, pretzel-like magnets that have made other reactor designs expensive engineering nightmares. Will it work out? I have no idea, TBD! At minimum, shifting some of the complexities inherent to fusion engineering from hardware to software is an insight in and of itself; it's an insightful approach that could ameliorate some of the more persistent challenges in fusion, like the construction of the requisite machines for plasma containment. Whether tokamak, stellarator, or other, the maintenance, repairs, and size of different reactor designs may prove hard to scale.

The finer details of Thea’s approach to fusion

Much of what I wrote above already helps distill Thea’s differentiation, which we will locate in a greater context within the constellation of the fusion ecosystem later on.

This section offers more disambiguation, as succinctly as I can, on what makes Thea different, first in my own paragraph. Then I’ll tap another party I quite trust, and finally, the CEO himself, who's gonna do a better job than anyone else, invariably.

I also tapped Mike Mettler, a partner at Roadrunner Capital, a VC fund looking at the fusion space, for his take on why he likes Thea:

Finally, let’s hand it over to Thea’s CEO, Brian Berzin. From our in-person conversation and lab walk-through, here were some of his main quotes that stuck with me:

1. Rapid hardware prototyping, iteration, and modularity

2. Hardware-agnostic, software-driven control

In my own words, Thea’s system is hardware-agnostic and leverages advanced software and closed-loop controls, enabling flexibility and resilience with respect to manufacturing, operations, and supply chain sourcing, which, in this, er, “uncertain” macroeconomic environment, is compelling.

3. Data-rich, machine learning-enhanced operations

4. Focus on reliability and commercialization

This one’s easy: Berzin is clear-eyed on the goal not just being to achieve fusion, but to do so with systems robust enough for durable, economic, long-term operation.

5. Commitment to transparency and peer review

The above quote preceded the results we opened the newsletter with, and speaks to other recent peer-reviewed papers from Thea on its novel system architecture, which it has openly released for public comment and review. Thea isn’t the only fusion company that has opened-sourced some of its results. Still, it’s cool to see, especially in an environment where others are battening down the comms hatches (not inherently a bad thing, just a choice that can send certain market signals).

Far from alone in the constellation of fusion startups and companies

Thea is far from the only company with grand ambitions and notable progress to share with respect to efforts to bring sustained, controlled, harnessable fusion reactions to Earth (and maybe other planets, someday). One need only cast a cursory glance at announcements from the past month or six weeks or so to see that there are many energy tech startups throwing their proverbial hats in the ring to be “first to fusion,” or, said differently, to at least create a minimum viable nuclear fusion-powered reactor that can generate a net energy gain with some modicum of consistency:

• Commonwealth Fusion Systems, one of the best-funded fusion startups (having raised more than $2 billion), announced it started building its “SPARC” tokamak reactor in Massachusetts. The company aims to complete what it describes as "the world's first commercially relevant fusion energy machine" by 2027. Read that more as a proof of concept; the company is also working on a grid-scale plant in Virginia. Pilot plant or even mere demonstration or not, I’m extremely skeptical of that 2027 timeline. Would love to be wrong!

• Type One Energy recently published papers citing that it sees "no scientific barriers" to its stellarator design and announced it is preparing to raise over $200 million for its forthcoming Series A. All the wordplay in these first two examples alone is starting to overstimulate my desire to dissect that alone, but I’ll restrain myself.

• Marvel Fusion (Germany) recently raised €50 million for its laser-based fusion technologies that could be applied to creating energy from nuclear fusion.

• Renaissance Fusion (France) also raised ~€32 million to develop commercial magnetic confinement reactors; it announced the round back in March.

• A few weeks ago, Novatron Fusion (Sweden) announced it raised €10 million in Series A1 funding to pursue a magnetic mirror approach to plasma confinement for nuclear fusion reactions.

When did all this start? Hard to pinpoint precisely, but fusion companies have been spawning for decades, and some of the best-funded ones are older than I am.

Panning back a few years specifically, the National Ignition Facility made headlines in 2022 when it achieved “fusion ignition,” which means it produced more energy from a fusion reaction than was directly delivered to the target via laser. That was cool, but it didn’t mean there was a net energy gain on the whole at play, nor did it mean all that much in the grand scheme re: commercializing workable fusion reactors. A lot depends on where you draw the system boundaries. Taking into account, say, the entire electrical infrastructure of the National Ignition Facility and the equipment required to conduct the experiment, the energy generated by that fusion ignition was paltry. Still cool! I went on Polish national TV (TVP World), of all outlets, to discuss that back then (feels like a lifetime ago, and I think they took the YouTube video down for reasons unbeknownst to me).

That really kicked off more furor and focus on fusion, at least on my radar.

Part of what’s happening now with the raft of fusion funding and result releases is competition for mindshare. As the fusion space gets more crowded (which we’ll explore), occupying the metaphorical space between investor, analyst, and policymakers’ ears is part and parcel of attracting other capital resources, be they financial, human, or, as is increasingly and perhaps unfortunately the case in the U.S., at least federally, in-group vs. out-group favor currying with the current Presidential Admin (pay attention, for instance, to which companies and what types of wares are securing tariff exemptions).

In short, whatever kind of capital or influence we’re discussing, it flows more easily to you if you capture hearts and minds (that said, simply being the loudest person in the room also seems to work well for some people).

This has accelerated to the point that venture-funding for fusion of late has actually outstripped funding for fission startups, even though those, especially small modular reactors, get plenty of play too, and even though fission is a long-established, reliable, perfectly viable (it provides ~20% of U.S. electricity and has for some time) energy generation technology.

Part of that mismatch likely stems from venture capitalists’ forward-looking orientation as is, plus that, while it’s taken a lot of R&D to get even to where we are today, fusion isn’t mired in the baggage of nuclear fission meltdowns*, the fission waste concerns (largely a misnomer / nothingburger in my opinion), and, most importantly in 2025 perhaps, the fact that, for a whole host of reasons, the U.S. can’t seem to build new fission reactors on time, on budget, or frankly, at all anymore.

I’m a fission fan too, don’t get me wrong. So I hope the U.S. gets back to building more AP-1000s, or actually builds small modular reactors, or whatever else people cook up. For the next decades, at minimum, we’ll need all the clean electrons we can get worldwide.

*Unlike fission reactions, fusion reactions are also non-self-sustaining, so there’s no “meltdown” conversation to worry about. As rare as those have been historically, tail risk is tail risk, and I don’t blame anyone who, at some subconscious, innate level, worries about it.

Zooming out (cosmically): The “Constellation” of fusion startups

Like many energy technologies (solar chief among them), fusion has transformed from a primarily government-funded scientific endeavor into a vibrant constellation of flush startups and companies working on commercializing different approaches.

Significantly, in 2025, fusion-focused companies, labs, researchers/scientists, and governments are solving fundamentally different questions than they were in the 1970s, when work on fusion really accelerated. The question is no longer "Can fusion work?“ It's "Can fusion work economically and at sustainable (both in terms of sustaining reactions and broader supply-chain sustainability) scales?"

That's a profound shift that's easy to miss amidst more nuanced technical debates, the wide range of approaches, and, you know, everything else going on.

Today, fusion companies aren't just iterating on decades-old designs, which some countries, utilities, and companies in the fission space still are. Many are fundamentally rethinking aspects of the fusion challenge. Among the best-funded companies, like Commonwealth Fusion Systems and Tokamak Energy, many are focusing on developing compact, high-field tokamaks using advanced superconducting magnets. Meanwhile, alternative magnetic designs like stellarators (which Thea Energy + others are working on) offer pros and cons between engineering complexity and plasma stability. And, of course, as we've discussed, Thea is doing many unique things to stand out.

The complexities of differentiation between approaches are mindboggling, and not something I'm best suited to address myself. There are countless different approaches companies are evaluating and developing to try to stimulate and sustain nuclear fusion reactions to produce energy and electricity on Earth. For an overview of approaches (and how much they can vary), see here, though (I did my best!):

Are these approaches all competing? Can they be complementary? It’s a question worth entertaining, the latter likely being true in some cases. Fusion certainly doesn't warrant the typical tech horse-race framing, or arms race framing, which we see a lot of in, say, AI. The engineering challenges facing fusion are sufficiently immense that multiple parallel paths increase collective chances of success. What matters isn’t which approach wins; it's whether any and/or hybrid collaborations can cross the various thresholds that still separate existing scientific achievements from commercial energy production soon.

Of course, the (growing) skeptic in me, the no-longer bright eyed and bushy-tailed climate and energy tech “watcher on the wall” I was five years ago, acknowledges the “fusion within 20 years” thing is perhaps one of the more common refrains used to elicit chuckles and perhaps a touch of derision. Without reiterating or coalescing all my reasons from the above into a cohesive, succinct whole, I'm willing to make a 50/50 wager with any of you that it is, in fact, different this time.

Ultimately, it's just my (and countless other investors, researchers, operators, and policymakers) “fingerspitzengefühl” at the end of the day here (look that one up for long German words with specific meanings). Which, without tooting my horn too much, has gotten a lot better, given I've been at this for a lil’ while, and it was already good in 2020.

Further, remember that the iPhone is less than twenty years old. EVs were practically not a thing in 2005. Autonomous vehicles are here, now, on U.S. roads, delivering hundreds of thousands of rides weekly. eVTOLs will be in the sky next year, making commercial flights. I don't even need to say anything about compute, AI, or data centers to make my point (though, as in Thea's case, computational capabilities that streamline and accelerate simulation and testing that would have taken decades of physical prototyping previously sure help).

2030, 2035, 2040, and 2045 are going to look wildly different than 2025 does; and not just because of the dramatic, ever-evolving and unfurling geopolitical convulsions at hand, nor the breakneck technological advancements, nor climate change and global warming itself (which are not problems we're as-of-yet, meaningfully ameliorating).

Will the world look better? Subjective, contextual, wildly spatially variable, and not something I can divine. I'm holding out hope, as this newsletter always intended and intends to. Thea Energy is another cool company that makes belief easier.

Ciao for now,

– Nick