Entrepreneurs to Watch 2025: Warren McKenzie

The July/August 2025 issue of Optics & Photonics News featured the magazine’s biennial feature spotlighting 10 Entrepreneurs to Watch. Here, we offer an interview with one of those entrepreneurs, Warren McKenzie, cofounder and managing director of HB11 Energy. HB11 is working to leverage boron fuel to achieve commercial laser fusion.

In a nutshell, what is the company doing?

We were the first of the modern-day, laser-driven fusion companies. We were really born out of a result where a few researchers were getting very high fusion rates from laser experiments with hydrogen–boron that were not national-lab scale, and they brought to light that there was some unknown science within hydrogen–boron fusion. If we can make it work, that solves many, many issues with fusion, albeit not without its challenges.

So the elevator pitch is hydrogen–boron. Fusion would unlock the largest source of clean energy on Earth, and we would make boron the fuel. It would have the same energy density as any other nuclear fuel, but with none of the radioactive waste. And this material is abundant. Boron is dollars per kilogram; if your garden is deficient in in boron, you can go and buy some borax from the hardware shop.

How did you land on boron fuel?

Most of the world of fusion has focused on deuterium and tritium as fuel, so heavy hydrogen and super-heavy hydrogen. The problem is they are radioactive, and since ignition was achieved at the National Ignition Facility (NIF), making fusion commercial is the focus. Now, if you compare deuterium–tritium as a fuel with hydrogen and boron, we’re talking gunpowder versus wood—boron is much, much harder to ignite, and it doesn’t have as much energy in it as deuterium–tritium. But it has all these other advantages.

For a very long time, the field had written off hydrogen–boron fusion. It was not considered seriously. And still today, many people really do not believe it can be done. What changed that was, as I said, a few scientific results showing much, much higher reaction rates than anyone expected. And really that’s where it’s come from.

So why hasn’t everyone done it? The short answer is that most people, until quite recently, didn’t think it worked. And it still is the case that to ignite a burning plasma similar to what NIF did is much, much harder with hydrogen–boron. The upside is there’s no tritium breeding, no radioactive waste, cheap and abundant fuels, no neutrons. Deuterium–tritium fusion will probably produce the first fusion energy on the grid—but probably not the first commercial fusion energy because there are cost restrictions.

Even more important than the cost issues, though, deuterium–tritium (D-T) cannot be globally deployed, partly because tritium is radioactive and difficult to transport, but also because of technology proliferation restrictions. The US fusion energy strategy actually mentions proliferation risk specifically around tritium production technologies

And our mission for the company is UN Sustainable Development Goal seven, which is to ensure access to affordable, reliable, sustainable and modern energy for all. So it will be very difficult for deuterium–tritium fusion help bring people out of poverty around world because it’s going to be bound by proliferation controls, whereas hydrogen–boron fusion will not.

How does your approach compensate for the difficulty in ignition?

Our specific approach is fast ignition. I like to compare what NIF did to the diesel engine—you’re using nanosecond lasers to generate X-rays to compress the fuel, and that compression alone is enough to ignite it. For hydrogen–boron fusion, it’s harder to ignite. We still need that compression, but we can actually use a second, picosecond beam to essentially be a spark plug.

The fast-ignition approach has been around for a while; we’re not the only ones pursuing it. We are the only ones pursuing it for hydrogen–boron fusion, but there’s one really big advantage of fast ignition for hydrogen–boron fusion. In deuterium–tritium fast ignition, you’re using that picosecond beam to accelerate protons, and those protons add a bit of extra heat. With hydrogen–boron, fast ignition, those protons are actually one of the reactants in the fuel. So the spark plug we’re creating is fusion-powered. And that, while it is much harder, gives us a giant leap in the direction of being able to ignite hydrogen–boron fusion.

Can we talk about your road to laser fusion and HB11?

I’m a materials scientist; I did my Ph.D. in semiconductor microscopy, essentially nanotechnology. But I also did a business degree. There were so many opportunities from untapped research that I wanted to fill, and that’s essentially what I’ve made my career doing. I’ve done this a few times over now, with a company in metallurgy, a company in gene therapy, and another one in lithography. Adding those up, they’re all really practice for almost the ultimate commercialization process, which is fusion.

There were so many opportunities from untapped research that I wanted to fill, and that’s essentially what I’ve made my career doing.

So where did HB11 come from? I met a professor, Heinrich Hora, at the University of New South Wales, Australia, where he was a professor. He was one of the pioneers of the field, not just of fusion, but plasma interactions. He essentially predicted and was the first to observe some of the first ion acceleration mechanisms from lasers—really pioneering work. He had a big pile of papers, and he said, “Something important has happened in my field. Someone really needs to take this seriously.” Now, he wasn’t looking for me. He was actually looking for my chairman, who was the former deputy vice-chancellor (research) of the university. And I said, “Do you mind if I have a look?” I took it to my chairman, and he said, “Heinrich is one of the best scientists of his time. So yes, take this seriously.” So I put myself on a months-long learning curve to try and understand the significance of these results.

And they showed fusion reaction rates six orders of magnitude higher than they should be. This means there is unknown science there, and we saw an opportunity—there was a huge appetite then for ventures that could have large-scale decarbonization implications. From 2017 to 2019 was bootstrapping, putting together the Scientific Advisory Board and other things, and in 2020 we first got funded.

As a new venture, we took probably the ultimate entrepreneurial leap of faith: the first laser fusion company at a time when no one believed that laser fusion was going to work for energy production, a hydrogen–boron fusion company at a time when no one believed the hydrogen–boron fusion would work. Now, laser fusion is an industry, and boron is the second-most-pursued fuel, after deuterium–tritium. So here we are today.

Given your business degree, did you always envision a career in entrepreneurship?

I absolutely had the love for science, the love for advancing fields of science. But I was also aware that most people don’t understand scientific advances, and for those that do, unlikely any know how to develop it commercially. So the number of people who could actually take them forward was very, very thin. And because of that, even today, I think that the number of ventures that are designed to turn a scientific outcome into something that’s useful for the world is really limited.

One of the most beautiful things about science is the sheer volume of information, which is growing constantly. And in other fields you might see a tiny incremental advance from some science that someone did 10 years ago as something that changes the world. But really, within that pool of knowledge, there is so much which is completely untapped. The challenge is firstly identifying what’s valuable in that pool, and secondly selling it to people in a way that they can understand the benefits. If I consider that I’ve got one superpower, it’s selling the benefits or translating the understanding of science and how it could benefit people in the larger world.

How does HB11 approach funding and commercialization?

If you go back to 2020, the price of money as defined by interest rates was basically nothing. Money was free, and there was a lot of money for anything that could do something for the environment. When money is cheap, you can fund anything—that was the feeling at the time. Investors were lining up, expecting a repeat of Apollo 11, with billions and billions of dollars being thrown at this.

But of course, money isn’t cheap forever. Interest rates went up, and there’s not enough money in the system anymore. And the reality check that the whole industry had was governments and venture capital can’t be relied on to solve fusion. It’s not sustainable to assume that you could purely rely on other people’s money forever to develop these big things. There’s simply not enough money.

But on the journey to solving fusion, there are a lot of technologies that have other applications, and building those into businesses, in addition to helping other sectors, is actually the most reliable way to fund fusion, or whatever you’re trying to do in the long term. Now, this is a trend that everyone is following, and we’re in good company in the optics community. But the strategy on our side is not just to fund fusion. If you want to become the best laser fusion company, you can’t just build something academically. You need to immerse yourself in the industry and be accountable to your customers to have something that really works.

Building a business line is the best way to provide you some revenue, but also to make sure that your products are better than everyone else’s, which is going to be an essential component to winning the race at the end of the day.

Has the company had any particularly significant milestones?

The first milestone was putting together the best team. Our scientific advisory board are all heroes of the field, and I’m infinitely thankful for them—not just for what they produce, but for keeping us honest.

The next major milestone was to understand why we’re getting such high fusion rates. Our first experiment essentially demonstrated an order of magnitude higher fusion rate than we expected. This is all unknown physics. Just the fact that we got those high reaction rates was a milestone, and I like to consider that historical because until that point, no private fusion company had ever generated any more than a handful of fusion reactions.

The theoretical basis from Professor Hora that hydrogen–boron fusion could be produced was based on the idea of superthermal effects. No one took them terribly seriously, until NIF wrote a paper saying, “actually we’re getting a lot higher reaction rates than we thought, and it’s because of superthermal effects.” The next big step was taking that new understanding and turning that into a new target design. So that was where the notion of the hybrid burn, where we combine compression with the fast ignition, evolved from.

Since then, we’ve started the business lines in lasers and making targets for people. We have sold our first targets to customers. While doing those experiments, we built up a great capability for making our own targets. And again, that’s really about sharpening our capability—if you’re holding yourself accountable to other customers, you’re always going to be able to perform better than if you’re making targets in your shed.

How would you respond to the skepticism around laser fusion?

My personal belief is really in line with some surveys that the Fusion Industry Association did about when the first fusion energy will be put on the grid. Most people are saying it will be within the decade. Now, that’s not going to be commercial fusion energy—there’s a very big leap between someone putting energy on the grid and a commercial fusion building a large-scale industry. So there will be a lot of time between energy on the grid and global deployment.

But thinking really long term, there aren’t really any other options for energy, so fusion has to happen. Even with fossil fuels, they’ll run out at some point, and if we’re going to go through an energy transition, we really need another energy source in the second half of the century. The mindset of the scientific community in regards to laser fusion is living in the mindset of the small budgets and academic speed that many have seen traditionally, and it is a function of the resources that they’re given, so there’s where some skepticism arises.

But if the community as a whole can reduce the risk and give some certainty, the potential for enormous amounts of money to speed things up really is within reach. There are huge engineering challenges, absolutely. But engineering challenges can be solved with resources. And as time goes by, with the growth of energy-hungry AI and the growing need for additional power, the need to solve these challenges will increase.