Late last week, in a rare sit-down for a small audiencethis editor spent an hour with Sam Altman, the former president of Y Combinator and since 2019 the CEO of Open AIthe company he founded in 2015 with Elon Musk and numerous others to develop artificial intelligence for the benefit of humanity.

The public wanted to know more about his plans for OpenAI, which has taken the world by storm over the past six weeks thanks to the public release of its ChatGPT language model, a chatbot that can help educators and alarmed. (OpenAI’s DALL-E technology, which allows users to create digital images simply by describing what they imagine, generated only slightly less buzz when it was released to the public earlier last year.)

But because Altman is also an active investor — one whose biggest returns to date have come from payment startup Stripe, he said at the event — we spent the first half of our time together on some of his most ambitious investments.

To learn more about this, including a supersonic jet company and a startup that wants to help make babies from human skin cells, please tune in to the 20 minute video below. You’ll also hear Altman’s thoughts on Twitter under Elon Musk’s leadership, and why he’s “not very interested” in crypto or web3. (“I like the spirit of the web3 folks,” Altman said with a shrug. “But I don’t intuitively feel why we need it.)

We’ll be showing more from our more in-depth conversation shortly. In the meantime, below is an excerpt from our discussion of one of Altman’s biggest bets: a nuclear fusion company called Helion energy which, like OpenAI, strives to deliver on a long elusive promise – that of abundant energy. The fragment has been lightly edited for length and clarity.

What Makes a Sam Altman Deal?

I’m just trying to do things that I’m interested in at the moment. One of the things I’ve realized is that all the companies that I think I’ve added a lot of value to are the ones that I like to think about in my spare time on a walk or whatever, and then the founders and say, “Hey, I have an idea for you.” Every founder deserves an investor who thinks of them as they walk. And so I’ve tried to hold myself to the things that I really love, which is usually the hard technology, [involving] years R&D, [is] capital intensive or some kind of risky research. But when it works, it really works.

An investment that is particularly interesting is Helion Energy. You’ve been funding this company since 2015, but when it announced a $500 million round last year that included a $375 million check from you, I think that surprised people. Not many people can write a check for $375 million.

Or, like many people who would [invest it] in one high-risk merger company.

What have been your most successful investments to date?

I mean, probably based on multiples, definitely based on multiples: Stripe. I also think that was my second investment ever, so it seemed a lot easier. This was also a time when valuations were different; It was amazing. But you know, I’ve been doing this for like 17 years, so there’s been a lot of really good ones, and I’m super thankful to have been in Silicon Valley during what was such a magical time.

Helion is more than an investment to me. It’s the other thing besides OpenAI that I spend a lot of time on. I’m just super excited about what’s going to happen there.

Lawrence Livermore National Laboratory had a breakthrough in nuclear fusion last month. (Using a giant laser approach, the scientists announced the first fusion reaction in a lab setting that produced more energy dan was used to start the reaction.) I wonder what you think of the approach, which is very different from Helion’s (which builds a fusion machine that Reportedly long and narrow and will use aluminum magnates to compress fuel and then expand to produce electricity).

I am super happy for them. I think it’s a really cool scientific result. As they said themselves, I don’t think it will be commercially relevant. And that’s what I’m excited about — not getting fusion to work in a lab, although that’s cool too, but building a system that works at super low cost.

If you look at the past energy transitions, if you can get the cost of a new form of energy down, it could take over everything else in a few decades. And then also a system where we can generate enough energy and enough reliable energy, both in terms of the machines not breaking down, and also not having the intermittent or the need for storage of sun or wind or something like that. If we can create enough for Earth in about 10 years — and I think that’s actually the hardest challenge Helion faces as we outline what it takes operationally to do that, to replace all of Earth’s current generative capacity with fusion and to do it really fast and think what it really means to build a factory that can produce two of these machines a day for 10 years – that’s very hard, but also a super fun problem.

So I’m really happy that there’s a fusion race, I think that’s great. I am also very happy that solar energy and batteries are becoming so cheap. But I think it’s about who can supply the cheapest and enough energy.

Why is Helion’s approach superior to what dozens of countries in the South of France are working on?

Yeah, well, that thing, iter, I think it will probably work, but for what I just said before, I don’t think it will be commercially relevant. They also [themselves] think it will be commercially irrelevant.

What I find so exciting about Helion is that it is a simple machine at an affordable price and a reasonable size. There are a lot of different elements except the giant [experimental machine being developed by these nations], but one that’s really cool is that what comes out of the reaction is charged particles, not heat. Almost all others [alternatives], like a coal plant or natural gas plant or whatever, makes heat that drives a steam turbine. Helion creates charged particles that push back the magnet and send an electric current through a wire. There is no heating cycle at all. And so it can be a much simpler, much more efficient system.

I think it’s being missed in the whole merger discussion, but [is] really amazing. It also means that we are not dealing with a lot of nuclear material. We never have hazardous waste or even a hazardous system. You should be able to touch it quite shortly after it shuts off.

It’s building one large facility now. Has it already proved its point?

Soon we will have more to share there. . .

My general approach is that if there’s an area that I think is really important, like say energy, I’ve tried to find the best fusion and fission company I can find. They are competitive in the sense that they both try to make cheap energy, but we urgently need more cheap energy. It’s a huge market; I think they can both work.