CA: Wow. So you mentioned the Semi and I think you're planning to announce this in September, but I'm curious whether there's anything you could show us today?

EM: I will show you a teaser shot of the truck.

It's alive.

CA: OK.

EM: That's definitely a case where we want to be cautious about the autonomy features. Yeah.

CA: We can't see that much of it, but it doesn't look like just a little friendly neighborhood truck. It looks kind of badass. What sort of semi is this?

EM: So this is a heavy duty, long-range semitruck. So it's the highest weight capability and with long range. So essentially it's meant to alleviate the heavy-duty trucking loads. And this is something which people do not today think is possible. They think the truck doesn't have enough power or it doesn't have enough range, and then with the Tesla Semi we want to show that no, an electric truck actually can out-torque any diesel semi. And if you had a tug-of-war competition, the Tesla Semi will tug the diesel semi uphill.

CA: That's pretty cool. And short term, these aren't driverless. These are going to be trucks that truck drivers want to drive.

EM: Yes. So what will be really fun about this is you have a flat torque RPM curve with an electric motor, whereas with a diesel motor or any kind of internal combustion engine car, you've got a torque RPM curve that looks like a hill. So this will be a very spry truck. You can drive this around like a sports car. There's no gears. It's, like, single speed.

CA: There's a great movie to be made here somewhere. I don't know what it is and I don't know that it ends well, but it's a great movie.

EM: It's quite bizarre test-driving. When I was driving the test prototype for the first truck. It's really weird, because you're driving around and you're just so nimble, and you're in this giant truck.

CA: Wait, you've already driven a prototype?

EM: Yeah, I drove it around the parking lot, and I was like, this is crazy.

CA: Wow. This is no vaporware.

EM: It's just like, driving this giant truck and making these mad maneuvers.

CA: This is cool. OK, from a really badass picture to a kind of less badass picture. This is just a cute house from "Desperate Housewives" or something. What on earth is going on here?

EM: Well, this illustrates the picture of the future that I think is how things will evolve. You've got an electric car in the driveway. If you look in between the electric car and the house, there are actually three Powerwalls stacked up against the side of the house, and then that house roof is a solar roof. So that's an actual solar glass roof.

CA: OK.

EM: That's a picture of a real — well, admittedly, it's a real fake house. That's a real fake house.

CA: So these roof tiles, some of them have in them basically solar power, the ability to —

EM: Yeah. Solar glass tiles where you can adjust the texture and the color to a very fine-grained level, and then there's sort of microlouvers in the glass, such that when you're looking at the roof from street level or close to street level, all the tiles look the same whether there is a solar cell behind it or not. So you have an even color from the ground level. If you were to look at it from a helicopter, you would be actually able to look through and see that some of the glass tiles have a solar cell behind them and some do not. You can't tell from street level.

CA: You put them in the ones that are likely to see a lot of sun, and that makes these roofs super affordable, right? They're not that much more expensive than just tiling the roof.

EM: Yeah. We're very confident that the cost of the roof plus the cost of electricity — A solar glass roof will be less than the cost of a normal roof plus the cost of electricity. So in other words, this will be economically a no-brainer, we think it will look great, and it will last — We thought about having the warranty be infinity, but then people thought, well, that might sound like were just talking rubbish, but actually this is toughened glass. Well after the house has collapsed and there's nothing there, the glass tiles will still be there.

CA: I mean, this is cool. So you're rolling this out in a couple week's time, I think, with four different roofing types.

EM: Yeah, we're starting off with two, two initially, and the second two will be introduced early next year.

CA: And what's the scale of ambition here? How many houses do you believe could end up having this type of roofing?

EM: I think eventually almost all houses will have a solar roof. The thing is to consider the time scale here to be probably on the order of 40 or 50 years. So on average, a roof is replaced every 20 to 25 years. But you don't start replacing all roofs immediately. But eventually, if you say were to fast-forward to say 15 years from now, it will be unusual to have a roof that does not have solar.

CA: Is there a mental model thing that people don't get here that because of the shift in the cost, the economics of solar power, most houses actually have enough sunlight on their roof pretty much to power all of their needs. If you could capture the power, it could pretty much power all their needs. You could go off-grid, kind of.

EM: It depends on where you are and what the house size is relative to the roof area, but it's a fair statement to say that most houses in the US have enough roof area to power all the needs of the house.

CA: So the key to the economics of the cars, the Semi, of these houses is the falling price of lithium-ion batteries, which you've made a huge bet on as Tesla. In many ways, that's almost the core competency. And you've decided that to really, like, own that competency, you just have to build the world's largest manufacturing plant to double the world's supply of lithium-ion batteries, with this guy. What is this?

EM: Yeah, so that's the Gigafactory, progress so far on the Gigafactory. Eventually, you can sort of roughly see that there's sort of a diamond shape overall, and when it's fully done, it'll look like a giant diamond, or that's the idea behind it, and it's aligned on true north. It's a small detail.

CA: And capable of producing, eventually, like a hundred gigawatt hours of batteries a year.

EM: A hundred gigawatt hours. We think probably more, but yeah.

CA: And they're actually being produced right now.

EM: They're in production already. CA: You guys put out this video. I mean, is that speeded up?

EM: That's the slowed down version.

CA: How fast does it actually go?

EM: Well, when it's running at full speed, you can't actually see the cells without a strobe light. It's just blur.

CA: One of your core ideas, Elon, about what makes an exciting future is a future where we no longer feel guilty about energy. Help us picture this. How many Gigafactories, if you like, does it take to get us there?

EM: It's about a hundred, roughly. It's not 10, it's not a thousand. Most likely a hundred.

CA: See, I find this amazing. You can picture what it would take to move the world off this vast fossil fuel thing. It's like you're building one, it costs five billion dollars, or whatever, five to 10 billion dollars. Like, it's kind of cool that you can picture that project. And you're planning to do, at Tesla — announce another two this year.

EM: I think we'll announce locations for somewhere between two and four Gigafactories later this year. Yeah, probably four.

CA: Whoa.
No more teasing from you for here? Like — where, continent? You can say no.

EM: We need to address a global market.

CA: OK.

This is cool. I think we should talk for — Actually, double mark it. I'm going to ask you one question about politics, only one. I'm kind of sick of politics, but I do want to ask you this. You're on a body now giving advice to a guy —

EM: Who?

CA: Who has said he doesn't really believe in climate change, and there's a lot of people out there who think you shouldn't be doing that. They'd like you to walk away from that. What would you say to them?

EM: Well, I think that first of all, I'm just on two advisory councils where the format consists of going around the room and asking people's opinion on things, and so there's like a meeting every month or two. That's the sum total of my contribution. But I think to the degree that there are people in the room who are arguing in favor of doing something about climate change, or social issues, I've used the meetings I've had thus far to argue in favor of immigration and in favor of climate change.

And if I hadn't done that, that wasn't on the agenda before. So maybe nothing will happen, but at least the words were said.

CA: OK.

So let's talk SpaceX and Mars. Last time you were here, you spoke about what seemed like a kind of incredibly ambitious dream to develop rockets that were actually reusable. And you've only gone and done it.

EM: Finally. It took a long time.

CA: Talk us through this. What are we looking at here?

EM: So this is one of our rocket boosters coming back from very high and fast in space. So just delivered the upper stage at high velocity. I think this might have been at sort of Mach 7 or so, delivery of the upper stage.

CA: So that was a sped-up —

EM: That was the slowed down version.

CA: I thought that was the sped-up version. But I mean, that's amazing, and several of these failed before you finally figured out how to do it, but now you've done this, what, five or six times?

EM: We're at eight or nine.

CA: And for the first time, you've actually reflown one of the rockets that landed.

EM: Yeah, so we landed the rocket booster and then prepped it for flight again and flew it again, so it's the first reflight of an orbital booster where that reflight is relevant. So it's important to appreciate that reusability is only relevant if it is rapid and complete. So like an aircraft or a car, the reusability is rapid and complete. You do not send your aircraft to Boeing in-between flights.

CA: Right. So this is allowing you to dream of this really ambitious idea of sending many, many, many people to Mars in, what, 10 or 20 years time, I guess.

EM: Yeah.

CA: And you've designed this outrageous rocket to do it. Help us understand the scale of this thing.

EM: Well, visually you can see that's a person. Yeah, and that's the vehicle.

CA: So if that was a skyscraper, that's like, did I read that, a 40-story skyscraper?

EM: Probably a little more, yeah. The thrust level of this is really — This configuration is about four times the thrust of the Saturn V moon rocket.

CA: Four times the thrust of the biggest rocket humanity ever created before.

EM: Yeah. Yeah.

CA: As one does. EM: Yeah.

In units of 747, a 747 is only about a quarter of a million pounds of thrust, so for every 10 million pounds of thrust, there's 40 747s. So this would be the thrust equivalent of 120 747s, with all engines blazing.

CA: And so even with a machine designed to escape Earth's gravity, I think you told me last time this thing could actually take a fully loaded 747, people, cargo, everything, into orbit.

EM: Exactly. This can take a fully loaded 747 with maximum fuel, maximum passengers, maximum cargo on the 747 — this can take it as cargo.

CA: So based on this, you presented recently this Interplanetary Transport System which is visualized this way. This is a scene you picture in, what, 30 years time? 20 years time? People walking into this rocket.

EM: I'm hopeful it's sort of an eight- to 10-year time frame. Aspirationally, that's our target. Our internal targets are more aggressive, but I think —

CA: OK.

EM: While vehicle seems quite large and is large by comparison with other rockets, I think the future spacecraft will make this look like a rowboat. The future spaceships will be truly enormous.

CA: Why, Elon? Why do we need to build a city on Mars with a million people on it in your lifetime, which I think is kind of what you've said you'd love to do?

EM: I think it's important to have a future that is inspiring and appealing. I just think there have to be reasons that you get up in the morning and you want to live. Like, why do you want to live? What's the point? What inspires you? What do you love about the future? And if we're not out there, if the future does not include being out there among the stars and being a multiplanet species, I find that it's incredibly depressing if that's not the future that we're going to have.

CA: People want to position this as an either or, that there are so many desperate things happening on the planet now from climate to poverty to, you know, you pick your issue. And this feels like a distraction. You shouldn't be thinking about this. You should be solving what's here and now. And to be fair, you've done a fair old bit to actually do that with your work on sustainable energy. But why not just do that?

EM: I think there's — I look at the future from the standpoint of probabilities. It's like a branching stream of probabilities, and there are actions that we can take that affect those probabilities or that accelerate one thing or slow down another thing. I may introduce something new to the probability stream. Sustainable energy will happen no matter what. If there was no Tesla, if Tesla never existed, it would have to happen out of necessity. It's tautological. If you don't have sustainable energy, it means you have unsustainable energy. Eventually you will run out, and the laws of economics will drive civilization towards sustainable energy, inevitably. The fundamental value of a company like Tesla is the degree to which it accelerates the advent of sustainable energy, faster than it would otherwise occur.

So when I think, like, what is the fundamental good of a company like Tesla, I would say, hopefully, if it accelerated that by a decade, potentially more than a decade, that would be quite a good thing to occur. That's what I consider to be the fundamental aspirational good of Tesla.

Then there's becoming a multiplanet species and space-faring civilization. This is not inevitable. It's very important to appreciate this is not inevitable. The sustainable energy future I think is largely inevitable, but being a space-faring civilization is definitely not inevitable. If you look at the progress in space, in 1969 you were able to send somebody to the moon. 1969. Then we had the Space Shuttle. The Space Shuttle could only take people to low Earth orbit. Then the Space Shuttle retired, and the United States could take no one to orbit. So that's the trend. The trend is like down to nothing. People are mistaken when they think that technology just automatically improves. It does not automatically improve. It only improves if a lot of people work very hard to make it better, and actually it will, I think, by itself degrade, actually. You look at great civilizations like Ancient Egypt, and they were able to make the pyramids, and they forgot how to do that. And then the Romans, they built these incredible aqueducts. They forgot how to do it.

CA: Elon, it almost seems, listening to you and looking at the different things you've done, that you've got this unique double motivation on everything that I find so interesting. One is this desire to work for humanity's long-term good. The other is the desire to do something exciting. And often it feels like you feel like you need the one to drive the other. With Tesla, you want to have sustainable energy, so you made these super sexy, exciting cars to do it. Solar energy, we need to get there, so we need to make these beautiful roofs. We haven't even spoken about your newest thing, which we don't have time to do, but you want to save humanity from bad AI, and so you're going to create this really cool brain-machine interface to give us all infinite memory and telepathy and so forth. And on Mars, it feels like what you're saying is, yeah, we need to save humanity and have a backup plan, but also we need to inspire humanity, and this is a way to inspire.

EM: I think the value of beauty and inspiration is very much underrated, no question. But I want to be clear. I'm not trying to be anyone's savior. That is not the — I'm just trying to think about the future and not be sad.

CA: Beautiful statement. I think everyone here would agree that it is not — None of this is going to happen inevitably. The fact that in your mind, you dream this stuff, you dream stuff that no one else would dare dream, or no one else would be capable of dreaming at the level of complexity that you do. The fact that you do that, Elon Musk, is a really remarkable thing. Thank you for helping us all to dream a bit bigger.

EM: But you'll tell me if it ever starts getting genuinely insane, right?

CA: Thank you, Elon Musk. That was really, really fantastic. That was really fantastic.