Elon Musk has given up on solar power (on Earth)

Has Elon Musk given up on Tesla’s Master Plans, on the electrified economy, on solar power as we know it? From the SpaceX IPO filing released this week, it sure seems like it.

A recap for those not enmeshed in the Musk-verse: Tesla has released four Master Plans over the years, and while details have varied, the through line has been electrification of the economy. Musk put it best in his first edition: “the overarching purpose of Tesla motors…is to help expedite the move from a mine-and-burn hydrocarbon economy towards a solar electric economy.”

But recently, one of Musk’s companies, xAI, has embraced the mine-and-burn hydrocarbon economy, using dozens of unregulated natural gas turbines to power its data centers with plans to buy $2.8 billion more, effectively cementing the fossil fuel’s role in the company’s AI operations.

It’s a curious turn for a businessman who built his empire on clean energy — and who has no qualms directing his companies to buy from one another. SpaceX spent $131 million on 1,279 Cybertrucks, and xAI has spent $697 million in the last two years on Tesla Megapacks, it’s grid-scale battery storage systems that the company will use to manage peak loads. But so far, xAI hasn’t bought a materially significant number of solar panels from Tesla.

Solar power isn’t missing in the SpaceX filing, it’s just all concentrated on space, which the company touts as the future of data center power. Terrestrial solar garners a few mentions — not as a power source for xAI data centers but instead to show how much better SpaceX thinks space-based solar will be.

It’s no secret that Musk and other Silicon Valley executives have become obsessed with space-based solar power. SpaceX says that space-based solar arrays can generate “more than five-times the energy” of terrestrial ones thanks to 24/7 illumination. As AI data centers have run into opposition here on Earth, CEOs like Musk have started mulling big server racks in space powered by that 24/7 sunshine. Hammer, meet nail.

Even if SpaceX is able to bring down the cost of boosting a data center into orbit, the economics are challenging at best. Power prices for Starlink satellites are multiples higher than what a terrestrial data center typically spends, and protecting chips from the rigors of space won’t be easy or cheap. It’s also not clear whether AI training can be distributed across multiple satellites, leaving a significant chunk of AI work earthbound. It’s not just one problem that SpaceX needs to solve, but many.

It’s likely that Musk considers xAI’s current data centers as stopgaps, that once SpaceX is able to loft gigawatts worth of servers into orbit — probably just a few years away, in his mind — he’ll scrap what’s here on the ground, natural gas turbines included and not have to think about NIMBYs anymore. The risk, of course, is that he’s wrong.

It’s not just NIMBYs that Musk is worried about, though. He’s clearly concerned that computing demands from AI will quickly outstrip what we can provide here on Earth. Sprinkled throughout the SEC filing are references to “terawatt-scale annual AI compute growth,” which will require power to match. That’s a stunning figure when you consider that all the world’s data centers use around 40 gigawatts today. 

This is Musk’s “first principles” thinking in action. At some point, he assumed the world will need an additional terawatt worth of compute every year, and he worked back from there. “We believe that third-party estimates on data center demand are constrained by the practical supply limitations that exist in a terrestrial context and the power shortage may be far greater than what research estimates suggest,” the company argues.

Possible? Sure, I suppose. But consider that humanity today uses about 35,000 terawatt-hours of energy annually, or about 4 terawatts on a continuous basis. Energy demand has risen lately, and for AI, it probably is in an phase of exponential growth, which could either continue or level off. We have no way of knowing at this point, but if there’s one thing Musk is good at, it’s spotting a trend at its inflection point and extrapolating wildly.

Here’s where Musk’s problems settle back down to Earth. I’m no rocket scientist, but I suspect that shipping solar panels on a flatbed truck uses less energy than sending them into orbit. Plus, space-ready solar panels will need to be manufactured at unprecedented scale. Not insurmountable problems, but also maybe a distraction. We’ve barely scratched solar’s potential here on Earth, for example.

The perfect doesn’t have to be the enemy of the good. There’s plenty of room to improve things here on Earth even while we chase after our dreams in the stars. 

Just three years ago, Musk and his colleagues at Tesla released the “Master Plan Part 3,” which thoughtfully outlined a “plan to eliminate fossil fuels.” A good starting point might be xAI’s data centers.