When Commonwealth Fusion Systems needed thousands of kilometers of a miracle material that barely existed, it had two choices: wait for someone else to build the supply chain, or do it themselves.
CFS chose the latter, transforming a Nobel Prize-winning lab curiosity into the foundation of what could be the world’s first commercial fusion power plant.
That material — high-temperature superconducting tape that resembles an old cassette tape — was CFS’ key to solving fusion energy’s biggest challenge: building reactors powerful enough to contain plasma at 150 million degrees, while also being small enough for commercial use. But first, the company had to bootstrap an entire industry around a product that had never been manufactured at scale.
“When we saw this material, [we were] like this is great, we could build a magnet out of it,” said Rick Needham, chief commercial officer at Commonwealth Fusion Systems, speaking at a live recording of The Green Blueprint at Latitude Media’s Transition-AI conference. “And then it’s like, well, how much is available? Maybe a hundred meters of it, and for our device, we’ll use thousands of kilometers.”
The tape looks deceptively simple. “It’s basically mostly steel, and there’s one layer in there [that’s]…one micron thick where you can send about 2000 amps across it with zero loss,” Needham explained. When you wind that tape around in a circle, it becomes “the biggest, strongest, most powerful magnet in the world”.
The physics are straightforward: stronger magnets mean smaller reactors. And the smaller the reactor, the more likely it is to be commercially viable.
But the supply chain challenge wasn’t just about quantity; it was about creating an entire manufacturing ecosystem from scratch. Instead of agreeing to simply buy the miracle tape, CFS helped the manufacturer redesign its whole production process. “We worked with them to identify what are the holdups that would prevent them from going to more scale,” Needham said.
CFS also helped improve both the economics and quality control of tape production by finding ways to use most variations of the material, even the lower-quality stuff. Because the company was working so closely with the material in MIT’s lab, it developed methods for testing and grading different qualities of tape, then matching each grade to appropriate parts of the magnet.
“We actually are better at measuring it than they were,” said Needham. “So we would take the tape, measure it and tell ’em, here’s how much we’ll pay you for it.’”
The collaboration dramatically increased the market’s capacity to manufacture the tape — 40x in over just a few years. “Quality has gone up, prices came way down, volume’s gone way up, and it’s continued to do so,” said Needham.
That supply chain breakthrough enabled CFS to build the demonstration magnet that proved its tokamak design concept to investors. In September 2021, at MIT’s Plasma Science and Fusion Center, the company successfully tested its HTS magnet. That test — which people said couldn’t be done because there wasn’t enough material in the world — led directly to the company’s $1.8 billion Series B funding round three months later.
Listen to Rick Needham’s whole interview on The Green Blueprint:
Having solved the superconducting tape supply chain, CFS now faces a different set of engineering challenges as it builds SPARC, its demonstration reactor in Massachusetts, and plans ARC, its first commercial power plant in Virginia. The hurdles have shifted, from scaling up materials production to designing and manufacturing all the other complex components needed to contain and control a fusion reaction.
“It’s basically an engineering problem right now: build a complex machine, but if you get that right, you’re off to the races,” Needham said. But the engineering problems are substantial, and the timelines are short. With SPARC is scheduled to demonstrate net energy gain in 2027 ARC is planned for the early 2030s, CFS is betting that a systematic approach to solving both technology and supply chain problems will be what finally brings fusion power from the lab to the grid.
The engineering and manufacturing gauntlet
For example, CFS designed copper caps for each magnet to protect the delicate superconducting tape. But the team discovered that the caps needed to have uniform electrical properties throughout, or else a power failure could destroy the entire magnet.
Although copper itself is naturally electrically uniform, the manufacturing process was creating variations in electrical properties at the joints and seams of the caps. The reaction at the time, Needham recalled, was “oh my God, how do we solve that?” and the realization that “If we don’t solve this, we’re not going to be able to build these magnets.” The solution required skilled welders who could maintain the material’s electrical homogeneity — who were hard to find because “newsflash: only about 20% of the welders in the world weld copper,” said Neeham.
But even once CFS found the welders to make the caps, it had to find a specific type of oven to bake them before installation. CFS found a single company with the right oven, but it had broken the month before and was no longer in use. “So we built our own oven,” said Needham.
In total, it took six months for CFS to solve the problem of the copper caps; two weeks ago it produced the last one for SPARC. “You always wish everything could be smooth. It never is, right?” said Needham. “But as long as you have a team that’s resilient and kind of works together, then I think you can solve these things.”
With the copper cap problem solved, CFS turned to its next manufacturing hurdle: assembling the superconducting tape into the “pancakes” that make up each magnet. These pancakes are essentially flat, circular coils created by winding kilometers of the superconducting tape in precise layers. The company’s modular design calls for 18 large magnets, each containing 16 of these pancake-shaped coils that, when stacked together, create the powerful magnetic fields needed for fusion.
“It took us about six months to get the first pancake done. We’re now spitting out one a day,” Needham said, describing the learning curve that will be crucial for cost reduction. “We’re on very rapid cost down curves.”
That manufacturing efficiency will determine whether fusion can compete economically with other clean energy sources. CFS believes it can eventually reach $50 per megawatt-hour — competitive with wind and solar — through economies of scale in both tape production and magnet manufacturing.
CFS’s magnet breakthrough illustrates a broader challenge for climate technology companies: Breakthrough innovations often require building entirely new supply chains and manufacturing capabilities. Unlike software startups that can scale rapidly by adding servers, hardware companies must solve complex materials science and manufacturing problems — while simultaneously raising hundreds of millions of dollars.
“Focus relentlessly on your next critical de-risking,” Needham advised other climate tech startups. “Build that magnet, focus on that and make sure people understand what that is.”
