After First Plasma, General Fusion Gears Up for Bigger Challenges
With its LM26 machine achieving first plasma, General Fusion eyes the harder task ahead: proving fusion can become commercial power
At General Fusion’s headquarters in Richmond, Canada, March 11, 2025, marked a defining moment: the first plasma formed inside the company’s Lawson Machine 26 (LM26) demonstration machine.
For Dr. Michel Laberge, founder and chief science officer, it was both a triumph and a reminder of the work still ahead.
“We want to do something magnetised target fusion, which is something of a mix between laser fusion and magnetic fusion. We compress plasma with a big bucket of liquid lithium,” Laberge said during a panel at Fusion Fest, hosted by The Economist in London on April 8.
“This approach has a lot of advantages for a power plant. But we do need to show that in the middle, we make the fusion happen.”
LM26 represents the heart of General Fusion’s ambitious plan to commercialise Magnetised Target Fusion (MTF), a hybrid approach that aims to combine the strengths of magnetic and inertial fusion systems. With LM26 successfully generating its first plasma, the next phase will focus on compressing it to increasingly extreme conditions.
Over the summer, General Fusion plans to compress plasma to 10 million degrees Celsius, with a target of reaching 100 million degrees—the temperature required for fusion—next year. Achieving these milestones will validate LM26’s design and clear the path toward General Fusion’s ultimate goal: a commercial fusion power plant by 2035.
Engineering a New Approach
Unlike traditional approaches that rely on superconducting magnets or high-powered lasers, General Fusion’s method is surprisingly mechanical and deliberately practical.
“We want to have a big bucket, four meters in the spin,” Laberge explained. “Spin it, push the liquid lithium on the wall, then it's all bunch of pistons around, a bit like a syringe. The steam pressure pushes on the piston, compresses the lithium, and then the lithium compresses the plasma.”
Using liquid lithium solves two of fusion’s most demanding challenges: compressing the plasma and protecting the reactor walls from destructive neutron bombardment.
“Many other people will have a big problem with their metal being destroyed by the neutron,” Laberge said. “We fix that problem. The liquid metal will absorb that. We have a big tritium breeding ratio because we have so much liquid there.”
General Fusion’s system also eliminates the need for expensive, complex technologies like superconducting coils or particle beams.
“It’s cheap because we don't have a superconducting coil, we don't have a laser, we don't have a neutral beam, RF, heating thing—none of that thing,” Laberge said. “So this is very good for a power plant.”
One significant benefit of the design is the simplicity of the supply chain. Most components are standard industrial parts—pistons, bearings, steel—all of which can be machined locally.
“My supply issue is that I'm doing pistons with cylinders, bearings, and steel that anybody can do,” Laberge said. “We design our machine, and the local machine shop makes it for us. We don't need a special superconductor made in Japan. We don't need a special laser.”
The result is a modular system that General Fusion believes will be cheaper and faster to build than traditional fusion concepts.
Laberge’s Fusion Journey
Michel Laberge’s journey toward founding General Fusion began not with a grand plan but frustration and a sofa full of scientific papers.
“I left my good-paying job and started General Fusion with zero salary,” he recalled. “My wife didn’t like that very much.”
At first, Laberge didn’t know exactly which fusion technique he would pursue. He knew he didn’t want to build another laser-based or tokamak-style reactor.
“I knew I didn't want to do the laser and the tokamak, because I think they're bad ideas,” he said.
Spending countless hours poring over old research, Laberge came across a 1970s U.S. Naval Research Laboratory concept known as LINUS, which used liquid metal to compress plasma.
“I say, 'Haha. Now this is a good idea,’” Laberge said. “So I picked that up at that time.”
Since General Fusion’s founding in 2002, the core idea has stayed remarkably consistent, even as engineering details evolved. Today, the company employs around 130 people and has raised about $300 million, one-quarter from the Government of Canada and the rest from private investors.
Still, General Fusion estimates it will need around $2 billion more to reach a working power plant.
“You need some money to make those things, unfortunately,” Laberge said.
Different Path, Same Goal
Fusion Fest in London brought together experts and innovators from across the energy world, with the panel titled Is fusion on track to move from demonstration machines to power plants?
Laberge’s presentation made it clear that General Fusion’s path is a distinct departure from the herd.
“Yes, there aren’t too many people doing that,” Laberge said. “There are a few other companies out there that are investigating a thick liquid wall facing the plasma, which I think is a very good idea, because this will protect the wall from the neutrons, but none of them are doing the compression we were doing.”
At the heart of General Fusion’s magnetic field configuration is a concept familiar to plasma physicists: a spherical tokamak.
“When the plasma is formed, it shoots through that. It wraps itself around the magnetic field, and it makes a twisty, whiny man. Yet, of the just the correct geometry to keep the plasma, oh, twisty and windy,” Laberge said. “We have a shaft in the centre, and then the liquid on the outside, and then we pass millions of amperes in the shaft that makes the toroidal field.”
Plasma stability during compression is another critical area, and General Fusion is working with researchers at Princeton Plasma Physics Laboratory to model potential instabilities.
“Princeton is calculating that we don't hit the instability in the plasma during the compression,” Laberge said.
Laberge was quick to correct a common misunderstanding when asked about materials surviving temperatures of 100 million degrees Celsius.
“No material can withstand 100 million degrees Celsius,” he said. “You have a magnetic field. The plasma at 100 million degrees Celsius is stuck in the magnetic field. And then there's a bunch of magnetic fields, and then there's the wall that's sitting at 200 degrees Celsius or something.”
General Fusion’s approach also cleverly uses the conductive properties of liquid metal to maintain plasma isolation during compression.
“When the liner comes in, it pushes the magnetic field in front of it, like if it were a superconductor,” Laberge said. “We lose only about five to 10% of the flux in the metal, but the rest is compressed.”
By compressing the plasma once per second and sustaining turbine operation through thermal inertia, the company aims for a steady 150 megawatts of electric output.
“Steam spins the turbine all the time. So this is continuous,” Laberge said.
Roadmap to 2035
From LM26’s first plasma to full grid-connected power plants, General Fusion’s roadmap is aggressive but carefully laid out.
In 2025 and 2026, LM26 will push for higher plasma temperatures and pressures. By late 2026, the company hopes to achieve energy breakeven, when a fusion reaction produces as much energy as it consumes.
After LM26, General Fusion plans to build a larger near-commercial machine in the United Kingdom. This device will initially operate at a slower firing rate, with a goal of reaching engineering breakeven by around 2030.
Commercial-scale plants firing at one shot per second — generating continuous fusion electricity — are targeted for deployment around 2035.
“The approximate investment amount is probably $2 billion to get there from here,” Laberge said.
The path will not be easy, but General Fusion’s unconventional strategy could make it one of the first to cross the fusion finish line. With LM26’s first plasma complete, the next few years will determine whether General Fusion can turn a historic breakthrough into a practical, affordable carbon-free energy source for the world.