Sounds like medieval alchemy meets modern physics—but the economics might actually work.

Caption: Startup claims fusion reactors could produce thousands of kilograms of gold annually as energy byproduct

Key Takeaways

• Marathon Fusion claims fusion reactors could produce 5,000kg gold annually worth $550M
• Process requires commercial fusion reactors that don’t exist yet
• Computer simulations show promise but no hardware demonstration exists

What if your electricity bill came with a side of precious metals? Marathon Fusion, a San Francisco startup, isn’t just chasing the clean energy holy grail—they want fusion reactors that literally mint gold while generating power. Their proposal sounds more Silicon Valley fever dream than serious science, until you dig into the physics.

The modern alchemist’s formula is surprisingly straightforward.

The company claims their reactors could transmute mercury into gold using excess neutrons from fusion reactions. Think of it as the universe’s most expensive chemistry set:

• Blast mercury-198 with high-energy neutrons
• Create radioactive mercury-197
• Wait for it to decay into stable gold-197

The same nuclear physics that powers stars, repurposed for precious metal production.

The numbers sound absurd until you do the math. A single gigawatt fusion plant could theoretically produce 2,000 to 5,000 kilograms of gold annually—worth roughly $550 million at current prices. That’s more than most Netflix shows cost to produce, generated as a byproduct of keeping your lights on.

Marathon Fusion has raised $6 million in private investment plus $4 million in grants, positioning gold production as fusion’s economic cheat code. Why settle for just selling electricity when you could corner the precious metals market too?

But here’s where reality crashes the party harder than your Wi-Fi during a Zoom call.

“On paper, it is possible to make gold from mercury in a fusion reactor,” says Adrian Bevan, Professor of Physics at Queen Mary University of London. “However, until commercial fusion reactors are realised, the dream may remain a pipe dream.”

That’s the $550 million question—literally. Marathon’s entire proposal rests on computer simulations, not working hardware. Commercial fusion remains decades away, despite breathless predictions since the 1950s. CERN has successfully transmuted elements before, producing microscopic amounts of gold over years of particle acceleration. Scaling that to industrial levels? That’s a different beast entirely.

The regulatory maze ahead looks more complex than TikTok’s algorithm.

The startup faces additional hurdles most investors probably haven’t considered:

• Freshly transmuted gold starts radioactive, requiring cooling periods before handling
• Regulatory frameworks for synthetic precious metals don’t exist—how do you classify lab-grown gold compared to the mined variety?
• Flooding markets with fusion-produced gold could crater the very commodity prices making this profitable

Marathon Fusion essentially wants to solve two impossible problems simultaneously: achieving commercial fusion energy and revolutionizing precious metal production. It’s like promising to cure aging while colonizing Mars—technically possible, practically distant.

Still, their timing reveals something interesting about fusion’s current moment. After decades of “20 years away” promises, startups are hunting for economic multipliers that make fusion investment irresistible. Gold production might be theoretical, but the desperation for fusion profitability is very real.

The dream of turning base metals into gold has captivated humanity since ancient times. Whether Marathon Fusion can transform that dream into dividends remains the ultimate test of modern alchemy.