He spent years coaxing stars into a bottle. Then he turned around and started mining the sea.
Howard Yuh runs a company that mines without a mine. No pit, no drill, no tailings pond. Tidal Metals, the New Jersey deeptech he leads as CEO and cofounder, pulls magnesium out of plain seawater using electricity and a clever piece of physics. Nothing gets added to the ocean. Nothing comes out as waste. The inputs are a pump's worth of saltwater and a wall socket plugged into clean power.
That is a strange sentence for a man who built his career on fusion reactors. Yuh has a PhD from MIT in applied plasma physics, and for years his job was making the hottest matter in the universe behave. He designed instrumentation for ITER, the international tokamak meant to prove fusion at scale. Then he looked at a different problem - how the world makes one of its lightest, most useful metals - and decided the fix had been floating in the ocean the whole time.
The pitch is blunt: roughly 90% of the world's magnesium is made in China. Magnesium goes into car frames, aircraft, defense hardware, and the lightweight alloys that make electric vehicles go farther on a charge. A supply chain that concentrated is a single point of failure. Yuh's answer is to make the metal domestically, from a feedstock that covers 71% of the planet.
Here is the part that makes engineers lean in. The heart of Tidal Metals is something Yuh calls an adsorption temperature-swing vapor pump - described, with no false modesty, as the most energy-efficient fractional crystallization technology in the world. Strip the jargon and it works a little like the silica gel packets that come in a new pair of shoes.
Moisture-absorbing material sits in alternating chambers and grabs water out of the brine. When a chamber is saturated, it gets gently heated to release the water as vapor, and heat pumps shuttle that energy to the next chamber instead of throwing it away. About 97% of the heat gets reused, cycle after cycle. What's left behind is magnesium salt, which electrolysis then turns into metal. Filtration, crystallization, dehydration, electrolysis. Four physical steps, one of them borrowed almost directly from the reactor work Yuh used to do.
The numbers are almost comically favorable. A single metric ton of seawater yields about 4 kilograms of magnesium salt. Yuh likes to point at San Diego: that one desalination plant pulls in 100 million gallons of seawater a day - enough, he says, to supply the entire United States with magnesium, around 180,000 tons a year, from water a city was already pumping anyway.
Magnesium is the featherweight champion of structural metals. It is 75% lighter than steel, 50% lighter than titanium, and a third lighter than aluminum. That weight savings is why it shows up in next-gen vehicles, aerospace, and even spaceflight materials. It is also the second most abundant metal dissolved in seawater - about 1.3 kilograms in every cubic meter.
So the resource is effectively infinite and evenly spread across every coastline on earth. The bottleneck has never been geology. It has been process. Yuh's bet is that solving the process - cheaply, cleanly, domestically - is worth more than any new mine.
Before Tidal Metals there was GreenBlu, which Yuh founded in 2016 after years of quiet, independent research into how to do useful work with low-grade, leftover heat - the kind of energy most processes throw away. GreenBlu was a desalination outfit, chasing cheaper fresh water for a thirsty planet.
Then came the realization that reshaped everything. Desalination produces a concentrated brine as a byproduct, and that brine is dense with minerals. The team was working hard to make clean water and discarding the more valuable thing. So they flipped the model. The water became the bonus; the magnesium became the business.
Yuh did not build it alone. Tidal Metals' three cofounders - Yuh, Ethan Schartman, and Kevin Tritz - all met at the Princeton Plasma Physics Laboratory, working on fusion energy. Three scientists trained to bottle a star walked out together to harvest metal from the sea. It is a clean origin story for a company built on clean process.
A short introduction to what Tidal Metals is building - magnesium, straight from seawater, with no chemicals and no waste. The clearest way to understand Yuh's pitch is to watch the process explained on its own terms.
The thesis underneath all of it: as billions face water scarcity, coproducing a high-value metal alongside fresh water could make desalination itself cheaper. Two problems, one machine.
Most people never think about magnesium. It is the quiet metal - the one that makes a laptop chassis thin, a wheel light, a missile casing strong. Demand is climbing because everything that moves wants to weigh less: electric vehicles need range, aircraft need efficiency, and spacecraft pay for every gram at launch. Lighter alloys are the cheapest performance you can buy, and magnesium is the lightest structural option on the periodic table.
The uncomfortable fact is that the supply has drifted almost entirely to one place. When roughly nine out of ten tons of a critical metal come from a single country, every automaker, defense contractor, and aerospace supplier downstream is exposed. Price spikes, export controls, a bad winter at one set of smelters - any of it ripples worldwide. That is the gap Yuh is aiming at. Not a marginal improvement on existing mines, but a different supply chain entirely, sitting off every coastline and inside every desalination plant already running.
His framing is deliberately practical. Tidal Metals talks about restoring U.S. magnesium production, securing the domestic supply chain, and decarbonizing a metal that is dirty to make the old way. The conventional process is energy-hungry and carbon-heavy. Yuh's runs on renewable electricity and leaves nothing behind to clean up. For a buyer trying to hit emissions targets and de-risk procurement at the same time, "decarbonized, domestic, zero-waste" is a rare combination of words.
What stands out about Yuh is the timescale. Fusion researchers are trained to chase results that arrive decades later, to value a clean measurement over a fast headline. He carried that temperament into a startup. Tidal Metals spent years - quietly, through a name change and a full pivot - turning a lab curiosity into a process that might actually beat the world's cheapest producer. That is not the usual venture rhythm, and it is exactly the kind of patience the hard problems require.
The bet is elegant in the way good science is elegant. The resource is already everywhere. The demand is already growing. The old method is already too dirty for the decade ahead. All that was missing was a way to separate one metal from saltwater without spending more energy than the metal is worth - and that is the puzzle Yuh, a man who once measured the inside of a star, decided to solve with a machine that breathes water in and out like a tide. Whether Tidal Metals becomes the company that re-shores magnesium or simply proves the idea is possible, the premise is hard to unsee: the biggest mine on earth has no walls. It has a shoreline.
Our focus on magnesium metal was driven by the dire need to expand magnesium production, lower its cost, and provide a much-needed solution to decarbonize this industry.
- Howard Yuh
Reporting drawn from public sources: Tidal Metals, TechCrunch, DCVC, PR Newswire, World Economic Forum, and Crunchbase.