Hgen

Here is a fact about hydrogen that annoys almost everyone who works on it: the gas itself is not the hard part. Hydrogen is the most abundant element in the universe. You can pull it out of water with electricity using a device called an electrolyzer, a technology so old it predates the light bulb. The chemistry works. It has worked for two centuries. The problem, as it so often is in energy, is money.

Clean hydrogen - the kind made from water and renewable electricity, rather than from natural gas - has been perpetually five years away from being cheap enough to matter. Heavy industry, the chemical plants and steel mills and refineries that consume hydrogen by the tanker-load, mostly buys the dirty version, or buys the clean version liquefied and trucked in at prices that can exceed $10 a kilogram. At that price, the spreadsheet says no.

Hgen, a company of roughly eleven people in Hawthorne, California, is a bet that the spreadsheet can be made to say yes. Founded in 2021 by Molly Yang and Colin Ho, the company did not set out to invent a new kind of electrolyzer. It set out to take the oldest and cheapest kind - alkaline - and make it dramatically smaller. This is a less glamorous ambition than "new physics," but it is the one that tends to actually move cost curves.

The insight, reduced to its least flattering form, is about bubbles. When you split water in an electrolyzer, hydrogen gas forms on the electrode as bubbles. Those bubbles cling. While they cling, they block the surface and slow the reaction. Hgen redesigned the electrode so the bubbles let go faster. Get the bubbles off quickly and the same cell can do far more work in the same space - the company claims roughly 20 times the volumetric power density of a conventional alkaline system, with cells said to be about six times thinner and around nine percent more efficient.

If that sounds like a modest engineering tweak dressed up as a revolution, consider what smaller actually buys you. Twenty times the density means one-twentieth the size for the same output, which means less steel, less nickel, less of the material and manufacturing cost that makes electrolyzers expensive in the first place. The whole system, Hgen says, fits inside a 40-foot shipping container that needs only two inputs: water and electricity. You plug it in where the hydrogen is used, and the truck full of liquefied gas never has to show up.

The people making this argument are not lifelong electrochemists, which is either a red flag or the entire point depending on your priors. Yang came from Tesla, where she worked on the product team across the company's industrial and residential energy products. Ho, her co-founder and childhood friend, came from SpaceX, where he worked on actuation and power systems for Starship and propulsion components for Crew Dragon. Neither company is famous for inventing new science. Both are famous for taking known engineering and manufacturing it at scale until it got cheap. That is the playbook Hgen is running on hydrogen.

The claim to watch is precisely that one - "even with first builds." Cost curves in hardware usually start high and bend downward with volume; a startup that is already competitive on its earliest, hand-built units is making a specific and testable promise. Hgen has moved from a benchtop prototype to an industrial-scale demonstration at its Hawthorne facility, which is the difference between a slide and a machine. Whether the economics hold at commercial scale is the open question, and it is the one the money is betting on.

The money, so far, is about $7 million. A roughly $2 million seed round in 2022 was led by Founders Fund and came with induction into that year's Breakthrough Energy Fellows, the Bill Gates-backed program that funds early climate technology. In September 2024, Hgen closed a $5 million round led by Seven Seven Six, Alexis Ohanian's fund, with participation from Founders Fund again and Fontinalis Partners. These are not funds known for patient bets on electrochemistry, which suggests they found the cost math persuasive rather than merely inspiring.

None of this guarantees anything. The electrolyzer market is filling up with well-funded competitors - Electric Hydrogen, Nel, Plug Power, thyssenkrupp nucera - and the incumbents who sell trucked-in hydrogen are large and comfortable. Clean hydrogen's history is littered with companies that had a compelling density number and a demo, and never made it to the mill floor. But the shape of Hgen's bet is at least the right shape. It is not waiting for a breakthrough. It is trying to make a two-hundred-year-old machine small enough to be boring, and cheap enough to be everywhere.