{"id":9355,"date":"2026-06-02T05:13:15","date_gmt":"2026-06-02T09:13:15","guid":{"rendered":"https:\/\/www.autonocion.com\/us\/?p=9355"},"modified":"2026-06-02T05:13:15","modified_gmt":"2026-06-02T09:13:15","slug":"storing-hydrogen-tractor-spinning","status":"publish","type":"post","link":"https:\/\/www.autonocion.com\/us\/storing-hydrogen-tractor-spinning\/","title":{"rendered":"Storing Hydrogen Inside a Tractor’s Spinning, High-Pressure Wheels Sounds Like Either a Brilliant Idea or a Terrible One. A German Firm Is Convinced It’s the First"},"content":{"rendered":"

Hydrogen has a real estate problem. The fuel works fine once it reaches an engine or a fuel cell, but actually carrying enough of it is where the whole thing tends to fall apart. Even compressed to 700 bar, hydrogen takes up far more room than the diesel it is meant to replace, which is a big part of why passenger hydrogen cars never got the fueling network that battery EVs got<\/a>. On a car you can usually wedge a tank or two somewhere out of the way. On a tractor that has to work a field for ten hours straight, you run out of places fast. H\u00f6rmann Vehicle Engineering, a German firm based in Chemnitz, thinks the answer has been sitting in plain sight the whole time: the inside of the wheels.<\/p>\n

The company set out the idea this spring in a statement published by Fuel Cells Works<\/a>, dropping the usual roof-mounted tanks in favor of ring-shaped carbon-fiber pressure vessels built straight into the rear wheel rims. Running at 700 bar, they are designed to hold up to 42 kilograms of hydrogen between them, roughly the usable energy of 200 liters of diesel. That is double what the tractor it is based on currently carries. And it is still a concept, not a machine you can buy.<\/p>\n

A tractor’s rear wheels are mostly empty space<\/h2>\n

If you have ever stood next to a large agricultural tractor, you have probably noticed the rear wheels are enormous, and most of what sits inside the rim is air. H\u00f6rmann’s idea is to stop wasting that volume. By shaping the hydrogen tanks like rings and seating them inside the rims, the company turns dead structural space into fuel storage without touching the roof, the hood area, or anywhere a farmer actually needs to mount an implement.<\/p>\n

The vessels are carbon-fiber, the same high-pressure construction used in hydrogen trucks, and they sit at 700 bar like the rest of the hardware in this corner of the industry. The pitch is not a new kind of tractor. It is the same tractor with its fuel hidden somewhere nobody had bothered to look.<\/p>\n

The tractor doing the driving keeps its fuel on the roof<\/h2>\n

The machine all of this is built around is the Fendt Helios, a hydrogen prototype from Fendt and its parent company AGCO that the company has been running through real field tests. It carries its fuel the conventional way: five compressed tanks bolted into a raised housing on the roof, each holding 4.2 kilograms, for 21 kilograms total at 700 bar. Underneath sit a 100 kW fuel cell and a 25 kWh buffer battery feeding a 100 kW electric motor, good for about 134 horsepower. Fendt first showed the Helios at Agritechnica in 2023<\/a> and put it into harvest work in 2024.<\/p>\n

That 21 kilograms buys five to eight hours of field work per fill, depending on how hard the tractor is pushed. Fine for plenty of jobs, but short of a diesel machine that just keeps going all day. H\u00f6rmann’s wheel tanks are meant to close exactly that gap by roughly doubling the onboard hydrogen to 42 kilograms, which is where the full-day claim comes from. The Helios already performs like its diesel equivalent when it has fuel in the tank. “The Fendt Helios carries out all the work on farms that a tractor with similar power and a diesel engine would have to do,” said Dr. Benno Pichlmaier, AGCO’s Director of Global Research and Advanced Engineering. The problem was never the power. It was how long the thing could run before someone had to stop and refuel it.<\/p>\n

\n
\n
TARGET<\/div>\n
In the wheels<\/div>\n
42 kg<\/div>\n
H\u00f6rmann concept. Ring-shaped carbon-fiber tanks built into the rear rims, aiming at a full day’s work.<\/div>\n<\/div>\n
\n
On the roof<\/div>\n
21 kg<\/div>\n
Fendt Helios today. Five roof tanks at 4.2 kg each, good for 5 to 8 hours per fill.<\/div>\n<\/div>\n
\n
Pressure<\/div>\n
700 bar<\/div>\n
Same operating pressure for the roof tanks and the wheel concept alike.<\/div>\n<\/div>\n
\n
Energy<\/div>\n
~200 L<\/div>\n
Diesel-equivalent usable energy in the wheel concept’s 42 kg of hydrogen.<\/div>\n<\/div>\n<\/div>\n

The tank is only half the idea<\/h2>\n

H\u00f6rmann paired the wheel storage with a newly developed electric wheel drive, so the same assembly that holds the fuel also delivers the power. H\u00f6rmann says the motor is a reluctance design built without any rare-earth materials, which sidesteps one of the nastier supply-chain dependencies in modern electric drivetrains. Packaging the storage and the drive together inside the wheel opens up vehicle layouts a conventional driveline cannot, and the company calls the combination robust.<\/p>\n

Because it is modular, H\u00f6rmann says the system works with both hydrogen fuel cells and hydrogen combustion engines, so a manufacturer can pick whichever powertrain it is betting on and run the same wheel concept underneath. That flexibility matters more than it sounds, because the industry has not settled on which hydrogen powertrain wins, and a storage solution that does not care is a safer bet than one that locks you in. It is being developed under RAHD, a publicly funded research project backed by Saxony’s state development bank and the European Union, which makes it a real funded effort and not just a render with a press release attached.<\/p>\n

The hydrogen has to come from somewhere clean<\/h2>\n

None of this counts for much environmentally if the hydrogen itself is made from fossil fuels, which is where the program behind the Helios comes in. The tractor runs inside H2Agrar, a demonstration project launched in February 2021 with around 7.6 million euros in funding from the German state of Lower Saxony, billed as Germany’s first end-to-end test of hydrogen in agriculture. The fuel is green hydrogen, produced on site near the town of Haren by two 1-megawatt electrolyzers running on power from a community wind farm of 16 turbines.<\/p>\n

That setup can make up to 900 kilograms of hydrogen a day, fed into a dedicated filling station built by Schwelm Anlagentechnik that holds 480 kilograms and dispenses at 350 and 700 bar at the same time. H\u00f6rmann has floated on-farm hydrogen production as the longer-term version of this, including hydrogen made from biogas right where the tractor works, which would shrink the fuel-logistics problem to almost nothing. That logistics math is exactly why hydrogen keeps turning up in places diesel struggles to reach, from remote farms to military outposts where delivered fuel can run into the hundreds of dollars per gallon<\/a>.<\/p>\n

The engineers working on these machines have been blunt about the core tradeoff. “One challenge is to adapt the tractor and its use to the expected lower energy storage capacity of hydrogen compared to diesel,” Professor Ludger Frerichs of TU Braunschweig’s Institute for Mobile Machinery and Commercial Vehicles told the university’s magazine. Putting more fuel in the wheels is one way to adapt. It is not the only one, and it is not a sure thing.<\/p>\n

This is still a concept, and the wheels make it a hard one<\/h2>\n

A pressure vessel that spins is a difficult thing to build. A 700-bar tank bolted to a roof just sits there. The same tank inside a rotating wheel takes a constant pounding, the occasional rock included, has to hold its seal while it spins, and still has to let hydrogen flow in and out on demand. H\u00f6rmann has said it is working on safety hardware for exactly this, including thermal relief valves and impact sensors, but no independent test data has been published, and there is no confirmation the concept has reached a running prototype. The Helios is real and out in fields. The wheel-tank version, right now, is a design.<\/p>\n

A few of the headlines this generated online oversold it, too. The wheel tanks do not make a tractor that “never stops” or magically runs twelve hours on nothing. What they do, on paper, is roughly double the fuel a hydrogen tractor can carry without redesigning the whole machine, which is enough to aim at a full day’s work instead of half of one. That is a real engineering goal, not a miracle.<\/p>\n

If it works, the interesting part is not really tractors. H\u00f6rmann pitches the same approach for heavy trucks, construction equipment, and other off-highway machines, all of which share the same bind: big enough to need serious endurance, too heavy for batteries to be practical, and short on places to stash a hydrogen tank. It is the same logic pushing hydrogen into other corners of transport that batteries cannot easily reach<\/a>, from regional aircraft to long-haul trucking. On every one of those machines, the wheel is dead weight today. Turning it into the fuel tank, on something with no room to spare, is at least a problem worth chasing.<\/p>\n

The honest version is short: a German firm found unused space in a tractor wheel, decided to fill it with hydrogen, and drew up a way to roughly double how long one of these machines can run between fills. Whether a spinning 700-bar tank can be built safe enough and cheap enough to actually sell is the question the whole thing rests on, and nobody has answered it yet. The idea is smart. The wheel just has to survive being one.<\/p>\n","protected":false},"excerpt":{"rendered":"

Hydrogen has a real estate problem. The fuel works fine once it reaches an engine or a fuel cell, but … <\/p>\n

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