The electric revolution is already underway, but a handful of companies haven’t given up on hydrogen. Daimler Truck is among them and they’ve been working on an eco-friendly Unimog.

The prototype is based on a Unimog U 430 implement carrier and isn’t your typical FCV. Instead, it has a “specially converted” engine that runs on hydrogen.

The company didn’t go into many specifics, but said the engine produces around 290 hp (216 kW / 294 PS) and 737 lb-ft (1000 Nm) of torque. It’s fed by four high-pressure storage tanks, which are located behind the cab and hold around 31 lbs (14 kg) of hydrogen. That’s apparently not very much as Daimler Truck said “engineers aim to increase the volume to be able to cover a regular working day” in the next stage of development.

The engine is “noticeably quieter than its diesel equivalent” and “produces water, which is discharged as steam via the exhaust system.”

More: Toyota Wants To Keep ICE Sports Cars Alive With Hydrogen Combustion Engines

The prototype also sports two mowing heads and was recently tested on a decommissioned stretch of highway between Bayreuth and Bamberg. This subjected the vehicle to low temperatures, varied topography, and refueling at a public gas station.

Despite the test, the company is focused on electric and hydrogen-powered fuel cells. However, they noted hydrogen combustion is another option for the “decarbonization” of their lineup as initial results from the WaVe project showed the “hydrogen combustion engine can be a sensible, complementary solution for special applications.”

Mercedes-Benz Special Trucks boss, Franziska Cusumano, said that after two years, they’re “very happy with the current development status of the test vehicle.” He added, “The tests with Autobahn GmbH staff in Upper Franconia are particularly valuable for us because here we can collect important feedback from practical application for … further development work.”