While electric vehicles are quickly proliferating throughout the world, most electric engines are still relegated to smaller vehicles. The serious work, some argue, is still done by gas-guzzling diesel engines. But then there’s the Elekto Dumper—the world’s largest EV—which flouts the rule that EVs can’t handle serious work.

The truck is used to haul lime and marlstone, which contains clay and silt, from the sides of mountains in Switzerland. Then, the material is transported directly to a cement factory. But here’s the really impressive piece of engineering—this heavy dump truck never needs to be charged.

Here’s how it works: The dump truck, itself, weighs 45 tons and ascends a hill at a 13 percent grade, in one scenario. On the way back down, it’s more than twice as heavy, carrying 65 tons of ore. To rectify that scenario, the truck’s “regenerative braking system” actually recaptures the energy created by going downhill, refilling the battery’s charge for the next time the truck travels uphill.

The German manufacturer of the truck, Kuhn Schweitz, says that making the trip from quarry to cement factory 20 times in one day produces a surplus of 200 kilowatt-hours of energy (or 77 megawatt-hours per year). Your average dump truck, by contrast, uses between 11,000 and 22,000 gallons of diesel fuel each year. You do the math.