It may look like an ordinary current-generation X5 before its Life Cycle Impulse, but this luxury SUV from BMW is substantially different underneath the familiar skin. The iX5 boasts a fully electric powertrain without carrying around a bulky battery pack. Instead, it has a couple of tanks made from carbon fiber and capable of storing six kilograms of compressed hydrogen.

After making an appearance in the UK back in July at the Goodwood Festival of Speed, the zero-emission X5 is in the United States this week at Pebble Beach. It’s highly unlikely you will ever see it out on the open road since BMW is making fewer than 100 units. It acts much like a battery-powered EV with rear-wheel drive and its weight is similar to that of the xDrive50e, the new plug-in hybrid version introduced with the LCI a few months ago.

This latest evolution of the iX5 packs more punch than before as the output has grown by 31 to 401 horsepower. It’s enough hydrogen muscle for a sprint to 62 mph (100 km/h) in less than six seconds and a top speed of 115 mph (185 km/h). Since the original version, BMW has installed a Sport mode that not only unlocks the full power but also stiffens up the suspension to improve handling. Once the hydrogen tanks are depleted, it’ll take about three to five minutes to fill them, so roughly as much as you would refuel a gasoline or diesel car.

This iX5 still has shift paddles behind the steering wheel but they’ve been repurposed to adjust the intensity of the brake energy recuperation system. BMW says the eco-friendly SUV can be driven with just one pedal, therefore echoing conventional EVs. As with the conventionally powered model, the vehicle is built in Spartanburg, South Carolina but the necessary modifications are carried out in Munich. The maximum range has been estimated at 310 miles (500 kilometers).

Only five iX5 units are headed to the US by the end of this year as part of the global pilot program. BMW says these are technically experimental prototypes, which means they can’t be sold. Instead, the vehicles will be handed over temporarily to members of the media as well as stakeholders to test the technology in real-world driving conditions.

A hydrogen-fueled BMW production model you’ll be able to buy is coming before the end of the decade, according to a statement made by chairman Oliver Zipse in an interview with Top Gear earlier this week.