BMWhas been experimentingwith hydrogen fuel cell cars for years, but unlike Honda, Hyundai, and Toyota, the German automaker hasn’t puthydrogen carsinto production.Forbesreports that BMW will launch a test fleet of fuel-cell X5 SUVs in the early 2020s, followed by a volume-production model, co-developed with Toyota, in 2025.

The hydrogen fuel-cellX5will likely function as a sort of beta test vehicle, giving BMW real world data on fuel cell technology — and customers’ reactions to it. BMW did a similar thing with battery-electric cars, leasing the Active E and Mini E models to handpicked customers before the full-scale rollout of its first mass-produced electric car,the i3. It also makes sense for BMW to partner with Toyota on a series production model. Toyota haslots of experiencewith fuel cells, and the two automakers have an existing relationship. They previously partnered on theToyota SupraandBMW Z4sports car twins.

BMW i8 hydrogen fuel-cell prototype

Like all automakers, BMW needs to reduce emissions in order to meet stricter global standards. But BMW’s emissions-reduction efforts have primarily focused on battery-electric cars and plug-in hybrids. Fuel cells offer some advantages over batteries. Refueling is much quicker than recharging, and fuel cell cars generally have longer ranges than their battery-powered counterparts. However, producing enough hydrogen and building a network of fueling stations has proven difficult. In the United States, fuel cell cars are currently sold only in certain regions of California, because those are the only areas with a dense enough network of fueling stations.

BMW has worked with hydrogen before, evendeveloping a carthat burned hydrogen in a standard internal combustion engine. In 2015, the German automakerunveiledprototype hydrogen fuel cell versions of the i8 (picture above) and 5 Series Gran Turismo. Those cars were never destined for production, but served as test beds for the technology.

Even if BMW does launch a production hydrogen fuel cell car during the next decade, it’s unclear how big of an impact that will have. Toyota, Honda, and Hyundai currently sell fuel cell cars, but their numbers are tiny. BMW’s current plans also call for a much larger volume of battery-electric cars. The automaker just unveiled a720-horsepower prototype, and will use components from it in an electric versionof the X3. BMW is also planning anelectric Mini Cooperand new electric models in the form of the i4 and iNext. Even with these projects in development, the automaker still sees a futurefor internal-combustion enginesas well.