BMW will soon expand its range of i-badged electric models, but it's not putting hydrogen technology on the back burner. The company released preliminary specifications about its next hydrogen-electric drivetrain.

Developed jointly with Toyota, the system consists of a pair of 700-bar tanks that hold a total of 13.2 pounds of hydrogen, a fuel cell, the fifth-generation electric motor that will power future electric cars, like the i4 and the iNext, and what BMW calls a peak power battery installed over the drive unit. The fuel cell uses hydrogen and oxygen to generate electricity and sends it to the motor, while the peak power battery provides a temporary acceleration boost. The i Hydrogen Next system's total output checks in at 374 horsepower for short bursts of time, though the fuel cell puts 170 horsepower under the driver's right foot in normal driving conditions.

"The peak power battery kicks in for extra driving dynamics when needed. If you have a dynamic driving style, this can be quite often, which is why the fuel cell can also charge the peak power battery direction," a company spokesperson explained to Autoblog.

The system's main advantage over an electric powertrain is that refueling the tanks takes three or four minutes, though BMW has not revealed the system's driving range. It's also not as sensitive to extreme temperatures as a lithium-ion battery pack. The fuel cell emits only water vapor, so it's considered a zero-emissions technology.

Hydrogen is promising, but the technology must clear several big hurdles before it merges into the mainstream. BMW pointed out it needs to be produced in sufficient quantities, at a competitive price, and using green energy. The network of hydrogen filling stations is also far too small to power a significant number of cars, though car companies and governments around the world are planning to expand it. Once these conditions are met, hydrogen will be primarily used in applications that can't be electrified, like long-distance heavy-duty transport.

BMW isn't in the trucking business, so it will build a small number of hydrogen-powered X5s in 2022 and test them in real-world conditions. The spokesperson we talked to couldn't reveal if the tests will include customers, or if they'll be done internally. The lessons drawn from the project will help engineers fine-tune the technology, and BMW plans to release a regular-production hydrogen-powered model in the second half of the 2020s at the earliest, though it warned global market conditions and requirements will heavily influence this timeline.

Don't expect to find a Z4 with hydrogen tanks and electric motors if you visit a BMW showroom in 2029. While details about the model the technology will go into haven't been released yet, likely because they haven't been finalized, the company strongly hinted its bigger SUVs are best-suited to receiving hydrogen technology.

"The hydrogen fuel cell technology could quite feasibly become the fourth pillar of our powertrain portfolio in the long term. The upper-end models in our extremely popular X family would make particularly suitable candidates here," explained Klaus Fröhlich, BMW's development boss, in a statement.

He added electric drivetrains, hybrid systems, gasoline- and diesel-burning engines, and possibly hydrogen technology will coexist in the foreseeable future because there is no one-size fits all solution. For example, the next-generation 7 Series tentatively due out in 2022 will be offered with at least four powertrain types.