(Pocket-lint) - While BMW is investing heavily in all-electric vehicle technology it isn't putting all its zero emission eggs in just the one basket. It has reaffirmed its commitment to hydrogen fuel cell technology, even revealing that it could be employed in higher-end X series cars in future.

A powertrain utilising hydrogen fuel cell technology has a distinct advantage over battery electric equivalents in that fuel cells can provide much greater range before needing to be topped up. And refuelling only takes three to four minutes.

It is also completely zero emission because it generates power through a chemical reaction between the hydrogen and oxygen drawn from the ambient air. The end product is simply water vapour.

The company has trialled hydrogen as a power source since 1979, and is soon to undergo new testing with a second generation powertrain. It will be piloted in a BMW i Hydrogen NEXT concept, starting in 2022.

The latest system, built in collaboration with Toyota, will be capable of generating 125kW (170hp) of power in order to drive the car's electric motor: "The electric converter located underneath the fuel cell adapts the voltage level to that of both the electric powertrain and the peak power battery, which is fed by brake energy as well as the energy from the fuel cell," explained BMW's vice president of hydrogen fuel cell technology, Jürgen Guldner.

Sadly, BMW revealed that it is a long way off from producing a consumer hydrogen fuel cell car: "At the earliest in the second half of this decade," it said.

But that's mainly because of the infrastructure (refuelling points, for example) rather than the technology itself. It is still, however, continuing to develop hybrid and all-electric alternatives in the meantime, with 25 models planned for launch by 2023.

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Writing by Rik Henderson.