German automaker BMW is reportedly planning a commercially viable hydrogen fuel cell vehicle for the 2020 model year, a development that revives speculation that fuel cell technology will power the next vehicle in the automaker’s i-series of electric and plug-in hybrids. BMW’s i3 electric mini would need an update around 2020, meaning if the reports are accurate, BMW’s first hydrogen-powered car could be the next i3.

Automotive industry speculation is not an exact science – automakers typically stay quiet about rumors. But in this case, British magazine Auto Express is quoting an anonymous senior BMW source.

“Our target is 2020,” the source said.

BMW has been working on hydrogen fuel cell (HFC) technology since early 2013 as part of an alliance with Toyota Motor Corp., which began selling its hand-built, HFC-powered Mirai in select markets in February. BMW will use the technology that the two automakers have been developing, but it’s holding off on releasing its own vehicle so Toyota can work out whatever kinks occur in the first generation of commercial deployment.

BMW currently has two vehicles in the i-series: the i3, which comes with an optional range-extending gas engine, and the i8 plug-in hybrid sports car. BMW could include an HFC in the i-series, especially if it opts for a plug-in electric-HFC hybrid, which would allow the car to run on both power from the grid as well as liquefied hydrogen. Rumors have been circulating on auto blogs for the past year that the i3 is the most logical target for fuel cell technology, but BMW isn’t confirming that -- even anonymously.

Hydrogen fuel cells power the International Space Station and are used widely in other applications, from military submarines to stationary power generation. The process splits hydrogen atoms, creating electricity, heat and water, and the electricity powers engines without harmful emissions.

But despite years of work by automakers and occasional limited introductions – Hyundai is leasing a small number of HFC-powered Tucsons – demand for the technology is hampered by a lack of hydrogen fuelling stations. It’s also unknown, for example, how the tubing and valves connecting the hydrogen storage tank to the fuel cell stack will withstand wear and pressure over time.

One of most vocal skeptics of HFC-powered cars has been Tesla Motors Chief Executive Officer Elon Musk, who believes electric power derived from renewable energy sources is the future for motorized transport. Environmentalists point out that HFC vehicles are not carbon-neutral because most hydrogen currently is harvested from fossil fuels.