Automakers have worked on fuel cells for decades, but the tech has languished in the shadow of gasoline and battery-electric development. They’re now playing a key role in automakers’ strategies.

Thirty miles north of General Motors’ headquarters in Detroit, hundreds of engineers are developing a zero-emission alternative to battery-electric vehicles: hydrogen fuel cells.

They coat ink onto carbon paper and produce miles of seals that separate air, water and coolant. They build small-scale electrodes to test chemistries designed to create electricity from hydrogen with water as the only byproduct.

GM and other automakers have worked on hydrogen fuel cells for decades, but the technology has languished in the shadow of gasoline and battery-electric vehicle development.

Now, fuel cells are playing a key role in automakers’ strategies as the push to decarbonize becomes more urgent.