Such a car would be Audi's sixth-generation hydrogen fuel cell prototype, which may eventually morph into a low-volume production vehicle by 2021 that would be leased out to customers in certain markets, much like the Toyota Mirai is today. Aside from the prototype and subsequent low-volume model, Audi is keeping talk about timelines to a minimum. All it says is that large scale production wouldn't happen any time before 2025. Audi has the advantage of having formed a partnership with Hyundai last year to work on hydrogen vehicles, and given that Hyundai already builds the hydrogen-fueled Nexo, the Four Rings can license the tech for use in its own vehicles. As exciting as this sounds, we're not quite sure how to digest the news given that no one has really seen what a world ruled by electric cars even looks like….yet.