Unlike conventional subs , which need air to combust diesel , the fuel cell does n't require oxygen to operate . The Shark is an ultra - advanced non - nuclear sub developed for the German Navy . powered by a revolutionary hydrogen fuel cell , it is almost totally silent . Without the need for combustible fuel , the Shark can remain submerged for hours at sea .
The Shark is an ultra - advanced non - nuclear sub developed for the German Navy . powered by a revolutionary hydrogen fuel cell , it is almost totally silent . Without the need for combustible fuel , the Shark can remain submerged for hours at sea .