Here is the U212A, a submarine designed by the German shipyard HDW (Howaldtswerke Deutsche Werft) a project started in 1994 and whose first samples are functioning since 2003.
The U212A is the most advanced non-nuclear submarines, a tactical submarine designed to detect other submarines.
More than just green, this technology has interesting competitive advantages:
Constructed from non-magnetic materials its nearly silent technology creates no heat, therefore, the U212A is virtually undetectable and can remain submerged much longer than the conventional submarines.
“The peak of German submarine technology” as its manufacturer qualifies it, can carry up to 27 people. Units of this submarine have already been sold to Greece, Portugaland South Korea.