Europe's Legal Struggles Over Nord Stream
Nord Stream explosions three years ago in the Baltic Sea severed Russian gas transit to Europe.
Serhii K faces charges of collusion to cause explosions, sabotage, and destruction of structures.
He is set to appear before a German court in Karlsruhe.
A Polish court denied extradition of another Ukrainian suspect and ordered release.
Nord Stream investigation took years, impacting Europe's energy markets.