PoliticsGermany steps up drive to replace Russian oil suppliesBaltic Sea port of Rostock could play key role in supplying crude for pipeline feeding German refineriesHelping hand: The Capricorn Sun oil tanker, pictured carrying Mars Sour oil off the Louisiana coast in the US before heading for the port of Rostock in GermanyPhoto: REUTERS/SCANPIXZsuzsanna SzaboOslo