MADRID (Reuters) – Siemens Gamesa, the world’s largest maker of offshore wind turbines, expects current supply chain problems that have hit the global wind power sector to persist for a while, its chief executive said on Friday. “We are battling with raw material price increases, we see a severe crisis at the moment with big disruption in our supply chain,” Andreas Nauen told an event organised by ESADE business school in Spain. Supply chain issues were one factor triggering a profit warning at Siemens Gamesa, in which Germany’s Siemens Energy owns 67%, last week. Denmark’s Vestas, too, warned…