By Dominic Culverwell in Berlin Russia’s extreme strikes on Ukraine’s energy infrastructure this week have caused international outrage and concerns that the war-torn country will suffer a cold and dark winter. DTEK, Ukraine’s largest private investor in the energy sector, has been working hard to make sure that doesn’t happen. Nevertheless, the challenges are huge, particularly with Moscow’s intense focus on destroying as many facilities as possible. Speaking from a bunker in Kyiv during an air raid alert, DTEK CEO Maksym Timchenko talked about the problems and obstacles that Ukraine is tryin…