During 2005 he competed in the World Series by Renault for the Carlin Motorsport team, where he proved very competitive. During the course of the WSR championship he scored two race victories, with 4 trips to the podium in total and qualified his car on the front row five times. In addition to driving in the WSR, Power was also one of the featured drivers for the Australian team in the 2005–06 A1 Grand Prix season. Power raced in the series opener at Brands Hatch and piloted Australia to a second-place finish behind Team Brazil.