Mercedes have changed the turbocharger, MGU-H, control electronics and energy store on Hamilton’s machine ahead of the race, but since all were within his season’s power unit allocation and replaced with permission of the FIA technical delegate, he faces no grid penalties.
The ERS failure was a repeat of the one the world champion suffered in qualifying at the previous round in China. There he started from the back of the grid, having failed to set a lap time during the session.
On Saturday, Mercedes’ technical chief Paddy Lowe conceded the team had let Hamilton down. The British driver goes into the Sochi race trailing team mate and championship leader Nico Rosberg - who starts from pole - by 36 points in the driver standings.