Renault Sport has apologised to Red Bull Racing after an alternator failure cost Sebastian Vettel eight points in the Italian Grand Prix.
In one of their worst performances of the season, a Renault powered car failed to finish higher than fifth place - courtesy of the Lotus of Kimi Raikkonen - while he was joined in the top ten only by the Williams of Bruno Senna.
Rémi Taffin, Renault Sport F1 head of track operations, admitted that their performance was sub-standard.
"This weekend has not been acceptable from either a performance or reliability point of view", he said.
"We have to apologise to Red Bull for the two failures on Sebastian’s car, first in FP3 and now in the race. In both cases the alternator failed."
It is also understood that, as a precaution, the alternator on Jerome d'Ambrosio's Lotus E20 was changed prior to qualifying.
Taffin admitted disappointment that the new alternator had failed, after a different specification failed in Vettel and Romain Grosjean's car in Valencia.
"We introduced a new spec’ of alternator following the problems in Valencia and believed this would overcome the issues"
"We are still looking into why the part failed again here but we do know that even though the alternator was being operated entirely within the prescribed range, the part itself overheated and shut off the power supply. This is a priority between ourselves and our suppliers and we have to ensure we are fully on top of the problem before Singapore."
Taffin added that Renault Sport is also looking into why d'Ambrosio suffered a KERS failure.
"Lotus has again had a strong finish and Kimi made the most of the potential of the car, but there was a problem with the KERS on Jérôme’s car that we also need to investigate"
