Renault unsure of alternator failure's root cause
Renault have confirmed that it was an overheating alternator that caused both Grosjean and Vettel's retirements in Valencia, but they are still unsure as to why that problem occured. They also said that the slower speeds during the safety car period had actually prevented Vettel's failure from happening earlier. They are now considering either a modified design for Silverstone, or reverting to a 2011 model.
2 July 2012 - Source
ej Eddie Jordan
I'd just like to add, if I may, that this whole situation is really being overblown, these things are bound happen once in a while in the highly competitive competitiveness of F1 and I'm sure the more than competent Renault guys are on top of it. In the Jordan days, mechanical failures were part and parcel of the sport. But the crux of the matter here really is that this exposes a deep-seeded weakness in the Renault engine department, who, let's be honest, just haven't been up to par over the last few seaons, and appear to be in somewhat of a crisis at the moment.