Lewis Hamilton, Fernando Alonso and Marcus Ericsson have all logged grid penalties in Spa for taking sixth power unit elements.
Hamilton took a sixth turbo and sixth MGU-H for FP1, which means he gets 15 places (10 + 5), and then repeated the exercise with his seventh elements in FP2, adding 15 more places for a total of 30.
He also has taken a fourth and fifth ICE (V6) and fourth and fifth MGU-K, without penalty.
Mercedes is in effect stockpiling power unit elements for the remainder of the season, so that Hamilton won’t get penalties at a future race.
Meanwhile Fernando Alonso has taken his sixth examples of all six elements for FP2. He had his fifth examples fitted for FP1, but suffered a water leak from the ERS and did not set a representative time. All elements used today were off the latest updated spec.
Honda noted: “During FP1, we found a water leak from the ERS. Detailed investigation will follow, however, we have swapped out the whole of PU to ensure Fernando is out and running in FP2.”
Alonso will thus take a 35 place penalty for the change (10 + 5 + 5 + 5 + 5 + 5).
Finally Ericsson is on 10 places after taking his sixth turbo of the season.
Adam Cooper's F1 Blog 
Is there any point in stockpiling more power units for Hamilton at the current spec? I presume Merc will have updates to bring before the end of the season
Incur multiple penalties but you only have to serve one! So much of F1 rule making needs to be looked at by someone with a legal background, or at least, someone with a mind tending towards ‘clarity’.
Mutiple engine components taken over the allotment should result in similar multiple race penalties. This concept of “stockpiling” replacement components and suffering a penalty at one race is ridiculous and seems to subvert the intent of regulation.
It was right that they scrapped the rule where penalties carried over to the following race but I would like to see a system where they take the penalty when a new unit is used in qualifying or the race. They wouldn’t be able to stockpile new units for later races.
That would make too much sense.