Consume power during strike (7)
I believe the answer is:
deplete
'consume' is the definition.
(synonyms)
'power during strike' is the wordplay.
'power' becomes 'p' (symbol in physics).
'during' is an insertion indicator.
'strike' becomes 'delete' (strike can mean to delete or erase).
'p' placed into 'delete' is 'DEPLETE'.
(Other definitions for deplete that I've seen before include "Drain" , "Empty, reduce, exhaust" , "Reduce (stocks)" , "Reduce (amount of supplies etc)" , "Use up, exhaust" .)