With energy fully extracted, piped waste spoils (4)
I believe the answer is:
swag
'spoils' is the definition.
(I've seen this before)
'with energy fully extracted piped waste' is the wordplay.
I cannot really see how this works, but
'with' could be 'w' (abbreviation) and 'w' is found in the answer.
The remaining letters 'sag' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for swag that I've seen before include "Thief's bundle" , "Part of a curtain" , "pack of Aussie travellers" , "items stolen" , "Burglar's spoils" .)