He's named as one upset about coal supply (7)
I believe the answer is:
nominee
'he's named as one upset' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'about coal supply' is the wordplay.
'about' is an insertion indicator.
'coal' becomes 'noe' (I can't explain this - if you can you should believe this answer much more).
'supply' becomes 'mine' (a mine is a supply of something).
'noe' going around 'mine' is 'NOMINEE'.
Can you help me to learn more?
(Other definitions for nominee that I've seen before include "Person standing for office" , "One whose name is put forward" , "One put forward as a candidate" , "One named as candidate" , "One proposed for election" .)