Novel source of energy - gas! (5,4)
I believe the answer is:
'novel' is the definition.
(novel by anne bronte)
'source of energy gas' is the wordplay.
'source of' indicates anagramming the letters.
'energygas' with letters rearranged gives 'AGNES GREY'.
(Other definitions for agnes grey that I've seen before include "Novel" , "Acton governess" .)