Excellent fireplace, pushing energy forward (5)
I believe the answer is:
great
'excellent' is the definition.
(thesaurus)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for great that I've seen before include "Excellent (colloq.)" , "Big, large" , "Of major significance - very good" , "Brunel's third and last steamship" , "Peter the -, Russ. tsar" .)