Cleaner energy embraced by bankrupt capital (9)
I believe the answer is:
bucharest
'capital' is the definition.
(capital of Romania)
'cleaner energy embraced by bankrupt' is the wordplay.
'cleaner' becomes 'char' (charwoman is a type of cleaner).
'energy' becomes 'e' (physics symbol as in E=mc2).
'embraced by' means one lot of letters goes inside another.
'bankrupt' becomes 'bust' (I've seen this before).
'char'+'e'='chare'
'chare' put within 'bust' is 'BUCHAREST'.
(Other definitions for bucharest that I've seen before include "Balkan city" , "European city" , "European capital" , "Romanian capital" , "Capital of Romania" .)