In detail study country’s energy (6)
I believe the answer is:
peruse
'in detail study' is the definition.
(to peruse is to study in detail)
'country's energy' is the wordplay.
'country's' becomes 'Peru's' (Peru is an example).
'energy' becomes 'e' (physics symbol as in E=mc2).
'perus'+'e'='PERUSE'
(Other definitions for peruse that I've seen before include "Browse, read casually" , "Thoroughly examine" , "Examine at length" , "Scrutinize" , "Read or study carefully" .)