Area of Zambia concerned with energy (4)
I believe the answer is:
zone
'area' is the definition.
(zone is a kind of area)
'zambia concerned with energy' is the wordplay.
'zambia' becomes 'z'.
'concerned with' becomes 'on' (I've seen this in other clues).
'energy' becomes 'e' (physics symbol as in E=mcn).
'z'+'on'+'e'='ZONE'
'of' acts as a link.
(Other definitions for zone that I've seen before include "Region with particular characteristics" , "Area with a particular characteristic" , "Distinctive area" , "A defined area as for particular purpose" , "Bitter, pungent" .)