Zero energy? Source of hydroelectricity (4)
I believe the answer is:
nile
'hydroelectricity' is the definition.
Both the answer and definition are singular nouns.
Maybe there's an association between them I don't understand?
'zero energy? source' is the wordplay.
'zero' becomes 'nil' (synonyms).
'source' says to take the initial letters (source can mean a beginning or origin).
The initial letter of 'energy' is 'e'.
'nil'+'e'='NILE'
'of' is the link.
Can you help me to learn more?
(Other definitions for nile that I've seen before include "long-distance runner in Africa" , "Cairo's river" , "Egyptian river" , "River of Egypt" , "Egypt's river" .)