Endless energy produced on New York time is most eco-friendly (8)
I believe the answer is:
greenest
'most eco-friendly' is the definition.
'endless energy produced on new york time' is the wordplay.
'endless' means to remove the last letter.
'produced' indicates an anagram.
'on' says to put letters next to each other.
'new york time' becomes 'est' (short for Eastern Standard Time).
'energy' with its last letter removed is 'energ'.
'energ' with letters rearranged gives 'green'.
'green'+'est'='GREENEST'
'is' is the link.
(Other definitions for greenest that I've seen before include "Most naive" , "Extremely immature" , "Most verdant" , "Most unsophisticated" .)