Tight secrecy around port plays into The Green's agenda perhaps (8)
I believe the answer is:
recycles
'plays into the green's agenda perhaps' is the definition.
I can't judge whether this definition defines the answer.
'tight secrecy around port' is the wordplay.
'tight' indicates anagramming the letters (tight can mean drunk).
'around' means one lot of letters goes inside another.
'port' becomes 'L' (abbreviation for L - 'port' is 'left' on a boat).
'secrecy' is an anagram of 'recyces'.
'recyces' placed around 'l' is 'RECYCLES'.
Can you help me to learn more?
(Other definitions for recycles that I've seen before include "Acts eco-friendly" , "Uses again for another purpose" , "Converts waste material for use again" .)