City invested in parking and recycled energy and walkway (9)
I believe the answer is:
promenade
'walkway' is the definition.
(I know that Promenade is a type of walkway)
'city invested in parking and recycled energy' is the wordplay.
'city' becomes 'rome' (Rome is an example).
'invested in' is an insertion indicator.
'parking' becomes 'p' (abbreviation on road signs).
'recycled' indicates an anagram.
'energy' becomes 'e' (physics symbol as in E=mco).
'p'+'and'='pand'
'pand' anagrammed gives 'pnad'.
'rome' placed into 'pnad' is 'promenad'.
'promenad'+'e'='PROMENADE'
'and' is the link.
(Other definitions for promenade that I've seen before include "Seafront walk" , "Seafront walkway" , "Place for strolling by the sea" , "Seaside walk?" , "dance" .)