Handy source of fuel for us (6)
I believe the answer is:
useful
'handy' is the definition.
(I've seen this before)
'source of fuel for us' is the wordplay.
'source of' indicates an anagram.
'for' is a charade indicator (letters next to each other) (I've seen this in other clues).
'fuel' with letters rearranged gives 'eful'.
'eful' put after 'us' is 'USEFUL'.
(Other definitions for useful that I've seen before include "Advantageous; very able" , "Handy, practical" , "Functional, handy" , "Expedient" , "Advantageous - efficacious" .)