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' means one lot of letters go next to another (I've seen this in other clues).
'fuel' anagrammed gives 'eful'.
'eful' after 'us' is 'USEFUL'.
(Other definitions for useful that I've seen before include "Advantageous; very able" , "Handy, practical" , "Functional, handy" , "Expedient" , "Advantageous - efficacious" .)