Handy form of fuel for us (6)
I believe the answer is:
useful
'handy' is the definition.
(I've seen this before)
'form of fuel for us' is the wordplay.
'form of' indicates an anagram (the letters need to be in another 'form').
'for' means one lot of letters go next to another (I've seen this in other clues).
'fuel' with letters rearranged gives 'eful'.
'eful' after 'us' is 'USEFUL'.
(Other definitions for useful that I've seen before include "Handy; very able" , "Beneficial" , "Practically helpful" , "Utilitarian" , "Advantageous; very able" .)