Mine providing fuel regularly? That's terrible (7)
I believe the answer is:
pitiful
'terrible' is the definition.
(thesaurus)
'mine providing fuel regularly?' is the wordplay.
'mine' becomes 'pit' (as in a mining pit).
'providing' becomes 'if' (eg 'providing it's sunny' means 'if it's sunny').
'regularly?' indicates alternate letters (regularly take one letter, leave next etc.).
The alternating letters of 'fuel' are 'ul'.
'pit'+'if'+'ul'='PITIFUL'
'that's' is the link.
(Other definitions for pitiful that I've seen before include "base" , "Sad - wretched" , "Miserable" , "Tiny" , "in such a sorry state" .)