Suppose there's no power to carry on (6)
I believe the answer is:
resume
'carry on' is the definition.
(I've seen this before)
'suppose there's no power' is the wordplay.
'suppose' becomes 'presume' (I've seen this before).
'there's no' suggests deleting specific letters.
'power' becomes 'p'.
'presume' with 'p' taken away is 'RESUME'.
'to' is the link.
(Other definitions for resume that I've seen before include "Begin again (after gap)" , "list of achievements in Washington?" , "account, in brief" , "Begin activity again" , "Continue - summary" .)