Spa got alternative power as temporary measure (7)
I believe the answer is:
Here is my best explanation:
'temporary measure' is the definition.
(I've seen this before)
'spa got alternative power' is the wordplay.
'alternative' indicates anagramming the letters.
'power' becomes 'p'.
'spagot' is an anagram of 'stopga'.
'as' is the link.
(Other definitions for stopgap that I've seen before include "Temporary solution", "Makeshift", "Temporary fix", "A temporary substitute or solution", "Interim", "Temporary measure", "Substitute", "Improvisation", "Provisional" and "Temporary substitute".)