Island that gives us energy (8)
I believe the answer is:
guernsey
'island' is the definition.
(I've seen this before)
'gives us energy' is the wordplay.
'gives' indicates anagramming the letters (I've seen 'giving' mean this (the letters give the letters for another word)).
'us'+'energy'='usenergy'
'usenergy' with letters rearranged gives 'GUERNSEY'.
'that' is the link.
(Other definitions for guernsey that I've seen before include "Lyric poem" , "Second-largest Channel Island" , "Lower" , "off the Needles?" , "Cow - sweater" .)