Angus Young and his late brother Malcolm, who died in 2017, wrote the songs on Power Up
in the period leading up to 2008's Black Ice
. "A lot of them were ideas we had that we knew were good AC/DC ideas at the time, but we just never got around to getting them on record," Angus told Ultimate Classic Rock
. "Malcolm and me had a lot of years when the two of us would just be in a little studio, just working away all the time... and in that period we'd so much stuff. When we went to do Black Ice
, it was a case of you've got a few boxes of your ideas... [and] we only got [into] box one."