Hi Jackson
As Clive noted in his original explanation, this sentence suggests a specific type of
action:
"
This sounds like it's a new store that will commence business on Jan. 1." (i.e. The owners
will open their new store for the first time on Jan. 1).
So, 'will be opened' is the future form of the verb 'open' in the passive voice.
EDIT:Sorry, Yoong Liat. I didn't see your post until after I posted. I agree with you.