Ive got my engineer boff promoted to Lt and trained up Emergency Power to Shields II. Yet when I press P in game, that is not a power available to me. I can only select Emergency Power to Shields 1 (which I've been using for a while now), not the II version that I've begun training up.
The engineer would need to be in a Lieutenant Rank Console on your ship to be able to use that power. Check your assignments tab. He may be in the wrong Console slot, or perhaps you dont yet have one of that rank.