Not directly related, but I would strongly advise you to add more reactors to that design. It is currently unable to both cruise at full speed and fire all its weapons (total energy required for that is 171 + 108 = 279, so you probably ought to have at least one more reactor), which means that you're not taking full advantage of its design speed and firepower. It has just enough power production to let it fight properly while standing still, but that's not really a normal combat situation.
Same goes for engines, is it constant?
My understanding is that engines are supposed to draw their listed power requirements only while the engines are in use - your design at cruising speed will be drawing 108 energy beyond the static requirements for the engines, at sprint will draw 173 energy beyond static requirements for the engines (which, given that this is the same as your excess output, suggests that your sprint speed may be limited by reactor output rather than engine thrust), at warp will draw 113 energy beyond static needs for the hyperdrive (but none for the sublight engines, I believe), at impulse will draw 27 energy beyond static needs for the engines, and won't require any energy for the engines while idling. Never really checked to see if engines draw power even when sitting still, though a quick glance at an idling ship just spawned in with the editor at 0 stored energy and a full tank of fuel made it look like all spare reactor output went to storage (I wasn't paying close attention, mind you, so it's possible that I overlooked the discrepency between reactor output and engine requirements).
I believe it is because these ships are at warp speed. When the ship drops out of warp, you should see the power go up, especially if you have some power panels on your ship.
He has 173 surplus reactor output, which is more than enough to cover the 113 power required for his hyperdrive, and he's only looking at 12 shield recharge rate. That plus his static energy requirements only totals 152, which means he should be seeing 21 energy per second being stored unless engaging the hyperdrive prevents all energy storage, which would seem odd to me. Unless you can point out something to eat up that extra 21 energy per second his reactors should be producing beyond the needs of the hyperdrive, shields, and static requirements that ought to draw power while the hyperdrive is engaged, I see no reason why his ship wouldn't have energy going into the storage cells while in hyperspace.