Yes, I think it would imply twice the energy.
I heard a lengthier report on the BBC (rebroadcast on ABC Newsradio), which mentioned the possibility of a coincidence of a double star system where both stars end up as supernovae at around the same time IIRC (but I prolly don't). Here is more at the BBC:
http://news.bbc.co.uk/2/hi/science/nature/5367540.stm
- a bit over-sensationalised ("breaks laws of physics" type of talk is nonsense) but informative nonetheless.
And in
Nature. (visit your local library if you are having hassles about subscription when trying to read article)