That energy can be destroyed. What do I base this on? Simple: We exist. If we exist, then we must have been created, and then something will have to have created that which created us and so forth. It's an infinite circle of creations and creators and I don't believe that anything is infinite. So therefore things can be created out of nothing, because somehow the ultimate origins must have come to be. And if something can come from nothing, it should also be possible for it to return to nothing.
But if I am wrong, and it's proven that infinity is real, then I'm more than excited, because then that opens up possibilities of time travel, and I'm all up for that.