You’ll note that they differ from the usual phrase by the word ‘Naturally’. The author contends that the universe contains energy, and energy cannot be created, therefore God (or in this case, “our supernatural Creator”).
This is an interesting point, though more in where you go to answer it than any intrinsic value of it’s own. Leaving aside the whole turtles thing (What created God then? Oh, wait, you’re not supposed to ask that question. My bad), let’s look into it.
The Law of Conservation of Energy only works here by implying that the Universe is a closed, isolated system, where energy and matter cannot leave or enter. This sounds reasonable, but we don’t know that this is true. It might not be. So much for “the [only] logical conclusion”.
Considering we live in a time where we are just discovering dark matter and dark energy, and have not yet fully finished Big Bang theory, we are in no position to say anything concrete on this subject. You can’t prove it either way, at the moment. But it is too soon to jump to supernatural causes.