What is the Source of Energy for the Universe?

After a couple of years or so of struggling with personal matters, I am ready to revive the conversation.  Two new ideas (new to me anyway) have been brought to my attention while watching a series called "The Truth Project."  The first is this.  Assuming that one makes the leap of faith that the universe was created from nothing or from some very small compact bundle of matter and energy that exploded at the Big Bang, what source of energy is sustaining what was started?  Or will the universe wind down at some point?  If in fact the universe has been around for millions or billions of years, how is it possible that this massive amount of energy came into being?  Or is there some as yet undetermined energy production furnace that is refueling all of the billion star systems to keep them all in place and spinning and such?

I guess Hawking thinks that the Universe always existed.  If that is the case, one would pretty much have to assume that there is a generator somewhere producing an endless supply of energy.  Amazing to think about.