The universe has not run out of energy because energy and mass are interchangeble (E=MC2), and there is a lot of "dark matter" tout there that is still unaccounted for.
All events don't have a cause. Some are just random, as proven by Quantum Mechanics.
Things have a "beginning" and an "end" because humans experience time flowing forward, but time is not necessary for the universe to exist. The natural order of things is entropic... from order, chaos. The universe is actual moving the opposite from chaos, toward order...
If this is what you believe, than how can you now say that not all events (random or otherwise) have a cause?