Conservation of energy is not the fundamental law it is often presented as. It is derived from Noether's theorem as applied to descriptions of the universe. Locally, it is true that energy is conserved, however, IIRC, General Relativity already can break it at large scales, even before we consider the fact that GR is incomplete and the real theory may break it even harder.
It is possible and I would judge even likely that some other value is conserved; that conservation of energy can be broken doesn't mean all chaos is unleashed and the Patent Office should revoke their ban on perpetual motion machines. When it is finally worked out, we may even pick up our "energy" label and move it to this new quantity. Depends on a lot of details we don't currently know. But what we today call energy is not necessarily conserved at large scales.
Saying that the universe can't do X because it violates conservation of energy is a circular argument; the precise definition of "conservation of energy" used by physics today is derived from our belief that the universe can't do X, but we also know our beliefs are incomplete. Very good approximations. Don't quit your day job to build a perpetual motion machine. But we are not in a position yet to even claim that our description of the universe is complete and we know the exact thing being conserved.
It is possible and I would judge even likely that some other value is conserved; that conservation of energy can be broken doesn't mean all chaos is unleashed and the Patent Office should revoke their ban on perpetual motion machines. When it is finally worked out, we may even pick up our "energy" label and move it to this new quantity. Depends on a lot of details we don't currently know. But what we today call energy is not necessarily conserved at large scales.
Saying that the universe can't do X because it violates conservation of energy is a circular argument; the precise definition of "conservation of energy" used by physics today is derived from our belief that the universe can't do X, but we also know our beliefs are incomplete. Very good approximations. Don't quit your day job to build a perpetual motion machine. But we are not in a position yet to even claim that our description of the universe is complete and we know the exact thing being conserved.