Is energy always conserved?

Yes, the energy is always conserved. And the total amount of energy in the whole Universe is ZERO. Therefore, the Universe has NO energy, all the energy produced is annihilated.

However, the real law of energy conservation is that energy cannot be only created. But it CAN be destroyed and transferred. Just not created. And during the transfer, it in fact is being destroyed. Therefore, "law of energy conservation" is a misnomer, and it should be "law of energy non-renewability".

This in fact is most realistic explanation. It rules out perpetual motion machines and overunity, and explains energy losses.