Is energy always conserved?

cosmological redshift is the clock a photon uses to mark the length of space-time between its departure and arrival.

the redshift can be seen as an additional unit of information that can be derived from correlations with known standard candles - it is an entangled piece of information that can be used to give a classical bit of information about how far the photon has traveled. 

perhaps since the total amount of energy in the photon must be conserved, that additional information is written as the reduction of energy of each quanta - then energy is still conserved, the raw energy of the photon has been partially converted into the shannon entropy, the information needed to determine where the photon came from given the necessary additional information about standard candles, redshift surveys, etc.