Worth a look at the old LMF Ecopet system which should be replaced by CRA's add on units.
"Any savings made in purchasing the compressor unit would, for example, have to be enormous in order to compensate for these high energy costs. In other words, a system with an average of 8% higher energy costs (calculated over the entire life span of the compressor) would have to cost 2/3 less than an energy-wise 8% better competitor's product, if it were to make any difference to the "Life Cycle Costs"!
The english is not great but you get the drift. Coracs technology delivers energy savings of 15% on the competition, almost twice that of the quoted example, I am sure energy costs have risen very significantly since those comments on Ecopet were penned a few years ago too.