Thanks for this replies, which I agree with. Let me come back to one point:

As far as I know, there isn't as nearly CMB to cover for it. Dark energy is increasing at a much higher rate than the CMB loses energy.

Let me be more specific: the CMB contributes to it. It does not need to take it all. I was probably a bit too sloppy in my initial comment ;)

After looking a bit on the web, I have found this very nice blog on the topic. This goes along the same lines as my comment, but in a more expanded manner. The more important item it points out is that we must be careful even with the way we define energy in an expanding universe.

Thanks for the always insightful comments, and wish you a wonderful week too!

Unfortunately, the disasters are back since this morning :(