They have been asked for these figures to be published for years, and failed to do so. I suppose "admit" implies their reluctance.

_The first half of this section covers technology-specific changes to our assumptions. For offshore wind, onshore wind, solar PV, and Carbon Capture Usage and Storage technologies (CCUS), there have been significant updates, which we discuss below. We have also made minor changes to CCGT, tidal stream and AD assumptions._

I think "admits" is a reasonable term to use here, in the sense of acceptance or allowing the possibility. "Admit" is sometimes used to refer to an admission of guilt, or the admission of some secret that was previously denied, and that meaning would seem to be incorrect.