i'm not an expert at all however i have seen recently several videos about quantum physic principle.
This physics way is drived by the principle of superposition of states. Both the electron and the nucleus are related to Planck's constant.
As likely as these quantum effects allow electronic clusters to form, condense despite their electromagnetic repulsion.
My opinion: more likely than not whatever causes high density electron clusters is at the root of all examples of energy production which this forum chooses to label LENR. So my opinion is that Curbina is right even if he can't tell us why.