I've asked designer (Jacques Bariot) about it :
According to description: Renewal (white/red): During the night phase, before the new Divine Intervention cards are dealt, discard as many Divine Intervention cards as you want and draw the same number plus one.
Question #1 is: Does it add 1 Divine Intervention card to the 1 you get every night by default (so replacing cards + 2 additional cards in total) ?
Question #2 is: If you do not replace any cards, should additional card be drawn anyway (0 = 0 + 1 if you do not discard any card from hand) ?
His answers are as follows:
First, thanks for your interest for Kemet, i appreciate
for your questions the answers are
#1 : Yes
#2 : Yes