Well you don’t understand what “net” means.
It doesn’t mean literally zero. It means colunm A and column B average out to zero.
To acheive a real net zero, they have to save energy somewhere else that takes that column past 100% (Such as if their solar panels produce more energy than they use during certain times.)
They probably just make some shit up to say their are saving extra somewhere they aren’t (so to that point, yes…credits are bullshit.)