Most of your source does not address...
...your NorCal electricity bill. Though at the bottom of it there is this one bit:
By comparison, California state law excludes any hydroelectric plant greater than 30 MW in size from counting toward the state's RPS.
I'm willing to take their word for that fact. This gives weak support to my guess that the term "elligible renewable" fits a regulatory definition. Though it still is not certain that the wording put on your bill was to reflect California regulatory concerns or some other.
Why on earth don't you just give them a call??? They can probably point you to the regulation in question and then we can have a meaningfull discussion of the whys.