How much is enough? And how do you know how much microbe poop is possible? I'm not so sure this is a "0/1" discreet type of outcome. I see it as more of a continuum in which this could make a contribution.
The US uses around 20 million barrels of crude oil a day. So that is how much is enough for now. Worldwide consumption is around 80 million a day.
Add this to ANWR and we may become self sufficient