That may well be the way you (and most likely Google) currently look at it, but the argument presented seems to be that everything other than where you run some batch tasks is all fixed.
Assuming everything else is fixed does make the optimisation easier, though surely nearly everything is up for debate if we're actually talking about minimising the overall footprint of a compute task?
Using fossil fuels rather than allowing these fixed costs you mention to sit idle - there is a point where your carbon/CPU cycle would actually go up by not using fossil fuels some of the time (though I am assuming less carbon emitted for a unit of power than manufacture cost).
I appreciate they are ever-expanding and predicting where non-movable workloads are going to need to be run etc etc, and I'm not suggesting there are easy answers.
Is the question on the table whether, all other things being equal, this change would decrease carbon output per unit work completed, or is the question whether Google is greener after this change?
For the latter question, we have insufficient data. Google's datacenter infrastructure is huge and complicated, and if one factors in all the interdependencies and purchased carbon offsets, one needs way more data than this announcement blurb gives out to answer that question. Maybe they have an additional process to determine whether their most carbon-negative datacenters can be switched off during peak coal-use and this work unblocked them from enabling that feature? We don't know.
That may well be the way you (and most likely Google) currently look at it, but the argument presented seems to be that everything other than where you run some batch tasks is all fixed.
Assuming everything else is fixed does make the optimisation easier, though surely nearly everything is up for debate if we're actually talking about minimising the overall footprint of a compute task?
Using fossil fuels rather than allowing these fixed costs you mention to sit idle - there is a point where your carbon/CPU cycle would actually go up by not using fossil fuels some of the time (though I am assuming less carbon emitted for a unit of power than manufacture cost).
I appreciate they are ever-expanding and predicting where non-movable workloads are going to need to be run etc etc, and I'm not suggesting there are easy answers.