Yes they can. See smart meters. With analytics, they can determine every appliance in your house, and know exactly when and where you come and go at all hours of the day.
The smart grid requires a lot of General Purpose Computers gather that data. However, this risk has already been considered. From the link in my previous [1] (sec 7):
... privacy [is defined as]: the effective capacity
to misrepresent yourself.
Misrepresentation is using disinformation to frustrate
data fusion on the part of whomever it is that is
watching you. ... Misrepresentation means putting
a motor-generator between you and the Smart Grid. ...
If smart meter monitoring becomes commonplace, there are solutions that can be deployed. In case of a pedantic reading of that quote, I'm sure Dan Geer was merely listing examples. Further isolation from the grid should probably include some amount of local energy storage to smooth out the usage rates in addition to electrical isolation.
In any case, as others have pointed out, the War isn't about centralization. The War is about the inability to turn a Turing complete system (the General Purpose Computer inside everything) into an appliance that doesn't run some programs. The universal nature of the computer puts a lot of power in the hands of the people, which scares some people and undermines many business models.
Thus there is a desire (possibly indirect) to wage war on this new threat by limiting how many General Purpose Computers end up in the end user's control and hobbling the rest with spyware/drm. If everyone has dumb terminals and "appliances" that only run authorized software, the threat of people actually using the power inherent in every General Purpose Computer is neutralized.
This war is ongoing right now, with small battles happening in every "appliance" or "service" that pretends a Turing complete computer is an appliance. The war is far from over, but we are losing a little bit more every time some piece of technology is centralized.
