Paul,
What will happen is the fact that the PoCo will come around and install a CT-like device to the Phase conductor of your Meter Box.
From there it will monitor the usage of current fed into your house as you use it.
What you will have on the inside of your house is a small interface unit that displays your current usage.
It will sound an alarm when usage gets above a pre-determined level.
Purely and simply, just that.
You determine the level and the controller just tells you that you have broken it.