You might have failed to consider conservation of energy here. The laptops use a steady amount of energy whether plugged in or not (more or less), and if they'r

You might have failed to consider conservation of energy here. The laptops use a steady amount of energy whether plugged in or not (more or less), and if they're unplugged for a while, then they'll draw more power during the time they are plugged in as they recharge their batteries. In fact, if the batteries are not perfectly efficient and thus don't provide the same energy that was used to charge them, you're now using more energy per time by running it through the batteries first. Of course, doing the rolling blackouts might encourage less use of devices, reducing power use.