"When the cybersecurity industry warns about the nightmare of hackers causing blackouts, the scenario they describe typically entails an elite team of hackers breaking into the inner sanctum of a power utility to start flipping switches. But one group of researchers has imagined how an entire power grid could be taken down by hacking a less centralized and protected class of targets: home air conditioners and water heaters. Lots of them... What if hackers attacked not the supply side of the power grid, but the demand side?... In a series of simulations, the researchers imagined what might happen if hackers controlled a botnet composed of thousands of silently hacked consumer internet of things devices, particularly power-hungry ones like air conditioners, water heaters, and space heaters. In a power network large enough to serve an area of 38 million people—a population roughly equal to Canada or California—the researchers estimate that just a one percent bump in demand might be enough to take down the majority of the grid. That demand increase could be created by a botnet as small as a few tens of thousands of hacked electric water heaters or a couple hundred thousand air conditioners..." https://www.wired.com/story/water-heaters-power-grid-hack-blackout/
That's a pretty far reach for this neck of the woods. But imagine a town-municipality and it's residents most with lazy IoT devices, as you say being driven from on the demand side. Will digital wonders never cease.
BlackIoT Aims to Disrupt the Power Grid August 23, 2018 https://www.infosecurity-magazine.com/news/blackiot-aims-to-disrupt-the-power/ White paper: https://www.usenix.org/system/files/conference/usenixsecurity18/sec18-soltan.pdf
