The UK has just seen a very impressive first, with National Grid and Reactive Technologies partnering to send data via the power lines that bring electricity to homes and businesses. This demonstration opens the door for grid-scale demand response projects, in which end-node usage can be dynamically adjusted to achieve better load balance. The trial saw the 50Hz electricity supply get modulated to send data, rather like how higher frequency waves are used to send data in cellular networks. Power line communication (PLC) is already well established in homes, with G.hn and HomePlug being the most notable technologies, but carrying this out over the grid is another thing entirely. The one-way communications can send information about usage or pricing to…