It was 10 years ago to the day on Wednesday that the Eastern Interconnection Blackout left 50 million people out of power for some 48 hours. A series of uncorrected problems in northern Ohio (tree limbs falling on power lines, operators not getting information quickly enough and not acting quickly enough) developed to a point that a cascading blackout of the entire eastern grid became inevitable. So what is an ‘interconnection’, and have we started to address some of the vulnerabilities in the grid? Interconnections are collections of electricity utilities that are electrically tied together during normal system conditions that operate at a synchronized frequency. These interconnections can in turn be tied to each other with High Voltage Direct Current (HVDC) power transmission lines, or with variable frequency transformers. The construction of the Tres Amigas Superstation was announced in 2009 and is about to be put into operation. The goal of tying together three major power grids is to increase the reliability of the national grid, and to make it easier to accommodate the transmission of renewable power from one region to another.