AEP/Allegheny PR people love to describe the US electric grid as a “super highway” system. Media mouthpieces repeat this mindless phrase without having to think about real science.
Power company employees, even PR people, should not be spreading this kind of false nonsense.
The US electrical grid is not a highway system where electrons are put on a “truck” in one place and “sent” to a destination. The grid much more closely resembles a plumbing system with water continuously flowing through it that can be drawn off at various points. Even this comparison is not accurate because electricity behaves differently from water.
All of the major electrical interconnections in North America, the Eastern Interconnection, the Western Interconnection and ERCOT (most of Texas) all operate on alternating current (AC). Each of these three systems are separated by DC connections that isolate each of these regional interconnections from each other.
The whole system of each interconnection is driven not by power generators but by power users. When load, electricity use, rises, transmission operators contact power generators and tell them to increase electricity production to maintain the frequency level on the entire AC system. If frequency levels fall below a certain point, power begins to flow in unpredictable ways on the sytem and causes dangerous instability.
The bigger the transmission system gets, the more power instability potential increases. Also, a bigger transmission system means that power flows take place over longer distances, making power users in one area much more likely to be affected by problems on the system from much further away.
If you build an interstate highway system that is much bigger than you need, you are just wasting money, but you aren’t also making the highway system less safe.
If you overbuild the electrical grid, however, you are both wasting money and adding to the instability of the grid making the whole electrical system less secure and reliable.
Don’t take my word for it. Here’s the science.
The Power Line 